Compositions – Liquid crystal compositions – Containing nonsteryl liquid crystalline compound of...
Reexamination Certificate
1998-08-24
2002-01-08
Wu, Shean C. (Department: 1721)
Compositions
Liquid crystal compositions
Containing nonsteryl liquid crystalline compound of...
C252S299670, C252S299660, C252S299610, C560S054000, C570S129000, C549S369000
Reexamination Certificate
active
06337034
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a liquid crystalline compound and liquid crystal composition. More specifically, it relates to a novel liquid crystalline compound which has an alkenylene group having 2 to 4 carbon atoms and ester bond as bonding group at the same time, relates to a liquid crystal composition comprising the compound, and relates to a liquid crystal display device comprising the liquid crystal composition.
BACKGROUND ART
Liquid crystal display devices comprising liquid crystalline compounds (the term “liquid crystalline compound” as used hereinafter is intended to use as a general name for compounds exhibiting a liquid crystal phase, or compounds which do not exhibit a liquid crystal phase but are useful as a component of liquid crystal compositions) are widely used in displays such as watches, tabletop calculators, and word processors. These display devices utilize optical anisotropy and dielectric anisotropy of liquid crystalline compounds.
Liquid crystal phase includes nematic liquid crystal phase, smectic liquid crystal phase, and cholesteric liquid crystal phase, and display devices utilizing nematic liquid crystal phase are most widely used.
As display mode using a liquid crystal, there have been devised dynamic scattering (DS) mode, deformation of aligned phases (DAP) mode, guest/host (GH) mode, twisted nematic (TN) mode, super twisted nematic (STN) mode, and thin film transistor (TFT) mode.
Liquid crystalline compounds used in these display devices have to exhibit liquid crystal phase in a wide temperature range with room temperature being its center, have to be sufficiently stable under conditions in which the display devices are used, and have to have properties sufficient to drive the display devices. However, no liquid crystalline compounds which satisfy these requirements by a single compound have been found up to now. Accordingly, it is actual circumstances that several kind or several tens kind of liquid crystalline compounds are mixed to produce liquid crystal compositions having required properties. These liquid crystal compositions are required to be stable against moisture, light, heat, and air which usually present under conditions in which the display devices are used, required to be stable against electric field and electromagnetic radiation, and further required to be chemically stable against the compounds to be mixed. The liquid crystal compositions are required to have proper values of such physical properties as optical anisotropy (&Dgr;n) and dielectric anisotropy (&Dgr;&egr;) depending on display mode and the shape of display devices. Further, it is important that each component in the liquid crystal compositions has an excellent solubility with one another.
Especially, it is desired to still more lower threshold voltage which largely contributes to high speed response necessary for expanding the size of screen of liquid crystal display, and contributes to saving of electric power (E. Jakeman et al., Phys. Lett., 39A. 69 (1972)). For the high speed response, low viscosity of the compositions is also important. Moreover, environments in which liquid crystal display devices are used are diversified in recent years, and keeping with such circumstance, development of liquid crystalline compounds which exhibit liquid crystal phase in a wider temperature range is earnestly desired.
In order to achieve these purposes, various compounds have heretofore been developed, for instance, the compound expressed by the following formula (a) or (b) is proposed in Laid-open Japanese Patent Publication No. Hei 4-279560, and the compound expressed by the following formula (c) is proposed in Japanese Patent Publication No. Hei 7-72148, respectively.
However, the compound expressed by the formula (a) can not be said to be sufficiently wide in temperature range of liquid crystal phase, and the compound expressed by the formula (b) has a problem that its viscosity is high.
Whereas the compound expressed by the formula (c) is a three ring compound containing an alkenylene group as bonding group, its disclosure is insufficient. That is, the physical properties of the compound are not shown, and besides, specific data are not disclosed at all about the utility expected when it is used as a component of liquid crystal compositions.
