Liquid crystal displays (LCDs) offer several advantages over traditional cathode-ray tube displays that make them ideal for several applications. Of course, LCDs are flat, and they use only a fraction of the power required by CRTs. They are easier to read and more pleasant to work with for long periods of time than most ordinary video monitors. There are several tradeoffs as well, such as limited view angle, brightness, and contrast, not to mention high manufacturing cost. As research continues, these limitations are slowly becoming less significant.
Today's LCDs come mostly in two flavors---passive and active. The less expensive passive matrix displays trade off picture quality, view angle, and response time with power requirements and manufacturing cost. Active matrix displays have superior picture quality and viewing characteristics, but need more power to run and are much more expensive to fabricate.
Liquid crystal displays show great potential for future growth and improvement, but what are the physical limits of this technology? In an attempt to answer this question, we will begin by surveying liquid crystal in general to determine what characteristics it has that makes it so appropriate for use in displays. Next we will examine in detail the two common kinds of liquid crystal displays---passive and active matrix---to see how each works and to find out what the state-of-the-art is. Then we will investigate possible ways of improving the performance of the economical passive matrix displays to make them more like their ``active'' counterparts but without the disadvantages associated with active matrix displays. Finally, we will briefly look into what is the most we could hope for in an LCD if we completely disregarded manufacturing and operation costs and just tried to make the best display possible. For example, will it be possible for an LCD to ever come close to having the picture quality (in terms of resolution, contrast, color saturation, etc.) of, say, a printed piece of paper or a photograph?