Note: Descriptions are shown in the official language in which they were submitted.
Back~round of the Invention:
This invention relates to an electro-optical elem~nt
employing nematic liquid crystal materials of a positive
dielectric ani~otropy.
It is known that nematic liquid crystals (hereinafter
re~erred to as "N-liquid crystals") can be used for display, light
modulation and the like by utilizing their specific property
that optical characteristics are changed under application of
electric ~ields, magnetic fields, ultrasonic waves and the like.
Such elements compri~e, in general~ an N-liquid crystal filled
and supported between two substrates disposed to confront each
other with a distance smaller than about 50 ~, at least one of
which is transparent, and t~e change in the molecular arrangement
caused under application of electric fields, magnetic fields,
ultrasonic waves and the like is utilized for light modulation.
Compounds forming such N-liquid crystal are divided into
two types depending on the molecular structure and dielectric
properties, one type being characterized in that the molecular
axis and electric dipole are substantially vertical to each
-- 1 --
-r~
- .- . .... ~ . . , . . -.~ . : . .. - - .. . -
V4~
othfr (the liquid crystal of this type will herelnafter be
referred to as "Nn-liquid crystal"~ and the other being charactff3-
rized in that the molecular axis and electric dipole are sub-
stantially in parallel (the liquid crystal of thi~ type will
hereinafter be referred to as "Np-liquid crystaln). Accordingly,
the Nn-llquid cry~tal indicates an N-liquid crystal ha~ing a
negatlve dielectric ani~otropy, and the Np-liquid crystal indicates
an N-liQuid crystal hav~ng a positive dielectrio ani~otropy.
The conventional Np-liqu~d cry~tal electro-optic~l element~
comprisfs8 a palr of electrode plates di~posed to confront each
oth~r and a Np-liquid crystal layer interpo~ed between said plates.
The molecular aXf3S of the Np-liquid cry~tal are made in parallel
w~th the electrode faces and are arranged in the sub~tantially
~amff dIrect~on in a plane parallel to the electrode plate, If
~een from the directio~ vertical to the eleotrode plate, moflecular
axos are arranged in the ~tate continuously distortf~d from one
anothf~r betwef$n ad~acent faoea. Such anorientatlon of *he
mo~;ecular ax ~ i3 prepared by rubbing the electrode ~ace along
- onQ~dlrfectlf~n with fabrlcs, paper or the like and plllng the tWo
2~ rubb~d ~ trode~ in su~h a way that the rubbing directlons are
at right angle~ to eac~ other. The molecular axes near by the
e~t~ode~face are oriented along the rubbing direction while
the~moleoular axes in the ll~uld crystal layer are oriented in
the':tt~te contlnuou~y d~torted. When polar1zed llght pas~e~
2S th~F~ ~d~th~ qu~d~Grystal layerj the pola;rlzatl~n plane ~f the
}ight ls rot~ted depending on the degre~ of distortlon of the
~olocular;~xl8 dir~lon. Thls distortion o~ th~ molecular axis
; dir~c;tion:can be relaxed by ~ppllcation o~ an appropriate elQctrlc
field.~Accordingly, by~adJu~ting th- intensity o~ the e~ectric
,. ;- ..~
-- 2 --
)S~044
~ it ls made possible to ad~ust rotation of th~ polarization
plane of polarized light passlng through th~ element.
When the Np-liqu~d crystal element is interposed between
two polarizing plates, it changes from the llg~t-shielding state
to the light-transmitting state or from the light-transmitting
state to tne light-shielding state depending on the applied
voltage9 and thi3 light modulation ls ut$11zed for display.
Since the light modulation process utilizing the Np-llquid
crystal element provided between two polarizing plates disposed
in such a way that the osclllation planes Or light ~ross to each
other exh~bits a mechanism quite dlfferent from a Nn-liquid
cry~tal electro-optical element, a higher contrast ratio can be
obtained in use for display o~ a pattern. Further, the ~p-liquld
~lectro-optical element can be utllized for construction of a Boolean
algebra generator, a loglcal product gate, a "nor" gate and a more
complicated loglcal circuit. Ir an Np-llquid crystal electro-
; optical element capable of responding quickly i8 employed, it canbe utillzed for display of a three-d~mensional televi~ion or
~oving picture. Fhrther~ $n the case o~ the Np-llquid crystal
electro-optical element, since the waYelength region of rays of
transmiss$on ~arie~ depending on the electrlc ~oltage when it
changes wlthin the range of the threshold value to the saturation
~oltage,` it can be used ~or display of color~
- . In the convent~onal Np-l~qui~ crystal eléctro-optlcal
elemènts, the procèsc of rubbing the electrode face directly ln
one dlrection is emplGyed ~or ori~ntation of the liquid crystal
molecules a~ mentioned hereinbefore.. W~th this process, however,
.
lt 1~ impo3~ble to or~ent the liqu~d crystal molecules u~iformly
80 that the di5play in the.obtained element become3 unu~iform and ::
.~, , ,:
1 ~ ,
~ . ._ _. ,
W~93/0~30 2 0 ~ 2 0 8 ~ PCT/~Sg2/049~ ~
- Z2 -
'":
Thus, it is advantageous to provide a new phase
shifter with the T1 and T2 pair of thyristor valves 206
and 208. It is also advantageous retrofit and upgrade a
preexisting phase shifter for faster performance by adding
the T1 and T2 pair of valves 206 and 208 to each phase.
Alternatively, a preexisting mechanical reversing switch
could be replaced by the entire reversing switch assembly
203 if desired for a particular applicat:ion. Furthermore,
the switching netwoxk 250 may be employed in a variable
susceptance phase shifter 20, a variable source phase
shifter 120, or a conventional phase shifter, such as that
shown in Fig. 8A or Fig. 9A.
