Stock material or miscellaneous articles – Liquid crystal optical display having layer of specified... – With viewing layer of specified composition
Reexamination Certificate
2002-04-19
2004-03-09
Wu, Shean C. (Department: 1756)
Stock material or miscellaneous articles
Liquid crystal optical display having layer of specified...
With viewing layer of specified composition
C252S299100, C252S299500, C549S041000, C549S456000
Reexamination Certificate
active
06703084
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a quinone compound, a liquid crystal composition and a guest-host-type liquid crystal cell employing the same.
RELATED ART
There are known various types of liquid crystal devices (see, for example, “Ekisho Debaisu Handobukku (Liquid Crystal Device Handbook), edited by No. 142 Committee of Japan Society for the Promotion of Science, published by the Nikkan Kogyo Shimbun, Ltd., 1989). For example, guest-host-type liquid crystal device has a cell having filled therein a liquid crystal composition which comprises liquid crystal as host and dichroic dye dissolved therein as guest. When a voltage is applied to the cell sufficient to rotate the liquid crystal molecules, the dye molecules rotate along with the liquid crystal molecules and allow changing of light absorption by the cell to thereby effect display. The reflective liquid crystal device employing guest-host mode is excellent in brightness. The guest-host mode device is disclosed for example in “Handbook of Liquid Crystals”, written by B. Bahadur, co to edited by D. Demus, J. Goodby, G. W. Gray, H. W. Spiess, and V. Vill, Vol. 2A, published by Wiley-VCH, 1998, Chapters 3 and 4, p. 257 to 302. Dichromatic dyes available for liquid crystal display are also disclosed in “Dichroic Dyes for Liquid Crystal Display”, written by A. V. Ivashchenko, published by CRC, 1994.
Various studies have been made of dichroic dyes of anthraquinone derivatives. In general, anthraquinone dyes however need be dissolved into liquid crystals in a large amount due to their relatively small absorption coefficients, which has often raised a practical problem. So that several studies have been made on other quinone dyes, available as dichroic dye, having molecular skeletons different from those of anthraquinone dye, where reported examples include benzoquinone derivatives and naphthoquinone derivatives. A device using a compound as shown bellow, having a benzofuran ring condensed on one side of a benzoquinone skeleton, as a dichroic dye was disclosed in Yoshida, et al., Chem. Lett., 2049-2052, 1990.
The absorption coefficient of such compound is however still small, so that there is a further demand for improvement. A compound having benzofuran rings condensed on both sides of a benzoquinone skeleton was disclosed in Aust. J. Chem., Vol. 29, p. 179, 1976. Such compound, however, has a methoxy group on the benzofuran ring and thus shows an absorption maximum wavelength at around 300 nm, which cannot allow such compound to be used as a dichroic dye.
It is therefore an object of the present invention to provide a novel quinone compound having a large absorption coefficient. It is another object of the present invention to provide a liquid crystal composition exhibiting a high order parameter. It is still another object of the present invention to provide a guest-host-type liquid crystal cell having an improved contrast of the display.
SUMMARY OF THE INVENTION
The foregoing objects are accomplished by the invention to provide a quinone compound represented by formula (1) or (2) below:
(wherein X
1
and X
2
independently represents an oxygen atom, sulfur atom or N—R
1
; R
1
represents a hydrogen atom, alkyl group, aryl group or heterocyclic group; Ar
1
and Ar
2
independently represents an atomic group necessary for forming an aromatic ring or aromatic rings, where at least one of such aromatic rings formed by Ar
1
and Ar
2
has a substituent selected from the group consisting of alkylthio group, arylthio group, heteroarylthio group and —N(R
2
)(R
3
) group; and R
2
and R
3
independently represents a hydrogen atom, alkyl group, aryl group or heterocyclic group, where R
2
and R
3
may be linked together to form a ring); and
(wherein X
3
and X
4
independently represents an oxygen atom, sulfur atom or N—R
4
; R
4
represents a hydrogen atom, alkyl group, aryl group or heterocyclic group; Ar
3
and Ar
4
independently represents an atomic group necessary for forming an aromatic ring or aromatic rings, where at least one of such aromatic rings formed by Ar
3
and Ar
4
has a substituent selected from the group consisting of alkylthio group, arylthio group, heteroarylthio group and —N(R
5
)(R
6
) group; and R
5
and R
6
independently represents a hydrogen atom, alkyl group, aryl group or heterocyclic group, where R
5
and R
6
may be linked together to form a ring).
