Patent ID: 7211304

Claim:
A multilayer compensator comprising one or more polymeric first layers and one or more polymeric second layers, wherein: said first layers comprise a polymer having an out-of-plane (Δn th ) birefringence not more negative than −0.01 or not more positive than +0.01; said second layers comprise an amorphous polymer having an out-of-plane birefringence more negative than −0.01 or more positive +0.01; wherein the term “amorphous” means that the polymer does not show long range order by X-ray diffraction and analysis; and the overall in-plane retardation (R in ) of said multilayer compensator is greater than 20 nm and the out-of-plane retardation (R th ) of said multilayer compensator is more negative than −20 nm in which case at least one second layer includes a polymer containing in the backbone a non-visible chromophore group and has a T g above 180° C. without containing a non-visible chromophore off the backbone or (b) more positive than −20nm in which case at least one second layer includes a polymer which contains off the backbone a non-visible chromophore group and has a glass transition temperature (T g ) above 160° C., and wherein the in-plane retardation (Rin) of said one or more first layers is 30% or less of the overall in-plane retardation (Rin) of said multilayer compensator.