Compositions – Liquid crystal compositions – Containing nonsteryl liquid crystalline compound of...
Reexamination Certificate
1999-05-26
2001-03-27
Kelly, C. H. (Department: 1756)
Compositions
Liquid crystal compositions
Containing nonsteryl liquid crystalline compound of...
C252S299610, C252S299660
Reexamination Certificate
active
06207076
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel liquid crystal compound useful as a liquid crystal display material. More specifically, it relates to a novel liquid crystal compound having suitable characteristics such as steep threshold properties, a low viscosity, a good compatibility with another liquid crystal compound and a proper optical anisotropy value, a novel liquid crystal composition and a liquid crystal display device formed by using this compound.
BACKGROUND ART
Heretofore, liquid crystal compounds are important as compounds for use in the manufacture of displays of various electrooptic devices. Among the various liquid crystal compounds, compounds having an alkenyl group as a side chain are suitable as the liquid crystal compounds for STN, and the various compounds having the alkenyl group have been synthesized and evaluated, and some of these compounds have been put to practical use. For example, the following compounds (s-1) to (s-3) have been disclosed in Mol. Cryst. Liq. Cryst., 122, p. 241 (1985) and Japanese Patent Application Laid-open No. 83136/1986, the following compounds (s-4) and (s-5) have been revealed in Japanese Patent Application No. 92740/1994, and the following compounds (s-6) and (s-7) have been disclosed in DE19520246Al.
However, the above liquid crystal compounds are poor in steep threshold properties which are required for the liquid crystal compounds for STN, and all of them have strong smectogenic properties, so that if a liquid crystal composition containing a large amount of such a compound is prepared, there is a problem that the compatibility of such a liquid crystal compound with another liquid crystal compound in the liquid crystal composition at a low temperature is low. In particular, the compounds (s-4) to (s-7) have each a high viscosity, and so there is a large problem that a response speed of the liquid crystal composition using such a compound is low.
Compounds (s-8) and (s-9) in which a fluorine atom is directly bonded to a double bond have been disclosed in Japanese Patent National Publication (Kohyo) No. 500343/1994, and a compound (s-10) has been revealed in Japanese Patent National Publication (Kohyo) No. 502627/1992. However, the compounds (s-8) and (s-9) are extremely poor in chemical stability (particularly, heat stability), and therefore the use of these compounds is practically impossible. Moreover, in Japanese Patent National Publication (Kohyo) No. 502627/1992, there have been disclosed compounds alone in which a terminal group is limited to a polar group such as a halogen atom.
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 fluorovinyl derivative compound represented by the general formula (1) has
(1) an extremely high elastic constant ratio (K
33
/K
11
),
(2) a very low viscosity,
(3) a wide nematic phase temperature range,
(4) a high chemical stability, and
(5) a proper optical anisotropy value and dielectric anisotropy value.
Furthermore, it has also been found that a liquid crystal composition in which the compound of the general formula (1) is used has
(1) steep threshold voltage properties,
(2) a feature that a response time is short,
(3) a wide operation temperature range (a good compatibility with another liquid crystal compound),
(4) a chemical stability, and
(5) a feature that a drive power is low.
In addition, it has also been confirmed that the compound of the general formula (1) is suitable for the preparation of the liquid crystal composition for STN (super-twisted nematic) which is most extensively used at present. In consequence, the present invention has now been completed.
Therefore, an object of the present invention is to provide a novel fluorovinyl derivative compound suitable for a display material, and a liquid crystal composition in which this compound is used. In particular, the object of the present invention is to provide a novel liquid crystal compound having steep threshold properties, a low viscosity, a good compatibility with another liquid crystal compound and a proper optical anisotropy value and dielectric anisotropy value, a novel liquid crystal composition and a liquid crystal display device formed by using this compound.
The present invention which can achieve the above object is constituted as follows.
The 1st aspect of the present invention is directed to a fluorovinyl derivative compound represented by the general formula (1)
wherein R
1
is an alkyl group having 1 to 18 carbon atoms, and a methylene group in the alkyl group may be substituted by an oxygen atom, a sulfur atom, —CH═CH— or —C≡C— and a hydrogen atom in the alkyl group may be substituted by a halogen atom or a cyano group;
rings A, B and C 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 a hydrogen atom in the ring 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—, —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
2
═CH—, —CH═CR
2
— or —CF═CF—, and R
2
is an alkyl group having 1 to 5 carbon atoms;
X is a hydrogen atom or a fluorine atom; p and q are each independently 0 or 1; and m is an integer of 0 to 5;
each element in the formula may be substituted by its isotope; but
except (1) a compound in which p is 0, q is 0, Z
3
is the single bond, —CH
2
CH
2
—, —CH
2
O— or —OCH
2
—, and the ring C is 1,4-cyclohexylene or 1,4-phenylene, and (2) a compound in which p is 0, q is 1, Z
2
and Z
3
are each the single bond, the ring B is 1,4-phenylene, and the ring C is 1,4-cyclohexylene or 1,4-phenylene.
The 2nd aspect of the present invention is directed to the fluorovinyl derivative compound according to the 1st aspect of the present invention wherein at least one of Z
1
, Z
2
and Z
3
is —CH═CH—, —(CH
2
)
3
—O—, —O—(CH
2
)
3
—, —(CH
2
)
2
—CH═CH—, —CH═CH—(CH
2
)
2
—, —CF
2
O—, —OCF
2
—, —CR
2
═CH—, —CH═CR
2
— or —CF═CF—; and R
2
is an alkyl group having 1 to 5 carbon atoms.
The 3rd aspect of the present invention is directed to the fluorovinyl derivative compound according to the 1st aspect of the present invention wherein at least one of Z
1
, Z
2
and Z
3
is —CH═CH—, —(CH
2
)
2
—CH═CH—, —CH═CH—(CH
2
)
2
— or —CF═CF—.
The 4th aspect of the present invention is directed to the fluorovinyl derivative compound according to the 1st aspect of the present invention wherein at least one of Z
1
, Z
2
and Z
3
is —(CH
2
)
3
—O—, —O——(CH
2
)
3
—, —CF
2
O— or —OCF
2
—.
The 5th aspect of the present invention is directed to the fluorovinyl derivative compound according to the 1st aspect of the present invention wherein at least one of Z
1
, Z
2
and Z
3
is —CR
2
═CH— or —CH═CR
2
—; and R
2
is an alkyl group having 1 to 5 carbon atoms.
The 6th aspect of the present invention is directed to a fluorovinyl derivative compound represented by the general formula (1-1)
wherein R
1
, X and m are as defined in the 1st aspect of the present invention; Z
1
, Z
2
and Z
3
are each independently a single bond, —CH
2
CH
2
—, —CH
2
O—, —OCH
2
— or —(CH
2
)
4
—; and rings A, B and C are each independently 1,4-cyclohexylene or 1,4-phenylene in which a hydrogen atom in the ring may be substituted by a halogen atom.
The 7th aspect of the present invention is directed to a fluorovinyl derivative compound represented by the general formula (1-2)
wherein R
1
, X and m are as defined in the 1st aspect of the present invention; r and s are each independently 0 or 1; and L
1
, L
2
, L
3
and L
4
are each independently a hydrogen atom or a fluorine atom.
Typical examples of the compound represented by the general formula (1-2) include compounds of the following formulae:
wherein R
1
, m and L
1
to L
4
are as defined above.
The 8th aspect of the present invention is directed to the f
Hachiya Norihisa
Koga Kouji
Matsui Shuichi
Miyazawa Kazutoshi
Nakagawa Etsuo
Chisso Corporation
Kelly C. H.
McDermott & Will & Emery
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