NDC 541．6
Molecular Alignment of Ferroelectric Liquid Crystals in a Cell with Dipping Polyethylene Glycol Films
Sh6ichi SOTA＊
Homogenegus aligning methods for ferroelectric liquid crystal＄ are investigated． A glass（ITO）
surface is coated with polyethylene glycol for aligning treatments， The film on the glass surface is formed by a dipping method． The dipping aligning film is easy to．prepare the fabrication of the cell＄ as compared with the spinni．ng aliignment， oblique evaporation and so forth，
Aligning chqracteristics are eXamined （1 ｝ Phe light transmission through a．cell placed between 6rosts nic61s ・attached to a polarization microscope ， （II ） the capacitance and DC biag voltage （C−V）
rblation， atid ｛M） the light transmittance and DC bias voltage （T−V） relation． Here， the bias voltage is chapged ?窒盾香@一6 to． 十6 V． The electric f ield characteristics and the response time in electro−opticai swit，ching under the cross nicols are investigated by applying a square wave voltage to the cells，
Experimenta！ results showed that the cell with the aligning films gf 50 eC， ．3e minutes and 80 times rubbing had the good aligning characteristics． Hysteresis behavior and the bistable characterlstics of molecular alignment were observed in all cells． The cell with the aligning film of 100 eC， 60 minutes， 80 times rubbing indicated the good characteristics on the electric field response qnd the response time under the square wave voltage， ln any case， the cells with 80 Pimes rubbing considered to the good aHgning treatment．
1． lntroduction
Industrial 1・iquid crystal 一displays have been stQdied by dernand for f lat pahdl and low power consumption displays． Liquid−crystal display devices such as multiplexed TN and STN types，
active．一matr2x driven TN type and ferroelectric liqutd ctystal type ha．ve been widely used tor，
digital watch， personal computer， word
proces＄or， TV， and so forth． 一 As ferro−
electric liquid crystals with a spontaneous polarization exhibit memor．y effects and raPid re．sponse as compared with nematic liquid crys一一 tals．， they have been widely uttlized． for a variety Of electronic devices．eunis）
su rf aeeL S tabil izad fetrbele etric smectic liquid crystal（SSFL．C） cells exhibit a high一一 speed respons．e tirne in electrooptical switch−
ing and． memory eftect due to bistability・in molecular alignrnent．S The SSFLC ce11s have beei｝ studied for large scale fiat and TV dl． spiay paneis， since they do not require thin−film transistors for driving and address−
ing．i）
Stabllized molecular alignments fOr ferro一
＊ Department of Electrical Engineering ReceiVed August 31 ， 1993
electric liquid cryStal at roorn temperature，
tabricatibn process for thin thickne．s s． and addressing method must be developed fot a reliable display application of the SSFLC cell．i6rr23） Disp1ay characteristics of the SSFLC cells depend on molecular alignment stTongly， whtch is still required to be im−
proved．
Molecular alignments for ferroelectric liquid crystals have been studied by the rnethods of applied rnagnetic field．2 applied electric field．25） spacer edge，2S shearing，S）
ternPerature inclination，27） grating．2S・2g）
rqbbing oC polymer films，SO and oblique evaporation of SiO．．9i． Most of aligning methods are in complexitY cosiderably． They are suitab1e for laboratory experiments． but a simpler method without degradation in display characteristics is desired f．or practical pro−
duction．
Author reports here molecular alignment characteristics of the SSFLC cellS coated with polyethylene． glycol． The filrn ．is formed on the cell surface with the dipping method． Light transmittapce by the cell rotation， C 一 V， T