Fig. 6 illustrates another embodiment of a
three-phase fast-acting, thyristor-augmented, phase shift
control switching network 350. Several of the items
numbered in Fig. 6 are the same a~ described with respect
- to the Fig. 1 embodiment and have item numbers increased
by 300 over the item numbers for the like components in
Fig. 1. For example, the excited windings 334 are coupled
to the switching network 350 by the three-phase conductors
346-348, as opposed to the single phase representation of
Fig. 1, where these conductors are represented by
conductors labelled 46 and 48. Also, for convenience and
clarity, the regulating windings 344 and ~TC 352 for each
phase are shown schematically within the switching network
350 in Fig. 6. Furthermore, for simplicity, while each of
the phases designated A, B and C are shown, the
illustrated embodiment will be discussed with reference to
only the phase a leg, labelled 302, since it is apparent
~rom Fig. 6 that each of the phases are constructed and
operate identically. The phase A leg 302 of switching
network 350 may optionally include a thyristor-augmented
reversing switch (not shown) as described above with
reference to Fig. 5.
In Fig. 6, the load tap changer (LTC) of the
previously describad embodiments has been substituted with
a switched load tap changer (LTC) 309. The switched LTC
309 comprises a mechanical switch 310 (also designated as
~' ''.
, . , : 1 . .; , ~ , . . .. . . . .
`` 105~044
An object of this invention is ta provide a Np-liquid
crystal element with uniform orientation of the Np-liquid
crystal molecules on an electrode face.
A further object of this invention is to provide the
Np-liquid crystal element with prolonged life.
A still further object of this invention is to
provide the ~p-liquidcrystal element with reduced deviation of
electro-optical properties among products in case of mass-pro- -~
duction.
The foregoing objects can be attained with use of the -
element of which at least one electroae is coated on its interior ~-
.. ...
face with a thin layer of a certain organic high molecular
material or magnesium fluoride, the coated electrode face
being rubbed along one direction by known means.
Thus, in accordance with the present teachings, ~-
a liquid crystal electro-optical element is provided which
comprises a pair of electrode plates confronting each other
and a thin layer of nematic liquid crystal materiaI which has
a positive dielectric anisotropy positioned between the two
plates. At least one of the electrode plates is coated on
its interior face with a thin layer of at least one member
selected from the group consisting of urea resins, melamine
:..:
resins, phenolic resins, opoxy resins, acrylic resins, unsatur- ~-
ated pQlyester resins, alkyd resins, urethane resins, poly- ;~
vinyl acetate, polystyrene, cellulose resins and polybutadiene.
Particularly, in case the electrode is coated with
nitrocellulose, acetylcellulose, cellulose acetate ~utyrate,
cellulose acetate propionate or methylcellulose or mixture ~ -
thereof, the element with good orientation of the liquid ~;
crystal molecules and excellent electro-optical properties
can be o~tained, and furthermore, deviation of electro-optical
D )~ ; ~
` `\
~OSb~0,44
properties among products is remarkably decreased in case of
mass-production. :;:
Detailed Description of the Invention:
It was found that a Np-liquid crystal element of which
the electrode plate is coated on its interior face with organic
materials, particularly, a certain organic high molecular
material and then rubbed with fabrics or paper along one
direction is superior in orientation of the liquid crystal
molecules and the life of the element to a Np-liquid crystal :
element in which the rubbing is conducted but no coating is
applied.
Examples of the organic high molecular material which
may
. ~ '' .
:~ , ., ," , :
'. ~ :
: '
..
- 5a -
, -, , ... , ., , . - , , . . ;
1~5~
be u~ed include urea resins, melamine resin~, phenolic resin~,
~poxy resins, acryllc resinsJ unsaturated polye~ter resins,
alkyd reslns, urethane resins, silicone resins, polyvinyl acetate,
polystyrene, cellulose resin~ and polybutadiene~ The pr~polymer~,
oligomers, monomer~ or mixtures thereo~ may al80 be u~ed for the
coating material~.
The coating material is dissolved in suitable solvents,
applied on the el~ctrode plates according to the known proces8es,
for example, by ~pray coating, dip coating, bru~h coating,
electrostati¢ coating, electrodepo~ition, roller coating or du3t
coating,~and then, dried naturally or by heating. Resin films
~m~y~be al80 adhered to the electrode face under appli~ation o~
pr~sure and h~at. Further, the monomer mat~rial may be coa~0d
~,
on th~ lectrode plate by vacuum-discharg~ polymerization.
15 The ;overcoat may be formed with use of a ~ingl~ coating materi:al
or;1~- mixtllr~- snd also, may be o~ single layer or lam~nat~d Illm.-
. ., ~ . ; .
~thi~kno~ of the overcoat i8 not particularly critical, but
ln~Ga~ of tho thiCkn8SB too lar~o the re~ultlng element i8 ~8~0W~
1n~e8ponding~ Pr~rably, th~ thic~n~8s Or th~ ov~rcoab~is
~le-8~*han ~about 5 ~, more prererably le~s than l ~.
Q~the org ~ c high molecular ma~rials the phenollc r~
~ac~yl~e r-~in- ant oellulo~ resins are partl¢ul ~ly ~uit ~le:
~ ob~In ~ the elcmon$ with good orientation of t~e liquid
;~c ~ .~ole~ul~- and a prolonged li~e ~ demon~trated in the
~ ~ o~1ng Ex~pl~. Amon~he cellulos~re5in~ par~icularly,~
tho-~u~e~ nitrocellulos~, acetylc~llulo~e~ cellulo3e acet~t~
e~ llula~e acetate proplon~t~ and methyl~ellulo~e a~d ;~
~ix~ure~th~reof ~enders the re~ulting element~ excellent
~l~ctro~ptlc~l propertle~ a~ compared with the ~ase of the
-- 6 --
., ., ~ .~ , . . .. . .
1()'~iO44
other organic high molecular materials.
