CHAPTER 4

PASSIVE MATRIX LIQUID CRYSTAL DISPLAYS

Thomas L. Credelle

INTRODUCTION

Liquid crystal displays (LCDs) have become commonplace in all aspects of our "information age." Uses range from wristwatches to computer displays to television. The most common type of LCD is the simple matrix twisted nematic LCD, although active matrix LCDs are becoming more common, especially in applications that require high-performance displays. A simple matrix LCD can be defined as an LCD that is addressed by applying voltage pulses directly to electrodes on either side of the liquid crystal molecules. This section of the report details the status and future prospects for passive matrix LCDs. The passive matrix LCDs covered in this report are twisted nematic, supertwisted nematic, vertically aligned nematic, and ferroelectric. Other LCDs have been investigated, but these are the main types either in use or under active development in Japan today. An important class of LCDs not covered here is polymer dispersed LCDs (PDLCs), because PDLCs are not multiplexible into high-information-content LCDs. The materials developments are covered in Chapter 2, and the use of the materials in conjunction with active matrix substrates is covered in Chapter 6, Projection Displays.


Published: June 1992; WTEC Hyper-Librarian