Acryl-base polymer film, optical compensation film, and liquid-crystal display device having the same

An optical compensation film for IPS or FFS-mode liquid crystal display devices, having the tilt angle β[°] satisfying 0<|β|≦45°, β[°] being defined as φ giving the minimum value of retardation R[φ] which is retardation measured for incident light coming in a direction tilted by φ° from a normal line relative to the film-plane, with the in-plane slow axis of the optical compensation film as a rotation axis;

• having retardation in plane at a wavelength of 550 nm, Re(550), of from −10 nm to 10 nm;
• and
• having retardation along the thickness direction at a wavelength of 550 nm, Rth(550), of from −30 nm to 30 nm, provided that Rth(550) is not equal to zero.