−V characterist±cs， elgctrooptical switching response characteristics to the electric field and the response time under the applicat．ion of
津山高専紀要
switching ，are investigated as a valuation of the atigning characteristics of the・cells．
2． Cell preparation and measurenents
2．ユ Cell preparation
The aligning agent （O．5 ．g of the dilution rate） used in this study is ． polyethy1ene glyc。1．isゆPlied f．r・皿HAYAsHI」y町akuk・ugy。u．
C6．）． The aligning ・film with polyethylene glycol was ， deposited 6n the ITO（・ln 一 Sn oxide）一coatbd glass substrates by the dipping 皿eth。d・ln thg dipPi叩methgd the subst「．ates were dipped into the dlpping agent for a coating film and．drawn with ho．lding the cdll edge at ．the．sPeed of abou．t 2d cm／min．
The aligning film with polyethylene glycol was baked at 50 6r lee ℃ fgr 30 qr 60 m．inutqs after the dipping coat．
2．2 Cell fabrication
ITO №撃≠唐刀@substrates with the aligning rilms were rubbed along one direction by absorbent
．Table r Fabricated Cells fo； experiments．
C…ヨLL BAKING BAKING RUBBING
NU凹「 TEMPRA． TIME TIMES
BER （℃） （M）
i 5 0 3．0 3 0
2 50 R 0 50
P
3 5 0 3 0 8 0
4 50 6 0 30
5 5 0 6 0 5 0
6 5 0 60 80
7 1 0 0 3 0 30
8 1 0．0 3 0 50
9．． 1 0 0 3 0 8 0
．1 0 1 0 0 60 3 0
1 1 1 00 6 0 5 0
1 2 1． O 0 6 0 8 0
cotton ln alignment・
films were in Table I
order to ?獅?≠獅モ?@a homogepeous The rubbing times of・ the．a11gning among 3e． 50 or 80 t imes as shown
．
第32号 （1993）
Ferroelectric liquid crystal was sandwiched between two conductirig ．ITO glass plates with a parallel configuration pf rubbing direction．
The cell size is about 1 （1×1） cm2 and the thigkneSs is about 2 pt．m held by the m±cro−r sphere （ESTAPOR−LIOO， suppXied．，from MORITEX
Co．） aS a spacer．
Figure 1 illustrates the top and cros s sectional view of schernatic represehtation of a sandwich type terroelectr 奄メ@liguid crystal cell．
Material of ferroe1ectric llquid crystal used in experiraents is ZLI−3654 ｛suppl ied from MERCK JAPAN Co．）． Table 1 indicates the
＼
）DA MICRO− FERROEI、ECTRIC In203 ALIASS SPHERE LIΩUID CRYSTAL COATING FI
F1LM
Fig． 1 Top and cross Seetional vidw of schematic representation of a sand−
wich ．type liquid ．crysta．1 9ell．
sample cells used in this experiment in cornbi−
nation of ・baking times， rubPing times and baking temperatures． Properties ot ferroelec一 tric li．quid @crystal are given belode．e2）
1． Transition teMPeratur9 （℃ ｝：
一3e 62 76 86
C一一一一一Smc幽一一一噌一SmA一一一一帥N噸一一一．一一1
2． Spontaneous polarization：
一29。O nC／cm2（20℃）
3． Tilt angle： 25．0 ［ n （20・℃）
Molecular Alignment of Ferroelectric Liquid Crystals in a Cell with Dipping Polyethylene Glycol Fil孤s 曽田
4． Herical pitch：
一3 ［pt m］ （20 ℃） in Sm ． phase L60 ［pt ml （sO ℃） in N phase
2．3 Measurements
The SSFLC cells were pl．aced on cross nicols attached to the polarization microscope． and the light transmittance unqer the・application
：二、s鑑搬。諸翻sd。零豊駅ed by the
Electrostatic capacitance 一一 DC・bias voltage
（c−v｝ and light transmittance 一一一 Dc bias voltage （T−V） characteristics of the SSFLC cells wer ?@measured under thb application of scanning DC bias vbltage coming and going from
−6 to 十6 V．
The electric iield characteristics and the response time against the applied square wave−
forrn （100 Hz） were measured by observing the watieform on a memory Ht−corder， i． e．， by observing the light transmittance in electro−
optical switching with the photornultipiier
tube ?撃獅п@a fibdr glass． Figure 2 shows the block diagram of the measurement system．
Oscillo−
@scope Light
rource
MicτO−
唐モ盾垂?
