in focusing on special topics. His most valuable assistance is gratefully appreciated. Dr. Mike Lee from Imperial College in London enriched the chapters on addressing techniques with some most helpful suggestions and enlightening discussions. I am very grateful for his support. I am also indebted to my co-worker at Stuttgart University, Dr. Christoph Zeile, who contributed to the sections about electro-optical effects by numerous discussions and his helpful observations. I thank Mrs. Heidi Schuehle very much for typing the manuscript with competence and patience and for alerting me to various inconsistencies. Mr. Rene Troeger has skillfully drawn the figures for which I am very grateful.
Finally, I wish to thank John Wiley for their always pleasant cooperation as well as for the attractive production of the book.
Ernst Lueder Scottsdale, Arizona, 2000
About the Authors
Ernst Lueder was born in 1932. At his graduation from high school he was awarded the ‘Scheffel’-prize for literary achievements. In 1962 he received his doctorate in electrical engineering, and in 1966 his Habilitation, which qualified him to teach theoretical electrical engineering. From 1968 to 1971 he worked for Bell Telephone Laboratories in Holmdel, New Jersey, USA, undertaking research into the design of miniaturized filters and communication systems, especially in thin film technology. He established laws for optimizing the dynamic range and the signal-to-noise ratio of two-ports.
In 1971 he was appointed a full professor at the Department of Electrical Communications, and was named Director of the Institute of Network and Systems Theory at Stuttgart University. He specialized in the design of hybrid thin and thick film circuits, the development of sensors, thin film transistors and flat panel liquid crystal displays, in the synthesis of circuits, in the theory of communication systems and in the optimization of systems. From spring 1991 he also headed a new DM80 million laboratory for the fabrication of flat panel displays. Research activities in this laboratory include TFT- and MIM-addressed TN, PDLC and GH displays, as well as bistable FLC and PSCT displays.
He retired in 1999. He was a member of the IEEE, and became an IEEE Fellow in 1985. As a member of the German Society for Information Technology, ITG, he was for two years a member of the society’s board of directors. He served in the Scientific Advisory group for the Heinrich-Hertz Institute in Berlin, and was chairman of this group for four years.
Starting in 1994 he participated as a member of the SID board of directors, as a director of the Mid-Europe chapter, and as vice-president for Europe. Further, he was a member of the SPIE, ISHM, FKTG, the German society for broadcast and television technology and the New York Academy of Sciences (NYAS). In 1991 he was awarded the order of merit 1st Class of the Federal Republic of Germany, and in 1998 he became a Fellow of SID and in 2009 received SID’s Slottow-Owaki Award.
During his career and retirement Professor Lueder has authored more than 200 publications on LCDs, network and system theory and optimization, and sensors and electro-optical signal processing.
Seung Hee Lee received his BS degree in Physics from Jeonbuk National University in 1989 and his PhD from the Physics Department of Kent State University in 1994. In 1995, he joined the LCD division of Hyundai Electronics (later named HYDIS Co.), where he did research on development of wide-viewing-angle TFT-LCDs with new liquid crystal devices until August 2001. During that time, he made a big contribution to the invention and commercialization of new wide-viewing-angle technology called ‘fringe-field switching (FFS)’ and introduced the FFS device to the public in Asia Display ’98, SID & IDW ’99, SID ’01, and IDMC ’02 for the first time.
In addition, his team has investigated unique and fundamental electro-optic performances of the FFS mode depending on electrode structure, cell parameters, and sign of LC’s dielectric anisotropy via journal and conference proceedings, and filed many key patents. His team proved the FFS mode was the only mode that can show high transmittance, low operating voltage, fast response time, wide viewing angle and pressure-resistant characteristics simultaneously, suggesting that the FFS mode can be applied to all kinds of high-end and high-image-quality TFT-LCDs.
In September 2001, he became professor in Department of Polymer Nano Science and Technology of Jeonbuk National University. Since then, he has worked on the development of new electro-optic materials and devices for displays and photonics. He was awarded ‘King of Invention’ twice while he was in industry. He has also received several major awards, such as the ‘SID Fellow’ in 2008, the ‘SID Special Recognition Award’ in 2012, and the ‘Merck Award-Major’ from the Korean Information Display Society in 2013, and the ‘Jan-Rajchman Prize’ in 2016.
Peter Michael Knoll was employed at Robert Bosch GmbH, Karlsruhe, Germany, from 1980 until his retirement in 2006. He is now a retired Associate Professor for Driver Assistance Systems and associated Human Machine Interaction at the KIT, formerly University of Karlsruhe, Germany.
He was head of the Bosch Companies Laboratory for Car Displays from 1980 until 1995; General Manager at ADT Inc. (Applied Display-Technology GmbH), Stuttgart, Germany, until 1999; Vice President Development New Products, Driver Assistance systems Business Unit, Robert Bosch GmbH, Leonberg, Germany, until 2007; Associate Professor for Display Technologies, Faculty of Electrical Engineering University of Karlsruhe, Germany, from 1988 to 2009; and Associate Professor for Automotive Information Systems, Driver Assistance Systems at the KIT, Germany, until 2013.
1
Introduction
Liquid Crystal Displays (LCDs) have established a firm foothold on the market as flat panel displays for computers, transportation, communication (especially in its mobile version), instrumentation and, in the future, with increasing importance for television. The understanding of LCDs requires knowledge about the various electro-optical effects of liquid crystal cells, and about the control of the grey shades and colours in the picture elements (pixels, or pels) by addressing circuits.
The electro-optical effects are based either on the propagation of polarized light through anisotropic liquid crystal cells, or on the propagation of unpolarized light through scattering cells. The grey shade controlling voltage across each pixel is provided mainly by either passive matrix or active matrix addressing. In passive matrix addressing, the voltage in each pixel is generated by voltages at the end of the rows (or lines) and the columns of the display, whereas active matrix addressing uses Thin Film Transistors (TFTs) or Metal Insulator Metal (MIMs) devices as switches in each pixel.
Further topics are the fabrication of conductors, transparent electrodes, TFTs and MIMs with thin film technology, the generation of colour filters, and the assembly and bonding of liquid crystal cells.
It is not only manufacturers of LCDs but also the vast community of users which need to grasp the essence of the physics and engineering of LCDs. The understanding of these topics enables users to select the appropriate LCD for their application, to tailor the optic performance to their needs (e.g. by optimizing the waveform at the addressing circuit by the addition of performance- enhancing sheets, or by selecting the appropriate location of the external ICs for signal processing), as well as for storing and feeding in of the picture information.
Further, manufacturers and users should be enabled to judge the suitability of future developments and trends for their purposes.
The first section of this book presents an overview of the properties of liquid crystal materials and a phenomenological description of the most frequently used type of LCDs, the TFT- addressed twisted nematic (TN) LCD. The aim is to familiarize readers with the main aspects of LCDs, to introduce most of the terminology, to establish an understanding without doing calculations, and to alleviate the subsequent more detailed discussion without losing the overall picture in which the details are embedded.
The remaining portions of the book are devoted to an analytical investigation of the electro-optic effects, and to an elaboration of the addressing schemes complemented by the manufacture of the thin film components.
Applications