Compositions – Liquid crystal compositions – Containing nonsteryl liquid crystalline compound of...
Patent
1989-08-16
1993-03-30
Stoll, Robert L.
Compositions
Liquid crystal compositions
Containing nonsteryl liquid crystalline compound of...
25229966, 25229967, 25229968, 359103, C09K 1912, C09K 1920, G02F 113, G09K 1934
Patent
active
051981505
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a ferroelectric liquid crystal material. More specifically, it relates to a ferroelectric liquid crystal composition having quick response properties which comprises a smectic liquid crystal compound and a optically active compound, and an light switching element in which the above-mentioned composition is contained.
BACKGROUND TECHNIQUE
Liquid crystal compounds are widely used as materials for display elements, and most of these liquid crystal elements are based on a TN type display system and liquid crystal materials are in the state of nematic phase.
The TN type display system has advantages such as less tiredness of the eyes and extremely small consumption of electric power because of being of the non-emissive type, whereas it has disadvantages such as slow response and disappearance of display at certain visual angles. In recent years, this system is being improved in such a direction as to keep up characteristics of flat displays, and in particular, quick response and the enlargement of the visual angle are demanded.
In order to meet these demands, improvements in liquid crystal materials have been attempted. However, as compared with other emissive type displays (e.g., electroluminescence displays and plasma displays), it is apparent that the TN type display system is much poorer with regard to response time and the extent of the visual angle.
In order that characteristics of the liquid display element such as features of the non-emissive type and the small consumption of electric power may be maintained and in order that the quick response corresponding to that of the emissive type displays may be assured, it is essential to develop a novel liquid display system in place of the TN type display system.
As one of such attempts, a display system in which the light switching phenomenon of ferroelectric liquid crystals is utilized has been suggested by N. A. Clark and S. T. Lagerwall (see Appl. Phys. Lett. 36, p 899, 1980).
The presence of the ferroelectric liquid crystals was announced for the first time in 1975 by R. B. Mayer et al. (see J. Phys., 36, p 69, 1975), and from the viewpoint of a liquid crystal structure, these crystals belong to a chiral smectic C phase, a chiral smectic I phase, a chiral smectic F phase, a chiral smectic G phase and a chiral smectic H phase (hereinafter referred to simply as "S.sub.C * phase", "S.sub.I * phase", "S.sub.F * phase", "S.sub.G * phase" and "S.sub.H * phase", respectively).
In the chiral smectic phase, molecules form a layer and tilt to the surface of the layer, and a helical axis is vertical to this layer surface. In the chiral smectic phase, spontaneous polarization takes place, and therefore, when a DC electric field is applied to this layer in parallel therewith, the molecules rotate about the helical axis in accordance with their polarity. Display elements containing the ferroelectric liquid crystals utilize this switching phenomenon.
Nowadays, of the chiral smectic phases, much attention is particularly paid to the S.sub.C * phase. As the display systems in which switching phenomenon of the S.sub.C * phase is utilized, there is a birefringence type system using two polarizers and a guest/host type system using a dichoric dye. Features of these display systems are as follows:
Thus, the display systems have the possibility of achieving the high-density display and are considered to be effectively utilizable in the display elements.
However, in the case that this ferroelectric liquid crystal is used in the practical display elements, there are now many problems such as slow response properties and very difficult alignment.
Therefore, requirements which are necessary for the ferroelectric liquid crystal materials are inclusive of room temperatures, and
At present, no chiral smectic liquid crystal compounds in a single state which satisfy all of such requirements are present, and thus one attempt is to provide a ferroelectric liquid crystal composition satisfying the above-mentioned requirements by mixing
REFERENCES:
patent: 4668427 (1987-05-01), Saito et al.
patent: 4753752 (1988-06-01), Raynes et al.
patent: 4780241 (1988-10-01), Furukawa et al.
patent: 4784791 (1988-11-01), Saito et al.
patent: 4882083 (1989-11-01), Terashima et al.
patent: 4911863 (1990-03-01), Sage et al.
patent: 4931208 (1990-06-01), Furukawa et al.
patent: 4952335 (1990-08-01), Furukawa et al.
Furukawa Kenjii
Ichihashi Mitsuyoshi
Kikuchi Makoto
Takeshita Fusayuki
Terashima Kanetsugu
Chisso Corporation
Harris C.
Stoll Robert L.
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