In the formula (1), X
1
and X
2
, preferably, independently represents an oxygen atom or sulfur atom; both of X
1
and X
2
are more preferably oxygen atoms.
In the formula (1), Ar
1
and Ar
2
, preferably, respectively represents an atomic group necessary for forming a substituted benzene, naphthalene or pyridine; both of Ar
1
and Ar
2
are more preferably benzenes substituted by —N(R
2
)(R
3
) group.
In the formula (2), X
3
and X
4
, preferably, independently represents an oxygen atom or sulfur atom; both of X
3
and X
4
are more preferably oxygen atoms.
In the formula (2), Ar
3
and Ar
4
, preferably, respectively represents an atomic group necessary for forming a substituted benzene, naphthalene or pyridine; both of Ar
3
and Ar
4
are more preferably benzenes substituted by —N(R
5
)(R
6
) group.
The present invention further provides a liquid crystal composition comprising at least one liquid crystal compound and at least one quinone compound represented by formula (3) or (4).
(wherein X
1
and X
2
independently represents an oxygen atom, sulfur atom or N—R
1
; R
1
represents a hydrogen atom, alkyl group, aryl group or heterocyclic group; Ar
1
′ and Ar
2
′ independently represents an atomic group necessary for forming an aromatic ring or aromatic rings which may be optionally substituted with one or more substituent); and
(wherein X
3
and X
4
independently represents an oxygen atom, sulfur atom or N—R
4
; R
4
represents a hydrogen atom, alkyl group, aryl group or heterocyclic group; Ar
3
′ and Ar
4
′ independently represents an atomic group necessary for forming an aromatic ring or aromatic rings which may be optionally substituted with one or more substituent).
In the formula (3), X
1
and X
2
, preferably, independently represents an oxygen atom or sulfur atom; both of X
1
and X
2
are more preferably oxygen atoms.
In the formula (3), Ar
1
′ and Ar
2
′, preferably, respectively represents an atomic group necessary for forming a substituted benzene, naphthalene or pyridine; both of Ar
1
′ and Ar
2
′ are more preferably benzenes substituted by —N(R
2
)(R
3
) group.
In the formula (4), X
3
and X
4
, preferably, independently represents an oxygen atom or sulfur atom; both of X
3
and X
4
are more preferably oxygen atoms.
In the formula (4), Ar
3
′ and Ar
4
′, preferably, respectively represents an atomic group necessary for forming a substituted benzene, naphthalene or pyridine; both of Ar
3
′ and Ar
4
′ are more preferably benzenes substituted by —N(R
5
)(R
6
) group.
This invention further provides a guest-host mode liquid crystal cell comprising a liquid crystal layer containing said liquid crystal composition comprising at least one quinone compound represented by said formula (3) or (4).
DETAILED DESCRIPTION OF THE INVENTION
Description will now be given first for the quinone compounds expressed by formulae (1) to (4) bellow, which may occasionally be referred to as “compounds of the present invention”.
In the formulae (1) and (3), X
1
and X
2
independently represents an oxygen atom, sulfur atom or N—R
1
. R
1
represents a hydrogen atom, alkyl group, aryl group or heterocyclic group. In the formulae (2) and (4), X
3
and X
4
independently represents an oxygen atom, sulfur atom or N—R
4
. R
4
represents a hydrogen atom, alkyl group, aryl group or heterocyclic group.
The alkyl groups respectively represented by R
1
and R
4
include both of substituted alkyl groups and non-substituted alkyl groups, where those having cyclic structure are also included. The alkyl groups are preferably groups having 1 to 40 carbons, more preferably 1 to 12 carbons
Burns Doane , Swecker, Mathis LLP
Wu Shean C.
LandOfFree
Quinone compound, liquid crystal composition, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Quinone compound, liquid crystal composition, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quinone compound, liquid crystal composition, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3236210