icrOSS−
獅奄モ盾P）
iCe11）
Photo−
高浮撃狽堰￨
oIier P ．「噛 ，， ， rr ●r
@ VOlt
@Meter
（1）Light Trqnsmittance by Cell Rotation
（3）T−V Characteristics
（4ｳh§潔濫。t高き馨e and叫ect「 c F eld
Fig． 2 Block． diagrarn of the rneasurernent sysYem
3． Results and discussion
3．1 Light transmittance by the cell rotation Figure 1 shows the results of the light transmittance characteristics by the cell ro−
tation changed ￡rom O to 180 degrees on the ceUs at 100 ℃． 30 minutes baking． The each cell was observed the symmetry curve to border an angle oi 90 degrees． The each cell had the sirnilar character istics havigg the contrast ratio o± diiterent kinds． The cell with 80 times rubbing indicated the good aligning characteristics compared with other cells．
100℃，30MINU丁ES BAKING Z 30 TIMES RUBBING A 50 TIMES RUBBING
Function fenerator
Micro−
唐モ盾垂?
iCell）
Photo−
lulti−
olier
Melno ry
gi−corder GP−IB A．C
uolt擁．
Light
rource Osci116−@scope PC−9800iDA）
Capacitance
Tester
Cell
PC．9800
（DA） RS−232C
G？一1B
DC Bias Generator
x−y
Protter
（．ｽ ．く︶国OZくトト一ΣのZく匡ト
（2）C7V Characteristics
DC ・Bias
・Gerierator
Micro−
scope
（Ce11）
432
1
0
Photo一一
multi−
plier
GP−IB PC−9800
（DA）
Meinory Hi−corder
︒r△﹀．ノ
Light
Source Oscillo− scope
，X 80 TIMES RUBB］NG
。／・・ロ ブ㌔＼
碁》、
O 20 40 60 80 100 120 140 160 180 ANGLE OF CELL ROTATION e（DEG．）
F±gure 3． Relat・ions between the l ight trans一 rnittance （T） and rotation angle of the
cells．（ e ｝．
3．2 C−V characteristics
Figures 4 ．v 7 show the C−V characteris一
津山高専紀要 第32号 ・（1993）
ties wi th changing the DC bias vo1tage coming and going from 一6 to 十6 V． The values of the ordinate in these figur ?刀@（figures 4 tv 7）
in−dicate the． variation in the electrostatic capacitance． Here， the capacitance at 一 6 V treat the standard values of the capacitance．
The arrow ．marks in figures 4 一v 7 indicate the
changing direction of the bias voltage in measurernents and the doted lines in ．figure 4
indicate．the returned characteristics， i． e．，
the 唐奄р?@of decreasing bias voltage from 十6 to 一6 V． Figures 5 N 7 shovti one side characteristics， i． e．． the side of increasing bias voltage from 一6 to 十6 V． Hysteresis be一 havior and the bistable characteristi・cs of rno一 1ecular alignment were observed in all cells．
50 C， 50 MINUTES BAKING 1．30丁iMES RUBBING 2． 50 TIMES RUBBING 3． 80 TIMES RUBBING
︵﹂⊂︶．山OZくト︻Oく氏くO
3
2
1
o
︑︑ 一1︑一︑ ︑︑︑︑ρ黛
1一 ノノ 一！！／3Z
！
／／っ ．ノ 誹︒髪
グ
N3Xx
N
一N
−NN N ＞X NJ 2EEミSミ 一
︵L⊂︶ 田OZくヒOく旧くO． 3
2
1
﹂な∪○︻
50 C， 6Q M［NUTES BAKING 1． 50 TIMES RUBBING 2． 50 TIMES RUBBiNG 3． sO TiMES RUBBING
一6
Zオ
一一S
DC
．；一．黷窒P
−2 0 2 4 BjAS VOL丁AGE（V）
6
Figure 5． Characteristics of electrostatic capacitance veTsus DC bias vbltage． The aligning agent is baked on 60 minutes at 50
℃・
rubbing showed the mediurn aligning character−
istics compared with the cellS of 3e and 80
100 C， 30 MINUTES BAKING 1， 30 TIMES RUBBING 2． 50 TIMES RUBBING 3． 80 TIMES RUBBING
一4 一2 O 2 4
DC BIAS VOLTAGE （V）
6
Figure 4． Characteristics of electrostatic capacitance versus DC bias voltage．
