Compositions – Liquid crystal compositions – Containing nonsteryl liquid crystalline compound of...
Reexamination Certificate
1999-02-11
2001-01-16
Kelly, C. H. (Department: 1756)
Compositions
Liquid crystal compositions
Containing nonsteryl liquid crystalline compound of...
C299S015000, C299S015000, C299S015000, C299S015000, C585S023000, C585S025000
Reexamination Certificate
active
06174457
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel liquid crystal compound useful as a liquid crystal material for a display device. More specifically, it relates to a novel liquid crystal compound which has a low viscosity, a mutually good solubility with another liquid crystal compound and a proper optical anisotropy (&Dgr;n) and which can obtain sharp electro-optical properties in the case that it is used in a liquid crystal display device, a liquid crystal composition containing this compound, and a liquid crystal display device.
BACKGROUND ART
Heretofore, as liquid crystal compounds which can suitably be used in a super-twisted nematic device (heretofore abbreviated to “the STN device” sometimes), various compounds having an alkenyl group as a side chain have been synthesized, and some of these compounds have practically been used. For example, compounds represented by the following formulae (s-i) to (s-3) are disclosed in Mol. Cryst. Liq. Cryst., Vol. 122, p. 241 (1985) and Japanese Patent Application Laid-open No. 83136/1986, compounds represented by the following formulae (s-4) and (s-5) are disclosed in Japanese Patent Application Laid-open No. 92740/1994, and compounds represented by the following formulae (s-6) and (s-7) are disclosed in DE 19520246A1. Furthermore, compounds represented by the following formulae (s-8) and (s-9) in which a fluorine atom is directly bonded to a double bond are disclosed in Japanese PCT Patent Application Laid-open No. 500343/1994, and a compound represented by the following formula (s-10) is disclosed in Japanese PCT Patent Application Laid-open No. 502627/1992.
However, the compounds represented by the formulae (s-1) to (s-7) all have strong inclination to show a smectic phase, so that it is difficult on occasion to use a large amount of the compound in a liquid crystal composition. In addition, the compounds represented by the formulae (s-4) to (s-7) have a high viscosity, and the compounds represented by the formulae (s-8) to (s-10) contain some portions which should be improved. For example, they are poor in chemical stability (particularly heat stability) on occasion. In particular, the improvement of a steepness of electro-optic characteristics is still desired.
DISCLOSURE OF THE INVENTION
The present inventors have intensively investigated to solve the above problems, and as a result, it has been found that a compound having an alkadienyl group at one terminal and an alkenyl group at the other terminal of its molecule has an extremely large elastic constant ratio (K
33
/K
11
), a very low viscosity, a wide nematic phase temperature range, a high chemical stability, a proper optical anisotropy (&Dgr;n) and dielectric anisotropy (&Dgr;&egr;). Furthermore, it has also been found that when a liquid crystal composition containing this kind of compound is used, there can be manufactured a liquid crystal display device having steep electro-optic characteristics, a short response time, a wide operation temperature range and a low driving voltage, and therefore, the above compound is suitable for a liquid crystal composition for liquid crystal display devices, particularly STN (super-twisted nematic) devices which are now extensively used. In consequence, the present invention has been completed.
Accordingly, an object of the present invention is to provide a liquid crystal compound having a low viscosity, a mutually good solubility with another liquid crystal compound, a proper optical anisotropy (&Dgr;n), a proper dielectric anisotropy (&Dgr;&egr;) and steep electro-optic characteristics. Another object of the present invention is to provide a liquid crystal composition using this compound. Still another object of the present invention is to provide a liquid crystal display device.
In the present invention, the term “liquid crystal compound” means a compound showing a liquid crystal phase and a compound which does not show the liquid crystal phase by itself but which exhibits suitable characteristics as a liquid crystal when mixed to form a liquid crystal composition.
