Chemicals to calculators: the early exploitation of cyanobiphenyl liquid crystals

Abstract

An account is given of the work needed to take the cyanobiphenyl liquid crystal (LC) series invented by George Gray and his colleagues and formulate them into ready-to-use mixtures required by display manufacturers. Two classes of formulated mixtures are described. Static addressed displays typical of those used in industrial and instrument displays as well as the first LC watches required mixtures with wide operating temperature ranges from at least −10°C up to 60–100°C. Later, mixtures optimised for multiplex drive made possible the more complex displays used in later watches, calculators and other alphanumeric devices. The principles involved and the difficulties encountered in formulating the mixtures are described. All of the mixtures used in practice required the use of other materials mixed with the simple cyanobiphenyls, and the essential part played in mixture development by these other materials, many of which originated in George’s research group, is highlighted.

Keywords:

• cyanobiphenyl
• eutectic
• LCD
• multiplex

Acknowledgements

The work described was carried out by a considerable number of scientists in addition to the authors and those named in the text, in the liquid crystals groups at Merck, Poole and RSRE, Malvern. Those making a major contribution at Malvern included John Kirton, Jenny Constant, Robert Smith and Madeline Bradshaw and at Poole, William Letcher, Michael Chambers, Peter Balkwill and Andrew Pearson. The work was made possible by constant support from the chemical synthesis teams at Hull and at Poole whose help we gratefully acknowledge.