The arrows indicate the direction of bias voltage change． The aligning agent is baked on 30 minutes at 50 ℃．
The each cell showed the bistability charac−
teristics of molecular alignment from 一1 V to
＋1 V． The cells with 80 times rubbing showed the good bistable characteristics under all eircumstances ・on the baking time・ and the baking ternperatur e l The cel； with 50 times
3
G E
w 2
2
匡
き 2 i．
9 6nt E＝＝L一一一一L 一一LH一）＝一4．一2 0 2 4 6
DC BIAS VOLTAGE（V）
Figure 6． Characteristics of electrostatic capacitance versus DC bias voltage． The aligning agent is baked on 30 minutes at 100
℃・
Molecular Alignment of Ferroelectric Liquid Crystals in a Cell with Dipping Polyethylene Glycol Films 曽 田
times rubbing． The cell with 30 times rubbing had the worst aligning characteristics compar−
ed with other cells．
Comparing the baking time and the baking temperature on the same rubbing times． align−
ing characteristics of each cell had not much different variation． The cells with 10e ℃， 60 ntnutes baking and 80 times rubbing showed the comparatively good characteristics among the all cells．
︵﹂⊂︶国OZくト一〇く匹くO
4
3
2
100 C， 60 MINUTES BAKING 1． 30 TIMES RUBBING 2． 50 T［MES RUBB（NG 3． 80 TIMES RUBBING
（．ｽ．く︶田OZくトヒΣのZく匡ト 5
4
3
2
1
o
50 C， 30 MINUTES BAKING ロ 30TIMES RUBBING A 50 TIMES RUBB］NG
× 80 TIMES RUBBING
ノ ロ ノ し暫！−x−−−−︐△一 ∬ ア 窟．詞吝△μ髪
百紅
@ @輩
@
@鷺
！！益コニ炎一 一『x｝ ｝一x ︵
郎君コ
旧
／11i・︐
ノx
1
﹂ハQO一
一4 一一2 O 2 4
DC BIAS VOLTAGE（V）
Figure 7． Characteristics of capacltance versus DC bias aligning agent is bakeG on 60
℃・
3．3 T−V characteristics
Figures 8 ・一v 11 shopug the T 一
tics by changing the DC bias and going from 一6 to 十6 V．
fig口res 4 ん． 7 indicate the decreqsing of the bias vo1tage
6
electrostatic voltage． The minutes at leO
and the downward arrow rparksin figures indicate the returned characteristics，
the side of decreasing ．bias voltage to 一6 V． Hysteresis behavior stable characteristics of molecular were observed in all cells．
V characteris−
voltage ごO皿ing The arrows in increasing and in measurements
8〜 1ユ i． e．．
from 十6 and the bi−
alignment
一6 一4 一2 O 2 4 6
DC BIAS VOLTAGE （V）
Figure 8． Characteristics of DC btas voltage versus the light transmittance． The aligning agent is baked on 3e minutes at 50 ℃．
The eaeh cell showed the inversed charae−
teriSties of moユecuユar aligηment frOm一ユVtO
＋1 V． ln case of 50 ℃ baking temperature and
∩⊃ ．く︶ 山OZくトト﹇ΣのZく匡ト 5
4
3
2
1
o
50 C， 60 MINUTES BAKING 口 30T［MES RUBBING A 50 TIMES RUBBiNG
× 80 TIMES RUBBING
ご ｝ 1
1
11
一＿△＿一一△＿．身
一．＝＿要＿．＿．＿覧＝二要4》・
×，．二炎ヲ管＝＝ft ＝＝「＝会
A一 k ．・
蕩ロプ ロロ
1ロ
ゾ
Figure versus agent
一6 一4 一2 O 2 4 6
DC BIAS VOLTAGE （V）
9． Charactertstics of DC bias voltage the light transmittance． The aligning
is baked on 60 minutes at 50 ℃．
津山高専紀要第32号 （1993）
30． minutes baking， th．e cell of 50 tirnes rubbing had @the good ali・gning characterist±cs．
The cell of 80 times rubbing had the high values of contrast ratio．工n case of． T0℃，60