The term of "cellulose resln" i~ used hereinafter a~
including the five cellulo~e type~ ~pecified abo~e. The coating
of the cellulo~e resin on the electrode i8 ac¢ompli~hed by dis-
solving the cellulose re~in into a suitable solv~nt ~uch asn-butyl acetate, acetone, methyl acetate, methyl ethyl ketone,
methyl isobutyl ketone, butyl cellosolve and oarbitol to form a
solution having a cellulose resin concentration o~ 0.1 to 5X by
weight, pre~erably 0.5 to 2% by weight, and then coating the
~olut~on on the electrode according to a cu~tomary coating m~thod,
~or example, by dip coating, spray coating, brush coating, roller
coating or the like. The coating i~ naturally dried or i3 dri~d
by heatlng it at 40 to 80C. The abo~e-exemplified cellulos~
rë~in~oan bo u~d aingly or $n the for~ of a mixture o~ tWo or
~or~;~o~ them.
~: Th~ eledtrode coated wlth the coilulose re~in i8 then rubbed
~n~-o~e~dlrection ~veral time~ under ~pplication of a pressuro
~ofiat lea~t 1 g/c~2 wlth a brush, paper or cloth. Espec1ally
g~od~or~éntatl~on can be at~ain~d ln molecul~s of the liquld
2~ ~ ~ stal~when ~ bing i~ conaùct~d und~r application Or a pressure
to~00 g/cm~, and ln thl~ ca~e elements excell~nt ln the~
~ratlo can b- obtained.
~ .A~p~lr~of~the 80 ~re - treated el~ctrode plates are dlsposed
t~ nf~o~t 6ach other wlth a di~tance Xept constant by a spa~er
~5 ~ . ~ quld-¢ry~*al is in~e¢ted into this ~pace d~tano~ to ~orm
elem~nt,~
e~ sh~w~ data o~ the ~n1t1atlon voltsge and 8aturatlon
tQg ~ ur~d ~ith r-3pect to el~mRn~ havlng an ~l~ctrad-
c~-a:t~d:i~lth th~ c~llulo~ resln and element~ h~ing an ~leetrode
-- 7 --
~os~o~s
coated with an acrylic, melamlne, epoxy or phenol res~n.
Elements used for the mea~urement were prepared ~n th~ following
manner.
A resin was dissolved in a 8uitabls solvent to form a
solution ha~ing a resln concentration of 1,0%, and the solution
was coated on a tran8parent electrode mounted glass according to
the dip coating method. Drying of the overeoat was conducted at
100C. for 10 mlnutes in the case of the cellulose resin~ and ~n
the ca8e o~ the other resins drying was conducted und~r th~ ;
pres~ribed curlng tem~erature and t~m~ conditions. In each
coatlng the thicknes~ was ad~usted to about l~u, Then, thé
çoated electrode face wa~ rubbed with cotton cloth under appli-
~ation of a pres~ure o~ 10 g/cm2 in th~ ca~e of the c~llulos~
re~ln or 30 k~/cmZ ln th~ ca~e of the other re~lns. In ~ach
lS elem~nt, as th~ Np-liquid crystal material there was employed~an ~ :
~p~ u$d crystal aompositlon~aompr~slng 2T% by woight of p-~etho~
~den~-p~-n-butylanllin~, 27X by weight o~ p-ethoxybenzyli-
n-bu~lanlllno, 26% by we~ght of p-ethoxyben~ylldene~
~:p ~ heptylan~lino, 10~ by weight Or p-oyan~benzylideneani1iné
. ~ .w~l~h~ of p-~yanophenyl-pt-nqoctyloxyben20at~,:and th~
~betw~n tho ~l-ctrode ~a~s wa~ ad~ustod to 7 *~ .S:~
ë~p~:c~ o ~h ro31n~2 one lot ~100 sheet~ of el-monts
r-d~, ~and d~Y~atlons of the inltl~tlon volt~go and ..
n ~ol~ag- w re exam1n~d among the elements, In T~bl~
-~ ~ dégre- o~ deviatlon of the ~oltage i8 expres~d ~y the l~gth;:
th~ rr~w~ ~nd b~ the lni~l~tion voltage is meant an app~led -
~
, - .. ;.: ~ ~
at whlch iO~ llght transmis~lQn was obtained and by the
s~tqrat~ vol~a~e 1~ m~ant an appllod vol~age at wh~ch gO~ light
t~ lo~ ~a~ ob~aln~d.
- 8 -
Table 1
Voltage
( Vrm~ )
Initiation Voltage upper arrow and
Sa~ration Voltage lower arrow
Resins 2 4 6 8 10 12 14 16 18 20
. , ,, . -- .
N~trocellulose
(HIG40 manufactured
by Asahi Kasei)
Acetylcellulose I ,.-~
(LT_105 manufac~
tured by Daicel)
~,
Cellulose Acetate ~-~
Butyra~e (EAB-171-2
manufactured by ~ >
-.' Eastman Rodak)
~ , . . .
Cellulo~e Acetate
. Propionate (ASP ~_~
$ manufactured by
Eastman Kodak) ~
~, ,., , . - . ,. ._. .
Methylcellulo~e
~65SH-4000
~anufactured by
Shinotsu Xagaku~
Acrylic Resln
(RE-377 manufac-
*ured by
M~tsubi~hi:Rayon)
..~
~lamine Rcsin
(D~llcan ~E#500
- manu~actured by
Dainlppon Toryo)
, . _ , ___ ~_ , __ __ , _ , _ _ _ . _ A . _ A_ ~
Re~i n ~Ahl3R#
6~ n~actured
A~hi Kase~ ~ -
. .~,
Ph~c: ~osin
(~ck~l
manu~actured by ~ - >
De,ini~pon Ink)
~A 1~ _A~ _ , . _I ~ _~ . . - .
