21.3: Invited Paper: Non‐destructive testing for uniformity evaluation of thin film plate polarizers

Abstract

Due to high technology requirements for modern display devices such as flexible, high resolution, thinner and higher transmission of polarizations, non‐destructive testing methods for evaluating quality of thin film plate polarizers are in high demand. In this paper, a system which can be used to observe defects and inhomogeneity of these thin film plate polarizers such as wide grid polarizers and thin film coating polarizers is proposed. This system consists of a collimated backlight light source, an afocal system, a polarizer, a rotation stage and a CCD camera. The collimated backlight is used to produces a collimating beam to pass through a sample under test. The afocal system shrinks the size of light beam from sample to pass through the polarizer. Based on Malus’s law, intensity of each pixel of images on CCD camera varies with the angle between the transmission axes of sample and polarizer, which is controlled by the rotation stage. Uniformity of thin film plate polarizers can be defined as polarization extinction ratio. This paper is to introduce the configuration and measurement theory, perform a setup used to implement it and present the experimental results from the uses of the setup. The results not only verify the validity but also confirm the feasibility of the proposed systems.