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Orthoconic antiferroelectric liquid crystals containing biphenyl, terphenyl, or naphthyl mesogenic unit

Dąbrowski R., Drzewiński W., Dziaduszek J., Gąsowska J., Henderson P. A., Kula P., Otón J. M., Bennis N.

Opto-Electronics Review

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2007

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Vol. 15, No. 1

32-36

EN

Three homologous series of orthoconic (45 degree tilt) antiferroelectric liquid crystals containing either naphthyl or terphenyl groups as mesogenic unit have been synthesized and their mesomorphic behaviour investigated by DSC and polarized light microscopy, and their properties discussed. X-ray difraction studies have shown the presence of a de Vries-type smectic A phase which does not exhibit a layer shrinkage on transition to the ferroelectric smectic C phase. Mixtures of the new materials have been formulated and their electro-optical properties investigated for their use in surface stabilized orthoconic antiferroelectric liquid crystal (SSOAFLC) devices.

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Video-rate multiplexed driving scheme for passive antiferroelectric liquid crystal displays

Quintana X., Castillo P. L., Otón J. M., Bennis N., Lara A., Urruchi V., Dąbrowski R.

Opto-Electronics Review

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2004

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Vol. 12, No. 3

291-297

EN

Antiferroelectric liquid crystals have been applied to high-end multiplexed displays. The interest on these materials chiefly comes up from their capability of being multiplex addressed with no need of active matrices. Antiferroelectric grey levels arise from a double symmetric hysteresis loop that can be stabilized by a constant holding voltage. Driving schemes are compatible with passive multiplexing, but limitations appear when the multiplexing rate increases. To avoid these limitations, new driving schemes for high multiplexing level at video rate have been designed. The problem of accumulated voltage on bias level arising from data voltages is tackled as well.

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Antiferroelectric liquid crystal displays

Otón J. M., Quintana X., Castillo P. L., Lara A., Urruchi V., Bennis N.

Opto-Electronics Review

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2004

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Vol. 12, No. 3

263-269

EN

In the last few years, the unique features of antiferroelectric liquid crystals (AFLCs) have been explored to develop high-end displays. A number of passive- and active-matrix prototypes have been presented. However, although their use in a number of application areas has been suggested, no commercial products have been announced yet. This work reviews the state of the art of AFLC displays, the reasons for their present low incidence in display markets, and the latest developments aiming to overcome the main shortcomings that hinder their development. V-shape smectic displays are also included in this study. Although not considered strictly antiferroelectrics nowadays, V-shape materials behaviour and scope are similar to traditional AFLCs.

4

Antiferroelectric and V-shape liquid crystal on silicon microdisplays

Otón J. M., Dąbrowski R., Quintana X., Urruchi V, Gayo J. L.

Opto-Electronics Review

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2002

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Vol. 10, No. 1

17-21

EN

In this work, the use of antiferroelectric and V-shape liquid crystals for video projection using LCOS microdisplays has been explored. Antiferroelectric grey levels arise from a double symmetric hysteresis loop that can be stabilised by a constant holding voltage, thus an active matrix is not strictly required in this case. If used, then the voltage levels and the waveform must be adjusted to fulfil the voltage limitations dictated by the matrix. V-shape materials lack hysteresis ; therefore the active matrix is mandatory to stabilise the levels. Voltage limitations, however, are less restrictive int his case, since V-shape smectics require just a few volts for full switching.