_ g _
~OS~i04~
As is apparent from Table 1, in the el~ment~ having an
electrode coated with the cellulo~e resin both the initiation
voltage and saturation voltage are much lower than in the Qlements
having an ~l~ctrode coated with an aorylic, melam$ne, epoxy or
phenol resin. In fihort, the former element i3 advantageous over
the latter elements in that the actuation voltage 1~ very low.
From Table 1, it i8 al80 apparent that in the oase o~ mass-
productlon, deviat~on~ of th~ initiation ~oltags and saturation
voltage are much 8maller among the ~ormer elementa than among
the latter element~.
When tho uniformlty in the electro-optical re8ponse wa8
ally ~xamlned wlth re~peet to each o~ the ~lem~nts ~h~w~ ~n
TaUe 1, it wa8 found that th~ el~ment having an electrode coated
w1th th~ c~llulo~ re~in ~xhlbit~d a more uni~orm el~tro-optical
re~pon~e throughout the entire element than the other elcm~nt~,
Furth~r, ln the elements ha~lng an ole~trode coat~d wlth the
~ellulo8~ re~ln shown ln ~a~le 1, ther~ wa~ ob8erved no subst~ntlal
d~f~renc~ o~ the actuation voltage in on~ element and lt wa~
found that ~ho dif~rence o~ the a¢~uation ~oltaga ln one ~l~ment
wa- 1~ or ~Q~er.
Tabl~ 2 illustrateJ data o~ the variation range of thC
~m~x1~u~ oontPa~t ~a~lo (perCQnt tran~mi8~10n und~r no voltag-/
;p-ro-n~ tran~mi3~10n under ~aturation volta~e) d~term~n~d wlth
ro*p~t to Rlemen:~ pr~pared by coatlng an el~ctrode with nitro- :
c-llulo~e and rubb~g the n$trocellulo4e ~oat under applicstion
o~ pre~ure Or 1 g/~m2 to 1 k~/cm2 and element8 prqpared by
ao~tln~ ~n el~troto With an acrylic, molamlne, epoxy or phenol
Pes;~ ~nd rubblng th~ co~t u~er appa~cati~n o~ presJure o~ 10
~m2 to 5Q kgJcm2. In e~eh of the element~ shown in Tabl~ 2,
-- 10 --
the coating thickness, the Np-liquid crystal material
composition and the distance between the electrode
faces were the same as those of the elements shown in
l'able 1.
Table 2
Maximum Contrast Ratio
Resin 10 20 30 40 50 60 70 80 90 100
Nitrocellulose
(HIG 40 manufactured
by Asahi Kasei)
Acrylic Resin
(RE-377 manufactured
by Mitsubishi Rayon
Melamine Resin
(Delicon DE#5
manufactured by ,
Dainippon Toryo)
Epoxy Resin (AER#664 , ::
manufactured by it ~ :
Asahi Kasei) l ;:~
Phenolic Resin
(Beckosol ~anufacture~
by Dainippon Ink)
I
As is apparent from Table 2, the elements having an
electrode coated with nitrocellulose have a much higher
maximum contrast ratio than the other elements and they
always have a maximum
~05~i~44
contrast ratio of at least 30 s 1. Further, it was fou~d t~at
wh~n the nitrocellulose coating is rubbed under appl~cation of
pres~ure of 5 to 100 g/~.m2, eæpecially good contrast ratios
ranging from 50 : 1 to 100 ; 1 can be obtained. Similar re~ult~
were obtained when acetylcellulose, cellulose acetate butyrate,
cellulose acetate propionate and methyl cellulose wer~ used
instead o~ the nitrocellulose.
The electro-optlcal characteristic~ o~ the element i8 hardly
in~luen~Qd by th~ moleeular welght (degree of polymeri~ation) or
degroo o~ ~ub~titutlon o~ the cellulo~e resln us~d f~r coatlng
the elQctrode. Mor~ speciiically, e~en when cellulo~e r~sins
dl~P~ring ln the moleeular weight tdegree of polymerizat~on) and
ths degr~ a~ substltutlon are employod ~or Goating eloctrode,
`thore~ ob~er~ed no ~ub~tantial dlffer~nce~ o~ the eleetro-
opt~cal ~haracterl~tic~ among the re~ultlng element~ Thl~~e~:tyr- will readily b~ understood from Table 3 ~llu~tratlng dat~
o the inltiation voltage an~ saturation volta~e mea~urod wlth
re,~p~ot.tc el~m~nt~ prepared by employing nltrocellulose and
: ~ellulo~- aa~tMt~ butyrate re~ins d~fferlng in th~ ~iscosiky (a
~` ` 2~ Yl~¢081ty ind~ca~os a hlgher molecular welght) and the
8u~atitutlon a~-an electrode coating material. In ~ach
o~ ement- ~hown ln Table 3, the rubbing pr~a~ure, the
hlckn~ th~ quld crystal materlal composltion and
d~ ~tan~e~b~t~ on th~ ~lectrode faces were ~he ~ame as tho~e of
2~ ~ e~ hown in Tabl~ 1~
~: ~ - , ,
~ ~ ,
- 12 -
:~OS~0~4
g~
., ~
tll bt ~ ~O O N ~ r~ 0 0 ~D O
:~ ~ ~ ~ ~ ~C) N ~I N rl O O
-
a~
s~l ~ J ~ 1~ N ~ ~C) N ~ ;1- N
;~ J ;t
r ,0
a
~J N~i r~l ~; 0~ 0~C-- ~ ~ 1~
,~; ~ ~ ~ ~ ~ ~ ~1
~Q ~ Il~ o o
,~ R
P ~ ~ 1 0 ~ ~ ~ ~ ~a~
'C
~ O ~1U~O
O
OO ~ ~
~ ~a
~ ~ O ~ OD O O ~U~ ~
11~~ 00 11 ~ ? rl
~e~-- ~ o o o ~ ~ o,1 ,~
~ `
3 :a ~ ~ ~ 0 ~ ~
2 bq ~ ,,9 ,~
h ~ 5 ,J
:, ~ ~ o
- ~ 3 ~ ~
g ~ V ~ ~ al 1~
'~C ~ ~
~ ~ ~ ~ ~ ~ o
~2 ~ ;~; ~ I g
.~ ~ U~
1 ~ 1 ~ ~ $ ~ ~ ~
' -
1~)5t~044
A~ is apparent from Table 3, in each of nitrocellulose and
cellulose acetate butyrate, there i8 brought about no substantial
difference of the initiation and saturation voltages, namely
the electro-optical characteristics, even when the molecular
weight and the degree of saturation are changed. Also in the
case of acetylcellulose, cellulose acetate propionate and
methylcellulose, it was found that the electro-optical characte-
ristics o~ the resulting elements were hardly influenced by the
molecular weight and the degree of substitution.
