Investigation of legibility and visual fatigue for simulated flexible electronic paper under various surface treatments and ambient illumination conditions.

This study employs simulated electronic paper to investigate critical issues and focuses on improving legibility of display and reducing users' visual fatigue. Three critical factors--choice of surface treatment, ambient illumination, and bending curvature--are evaluated through the method of a letter-search task. The results show that subjects performed better on legibility and felt less visual fatigue with an anti-glare treatment. Choosing the better anti-glare treatment instead of the anti-reflection series can save significant cost for manufacturers. In addition, ambient lighting of 1500 lux is more appropriate for reading on electronic paper than an environment with extreme illumination (e.g., 8000 lux). The present study also found that curvature had no impact on legibility or visual fatigue. These evaluations of simulated electronic paper may provide manufacturers useful information in fulfilling ergonomic requirements for product design.

Nanoparticles-doped guest-host liquid crystal displays.

The technique, nanoparticles-induced vertical alignment (NIVA), was applied to fabricate a guest-host liquid crystal display (GH-LCD) without conventional alignment layers. The GH-LCD produced by NIVA exhibited a high reflectance of approximately 59% in the voltage-off state and a low threshold voltage of approximately 2.1 V(rms). NIVA is very suitable to be applied for fabricating a plastic LCD requiring a low temperature process, and a flexible timepiece by using NIVA was demonstrated.

A polarizer-free flexible and reflective electrooptical switch using dye-doped liquid crystal gels.

A polarizer-free flexible and reflective electro-optical switch using dye-doped liquid crystal (LC) gels is demonstrated. The electro-optical performances of both scattering and absorption based dye-doped LC gels depend on curing temperatures due to domain sizes of polymer networks. Such flexible electro-optical switch is bendable and trim-able because of the vertical polymer networks and gel-like materials. The dye-doped LC gel shows good reflectance ~55%, good contrast ratio~450:1 and fast response~6.4 ms at curing temperature 10 degrees C. The bending curvature is 21 mm. The dye-doped LC gels open a new window for trim-able electronic papers, decorative displays, electrically switchable curtains, and electrically switchable sun control film for the automobiles, homes or commercial buildings.

Optical simulation of cholesteric liquid crystal displays using the finite-difference time-domain method.

The finite-difference time-domain (FDTD) method is a powerful numerical algorithm used to directly solve Maxwell's equations. We introduce the idea of the FDTD method and the techniques required for optical simulation of cholesteric liquid crystal (Ch-LC) devices. Bragg reflection characteristics of Ch-LC cells are investigated using the FDTD method. Three approaches to broadening the bandwidth of Bragg reflection are demonstrated: (1) using a higher birefringence LC, (2) using a cell with a gradient pitch length, and (3) using a cell with a new multidimensional structure of a Ch-LC.