DISCLOSURE OF THE INVENTION
An object of the present invention is to remove the problems in the background art described above. Another object of the present invention is to provide novel liquid crystalline compounds which are wide in temperature range of liquid crystal phase, are low in viscosity, have a low threshold voltage, and are excellent in stability and mutual solubility with other liquid crystal materials, to provide liquid crystal compositions comprising the liquid crystalline compound, and to provide liquid crystal display devices comprising the liquid crystal composition.
The present invention for achieving the purposes described above is summarized as follows:
(1) A vinylene compound expressed by the general formula (1)
Ra—A
1
—Z
1
—A
2
—Z
2
—A
3
—(Z
3
—A
4
)
m
—Rb (1)
wherein Ra represents an alkyl group having 1 to 20 carbon atoms one or more —CH
2
— in which alkyl group may be replaced by —O—, —S—, —CO—, —CH═CH—, or —C═C—, but in no case —O— and/or —S— continues, and one or more hydrogen atoms in which alkyl group may be replaced by a halogen atom; Rb represents Ra, a halogen atom, or cyano group; A
1
, A
2
, A
3
, and A
4
independently represent trans-1,4-cyclohexylene group, cyclohexenylene group, 1,4-phenylene group one or more hydrogen atoms on which ring may be replaced by a halogen atom or cyano group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, or 1,3-dioxane-2,5-diyl group; Z
1
, Z
2
, and Z
3
independently represent an alkenylene group having 2 to 4 carbon atoms, —COO—, —OCO—, —(CH
2
)
2
—, —C≡C—, —CH
2
O—, —OCH
2
—, or a covalent bond provided that at least one of Z
1
to Z
3
represents an alkenylene group having 2 to 4 carbon atoms, and at least one of Z
1
to Z
3
represents —COO— or —OCO—; and m is 0 or 1.
(2) The vinylene compound recited in (1) above wherein m is 0.
(3) The vinylene compound recited in (1) above wherein m is 1.
(4) The vinylene compound recited in (2) above wherein either Z
1
or Z
2
is vinylene or butenylene.
(5) The vinylene compound recited in (3) above wherein either Z
1
or Z
2
is vinylene or butenylene.
(6) The vinylene compound recited in (4) above wherein A
1
and A
2
are independently trans-1,4-cyclohexylene group, or 1,4-phenylene group one or more hydrogen atoms on which ring may be replaced by a halogen atom or cyano group.
(7) The vinylene compound recited in (5) above wherein A
1
and A
2
are independently trans-1,4-cyclohexylene group, or 1,4-phenylene group one or more hydrogen atoms on which ring may be replaced by a halogen atom or cyano group.
(8) A liquid crystal composition comprising at least one vinylene compound recited in any one of (1) to (7) above.
(9) A liquid crystal composition comprising, as a first component, at least one vinylene compound recited in any one of (1) to (7) above, and comprising, as a second component, at least one compound selected from the group consisting of the compounds expressed by any one of the general formulas (2), (3), and (4)
wherein R
1
represents an alkyl group having 1 to 10 carbon atoms; X
1
represents F, Cl, OCF
3
, OCF
2
H, CF
3
, CF
2
H, or CFH
2
; L
1
, L
2
, L
3
, and L
4
independently represent H or F; Z
4
and Z
5
independently represent —(CH
2
)
2
—, —CH═CH—, or a covalent bond; and a is 1 or 2.
(10) A liquid crystal composition comprising, as a first component, at least one vinylene compound recited in any one of (1) to (7) above, and comprising, as a second component, at least one compound selected from the group consisting of the compounds expressed by any one of the general formulas (5), (6), (7), (8), and (9)
wherein R
2
represents F, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms any methylene g
Kondo Tomoyuki
Matsui Shuichi
Miyazawa Kazutoshi
Nakagawa Etsuo
Sekiguchi Yasuko
Chisso Corporation
Wu Shean C.
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