Further, in the case of the element of this invention, the
pressure to be applied at the rubblng treatment 1~ remarkably
decreased,~and therefore, the rubbing treatment can be gr~atly
fac1litated. Accordingly, in the caae of mas~ production, the
deviation o~ the electro-optical characteri~tic~ can be highly
reduced, and it is po~s~ble to prepare at low C08t8 in large
qua~tltle~ the liquid crystal elem~nts. ;
~ Aooording to further embodiment of thl~ inrontion, adhe~ion
of thë celluloae resi~n coat to th~ electrode fa¢e can be lmproved
by:~:pr ~ d~ng b~tween th~ cellulose resin and electrode layers
O a~ther~Dootting orgflnic high molecular sub~tanoe layer ha~ing
~o`od-~ ~ sion~to bothe~he cellulo~e resin A~d electrod~
~x ~ le~ Q~ ~u~h-thermosett$ng sub~tance~ ~nclude epoxy, phenolic
~ acrylie resins, and the other con~entional,
t ~ o~at~i~g orEanic hlgh ~olecular ~ubstance~ may be ai8.0
us~ The:1~nterpo~ed thermose~ting ~ubstanGe layer ~hould not
~- o~hic~ne8~ too large in ~iew oi formlng further the
e~ lo~ r~ln lay~r o~ said layer, and.proferably, the
~;thi~kne~ le.8,~ ~han about 1.0 ~, more preferably ~h~ range
. , .
of Oil ~Q Q.5 ~.
- 14 -
l(~SW44
According to this invention, it was further fou~d that
elements prepared by coating the electrode with magnesium fluoride
and rubbing the overcoat have the same effects as the case o~
the organic high molecular coating material~. Formation o~ the
overcoat of magnesium ~luoride may be effected according to the
conventlonal thin-film formation of the inorganic material,
for example by vacuum evaporation. The thickness of the overcoat
may be less than about lJu, pre~erably less than about 0.5 ~.
This invention i9 illustrated by the following non-
limitative example~.
-- 15 --
105~044
Example 1
A glass plate of 3 X 4 cm~ provided with conductive
layer of SnO2 ~ referred to a~ glass electrode in the
follo~ing Ex~mples up to Example 14 ~ wa~ dipped lnto a 3 .
weight % solution sf cyanoacrylate adhe~ }5p-10
~anufactured by TAORA Chdcal Co. Ltd ~ in acetorle~ Thu~
obtained o~ercoat was dried at room ten~peratue t and t~2en
baked and drled in ~ dryer at 120-C for 30 1ainutes. The coated
~l~ctrode wa~ rubbed along one direct:ion with ~abrics under
pre~r~ of lûg/¢m2 and a pair o~ the 80 pre-~xeated el~ctrode
plate~ was po~itioned ~o that the rabb~ ng dir~ctlons are a~
right ~glQs to ~ch other, ~he two pla~es be~ ~rgined by
an ~ngulatlng ~p~er of 4 ~ ln ~:hicJm~5~ f tbe aperture~
othex than ~ho Qp~nl~g for i~ tiag of zl ~iq~id cry~al
~terlal w~re ~led ~ith ~n ~dhe~i~re.
3 S ~ 2
The glass electrod~ ba~ dipped into a 1.0 ~e~gh~ % ~o3ut~on
e of ~h0~ol~c resin (~cko~ol~ thy~a Lcohol to ~ppl~ the re~on
~olut~n on the el~etrode fae:e. The o~er~:oat w~s dr~ad at room
te~p~r~tur, ~nd then b~ked ~d arled ln ~ er at 200-C for 10
~n~t 8. ~FAe coa~d e~e¢~roae ~a~ ~b~a aloag one directlon
~: ~lth fa~r~ ~d~r pr~s~ure o~ 3û l~g~. The sa~ coll as that
o~ E~le 1 ~fith t~ ~xc~ption of ~rQs~lnq ~e rubb~ng d~rec-
~o~ at ~ u~gle o~ 45~ was fon~od,
l~x~l~ 3
of ~ aone
~rho g~a~s ele¢~r~o wa~ dipped into ~ 200 ~ight % ~ol~ic~n
~ln ~ 45, li;h1n~t~u Kagak~ C~o.,Ltd J~an) ln hox~ ts~ appl~
solu~ic~ o~ ~ ~lel:trsde f~e. q!he o~ t wa~ dr~ea
~t ~o~ t~r~, ~d-~n b~l~od a~d drl~a in a dr~er ~t 210C
~or lû ~l~e~. ~e oo~ted ~ trode w~ bed along one
dlr~ctiQql ~th ~abrlc~ ~nder p~es~ur~ of 30 Kg/~2.
-- 16 --
10S~044
The 8ame cell as that of E~ampl~} 1 wa~ formed, the rubb~ng
directions }: eing at right angle~ to each other.
Example 4
Polyester f~lm oî 1)1 ~n th~ckne~ (Lum~rror, manufacturea
S ~y Toray Co. ,Ltd. ) wa~ po~itic~ned on the gla~ electroae and
adhered to the electrode ~ace by pressure of 15 Rg~cm2 at 200C
T~e treated electrode wag r~bbe~ along one direction with
- pressure/
~abrics ~nder o~ 30 ~/cm2. q!he same c:ell a~ that o~ Example
~ wa~ for~e~, the n~bing directions b~ing at right angles to
10 each other.
