Contents

Abstructs of Reviews

Chemistry of Fluorinated Liquid Crystals

Shunsuke TAKENAKA and Hiroaki OKAMOTO
Graduate school , Yamaguchi University
2557 Tkowadai, Ube, Yamaguchi pref., 755-8611 JAPAN
E-mail: takenaka@po.cc.yamaguchi-u.ac.jp
E-mail: oka-moto@po.cc.yamaguchi-u.ac.jp

Abstract�FThis paper reviews liquid crystalline properties of molecules, from the chemical point of view, having a fluorinated alkyl group such as those of perfluoroalkyl and trifluoromethyl. Summarizing 65 papers, we came to the following conclusions concerning the effect of fluoroalkyl groups on the mesomorphic properties. First, in many liquid crystals having perfluoroalkyl group(s), smectic A and B phases are preferentially formed, where a phase separation due to strong interaction between perfluoroalkyl groups is very important in determining the thermal properties and the layer structure of liquid crystalline phases. Secondly, in many liquid crystals having a terminal trifluoromethyl group the trifluoromethyl groups are arranged around the smectic layer boundary, and the inter-layer interaction around the trifluoromethyl groups facilitates and stabilizes the layer arrangement of molecules.
Keywords:Liquid Crystals, Thermal Properties, Fluoroalkyl Group, Smectic, X-ray Diffraction

Present and Future of the Display technologies for the Mobile information appliance

Shoichi IINO
Seiko Epson, Co.,LTD
3-3-5 Yamato, Suwa, Nagano pref., 392-0001 JAPAN
E-mail: iino.shoichi@exc.epson.co.jp

Abstract:The field of mobile information appliances, which includes cell phone and PDA (Personal Digital Assistant), has been growing very rapidly from 1995. This growth has been accelerated by the construction of wireless communication infrastructure and the spread of the internet, as well as the progress of LCD technologies such as low power, high image quality, capable of higher information content and especially reflective color technology. Cell phones with transflective color LCDs were released at the end of 1999, and it is expected that the mobile information appliance with color display will increase rapidly from 2000. The cell phone for IMT - 2000 will appear in 2001, and same cell phone can be used worldwide and moreover data communication with 2Mbps high - speed transfer rate becomes possible. The earliest displays in the cell phone market were typically 1 to 2 line displays. They may have also included a few standard single pixel indicators, so - called "icons". In recent years, these displays have all evolved into full graphic displays, capable of alphanumeric characters in any language and with scaleable fonts. A typical cell phone display ranges anywhere from 32 to 64 rows, and 96 columns. In addition, last year it reached 120 to 160 capable for e - mail content. Moreover, concerning the thin profile and light weight, adoption of thin thickness glass substrates such as 0.5 to 0. 3 mm and plastic substrates have been proceeded. With respect to low power, the development of low power consumption drive techniques and adoption of reflective/transflective color technologies have been progressed, and 4mW active displays with 2.6 inch diagonal, 4096 colors, and 160x240 pixels were realized. Meanwhile, the development of organic ELs, which are in the spotlight as applications for new flat panel displays, have progressed and area color display systems are already being put into the practical use since 1999. Liquid Crystal Displays (STN, TFD, a - TFT, low temperature Poly - Si TFT) and Organic EL displays will be used in the future by making the most of each of the advantageous characteristics. This paper discusses some of the requirements placed on these displays, and includes the challenges that remain.
Keywords: mobile information appliance, low power consumption, thin and light weight, reflective/transflective color LCD, organic EL display

Characterization of the local layer structures in the smectic liquid crystals using synchrotron X-ray micro-diffraction

Atsuo Iida and *Yoichi TAKANISHI
High Energy Acceralator Research Institute
1-1 Ohho, Tukuba, Ibaraki 305-0801 JAPAN
E-mail: atsuo.iida@kek.jp
E-mail: ytakanis@o.cc.titech.ac.jp


Abstract: The synchrotron X-ray micro diffraction experiment reveals the local layer structure directly in the smectic liquid crystal cell. The microbeam system having a few um spatial resolutions has been introduced. The characterization of various types of layer structure defects in homogeneously aligned cells, the dynamic analysis of the layer structure by the time resolved diffraction technique, and the determination of the layer structure of the bent-shaped molecules were described. The analysis of two types of the defect boundaries at the zigzag defect and the needle-like defect in the ferroelectric liquid cell showed the bent layer structure was realized and the importance of the surface anchoring effect in the surface stabilized state was confirmed. Using time resolved X-ray diffraction in a small area, the dynamic behavior of the layer response of the anti-ferroelectric liquid crystals to the electric field were analyzed with a time resolution of 10us. The transient local layer response was analyzed for the first time. The frustrated layer structure of an achiral bent-shaped molecule liquid crystal was also analyzed.
Keywords:smectic phase, local layer structure, (anti) ferroelectric liquid crystal, synchrotron X-rays, X-ray microbeam

Actions to environment and safety of LCD

Nobuo KAWANISHI, Yukishige MAEZAWA, Hideaki KUROKAWA, Minoru SHIOTA, Ikuo TOMITA, Hideo SAITO, Haruyoshi TAKATSU, Keiko KOBAYASHI
JAIST
Toyo-Kaiji Building 8thF, 1-5-13, Nishi-shinbashi, Minato, Tokyo 105-0003 JAPAN
E-mail: kawlirec@opal.famille.ne.jp

Abstract:There has been considerable growth in the demand for liquid crystal displays (LCDs), because of their space-reducing and energy-saving merit. To accept the environmentally friendly contribution of LCDs, some additional actions are still necessary along with expansions in the scale of production. In order to restrain and reduce emissions of gases that contribute to global warming produced during the manufacturing process, the actual conditions of use of the gases and abatement technologies were investigated. Secondly, to device countermeasures to deal with the treatment of waste LCDs, material recycling technologies were studied for LCD glasses, and the economics of new recycle plants were evaluated. Finally, law and regulations specifically targeting chemicals used only for LCDs and their toxicity were investigated.
Keywords:PFC abatement, Material recycle, Regulations, Toxicity test