Presently described are multilayer optical films, oriented polyester films, negatively birefringent copolyester polymers, fluorene monomers, and polyester polymers prepared from such fluorene monomers. In one embodiment, the multilayer optical film comprises at least one first birefringent optical layer; and at least one second optical layer having a lower birefringence than the first optical layer; wherein at least one of the optical layers comprises a negatively birefringent polyester polymer comprising a backbone and repeat units comprising at least one pendent aromatic group that is conformationally locked relative to the backbone.
本文介绍了多层光学薄膜、取向聚酯薄膜、负双折射共聚酯聚合物、
芴单体以及由此类
芴单体制备的聚酯聚合物。在一种实施例中,多层光学薄膜包括至少一个第一双折射光学层;以及至少一个比第一光学层具有较低双折射率的第二光学层;其中至少一个光学层包括一种负双折射的聚酯聚合物,该聚酯聚合物包括主链和重复单元,其中至少有一个悬挂的芳香基固定在主链上。