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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.

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. IntroductionThe development of cellular phones and digital cameras has created the need for LCDs with improved viewing angle performance, including high contrast ratio and outdoor visibility. Transflective LCDs already include both transmissive and reflective display modes in one pixel. In the case of a conventional transflective LCD, retardation film for the reflective display mode is also laminated over the transmissive region. Recently, in-cell retarder materials and manufacturing processes have been developed [1], and some examples of applications on transflective LCDs have been presented [2-3]. By separating the optics of the transmissive and reflective regions of a pixel with in-cell retarder technology, wide viewing angle performance and high-quality pictures equal to those produced by transmissive IPS (In-Plane Switching) can be achieved [4]. By deepening this concept, we can apply different display modes to the transmissive and reflective regions.Since the cell gap of reflective IPS is narrower than that of transmissive IPS, surface anchoring has a strong influence on liquid crystal alignment. Therefore additional development is required to achieve high reflectance in the case of reflective IPS. A first approach was to improve the design of the pixel electrodes [5]. This technology has already been applied to the product. A second approach was to use a normally white reflective IPS while independently altering the voltage applied to the transmissive and the reflective regions [6]. A third approach, the combination of transmissive IPS and in-cell retarder reflective ECB (Electrically Controlled Birefringence), is considered in this paper. Using this approach, we developed a 2.2" QVGA transflective LCD that combines transmissive IPS for wide viewing angle performance and reflective in-cell retarder ECB for high reflectance. Figure 1 shows the cross section of a pixel of the developed transflective LCD; Part (a) shows the dark state and part (b) shows the bright state. IPS-Pro structure [7] was selected for the transmissive region in order to achieve wide viewing angle performance. An in-cell retarder ECB structure was adopted in the Structure of the transflective LCD combining transmissive IPS and reflective incell retarder ECB

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 brightnessvoltage (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.

Various experimental results of interferometry with metastable Ne and Ar will be discussed together with their implication towards applications.