minutes baking， Each cell bad the almost same characteristics on hysiteresis behavior． ln case of 100 ℃， 30 minutes baking， the cell with 3e times rubbing had the good bistability and the cell with 50 times rubbing had the low contrast ratio． ln case of 100 ℃， 60 rninutes baking， the ce11 wtth 50 times rubbing had the gbod aligning characteristics．
As a general rule， baking te．mperature and baking time indicated the little affectioh on the molecular alignmen 煤D
（。ｽ．く︶山OZく↑ト一ΣのZく匡ト 5
4
3
2
1
o
100℃，30MINU丁ES BAKING M 50 TIMES RUBBING
A 50 TIMES RUBBING
× 80 TIMES RUBBING
ア ココノ ロ −ムム〆㎡ノロロψ×
ﾚ〆！ 口△X 二
@
一一
口△．× 二 一一 ＝
，rпi一．一．一×n一一 一x
口 ロ ロ
（．ｽ．く︶山OZくトヒΣのZくぼト
7円
ユ．r
4
3
2
100 C， 60 MINUTES BAKING
口． R0TIMES RU日BING A 50 TIMES RUBBING x80丁］MES RUBB【NG
ノ
4
。〉呂鯨
二7＝＝負三ニニ＝金轟ノざ
PA1
乱丁
Ilt ！
！t
f
1 ／ l x
△X口一一一﹁
．＝△Xロ﹂一；
一丁△炎ロ客町ψーード︒召スn−⁝ーメノ
ft＝会二二＝＝，△一一一一△
Figure
versus agent
3．4 Electric field characteristics
The memory Hi 一corder graphic examples of a electro−optical switching resiponse are shown in figures 12 and 13． The applied square waveform （lower side） and the cgrresponding electro−optic response．waveform （upper side）
are．shown in figure 12 where the field is
varied fro皿 0．75 to 7．5 Vノ轟．m．
6 ・一4 一2 ． 0 2 4． 6
DC BIAS VOLTAGE （V）
10． Characteristics oi DC bias vo1tage the light tran8皿ittance． The aligning
is baked on 30 minutes at leO ℃．
0
6 一4 一2 O 2 ．4 6 DC BIAS VOLTAGE（V）
Figure 11． Characteristics of DC bias voltage versus the l ight transmittanee． The aligning agent is baked on 60 minutes at 10e ℃．
These wave forlns are also shown in figure 13 where the electric field is varied from O．75
H ： 2m si／ div．
v：
upper 20V／div lower 10V／div Applied Voltage
O．75 V
H：2mS／div．
v：
upper 20V／diy lower 10V／div．・
Applied Voltage
1．5 V
」
一
H： 2ms／ div
v：
upper 20V／div lower 10V／div Applied Voltage
3 V
H：2ms／div
v：
up 吹f?秩@20V／div lower・ 10V／div
Appiied Voltage
s V
Molecular Alignment of Ferroelectric Liquid Crystals in a Cell with Dipping Polyethylene Glycol Films 曽 田
1
一
．一
『
H：2ms／ div
v：
upper 2QV／div lower 10V／div Applied Voltage・
7．5 V
Ftgure 12．
electrooptic of the indicates
皿S／div）
response．
show the corresponding form， respectively．
H：2ms／div
v；
upper 20V／div lower 500mV／div
（Driving Current）
Applied Voltage
7．5 V
sample of oscilographs of the response under the apPユication squarewave voltage． Each figure the oscilogram （sweep time of 2
0f electrooptical switching
Lower and upper side waveforms applied square waveform and the electrOoptic response wave一
to le V／it m and the horizontal scale in figure 13 is magnified to 10 tirnes from・ O．5 ms／div to 50 pt sfa iv to read the electric field and the response ．time characteristics from these wave￡orvas of the oscUloscope screen and the rnemory Hi−cOrder．
H：200pt s／ div
v：
upper 20V／div lower 2 V／div Applied Vpltage
O．75 V
H：200＃ g／ div
v：
upper @20V／div lbQer 5 V／div Applied Voltage
3 V
一
H：2001t s／div
v：