.- - . - . - . .:- .
3~a~nple 5
.
~.0 ~e~ght ~ of ure~ resin tUlo~df manufactured by M~tsui
To~tsll Co.,Ltd) were dis~ol~ed ~n an equl-weight ~i~tclre of
acetono ~d methanol (referre~ ~ereinafter to as mixed solvent~.
.'15 ThQ res~n ~olut~o2l was ap~lied on the glas~ electrode ~y
~oller ccat~ng and aried ~t room temperatur~ a~d t~e~ baked
.
~d dried in ~ dryer at 150-C for 20 ~utesO The coated
electroae gra5 rubbed along one d~rect~on under pre s~re of
. . . . . . . .
- 30Rg/c~. ThQ same cell as that of }~xample 1 was formed, the
rubbing directi~ns be~ng crossed at the angle of 45-C, .
~mple 6
T~e gla~ slectrode wa~ dipped lnto a 1.5 weight %
801utio~ of ~tyrene resi~ ~Stylit, Manufactured by Daido l~ogyo ~:
~ao.,~d~ ln th~ n~ed solve~t. ~e overcoat ~a~ dricd at room
2~ te~perature ana then, baked and ~Iried in ~ e~ at 180-~ ~or
10 ~ute~. ~he coa~ea elec:trod~ wa~ rubbed along one
~roction with f~brics under pre~su~e of ~g/C~12.
Tbe ~e cell a~ at of E~ample 1 was formed, th~ rabbing
d~rectlon~ be~ng at right i~ngles t~ ead other
30 E~C~mP1Q 7
. ~,.
A
44
A resin sol~tion wa~ apE~lied o~ the glas~ elec~rod~
by dipping it ~nto a 2.5 weight ~ ~olutlon of ~l~ethan~
resin ~ V-Chroma, manufactured by ~ai Nlppon Toryo Co. ,Lt~. ~
~n the ~ix~d ~ol~nt and dri~d ~t room t~perature and ~hen,
S balc~d and dried i~ a dryer at 150~C for 20 m~ntlte~.
The treat~d elec:trode wa~ r~bbed along one d~r~ction ~Ith
fabri~ der pr~#sure of 30Kg/~:m2. The ~ 8 th~t
of l~pl~ 1 wa~ for~ed, th~ rubbiAg dir~ctic~n~ being a~
right angles to ~ch o~er~
10 ~le 8
A 3~0 weight ~ solut~on of poly~mia2 (~ ~oera 11~,
m~u~ctu~ed by 8u~o D~ko Co., Ltd.) ~n t~Q ~xe~ ol~n~
w~ ~pl~a on ~:he gl~8 elec~ pray coat~
The 0~es~:0~t wa~ arled ~t roo~ e~r t-are ~ n Wc~d and
~:S ~ ed in a ar~ar at aoo-c ~!or 20 ~v~. q!ho ~ated ~lectrodo
~aJ rub~ lo~g o~ d~xection ~ abr~cs un~l~r pr~e
o~ 30 Rg~a~2. The ~ coll ~8 that of 13x~le 1 ~as forD~a,
t~e ~ iag dir-ot~o~ ~ing ~t ~ght ~Igl~18 *0 ~aah o~her,
.~ ~ 9
2~) A s~r s~lution w~8 applied on ~he ~la~ ~lectrode Sy~
dipping lt ~nto ~ 3.5 w~lght ~ solut~on o~ ~nyl acet:ate res~n
tri~yo 1~ ~uf~:u~d by Illchia Pa~nt Ço.,~ n t~tQ l~liX~
a~3rco~ w~ dr~a at roo~ ~r~t~ and
~h~a~t0r, ~akod ~d dr~a in a dryer at 200C f~r 10 D~nu1:e~.
25 q!h~ ~oa~d ~c~ wus n~b~ed along one aire~:tion ~ith
~iG~ r pros~ of 1 }~g~. 2he s~e ce}l ~ that of
E~ 1 was f~#d~ the 3~bing direc~ion~ b~ing at right
., ~ .
J tO ~a~h 0~.
~ea. 10
~ ~0 ~ 5Iht % ~ tio~ of ~la~e r2~ Delicon,
-- ~8 --
lOSt~044
Manufactured by Dai Nippon Toryo ~.K.) in ~he m$xed ~olu~1On
wa~ appl~ed on the gla83 electrode by spray coating.
The overcoat wa~ dried at room temperature ~nd th~reaft~r,
baked and dried ~n a dryer at 190C for 15 ~inutes. T~e coated
elect~ode wa~ rubbed along one direction with fabric~ ~na~r
pr~ur~ of 30 ~/C~2. The sa~ cell as that of ~xampl~ 1 wa~
for~ed~ the rubbin~ direations belng at right angles to ~ach
~ther.
~1.~ 11
1~ ~he glasg ~l~ctrode wa~ dipped ~t~ a 3 ~æ~ght % ~olu~
of n~trocelSulos~ ro~in ~IG 40~ ~anu~actur~d ~y A~hi ~a~i
Co.,~t~ n ~-butyl a~etate. Thus ob~ained o~r~uat wa~
dr~od ~t roo~ t~mp$rature ~D~ ths~, b~ked and drled in 2 dryer
at lOO-C f~r S ~AUt~. Th~ coat~d eleGt~od~ w~ rubbod along
onoe direetion ~1th fabric~ u~der pre~sur~ of 10 g~cm~. The
~ e~ll aJ that o~ Ex~ple 1 w~ ~or~ed, the r~bb~ng direc-
t~ eln~ ~t right ~n~ to each o~h~r.