A compound represented by the following formula (s-11) having an alkadienyl group as a side chain is disclosed in Japanese Patent Application No. 310039/1995, and a compound represented by the following formula (s-12) simultaneously having alkenyl groups at both the terminals thereof is disclosed in DE414647A1. However, there have not been any concrete description of a compound having an alkadienyl group at one terminal and an alkenyl group at the other terminal of its molecule. Furthermore, Japanese PCT Patent Application Laid-open No. 502627/1992 discloses a compound alone in which a terminal group is a polar group such as a halogen atom, and it does not disclose the compound simultaneously having the alkadienyl group and the alkenyl group.
The aspects of the present invention will be described in the following paragraphs [1] to [15].
[1] A compound represented by the general formula (1)
wherein R
1
is an alkadienyl group having 4 to 10 carbon atoms in which at least one hydrogen atom may be substituted by a fluorine atom, a chlorine atom or a cyano group; R
2
is an alkenyl group having 2 to 10 carbon atoms in which at least one hydrogen atom may be substituted by a fluorine atom, a chlorine atom or a cyano group; one or more non-adjacent methylene groups (—CH
2
—) in the alkadienyl group or the alkenyl group may be replaced by —O—, —CH═CH— or —C≡C—; rings A
1
, A
2
, A
3
and A
4
are each independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,3-dioxane-2,5-diyl, pyridine-2,5-diyl or pyrimidine-2,5-diyl in which at least one hydrogen atom may be substituted by a halogen atom; Z
1
, Z
2
and Z
3
are each independently a single bond, —CH
2
CH
2
—, —CH═CH—, —C≡—C—, —CH
2
O—, —OCH
2
—, —(CH
2
)
4
—, —(CH
2
)
3
—O—, —O—(CH
2
)
3
—, —(CH
2
)
2
—CH═CH—, —CH═CH—(CH
2
)
2
—, —CF
2
O—, —OCF
2
—, —CR═CH—, —CH═CR— or —CF═CF—, and R is an alkyl group having 1 to 5 carbon atoms; p and q are each independently 0 or 1; and each element in the formula may be substituted by its isotope.
[2] The compound according to the above paragraph [1] wherein R
1
is a 1,3-alkadienyl group; and R
2
is an alkenyl group.
[3] The compound according to the above paragraph [1] wherein R
1
is a 1,4-alkadienyl group; and R
2
is an alkenyl group.
[4] The compound according to the above paragraph [1] wherein R
1
is a 1,5-alkadienyl group; and R
2
is an alkenyl group.
[5] The compound according to the above paragraph [1] wherein R
1
is a 1,6-alkadienyl group; and R
2
is an alkenyl group.
[6] The compound according to the above paragraph [1] wherein R
1
is a 3,7-alkadienyl group; and R
2
is an alkenyl group.
[7] The compound according to the above paragraph [1] wherein R
1
and R
2
are each an alkadienyl group.
[8] A liquid crystal composition comprising two or more components which contains at least one of the compounds described in the above paragraphs [1] to [7].
[9] A liquid crystal composition which comprises, as a first component, at least one of the compounds described in the above paragraphs [1] to [7], and as a second component, at least one compound selected from the group consisting of compounds represented by the general formulae (2), (3) and (4)
wherein R
3
is an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen, atom may be substituted by a fluorine atom, and one or more non-adjacent methylene groups (—CH
2
—) in the alkyl group may be replaced by —O— or —CH═CH—; Y
1
is a fluorine atom, a chlorine atom, OCF
3
, OCF
2
H, CF
3
, CF
2
H, CFH
2
, OCF
2
CF
2
H or OCF
2
CFHCF
3
; L
1
and L
2
are each independently a hydrogen atom or a fluorine atom; Z
4
and Z
5
are each independently a 1,2-ethylene group, a 1,4-butylene group, —COO—, —CF
2
O—, —OCF
2
—, —CH═CH— or a single
Hisatsune Yasusuke
Kato Takashi
Katoh Takashi
Koizumi Yasuyuki
Matsui Shuichi
Chisso Corporation
Kelly C. H.
McDermott & Will & Emery
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