Applied Physics

A Brighter Future by Going Dark

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Science  30 Jun 2000:
Vol. 288, Issue 5475, pp. 2285
DOI: 10.1126/science.288.5475.2285d

Microsecond-scale switching times, large viewing angle, and gray-scale capabilities make antiferroelectric liquid crystals (AFLCs) attractive candidates for electro-optic devices such as displays. However, their relatively poor dark state, which results in unacceptable amounts of light passing through crossed polarizers and in poor contrast between on- and off-states, has limited their utility. Inhomogeneities and misalignment of the AFLC layers, as well as wiggling of the optic axis in the presence of an applied electric field, have been thought to be the culprit. Most AFLCs have tilt angles (the angle between the polarizer axis and its optic axis) of 25° to 35°. D'havé et al. show that, in materials designed to have a tilt angle of 45°, the directors in alternating layers are orthogonal to each other and the dark-state problem is solved; the zero-applied field material becomes uniaxial with its optical axis in exactly the direction needed to block transmission. – ISO

Appl. Phys. Lett.76, 3528 (2000).

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