Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
104~it
The present invention relates to a liquid crystal
display device, and more particularly to an electro-optical
liquid crystal display device for modulating light beam from
a light source by making use of a thin layer of a composition
in the form of a nematic liquid crystal having a constant mole-
cular orientation.
The present invention thus provides a liquid crystal
to be used in an electro-optical liquid crystal display device,
which liquid crystal comprises a novel liquid crystal of nematic
structure at a room temperature.
The present invention will be more fully understood
from the following detailed description of the present invention
when taken in conjunction with the accompanying drawings, in which:
Figs. la and lb show a typical liquid crystal display
device structure in which Fig. la is an elevational view thereof
and Fig. lb is a section taken along the line lb-lb in Fig. la.
Referring to Figs. la and lb, there is shown a typical
structure of a liquid crystal display device which comprises a
first light transmitting substrate 1 with a first light trans-
mitting and electrically conductive films 4, 4', 4" coated on asurface of the first substrate, and a second substrate 2 with a
second light transmitting and electrically conductive film 5
coatea on a surface of the second substrate, the space between
the first and second substrates 1 and 2 being filled with nematic
liquid crystal substance 6 to complete an optical cell, and
incident light to the cell being controlable by an electric
field or a magnetic field.
The surfaces of the first and second substrates 1 and
2 and the first and second coating films 4, 4 , 4" and 6 may be
treated in such a manner that the liquid crystal molecules at the
interfaces are oriented in a preferential direction while main-
taining their longitudinal axis in parallel with the first and
-1- ~
the second substrates 1 and 2 and the first and second coating
films 4, 4', 4" and 6. Polarizers, not shown, may also be
positioned on both sides of the electro optical liquid crystal
display device, the direction of polarization being selected in
parallel with or transverse to each other.
In an optical cell of such a construction, it has been
well known in the art that the liquid crystal substance operates
to modulate light from a light source under the control of a
magnetic field or an electric field.
Many applications of the chemical compounds having a
liquid crystal property have also been known. The optical devices
disclosed in the prior art technologies, have made the use of
compositions having a nematic liquid crystal property which may
be applicable to the electro-optical liquid crystal display
devices operable at a temperature normally encountered in a
residential construction, i.e. in the neighborhood of 25C. The
provision of such compositions is highly desirable because it
can completely eliminate the need for maintaining the electro-
optical liquid crystal display device at a constant temperature.
According to the present invention it has been found
that a novel compound 4-normal-butylbenziridene-4'-cyanoaniline
having the following formula
CH3(CH2)3 ~ CH = N ~ CN (Compound A)
which has a crystal-mesomorphic transition temperature of 28.5C
and a mesomorphic-isotropic liquid transition temperature of
51.8C in the form of a liquid crystal exhibits a nematic stru~
cture at room temperature and is useful in a liquid crystal
displaying device.
In accordance with the present invention therefore
there is provided a liquid crystal display device including a
li~uid crystal exhibiting a nematic structure at room temperature
consisting o~
- 2 -
~04065~
CH3(CH2)3 ~ CH = N ~ CN.
It has been also found that a mixed liquid crystal
having a wide mesomorphic range could be easily produced by
adding the compound A to another compound as listed below.
CH3CH2 ~CH = N ~ CN (Compound 1)
CH3O ~ CH = N ~ CN (Compound 2)
CH3CH2 O ~ CH N ~ CN (Compound 3)
CH3(CH2)2 ~ C~ = N ~ CN (Compound 4)
10CH3(CH2)3 O ~ CH = N ~ CN (Compound 5)
; CH3(CH2)4 O ~ CH = N ~ CN (Compound 6)
CH3(CH2)5 O~CH = N ~ CN (Compound 7)
CH3(CH2)6 O ~ CH = N ~ CN (Compound 8)
CH3CH2 C O ~ CH = N ~ CN (Compound 9)
(CH2)2 C O ~ CH = N ~ CN (Compound 10)
CH3(cH2)4 C O ~ CH = N ~ CN (Compound 11)
20CH3(CH2)6 3 O ~ CH = N ~ CN (Compound 12)
CH3 ~ CH = N ~ (CH2)2CH3 (Compound 13)
CH3(CH2)3 O ~ CH = N ~ (CH2)3CH3 (Com~ound 14)
CH3 O ~ CH N ~ (CH2) 6CH3 (Compound 15)
CH (CH2)2 O ~ CH = N ~ (CH2)~CH3 (Compound 16)
The mixed liquid crystals having the nematic property
are particularly applicabla to the liquid crystal used in the
electro-optical liquid crystal display device which utilizes
3Qthe polarization. ~
In preparing the Compound A, 0.10 mole of paranormal- - -
butylbenzoaldehyde, CH3 (CH2)3 ~ CHO and p.l0 mole of para-
3 -
.
.
cyanoaniline, CN ~ NH2 were refluxed in a solvent of 500 ml of
benzene for foux hours in a 1000 ml round bottom flask provided
with a reflux condenser including a calcium chloride drying tube.
A Dean-Stark trap is used to collect the water which is azeo-
tropically removed. After refluxing, the solvent is removed
by evaporation under reduced pressure in a rotary evaporator.
The residue is collected and recrystallized from isopropyl
alcohol.
The recrystallization process is repeated until a
constant melting point is reached. Compounds 1 through 16 are
also prepared and purified in the same manner.