upper 20V／div lower 2 V／div Appiied．Voltage
1．5 V
一
「
H：200pt s／ div
v：
upper 20V／div lower 10V／div
．Applied Voitage
7，5 V
H：200p s／div
v：
u 垂垂?秩@20V／div
lower 10V／div Applied Voltage
10 V
H：200st
v：
upper lower
s／div
20V／div ・ 5 V／div
Applied Voltage
5 V
Figure 13． Exarnple of oscilograms of the electrooptic response under the application of the sguarewave voltage． Each figure indicates electrooptical switching response by the oscilograph magnified the horizontal sweep time from 2 mS／div to ・2eO lt S／div compared with figure 12． Lower and upper stde waveforms show the applied square wave−
form and the corresponding eleettooptie re−
sponse waveform， respecttvely．
Figures 14 一v 17 show the electric tield characteristics on the electrooptical switch−
ing response． As these data i．n figures 14 一v 17 show the var±ous values of llght transmit−
tance through the cells． the figures here are shown for qonvenience to evaluate the data of
（．ｽぐ︶ωOZくトヒΣのZく匡↑
5 4 3 2 1
o
sO ，C， 50 MINUTES BAKING ロ 30丁IMES RUBBING A 50 TIMES RUBBING
× 80 TIMES RUBBING
7
口
益
メロ／／．．．．／ゾプ
口
O O．75 1．5 3
ELECTRIC FIELD （V／pm）
6
騰嶽灘構撫
津山高専紀要第32号 （1993）
other cells． Here， data of the cell （12） is taken as the standatd， since the eell shows the highest value of the light transmittance at the electric field of 5 Vノμm．
（．ｽ．く︶山OZくトヒΣのZく匡↑ 5 4 3 2 1 o
so ・C， 60 MINUTES BAKING 口 30TIMES RUBBING
−A 5e TIMES RUBBING
× 80 TIMES RUBBING
話＝＝；二＝r7△
・／（
プ
ロ．
A
ノ
（．ｽ．く︶田OZ＜トヒΣqりZく匡ト 5 4 3 2 1
0
100 C， 30 MINUTES BAKING O 50 TIMES RUBBING A 50 TIMES RUBB［NG
× 80 T［MES RUBB［NG
口
A／／｛
4二く口
己 口
O O．75 1．5 3 6 ELECTRIC F［ELD （V／pm）
Figure・15．・ Electric field characteristics ．on the electrooptical switching under ．the applicat ion of the squa rewave vol tage．
The alignlng agent is baked on 60 minutes at
50 ℃．
Zn case of 5Q c baking temperature and 30 rninutes baking， the cdll with 80 times rubbing had the good electric field characteristics and the．cells ・with 30 and 50 times rubbtng indicated the characteristics of the same degrees． ln c，ase 盾?@50 ℃ and 60 minutes，
baking， the cel．1 with 50 times ・rubbi ng had the
bad characteristics compared with the pther cells． The cell with 30 and 80 times rubbing showed the equal characteristics from the electric field of 1．5 V／ rn up． ln． case of 100 ℃ and 30 minute rubbing， the cell．s with se and 80 times rubbing had the good chardc−
teristics of the same degrees． The cell with 30 times rubbing had a little baa chracteris−
tic compared with the other ce11s D ln case of 100 c and 60 高奄獅浮狽?刀@rubbing． the each cell had the scattering characteristics． The cell with 80 times rubbing had thO good chatacter一
O O．751：5 3 U ELECTRIC FIELD 〈V／pm）
Figure 16． Electric tield characteristics on the electrooptical switching under the application of the sguarewave voltage．
The alignin g agent is baked on 30 minutes at 100 ℃．
100 C． 60 MINUTES BAKiNG ロ50TIMES RUBBING A 50 TIMES RUBBING × 80 TIMES RUBB［NG
