Compositions – Liquid crystal compositions – Containing pleochroic dye
Patent
1997-07-10
2000-03-07
Kelly, C. H.
Compositions
Liquid crystal compositions
Containing pleochroic dye
25229963, 25229966, C09K 1900, C09K 1930, C09K 1912
Patent
active
06033598&
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a liquid-crystal composition for use in display elements, etc., and to a liquid-crystal display element employing the same.
BACKGROUND ART
A guest-host liquid-crystal display element employing a guest-host liquid-crystal composition obtained by mixing a host liquid-crystal composition with one or more dichroic dyes is receiving attention as a reflection type or another display element for use in future potable information apparatus, because of its superiority in viewing angle, brightness, etc.
The display qualities, such as contrast, of this guest-host liquid-crystal display element directly correlate with the dichroism or order parameter of the guest-host liquid-crystal composition used. Hence, the guest-host liquid-crystal composition has hitherto been required to have a high order parameter. In particular, a guest-host liquid-crystal composition having a high order parameter is desired recently which employs a new host liquid-crystal composition such as a fluorine-containing liquid-crystal composition and is usable in a thin-film transistor type liquid-crystal display element (TFT-LCD) and the like.
Improvements of such guest-host liquid-crystal compositions in dichroism or order parameter should be conducted with respect to both of dichroic dyes and host liquid-crystal compositions. However, the host liquid-crystal compositions which have. conventionally been investigated or improved in dichroism or order parameter have been substantially limited to those containing as a major component an Np liquid-crystal composition having a bicyclic skeleton structure such as a biphenyl or cyclohexylphenyl skeleton having a cyano group, as described later.
Consequently, in the case of using new liquid-crystal compositions such as the aforementioned fluorine-containing liquid-crystal compositions, conventional common sense does not always hold and the requirements which such a host liquid-crystal composition must satisfy have been unknown. This has made it difficult to develop a guest-host liquid-crystal composition having a high order parameter which contains a fluorine-containing Np liquid-crystal composition or Nn liquid-crystal composition.
The reasons for the above are as follows. Effects of the components and compositions of host liquid-crystal compositions on the dichroism or order parameter of guest-host liquid-crystal compositions were initially investigated with respect to liquid-crystal compositions of the Schiff base type, ester type, or the like. Thereafter, investigations were directed mainly to liquid-crystal compositions containing as a major component a bicyclic Np liquid-crystal composition having a cyanophenyl structure as a skeleton structure, such as Np liquid-crystal compositions of the biphenyl or phenylcyclohexane type having a cyano group in the direction of the molecular axis.
In the above investigations, there was an idea that the nematic/isotropic transition temperature (TNI) of a host liquid-crystal composition employed in a guest-host liquid-crystal composition should be used as an index, because the dichroism or order parameter of the guest-host liquid-crystal composition must depend on the order parameter of the host liquid-crystal composition itself used, and because the order parameter of the host liquid-crystal composition itself must depend on the thermal stability of the liquid-crystal composition. Namely, it was presumed that a guest-host liquid-crystal composition containing a host liquid-crystal composition having a high TNI generally shows high dichroism or a high order parameter.
However, the above presumption does not hold for host liquid-crystal compositions having different makeups, although almost applicable in the case of using host liquid-crystal compositions having similar makeups. Therefore, the TNI of a host liquid-crystal composition has no correlation with the order parameter thereof.
For example, it was reported in Preprints of the 9th Liquid Crystal Symposium, p. 159 and in Mol. Cryst. Liq. Cryst., 1993, Vol.
REFERENCES:
patent: 4985171 (1991-01-01), Miura et al.
patent: 5006276 (1991-04-01), Kaneko et al.
patent: 5026505 (1991-06-01), Kaneko et al.
patent: 5104572 (1992-04-01), Ozawa et al.
patent: 5453217 (1995-09-01), Kaneko et al.
patent: 5560865 (1996-10-01), Nakagawa et al.
patent: 5589100 (1996-12-01), Graso et al.
patent: 5653912 (1997-08-01), Nakagawa et al.
patent: 5683624 (1997-11-01), Sekiguchi et al.
Mol. Cryst. Liq. Cryst., 1993, vol. 225, pp. 197-210.
Kadowaki Masami
Kaneko Masaharu
Sato Hideki
Kelly C. H.
Mitsubishi Chemical Corporation
LandOfFree
Liquid-crystal composition and liquid-crystal display element does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid-crystal composition and liquid-crystal display element, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid-crystal composition and liquid-crystal display element will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-359731