Applications Of Multidirectional Asymmetrical Microlens-Array Light-Control Films On Reflective Liquid-Crystal Displays For Image Quality Enhancement

The multidirectional asymmetrical microlens-array light-control film (MAMA-LCF) is developed for enhancing the image brightness and contrast ratio of various reflective liquid-crystal displays. By use of index-matching material, the interface reflection is greatly reduced. Through optimized designs, the surface-scattering effect is also suppressed; thus the contrast ratio is much enhanced. From experimental results, the MAMA-LCF leads to a ∼1.5× gain in brightness over the MgO standard white and a 15:1 contrast ratio for the reflective color super-twist nematic liquid-crystal display, 2.8× MgO and a 23:1 contrast ratio for the polymer-dispersed liquid-crystal, and 2.8× MgO and a 13:1 contrast ratio for the cholesteric liquid-crystal display. Potential applications of this low-cost plastic thin film for reflective liquid-crystal displays are foreseeable. © 2004 Optical Society of America