The gla~s d ~ctrode w~s dlpped into a 3 ~eight ~ 801ut~0n
2Q of ~a-~n ~ opro~yl ~loohol. Th~ over~oat on th~ ~loct~
~8 ~rie~l *.t r00~ ~at~e a~a t~ea, ~ea ~na ~ ~a
~r a~ l~O~C ~o~ 10 inE~ oatd ~le~ro~ ~41~
~bl3~ al~lg ~ ~ire~tion w~ abr~ nder pres~ure of 1
~/~. ~ ~ c~ th~t of ~ fon~d, ~h~
25 ~r~b~:ng d~3tions l~ll~g ~t rlqht ~ngles to ~a~h oth~r.
h r ~ n ~ # a~l~e~ on th~ glass ¢lectx~e ~y
~pl~lag ;lt l~t~ a 3 ~a~h~ ~ ~olu~lon of a a~x~re of 9Q~
by ~o~g~t of 1.4 - ~dd3tl~n p4~ly~ P~ly~ 3o~t
30 ~a~actt~ d la~ ln~ ) ~a lo~ ~y w~ight o~ p~ lde ¢at~ly~t
_ ~,9 _
, . ~ . , ., - - . . - ., .
~t~ ~ 44
in methanol. 'rhe obtained overcoat was dried at room
temperature and then, baked in a dryer at 150 C for 20
minutes. The coated electrode was rubbed along one direc-
tion wlth fabrics under pressure of 30 Kg/cm . The same
cell as that of Example 1 was formed, the rubbing direc-
tions being at right angles to each other.
A Np-liquid crystal composition consisting of 80% by
weight of an equi-weight mixture of p-methoxybenzylidene-p'
-m-butylaniline and p-ethoxybenzylidene-p'-m-butylaniline
and 20% by weight of a compound represented by the formula,
H0- ~ CH = N _ ~ N2
was injected into each cell of Examples 1 to 13 and the
opening for injection was sealed with an adhesive. The
liquid crystal electro-optic element obtained from the
cell of Example 1 is referred to as Specimen 1 and the same
applies correspondingly to Specimens 2-13. A blank ele-
ment was formed by preparing the same cell as that of
Example 1 except use of a non-coated electrode, injecting
the above-mentioned Np-liquid crystal composition and
sealing the cell.
Table 4 shows the characteristics of a light modul-
ation apparatus where each element of gpecimens 1-13 and
thè blank element were positioned between two polarizing
plates.
-20-
10~ 4
a~ ~J ~ ~ ~ O ~ O~ ~ O
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U~ ~10 r~l r-l N ~I N CU
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q~ ~ ~ ~ o ~ o~ o o~ ~ o
h .,1
O O r~ O O rl O O ~I r1
:SH
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~H O U~
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o
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td
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h t~ ~
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w
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~q o t~ O . ~
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-
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l o ~
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C> ~ ~ 0 1~ ~D ~ r
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V PO.
~ ~t`
E~ ~~ ~8
lOStiO4~
*l I : Q~c~llation plane~ of light are at r~ ght angle~ to
each other.
~: O~dlla~ n pl~ne~ v~ light ~Ire ~n par~ l to
each oth~r.
hr~shold and sa uration ~ eg in case eleme~t~ wer~
v~ually o~er~ed.. ThQ actu~l ~t~rat~on ~oltagQ (~or
e:~pl~, ln c~u3 a p~rcent l~stht-~ra~ lon Gf 90%
attained ln the colour ch~nge o~ fr~ laclc to whl~
higher t~ he ob~ d ~al~e.
~3 Qn~ cycle ~clud~s ~ g ~l~nt~ ana at -20'C
for 14 hr~ d at 70~C for 10 hr~. w~ eh no flsld applled~
N~r~ of the l:yc~ ll the ~on~st rat~o ha~ ~eac~ed
th~ so~ r~lat~ve to t~ l~for~ test. Th
~ ~t l~ber~ of thQ ~ycle ~ l~r~e ~how~ ~n ~ro~ed
Jt~b~llty of o~Ientatlo~.
*~ . ) tlll S ~ ~!or 5û~2 ~ ontln~u~ appl~ed
~t SO-C a~d ~o ~:oatr~t ~ ~o r~a~ho~ a ~1~ of 1~8~
~ 50~ r~la~ at b~or~ applit~ lon of th~ flsld.
A 1~ t~ ~ d st~lllty of or~ tion.
~5 ~ 5 ~ o3~ 5~ ~z ~r~ contla~ ly ~pplled at 25-C ~r
50 bo~ M~Tpt t l~ ic~ rop~c tra~lt~on tq;~ra-
~ ~ ol! ~ii~itl ~ dt~on ~ he ln~tlal
appl1c U_ s~d ~t~ 1AP~ ~3f 500 ~w~ ! ~y ole~
~la~ ~ct~ 8 p~:e at 'ch ~terfaa~ b-
~uid cryst~ ~rlaL ~d ~l.ectrod ~r~ 1~o
}d ~a S~C d ~ 0ll ol~ ~ha lig~id
gly, el~nt~ e~h~lti~g u
_ ~ r~ p~d~ ~p~dl~ a~ th~ o~:e,
-- 23 --
'l'he liquid crystal composition used in the Examples
has a mesomorphic range of -15~ 61C. '
Current density per 1 cm2 through an element at the
initial applica-tion and after 500 hours.
The application conditions are the same as in *5.
If the electro-chemical reaction takes plase at the
interface between the liquid drystal and electrode
layers, the current density becomes large. Accordingly,
elements exhibiting a large increase in the current
density after 500 hours show that the electro-chemical
reaction proceeds rapidly and therefore, the life of
the element becomes short.
