Abstract
This thesis involves the fabrication of high-performance wire-grid polarizers (WGPs) by using nanoimprint lithography (NIL) for the application of liquid crystal displays (LCDs). To obtain the optimal level of polarization performance in the visible spectrum, the WGPs require an ultra-high-precision and reproducible manufacturing process that can fabricate extremely fine metallic gratings that possess a low density of defects. Most current manufacturers are confronted by a bottleneck, struggling to produce a large volume at a low cost. Therefore, three nanoimprint platforms were developed using glass and plastic substrates, including batch-type thermal NIL, UVNIL, and roll-to-roll (R2R) UVNIL, and flexible working stamps composed of plastic and nickel alloys to facilitate large-area nanoimprinting that yields products of excellent quality and uniformity. These approaches allowed the optical properties and characteristics of each fabrication process to be thoroughly investigated. To enhance the fabrication tolerance, repeatability, and optical performance of the WGPs, the grating aspect ratio, profile symmetry, and varying residual layer thicknesses (RLTs) were precisely simulated and controlled to achieve the targeted designs. Applying multilayer WGP grating configurations and optimal metal deposition processing substantially reduced manufacturing difficulties, enabling small WGP pitches to be replaced with large pitches, achieving improved optical performance. Consequently, 9-nm-linewidth gratings with high aspect ratios larger than 18:1 were fabricated using R2R nanoimprinting and plasma trimming, achieving flexible WGPs that demonstrated high levels of optical performance (up to 12000:1 extinction ratio (ER) with an average transmittance of 83%) and a low color shift (transmittance variation less than 3%).