Osamu Itou

57.1: Novel Pixel Design for a Transflective IPS-LCD with an In-Cell Retarder

We have successfully developed 2.4″QVGA transflective IPS-LCDs which maintains excellent transmissive performance and higher reflectance. We have an in-cell retarder patterned only in the reflective region. And we devised the pixel design so that the reflectance became higher. We have realized transflective LCDs with sufficient outdoor readability and wide viewing angle. Furthermore, we reduced thickness of the LCD panel at the same time.

P-231L: Late-News Poster: A Wide Viewing Angle Transflective IPS LCD Applying New Optical Design

Viewing angle performance of transflective LCDs, affected by many optical parameters such as Nz of retardation films and azimuth of slow axis, is improved when the optical parameters obey a simple rule. A new optical design is deduced from the rule, and applied for transflective IPS-LCD with a single gap structure and a twisted liquid crystal layer. A viewing angle performance comparable to transmissive IPS LCDs is realized in transflective IPS-LCD.

57.4L: Late-News Paper: Transflective LCD Combining Transmissive IPS and Reflective In-Cell Retarder ECB

In-cell retarder technology enables two kinds of display modes with different features to be realized in the pixels of transflective LCDs. Using this concept, we have developed a prototype 2.2″ QVGA transflective LCD that combines transmissive IPS for wide viewing angle performance and reflective in-cell retarder ECB for high reflectance.

Enhancement of Viewing Performance of New Transflective In-Plane Switching Liquid Crystal Displays Using In-Cell Retarder(s)

High-viewing-performance transflective in-plane switching (IPS) liquid crystal displays (LCDs) with in-cell retarders have been developed. Transflective LCDs have pixels with transmissive and reflective display portions; the transmissive display portion is designed to have the same structure as the transmissive IPS-LCDs, and the reflective display portion is formed by patterning the in-cell retarder. The latter is designed to give a normally close mode characteristic, which has a brightness–voltage (B–V) curve similar to that of the former. The reflective display portions, which work as quarter-wave plates at dark states, can be classified into five structures according to the number of in-cell retarder(s) and the stacking order of the liquid crystal layer. In this study, on the basis of the five possible structures, the viewing performances of the transflective IPS-LCDs are investigated by simulation, and suitable solutions are also discussed.

An optical design for reflective color STN-LCDs

— In reflective color STN-LCDs, it is necessary to achieve achromatic representation in single-polarizer STN-LCD modes. We propose an optimization method for the optical components of single-polarizer STN-LCD modes in order to achieve achromatic representation. By applying this method, it is shown that a contrast ratio of more than 20 can be achieved in the normally black (NB) mode. Furthermore, we prove that the normally white (NW) mode can be realized as well as an NB mode which is usually used in current reflective color STN-LCDs. Comparing the viewing-angle characteristics of the NW and NB modes, it was found that those of the NW mode are better than those of the NB mode. Particularly, high reflectance can be realized even at larger viewing angles in the NW mode.