（，ｽ︐く︶田OZく﹂﹁ヒΣのZく匡ト 5 4 3 2 1
o
x
ノム
ロ
Z／．
A／m
口
盗7r一一一一口
O O．75 1，5 ．3 ． ． 6 ELECTRIC FIELD （V／gem）
・・增F611邑。鵠錨、f egS、認鵬cte言器cs t器 霊ε1毒躍届。。tt皇：、幽幽端e血・継9：モ
100 ℃．
istics in this experiment．
Molecular Aligntnent of Ferroelectric Liquid Crystals ip a Cell with Dipping Polyethylene Glycol Films 曽 田
As a・general rule， the cell with 80 ttmes rubbing had the comparative well eharacteris−
tics on the electric field responSe．
3．5 Response time in electrooptical switching Figures・．18 A． 21 show the response tirnes
｛rise， delay and total times） in electro・一
〇ptical switching． We investigated the delay time， the rtse time and the total time． i．e．，
the Su皿 of the delay time and the rise ．ti皿e
・upder the application of square waveforrn to each ce11。 The symbols 口， △ and x stand for the delay time． the r1se time and the．
total time characteristics in all figures D reSpectively． The delay time indicates the difterence between the onset of the applied voltage and the corresponding electrooptic response．
As can be seen in figures 18 ．・一 21． the delay time was 1O tv seO pt S at the electric
︵の∈︶国≧↑田のZO匪の国恥 3
2
1
o
so ．C， 30 MINUTES BAKING ロ DELAY TIME
A RISE TIME．
．×．丁OTAL（R＋D）TIME 30 TiMES RUBBING
一一一T0 TIMES RUBBING
一・一W0 TIMES RUBBING
︑鄭飛︑
、、
X
××X斌ロ．＼掛 日
X溢ムロロロ＼§
＼濾▽︑ ＝﹁
一．こ
＝
口口口．
二
・ 7
．匹田．
祠ノ出
O ．1．5・ 3． 5 7．5 10
．ELECTRI．．C．F旧し．D．（V／pm）
18． Electric ・field dePendence 6f the tSme by i the application bf・the voltage． The aligning agent is 30皿imtes at 50℃．
0．75to 3 vノμm、 100〜 300 μsat field from 3 to 5 Vノμm， and ユ00 at the field from 7．5 to 10 V／urn．
rule， the delay time in e1ectro一
︵のE︶ω≧↑田のZO吐Qり田匡
4
3
2
1
o
so 一・C， 60 MINUTES ・ BAKING ロ DELAY T「ME
A RISE TIME
＞くTQ丁AL（R＋D） TIME 30 TIMES RUBBING 一一一50 TIMES RUBBiNG 一一一80 TIMES RUBBING
盈 ftx．
X x，
N X，
xい．
N， X． 5 x． xx・×
4 XxA x．1Xx．
夷＼ こ＼＼こ s・ここ㌦＼
毒≦垂
r ロ 一 茶香[一・一呂・＝＝＝＝呂．ここ乱＝日
o
Figure 19．
response baked on
squarewave
Figu re
︵のε︶ 山Σ一ト 田QりZO﹂しり山匡 3
respbnse squarewave baked on
2
field from the electric N300 S
As a genera］
1
o
1，5 3 5 715 10
ELECTRIC FIELD （V／pam）
Electric field dependence of time by the application of voltage． The aligning agent 60 minute at 50 ℃．
100 c， so MINuTEs BAKING M DELAY TIME
A RISE TIME
× TOTAL（R＋D） TIME 50 TIMES RUBBING 一一一50 TIMES RUBBING 一・一80 TIMEs RUBBING
x
xXx
外＼
thethe is
o
Figure 20．
response baked on
squarewave
1．5 3 5 7，5 10
ELECTRIC ・ FIELD （V／pm）
Electric． field dependence of time by・ the aPplication of voltage． The aligning agent 30 minutes at 100 ℃．
the the
is
津山高専紀要第32号
optical switching indicated a rapid response time when the applied electric field was
either low ．（O．75 Av 3 V／ m） value or hSgh
（7．5 N 10 V／pt m ） value， and． a slow．res．ponse
time when the electric field was intermediate value（3 〜 5 Vノμm）． Significant difference in the delay time．among cells was not recognizi ed at the electric field frpm 7．5 to 10 V／pt m．