Example 14
In203 was coated by vacuum evaporation on a square
sheet of hard glass of a size of 5 cm x 5 cm so that the
surface resistivity of 500JQcm was attained, to thereby
form a transparent electrode plate having a percent
transmission of 89%. Then, a 1.0% by weight solution
of nitrocellulose (HIG-40 manufactured by Asahi Kasei) in
n-butyl acetate was brush-coated on the electrode face
and dried at 100 C. for 10 minutes. The thickness of the ~"
so formed nitrocellulose coat was about 1~ . Six pairs
of the so formed electrode plates having an electrode face
coated with nitrocellulose were prepared, and they were
rubbed three times along one direction under application
of pressures of lg/cm , 5 g/cm2,. 25 g/cm2, 125 g/cm2,
250 g/cm . and 1 Kg/cm , respectively. Then, 6 pairs of
the so rubbed electrode plates were formed into 6 liquid
crystal elements by employing as a Np-liquid crystal ~ -
material a composition comprising 27% by weight of p-meth- '
oxybenzylidene-p'-n-butylaniline, 27% by weight of
-24-
p-ethoxybenzylidene-p'-n--butylaniline, 26% by weight of
p-ethoxybenzyldene-p'-n-heptylaniline, 10% by weight of
p-cyanobenzylidene-aniline and 10% by weight of p-cyano-
phenyl-p'-octyloxybenzoate. In each element, the distance
between the electrode faces was adjusted to 7 + 1.5y .
Each element exhibited a completely uniform electro-opti-
cal response throughout the entire element. These ele-
ments has an initiation voltage of about 4.3 V and a
saturation voltage of about 6.5 V. Each of these elements
had a maximum contrast ratio of at least ~0 : 1.
Especially, the elements obtained by conducting the
rubbung under 5 g/cm and 25 g/cm2 had a maximum contrast
ratio of 80 : 1. .
Example 15
---- '' ' '~ ,'
In203 was coated by vacuum evaporation on a square -:
sheet of hard glass having a size of 5 cm x 5 cm so that
the surface resistivity of 1 KJ~- cm2 was attained, to
thereby form a transparent electrode having a percent trans- .
mission of 90%. Four pairs of the so formed electrode
plates were prepared. The electrode faces were coated ~:;
according to the dip coating method of employing a 1.0% ~:
by weight solition of acetylcellulose (LT-105, manufactured ;-
manufactured by Daicel~, cellulose acetate butyrate (EAB-171-2, ::.
by Lastman Kodak), cellulose acetate propionate (ASP, man- -
ufactured by Eastman Kodak) or methylcellulose (65-SH-4000, -
manufactured by Shinetsu Kagaku) in n-butyl acetate, and
the coat was dried at 100C. for 10 minutes. In each ~ ~
pair, the thickness of the coat was about 1~.~. Then, the ~ :
electrode faces were rubbed three times in one direction :-
under a pressure of 50 g/cm . Thus, 4 liquid crystal
elements were prepared by employing 4 pairs of the so
rubbed electrodes, differing in the electrode face-coating
material.
-25-
The same Np-liquid crystal composition as used in Example 1
was employed, and the distance between the electrode was the
same as in Example 1. Each of the so obtained elements exhibit-
ed a completely uniform electro optical response throughout
the entire element, The initiation voltage, saturation
voltage, and maximum contrast ratio of the so prepared elements
are shown in table 5.
Table 5
Resin Initiation Saturation Maximum
Voltage (V)Volta&e (V) Contrast Ratio
Acetylcellulose 5.2 12.0 50 ~
Cellulose acetate 4.4 10.6 60 1
butyrate ~ -
Cellulose acetate 5.0 9.6 45 : 1
propionate
Methylcellulose 4.6 8.6 65 : 1
Example 16
In2Q3 was coated by vacuum evaporation on a square sheet
of hard glass of a size of 5 cm x 5 cm so that the surface
resistivity of 1 K r~cm2 was attained~to thereby form a
transparent electrode. A 0.3 weight /~ solution of phenolic
resin (Beckosol, manufactured by Dainippon Ink Co., Ltd.) in
àcetone was applied on the electrode face by brush-coating
and then, dried and cured at 200C for 30 minutes. The
thickness of the overcoat was about 0.3~. Further, a 1.0
weight ~/O solution of nitrocellulose (HIG 40, manufactured
by Asahi Kasei Co.~ Ltd.) in n-butyl acetate was applied over
the phenolic resin cost by brush-coating and then, dried at
100C for 10 minutes. The phenolic resin and nitrocellulose
layers had a thickness of about 1.3~ in total.
The overcoat on the electrode was rubbed three times
along one direction under pressure of 10 g/cm2. Ten liquid
crystal elements were made from 20 sheets of the so treated
electrode.
-26-
..... . . .. . . . . .. .
`~,
The used Np-liquid crystal material and distance between
electrode faces of each cell were the same as in Example 14.
All of the ten elements exhibited a completely uniform
electro-optical responese throughout the entire element.
These elements had an initiation voltage of about 4.5 Vrms
and a saturation voltage of about 6.5 Vrms, there being
observed little difference from the case of Example 14.
Further, 10 pieces of elements of this example and 10
pieces of elements of Example 15 were subject to a -
temperature cycle test (One cycle : Allowing elements to
stand at -20C for 10 hours and at 70C for 14 hours).
In case of Example 14, 8 pieces of the 10 pieces brought
about peeling of the overcoat off the electrodeFface after
20 cycles and thus, blowholes generated in the element.
On the contrary, in case of this example~ there was observed ~-~
no generation of blowholes in all of the elements after 20 ~ ;
cycles. -
With use of a 0.3 weight % solution of urethane resin
(V-chroma, Dai Nippon Toryo) in methyl ethyl ketone or a
: .
0.3 weight % solution of a mixture of 90 weight % of epoxy
resin ( AER #664~ Asahi Kasei ) and 10 weight % of tri
~dimethylamino methyl ~ phenol - tri -2- ethylhexate as a
curing agent in butylcellosolve instead of the above-mentioned
0.1 weight % solution of phenolic resin in acetone~ the same
effectc as io this example were att~ined.
_27-
. .