A small number of compounds having a nematic crystal
property exist which are in the form of simple substance and
exhibit liquid crystal state at a room temperature. The
temperature range within which the nematic property is substained
is relatively narrow for those compounds. Thus, it has been
investigated heretofore to use the mixed liquid crystal consisting
of more than one compound in order to make it possible for the
mixture to exhibit a liquid crystal state at or below a room
temperature and to provide a wider temperature range within which
the nematic property is sustained. Several examples thereof are
given in the following Table 1.
.
~ ~,,',
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~ ~ ~ ~ ;3 ~Q ~ ~ ~ : '
W
O O ~ ~ O ~ ~3 o ~ ~
~ ~ O
~3 ~ ~3 ~ ~3 (~ ,.
Z ~: ~ ~ ~ ~ ~ Z ~ ~ X'
~ ~ 11 ~ ~ , ~ ~ ~
O OQ Z Z O ~ ~ ~ ~ ~)
) 1--~ -~ ~ ~ ~Q ~ .
r~ o z Q ~ Q Q Q 10
~_ Q ~ ~_ m m m
o 11 ~ ~ ~ ~ In
x m ~Q r~ ~ ll 1I mQ ~
~ ~ Qm ~ m ~ ~ IJ
~ ~ o o ~
o ~m m ~
~ ~ ~ ~o p~
. ~1 I- :
~QC ~
1- ~ I- ~D
~( ~ O O O O
~a
~ ~ ~ ~ ~ ~ ~ ~:
~ ~ ~ ~ ~ ~ ~ ~ eq ~ . ~:
~D ~ ~ .~ :.
(D tD ~D ~ I'~ IJ- 1'- 1'-
IJ- I'- ~''- ~ Oq (Jq t1CI oCI ~ Oq
aq oq vq 5 ~ ~ ~5 ~ ~ ~
t ~ ~ ~ .-
-- .
., ~ ~ '
~ :'~ ~
IV l I_ I~ ~ ~ ' -
1- ~C) I~ P~
~-
O 1- ~ ~ (D I'~
1-
Q ~0 Q Q ~0~
~t ~`
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r~
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104~653
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o (~)o ~o ~:; @i ~Q O O
(~ Q ~ ::~
:~ Q=O ~ ~ ~C- :
Z Z 11 ~ ~ ~ ~ ~ ~ Q~
O Q O ~) ~ ~-
Z Z O=Q [~ ~, ~ Q=o~ ~
~ . ~ :.
I æ ~ ~;3 ~ O
X . ~ ,'~ '
:~
o~ o o ~ o o
I ~ ~
I- 1-
~, _ . . _ _ ~Q ~ H
a ~) ~ l F O ~ -:-
~0 ~0 o ID I'~ ~
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The present invention provides mixed liquid crystals
having wider temperature range for nematic maintainence and
exhibiting a nematic phase at room temperature obtained by mix-
ing the novel Compound A having the nematic property with another
compound of benziridene-4'-cyanoaniline in a suitable proportion.
The examples of the mixture are given in Table 2 below.
Table 2
_ _ _ _ _ _
Composition of Proportion in Temperature range
mixed liquid for nematic property
crystal % by weight sustenance
_ _ _ -- :
Compound A 75
Below OC-37.3C
Compound 1 25
_ :
Compound A 75
Below OC-56.0C
Compound 2 25 ~ ~
_. : .
Compound A 75 23.0 -67.2C
Compound 3 25
Compound A 80
25.0 - 48.9C ~
Compound 4 20 _ -
Compound A 50 13.2 - 75.8C
Compound 6 50
~. .., . - . .
Compound A 50
14.0 - 79.0C
Compound 7 50
Compound A 67
Below 0C-54.0C
Compound 8 33
_
.
. .
L;~, ~ 7
~ .. . . . . .. , . . - : .
104~6S3
Composition of Proportion in temperature range
mixed liquid for nematic property
crystal % by weight sustenance
Compound A 83
: 11.0-40.6C
CCompound 9 17
Compound A 75
25.0 - 42.2C
Compound 10 25
Compound A 50
6.0 - 66.2C
Compound 11 50
: Compound A 50
: 15.0 - 75.6C
Compound 12 50
Compound A 33.3
Compound 7 33.3 Below -25C-80.6C
Compound 12 33.3
Compound A 33.3
Compound 5 33.3 Below -25C-83.3C
Compound 6 33.3
Compound A 50
` Compound 5 25 Below -25C-76.1C
Compound 12 25
Compound A 33.3
Compound 5 33.3 18.0 - 86.6C
Compound 7 33.3
.. , ~
~ - 8 - :
.
, . . .
1~41~)653
Composition of Proportion in temperature range
mixed liquid for nematic property
crystal % by weight sustenance
Compound ~ 33.3
Compound 13 33.3 1~.0 - 57.2C
Compound 1~ 33.3 ;
Compound A 33.3
Compol~nd 15 33.3 20.0 - 59.3C
Compound 16 33.3
1 Following organic substances may be further
added to the Compound A in the form of single sub-
stance or the mixture of the Compound A with the
Compounds 1 - 16.
5 (1) Pigmentary additive for presenting a poly-
chromatic property~ such as methy] Red or
indophenol blue.
(2) Additive for improving durability~ such as
hydroquinone or 2~ 4~ 6-tri-tertiary-
butylphenol.
! These organic substances may be mixed as
required. As described hereinabove, the liquid crystal
display device according to the present invention
uses a novel liquid crystal having a broad temperature
~: 15 range for nematic property sustenance and exhibiting
the nematic property at a room temperature, as a liquid
crystal used for the electro-optical liquid crystal
display device for modulating light beam from a light
source. Accordingly~ the device of the present inven-
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1~4~653
1 tion also provides the same advantages and is
valuable in industrial applications.
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