Optical characterization of all types of displays is mandatory to quantify the different imperfections and compare the different technologies. Standard characterization is focused on luminance and color measurements of the light emitted by the displays. Viewing angle measurements devoted to the angular characterization and homogeneity measurements are the most frequently used. In the present paper we demonstrate that the same type of measurements extended to the polarization analysis of the light emitted by the display can be a powerful tool in order to understand the origin of many imperfections. The present paper is composed of two main parts: first the different measurement tools for viewing angle and imaging characterization are presented and the method used to analyze the polarization state of the light is explained. The second part gives details on some examples of applications for the characterization of display components (brightness enhancement film, backlight), the measurement of the crystal cell rotation inside a standard LCD display, and the characterization of a passive 3D TV.