Twisted nematic liquid crystal polymer-based multi-layer composite polarizer with low azimuthal transmittance variation

Abstract

The polarizer is an indispensable element in modern displays, but the azimuthal transmittance variation of the polarizer also affects the display quality, and it is hard to eliminate the azimuthal transmittance variation because of the polarizer’s structure. In this paper, we propose a multi-layer composite polarizer with polarizing layer – twisted nematic liquid crystal polymer layer – polarizing layer structure. An iodide molecule distribution model is introduced to explain the azimuthal transmittance variation of the normal polarizer and guide the design of the multi-layer composite polarizer. The azimuthal transmittance variation of the multi-layer composite polarizer and normal polarizer is measured and calculated, and the results show that the azimuthal transmittance variation of the multi-layer composite polarizer is only about one-fifth of that of the normal polarizer. Except for the most uniform transmittance distribution, the transmittance distribution of the multi-layer composite polarizer can be adjusted to meet different requirements. The potential concerns about low transmittance and color shift are also discussed, and they can be solved by reducing the polarization degree of the polarizing layers and increasing the thickness of the liquid crystal polymer layer. The results show that the multi-layer composite polarizer can replace the normal polarizer to reduce the viewing angle defects of the emissive displays.