Nondisplay applications

Crossland W A and Wilkinson T D 1998 Nondisplay applications of liquid crystals Handbook of Liquid Crystals Vol 1. Fundamentals ed D Demus, J Goodby, G W Gray, H-W Speiss and V Vill (New York Wiley-VCH)... 

There are many nondisplay applications of liquid crystals, and it is not possible to do justice to aU of them here in this section. Here we will outline some key examples, and summarize briefly a wider selection. Some of the most developed applications that are currently being researched are in optical correlators, optical interconnections, wavelength filters, and optoelectronic neural networks. Most of these systems use liquid crystal spatial light modulators (SLMs). In addition, we will describe how SLMs are used in autostereoscopic displays. 

The rear glass wall can be replaced by a silicon VLSI die to make a silicon backplane SLM as in Fig. 5 b. The SLM is now a reflective modulator with the aluminum from the second metal layer of the VLSI process acting as a mirror [8]. Circuitry on the backplane can be used to address the FLC pixels as either dynamic random access memory (DRAM) [9] or static RAM (SRAM) [10]. The silicon backplane SLM is very important to the development of nondisplay applications as it allows large arrays of small pixels to be built on a silicon wafer capable of high addressing speeds. Compared with line-at-a-time multiplexed SLMs, these sil-... 

From this analysis it is possible to see why FLC SLMs form a vital part in optical systems. The liquid crystal modulation allows the display of information into coherent optical systems as both intensity and phase images. The nature of the FLC molecular interaction makes it fast and this ideally suits nondisplay applications. Even the restriction of binary modulation does not limit the usefulnes of FLC SLMs, although fast grey scale and multilevel phase modulation would be desirable. In fact, for some applications, binary modulation is a bonus and enhances performance. 

One of the most important elements in nondisplay applications of liquid crystals is the positive focal length lens and its relationship to the Fourier transform. It is a Fourier transform and its unique mathematical properties that allow us to perform many... 

Some of the most promising nondisplay applications for liquid crystals eligible for commercial exploitation are in the area of optical interconnects and switches. Potential applications include optically transparent fiber-to-fiber switches for use in the telecommunications transmission network. 

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