Retardation film, process for producing the same, optical film, image display, liquid crystal panel and liquid crystal display

A process for producing a retardation film comprising a stretched film of a polymer film containing a norbornene-based resin, wherein

• the stretched film satisfies the following equation (1) and the equation (2);
• 100 nm≦(nx−ny)·d≦350 nm (1)
• 0.1≦(nx−nz)/(nx−ny)≦0.9 (2)
• where the refractive indices in the slow axis direction, the fast axis direction and the thickness direction of the film are nx, ny and nz, respectively, d(nm) is thickness of the film, and the slow axis direction is a direction that the refractive index in film plane is maximum,
• said process comprising steps of:
• applying a shrinkable film on one side or both sides of a polymer film containing a norbornene-based resin, and
• heat-stretching the polymer film so that the stretched film satisfies the following equation (1) and the equation (2);
• 100 nm≦(nx−ny)·d≦350 nm (1)
• 0.1≦(nx−nz)/(nx−ny)≦0.9 (2)
• where the refractive indices in the slow axis direction, the fast axis direction and the thickness direction of the film are nx, ny and nz, respectively, d(nm) is thickness of the film, and the slow axis direction is a direction that the refractive index in film plane is maximum.