We investigated a viewing angle control of a liquid crystal display (LCD) under optical compensation for the enhancement of viewing angle characteristics in a wide viewing angle mode. The viewing angle controllable (VAC) LCD was operated in the configuration of three terminal electrodes consisting of a fringe-field-switching electrode at a bottom substrate and a common electrode at a top substrate. Using Poincaré sphere analysis, the optical compensation for the VAC LCD was designed so that the viewing angle characteristics were much improved in the wide viewing mode while they were degraded in the narrow viewing mode.
Flexible display devices are widely and extensively studied for using the applications such as smart cards, PDA, head
mounted displays and all kinds of mobile display because of their lighter weight, thinner packaging, and flexibility.
However, it has some obstacles such as mechanical stability and tight adhesion of two plastic substrates. In this
presentation, we will suggest a new bonding technologies with rigid spacers and bonding materials, which will serve
mechanical stability and good adhesion strength. The micro-contact printing method is used to place bonding material
on the rigid spacers that may be easily applicable to roll-to-roll fabrication processes. The performances of prototype
samples fabricated will also be demonstrated by this technology.
Anisotropic phase-separation of liquid crystal and polymer composite is highly applicable for obtaining the durable
electro-optic devices. In this presentation, the theoretical model for phase separation phenomena based on the onedimensional
kinetic approach is introduced. For the applications of phase-separated LCs, we propose the fabrication of
mechanically stable flexible display and electrically controllable microlens array using two- or three-dimensional
anisotropic phase separation. Since LC molecules are isolated by polymer structure due to the anisotropic phase
separations, resultant devices show very good mechanical stability against external pressure and stable electro-optic
An active microlens device is demonstrated by using a stacked layer structure of UV curable polymer, liquid crystalline polymer (LCP) and a liquid crystal (LC). The incident linearly polarized light is focused after passing through the combined refractive type microlens array system of UV curable polymer and LCP. Because used LCP shows highly birefringent macroscopic property from the well-ordered molecular structure, the additional polarization state control layer was inserted to modulate the dynamic focusing characteristics of the device. From the additional twisted LC layer's electro-optic response, we obtained good focal switching characteristics of microlens array with a small operation voltage application. This enhanced dynamic focusing characteristic of device was originated from the separate operation of polymer lens structure's beam focusing and twisted LC layer's polarization control ability. The measured focal length was well matched to the calculated one. This proposed LC microlens array is expected to play a critical role in the various real photonic components such as highly reliable optical switch, beam modulator and key device for 3-D imaging system.
The process of phase separation leads to several well known display technologies such as Polymer Dispersed liquid crystals and Polymer Stabilized cholesteric and ferroelectric devices. Several new limits of the general phenomena of phase separation have been discovered in recent years. In one of the limits, a very simple and powerful process known as the phase separated composite structures method permits the construction of conventional devices; such as, TN, STN, and FLC devices with great ease and with flexible substrates. It has also been employed in the fabrication of one- and two-dimensional optical gratings and fly's eye lenses (micro-lens array) with electrically controllable focal length. In the second limit, one obtains microscopic polymer columns perpendicular to the substrates. These structures have been used to fabricate large area homeotropic nematic devices having very high-contrast.