| 摘要 |
PROBLEM TO BE SOLVED: To provide optical sheets excellent in the surface smoothness, small in the retardation birefringence in the plane, in other words, small in the optical phase difference, reduced in the warpage of the sheets, and capable of being used in liquid display panels. SOLUTION: Optical sheets are thermoplastic polymer sheets extruded from a T die or a coat hanger die, and have a glass transition point of not lower than 150 deg.C, a thickness of 150-1,000μm, a retardation in the plane of not greater than 20 nm, a degree of roughness of at least one surface of a maximum of 0.1μm, and a maximum warpage of the sheets 300 mm square of not greater than 5 mm, and liquid crystal display devices use these optical sheets. |
