The smectic C phase of liquid crystals first appeared in literature in 1933. However, it was not until 1974 that it was realized that the phase ought to be ferroelectric, meaning that the phase has a permanent polarization without the need for an electric field. This was discovered by Robert Meyer (Meyer, 1975), who later demonstrated it in a synthesized chiral smectic C material DOBAMBC, shown here. The asterisk (*) by the carbon atom near the right end represents the chiral center of the molecule (see Polymers - Chemistry Basics for a discussion of chirality and the following section for its role in ferroelectric liquid crystals).
This lead to further study of ferroelectric liquid crystals (FLC). In 1980 Clark and Lagerwall published the concept of the Surface Stabilized Ferroelectric Liquid Crystal (SSFLC) device. This was a major step forward in the possibility of useful applications of FLCs. It also led to large-scale development of FLC chemistry. As FLC products became more feasible, the technology became commercialized. The initial products appearing in 1989 were direct-view displays and print bars.
There is still major interest in FLC technology. This is due to the promise of fast switching and high resolution. These advantages and the possibility for dynamic gray scale and full color of SSFLC give it great potential for use in demanding applications such as high definition television (HDTV). The advantages do not come without some complications in production however. These difficulties explain the lack of major commercial breakthroughs in recent years.
FLCs have already been developed for miniature displays. These displays can be magnified or projected for a full screen image. They can also be used in head mounted displays such as those used for virtual reality. Such displays are highly portable and also allow for interactivity with the user (image changes as user's head turns). Since the display is supported by the user, weight is of great importance. The simplest way to reduce the weight of the system is to reduce the size of the screen needed (relatively lighter magnification devices can be used to increase the field of view). Meanwhile, the resolution must be high to make the image realistic to the user. FLC displays allow for this by their small pixel sizes. Also, FLCs can use reflective illumination to eliminate bulky (and high energy consuming) backlighting devices. The bistability offered by SSFLC devices makes them ideal where low energy consumption is a concern for still images since additional power is not required once image is created. Yet, their switching time is fast enough to provide high frame rates required for video. The fast switching time also allows full color on each pixel which means higher quality on a display of a given size.
The following graphic, provided by Displaytech, nicely illustrates the comparison between images produced by their FLC with VLSI backplane devices and the typical AMLCD device. Notice that the FLC device (left) allows full color on each pixel while each pixel has only one color for the AMLCD device (right).
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FLC Structure |  |