Chapter 14: Liquid Crystal Displays

14.1 Overview

The electronics that perform calculations inside a computer are not all that a computer needs. Calculating an answer and keeping it hidden in memory serves no useful purpose. Thus, all computers have an output device. Since one of the goals of this book is to understand a laptop computer, the output device we ll focus on is a display. The most common display in laptops is a liquid crystal display (LCD). This chapter builds on many earlier chapters and the reader will see how much of the earlier basic science and materials discussion is important to the present discussion. This chapter will address the following questions.

1. What are liquid crystal displays (LCDs)?

2. What types of LCDs exist?

3. How do LCDs work?

4. How does a computer address an LCD?

5. Where is LCD technology going?

14.2 Introduction

One of the most common, everyday uses of liquid crystals is in displays. The simplest of these LCDs are temperature indicators and the digital displays in calculators and wristwatches. More sophisticated types of LCDs are used in laptop computers, projection TVs, overhead projector modulators, and similar devices. New types of LCDs are continuously being developed.

The commercial development of liquid crystal devices began in the 1960s. The first devices were not displays but chiral nematic temperature indicators and nematic electro-optic devices. LCDs first became viable in the 1970s. Their growth paralleled and depended, in part, on the great strides of the semiconductor industry. The first major commercial market was watches and calculators. This chapter...