3,3′-difluorobiphenyl derivatives, liquid crystal...

Details 3,3′-difluorobiphenyl derivatives, liquid crystal... 3,3′-difluorobiphenyl derivatives, liquid crystal...

1999-05-25

2001-03-06

Kelly, C. H. (Department: 1756)

Compositions

Liquid crystal compositions

Containing nonsteryl liquid crystalline compound of...

C252S299630, C252S299610

Reexamination Certificate

active

06197217

ABSTRACT:

TECHNICAL FIELD
The present invention relates to novel liquid crystalline compounds and liquid crystal compositions. More specifically, the invention relates to liquid crystalline compounds having 3,3′-difluorobiphenyl-4,4′-diyl group, liquid crystal compositions comprising the compound, and liquid crystal display devices fabricated by using the liquid crystal composition.
BACKGROUND ART
Display devices produced by using liquid crystalline compounds (the term “liquid crystalline compounds” is used in this specification as a general term for the compounds which exhibit a liquid crystal phase and for the compounds which do not exhibit a liquid crystal phase but are useful as component of liquid crystal compositions) have widely been utilized for the display of watches, tabletop calculators, word processors, or the likes. In recent years, researches on in-plane switching (IPS) mode and vertical alignment (VA) mode by which viewing angle can be improved at a moderate cost have extensively been conducted.
Among the liquid crystal compositions for IPS mode or VA mode, those having a negative dielectric anisotropy value are preferable, and further the compositions are sought having such physical properties as voltage holding ratio is high, threshold voltage is low, their dependency on temperature is small, temperature range of liquid crystal phase is wide, miscibility with other liquid crystal materials is excellent, and viscosity is low.
As the component for such liquid crystal compositions, many liquid crystalline compounds in which fluorine atom substituted at a lateral position were investigated, and the patents disclosing, for example, the following compounds are published:
However, compounds of the formula 1) are high in viscosity and low in voltage holding ratio since they have ester bond. Compounds of the formula 2) or 3) have problems such that the compounds readily exhibit smectic phase, and hardly form stable nematic phase when used as component of liquid crystal compositions, particularly at low temperatures.
DISCLOSURE OF THE INVENTION
In view of the required characteristics described above, an object of the present invention is to provide liquid crystalline compounds which exhibit a negative dielectric anisotropy value, have an extremely high voltage holding ratio and a low threshold, voltage, are small in their dependency on temperature, hardly exhibit smectic phase, and are excellent in miscibility with other liquid crystal materials at the same time; to provide liquid crystal compositions comprising the compound; and to provide liquid crystal display devices fabricated by using the liquid crystal composition.
As a result of diligent studies by the present inventors to solve the problems described above, it has been found out that
[1] 3,3′-difluorobiphenyl derivatives expressed by the general formula (1)
wherein Ra and Rb each independently represent a straight chain or branched alkyl group having 1 to 20 carbon atoms in which alkyl group not-adjacent any methylene group (—CH
2
—) may be replaced by oxygen atom, and any hydrogen atom in the alkyl group may be replaced by a halogen atom; A
1
, A
2
and A
3
each independently represent trans-1,4-cyclohexylene, dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, 1-silacyclohexane-1,4-diyl, or 4-silacyclohexane-1,4-diyl, or 1,4-phenylene in which one or more hydrogen atoms may be replaced by fluorine atom; Z
1
, Z
2
and Z
3
each independently represent —(CH
2
)
2
—, —(CH
2
)
4
—, —CH
2
O—, —(CH
2
)
3
O— or single bond; m and n are independently 0 or 1 provided that when both m and n are 0, and A
2
represents 1,4-phenylene, then at least one hydrogen atom on ring A
2
is replaced by fluorine atom; and any atom which constitutes the compound may be replaced by its isotope, have expected properties, leading to the accomplishment of the present invention.
Also, the present invention has the following aspects:
[2] The 3,3′-difluorobiphenyl derivative recited in aspect [1] above wherein both m and n are 0.
[3] The 3,3′-difluorobiphenyl derivative recited in aspect [1] above wherein either m or n is 1.
[4] The 3,3′-difluorobiphenyl derivative recited in aspect [2] above wherein A
2
is trans-1,4-cyclohexylene.
[5] The 3,3′-difluorobiphenyl derivative recited in aspect [2] above wherein A
2
is dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, 1-silacyclohexane-1,4-diyl, or 4-silacyclohexane-1,4-diyl.
[6] The 3,3′-difluorobiphenyl derivative recited in aspect [2] above wherein A
2
is 1,4-phenylene in which at least one hydrogen atom is replaced by fluorine atom.
[7] A liquid crystal composition comprising at least one derivative recited in any one of aspects [1] to [6] above.
[8] A liquid crystal composition comprising, as a first component, at least one derivative recited in any one of aspects [1] to [6] 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 in which alkyl group not-adjacent any methylene group may be replaced by oxygen atom or —CH═CH—, and any hydrogen atom in the alkyl group may be replaced by fluorine atom; x
1
represents fluorine atom, 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
each independently represent hydrogen atom or fluorine atom; Z
4
and Z
5
each independently represent —(CH
2
)
2
—, —(CH
2
)
4
—, —COO—, —CF
2
O—, —OCF
2
—, —CH═CH— or single bond; ring B represents trans-1,4-cyclohexylene or 1,3-dioxane-2,5-diyl, or 1,4-phenylene in which hydrogen atom may be replaced by fluorine atom; ring C represents trans-1,4-cyclohexylene, or 1,4-phenylene in which hydrogen atom may be replaced by fluorine atom; and an atom which constitutes these compounds may be replaced by its isotope.
[9] A liquid crystal composition comprising, as a first component, at least one derivative recited in any one of aspects [1] to [6] above, and comprising, as a second component, at least one compound selected from the group consisting of the compounds expressed by the general formula (5) or (6)
wherein R
2
and R
3
each independently represent an alkyl group having 1 to 10 carbon atoms in which alkyl group not-adjacent any methylene group may be replaced by oxygen atom or —CH═CH—, and any hydrogen atom in the alkyl group may be replaced by fluorine atom; X
2
represents —CN or —C≡C—CN; ring D represents trans-1,4-cyclohexylene, 1,4-phenylene, 1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl; ring E represents trans-1,4-cyclohexylene or pyrimidine-2,5-diyl, or 1,4-phenylene in which hydrogen atom may be replaced by fluorine atom; ring F represents trans-1,4-cyclohexylene or phenylene; Z
6
represents —(CH
2
)
2
—, —COO— or single bond; L
3
, L
4
, and L
5
each independently represent hydrogen atom or fluorine atom; b, c and d are independently 0 or 1; and an atom which constitutes these compounds may be replaced by its isotope.
[10] A liquid crystal composition comprising, as a first component, at least one derivative recited in any one of aspects [1] to [6] above, 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) described above, and comprising, as a third component, at least one compound selected from the group consisting of the compounds expressed by any one of the general formulas (7), (8) and (9)
wherein R
4
and R
5
each independently represent an alkyl group having 1 to 10 carbon atoms in which alkyl group not-adjacent any methylene group may be replaced by oxygen atom or —CH═CH—, and any hydrogen atom in the alkyl group may be replaced by fluorine atom

Affiliated with

Also associated with

Rating

3,3′-difluorobiphenyl derivatives, liquid crystal... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with 3,3′-difluorobiphenyl derivatives, liquid crystal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 3,3′-difluorobiphenyl derivatives, liquid crystal... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2488738