Optical design of low-cost polarizer without chromatic fringe pattern

Abstract

Recently, polyethylene terephthalate (PET) has been considered as a substitute material for a protection film in a polarizer in order to reduce the cost. However, PET film exhibits high retardation intrinsically due to the stretching process, which induces a chromatic fringe pattern so called a color mura in oblique viewing angle directions, associated with a strong wavelength dispersion. Based on simulation and experimental results, placing an optic axis of PET film in plane can suppress the color mura without the need to use any compensation films; the film thus exhibits high performance as well as low cost.

Wideband antireflective circular polarizer exhibiting a perfect dark state in organic light-emitting-diode display

“…2(b). In general, when the N z of the wideband quarter wave film is greater than 1, the film becomes a negative biaxial plate which has two optic axes existing out of plane such that the retardation that an incident light experiences becomes so high in oblique direction, resulting in strong wavelength dispersion [21]. Therefore, a strong light leakage occurred in specific viewing angle directions, as shown in Fig.…”

“…To make a retardation film with N z = 0.5, the film should be stretched to machine direction at first, and then shrunken to transverse direction. In order to shrink the film to transverse direction, a pair of films stretched to transverse direction is attached at both sides of a film stretched to the machine direction and then heats the set of the film, resulting in a shrinkage of the film to the transverse direction [21]. Figure 4(a) shows polarization states of the proposed antireflective film on the Poincare sphere in the red, green, and blue wavelengths after the light passes through the HWP and QWP in the oblique direction.…”