To improve the LCD picture quality from oblique directions, two optical compensation films (retardation films) have been applied to LCD panels. However, nowadays, the optical compensation using only one film is required to realize thin LCD panels. For this purpose, both in-plane and out-of-plane birefringence (3-dimensional birefringence) must be controlled. In this paper, a method for achieving three dimensional birefringence control of uniaxial films will be presented. In uniaxial films, in-plane and out-of-plane birefringence cannot be controlled independently. However, it was found that when adding plate-shaped smectite nanoparticles to uniaxial films, the value of the out-of-plane birefringence increased more than expected values. Using these results, uniaxial films with no out-of-plane birefringence and negative in-plane birefringence can be formed by adding smectite nanoparticles to polymer films with negative in-plane birefringences. By these methods, the three dimensional birefringence of uniaxial polymer can be controlled and the possibility of the uniaxial films could be drastically extended.
