Dmitry A. Yakovlev

P-55: Contrast and Brightness Enhancement of RTN-LCDs Using Antireflective Layers

New constructions of RTN-LCDs with antireflective (AR) coatings were proposed. Both one polarizer and Polarizer Beam Splitter (PBS) variants were considered. The AR coatings can be made both in the outer surface of the one-polarizer RTN-LCD and on the upper substrate between the glass plate and aligning layer. The damping of the LCD reflection in the “dark” state of one-polarizer RLCD by introducing AR layers considerably improves the contrast ratio and only slightly affects the brightness of RLCD. The application of AR-layers in PBS-RLCD results in an improved brightness.

A robust polarization-spectral method for determination of twisted liquid crystal layer parameters

An experimental method for determining the configurational and optical parameters of the liquid crystal (LC) layers with a twisted structure is proposed. This method provides the determination of the twist angle and orientation of LC structures as well as the spectral dependence of the LC layer retardation. These parameters are estimated from the polarized transmission spectra of LC cell, which are measured using the polarizer-sample-analyzer scheme. In contrast to known methods, the proposed method is insensitive to the presence of moderate anisotropic losses in LC cell (usually, the loss anisotropy is a consequence of the multibeam interference in the thin-layer system including the LC layer); furthermore, the proposed method does not use the small birefringence approximation. The accuracy of the method under various experimental conditions is estimated by numerical modeling.

LCD Optimization and Modeling

The application of the LCD modeling and optimization system, LCD DESIGN, for the design and development of new advanced LCD configurations was demonstrated. The software includes a powerful optimization module that allows for spectral and angular averaging, thus enabling the production of LCDs with wide viewing angles, achromatic (black/white) switching, and fast response time. We describe the basic principles of the software development and present several examples of LCD optimization in various electro-optical modes. A brief review of our results of LCD optimization and modeling using LCD DESIGN software is also given.

The Novel 8x8 Transfer Matrix Method of the LC Optics Simulations: Application to Reflective LCDs

Abstract A new effective matrix method for the calculation of optical characteristics of Reflective Liquid Crystal Displays (RLCDs) with consideration for multiple reflection is proposed.

Optimization and Modeling of Liquid Crystal Displays

The application of the LCD modeling and optimization system (MOUSE-LCD) for the design and development of the new advanced LCD configurations is demonstrated. The proposed new method of LCD optimization can be successfully applied for the design of the new advanced LCD configurations operating in various electrooptical nematic, cholesteric and ferroelectric LC modes, such as TN, STN, ECB, VAN, HAN, π-cell, book-shelf and others. We have found the conditions, which enable to realize perfect dark and bright states and wide viewing angles in LCDs for various LC physical characteritics, LC orientation in the cell and operating voltage as a function of the parameters of the phase compensators, anti-reflective layers, LC cell thickness and orientation of the polarizers. The optimization module allows for the spectral and angular averaging, thus enabling to produce LCD with wide viewing angles, achromatic (black/white) switching and fast response time. We have also shown, that some important LC elements of fiber optical systems, e.g., polarization controllers and polarization rotators can be designed and optimized. We demonstrate also 2D version, which enables to simulate the optical performance of LCD, as a function of the coordinate parallel to the LC layer. Liquid crystal (LC) structures in high resolution LCDs with a rapid lateral variation of optical parameters (microdisplays, multi-domain LCDs, IPS-LCDs) is characterized taking into account the effects of light diffraction. This software provides the simulation of various experimental tests with fine–structure LC cells. In particular, the simulation of LCD measurements with a polarizing microscope is performed.

5.4: Advanced Tools for Modeling of 2D-Optics of LCDs

Liquid crystal (LC) structures in high resolution LCDs with a rapid lateral variation of optical parameters (microdisplays, multi-domain LCDs, IPS-LCDs) must be characterized taking into account the effects of light diffraction. In addition to earlier reported MOUSE-LCD, we have developed a new software allowing estimation of diffraction effects in LCD optics. This software provides the simulation of various experimental tests with fine– structure LC cells. In particular, the simulation of LCD measurements with a polarizing microscope can be performed.

28.1: LCD Optimization and Modeling

The application of the LCD modeling and optimization system LCD DESIGN for the design and development of the new advanced LCD configurations is demonstrated. The software includes a powerful optimization module, that allows for the spectral and angular averaging, thus enabling to produce LCD with wide viewing angles, achromatic (black/white) switching and fast response time. We describe the basic principles of the software development and present several examples of the LCD optimization in various electrooptical modes. A brief review of our results of LCD optimization and modeling using LCD DESIGN software is also given.

Polarization monitoring of structure and optical properties of the heterogeneous birefringent media: application in the study of liquid crystals and biological tissues

The original method of the polarization monitoring of heterogeneous anisotropic media is proposed. In contrast to the known approaches, the proposed method is applicable for the analysis of structure and optical properties of anisotropic media with an azimuthal variation in the local optical axis orientation with respect to the direction of probing. As a consequence, it can be used for studying the media, which contain anisotropic chiral structural fragments. The experimental examples are given, which show the possibility of applying this method in the study of liquid crystals and tissues.

Mapping of optical properties of anisotropic biological tissues

A simple polarization method of mapping of tissue structures that allows for a variation in optical properties of medium in the direction of probing is proposed. This method is based on the use of rotationally invariant polarization parameters of sample. The relation between these parameters and Mueller matrix elements is shown.

Optimization of One-polarizer Reflective LCDs with Phase Compensator

New approach to optimization of reflective LCD, based on “Polarization Transformation Efficiency” (PTE) conception, is presented. This approach is used for optimization of one-polarizer RLCD in RTN mode. We have found the conditions, which enable to realize perfect dark and bright states in RTN-LCDs with a phase compensator between the polarizer and LC cell. We believe that the proposed new method of LCD optimization can be successfully applied for the definition of the new advanced LCD configurations with a high brightness, contrast and duty ratio.