The．rise tirne was 1 A 2 mS at the electrie field of O．75 VIIz m and O．5 tv ．1 mS at ．the electric field of 10 Vノμm． The rise time was improvea with increasing the eleetric field．
The rise time had the slow response time at the applied electric field of 1．5． V／ m and then indicated．1．8 A 2．3，1．nS．，The cells with 100 ℃ and ．6e minutes baklng．and 50 ℃， 60 minutes indicated the fast ．response time com−
pared with． the cells of other baking treat−
ments and rubbing times． As a geneTal ru．le，
the cell having the 80 times rubbing inqicated the rapid response characteristics．
The total time of the delay and the rise times were e．7 N 1．2 inS at the electric field of 10 V／um． The cells with IDO ℃ and 60
100 C， 60 MINUTEs BAklNG 口DELAY TIME
A RISE． TIME
＞くTOTAL（R＋D）T［ME 50 TiMES RUBBING 一一一50 TIMES RUBBING 一一L−80 TIMES RUBBiNG
︹のE︶田≧−﹁田のZO庄のω匡
3
2
1
o
雲一。＼x一＿顧 ・
戦：1へ・こミ碧き一書くこ・
△一・「・△＿・一・一△面傷ミ蒼 尋タζ呂Eit｝一．ミ号…三ミ…暑ミ三；：
1．5 3 5 7．5 10
ELECTRIC FIELD （V／i．tm）
Electric fi ?撃п@dependence of the ti rbe by the appl−ication of the voltage． The aligning agent is 60 ml nute at 100 ℃．
（1993）
m軸teS均・king i・diCated the faSt「eSp。nSe characteristics compa；ed with the cells havlng other baking treatrnents． As can be seen the rise time characteristics， the tota1 狽奄高 characteristics showed th．e identical results coiitpared with the rise time response． The cell with 100℃． 60 minutes baking qnd 8e times rubbing had the rapid．response time at the electric field of 10 Vノμm．
s・a general ruie， total time had the rapid response characteristics on 狽??@cgll with 80 times rubbing．
4． Conclusipns
o
Figure 21．
response squarewave baked on
1． Comparing the aligning characteristics by the li・ght transmittance of cell rotatien， the eells with 80 times rubbing had tbe №盾盾
aligning eharacteristics．
2． Hysteresis and bistability characteristics
−were observed in C；V and T−V character・一 istic． The each cell・ showed the inversed char−
qcteristics of molecular alignment from 一1 V t・＋1V・The cell wヰh 80 ti皿es rubbi叩iゆ一 cated the ＄haTp bistabiliFy characterist；cs．
3． The．electric fi．eld characteriStics indi一一 cated the similar properties in alinost all cells and saturated on values of 6 V／um． The cell with ±OO c ， U0 minutes． baXing and 80・
times rubP． ing showeq ．thq good．．c．1；． arap．t．eiT istics．
4． Total timd of ．the delay and the rise times
inqicqted e． 5． 一一・ 1．2 m＄ ・ at ．．the ・ el e．ctri．c field
。f 10 v／岬・ハ6c。rding．t。 the e・pe・i皿eht・1 results． ・the cell with leO ℃．．60 minutes baki．ng and 8e times rubbing had the rapid response・ time． The response tirne at the low electric field had the slow optical switching time in all cells． The モ?撃撃刀@with 100 ℃． 60
minutes baking showed thO rapid response time compared with the eells having the other baking treatmen 煤D
As the aligning films of polyethylene glycol by the dipping method in this study have a litYle superior or the sarne characteristtc．s on molecular a1ignrnent and the response Vime compared with fabticated aligning films up to
Molecular Alignment of Ferroelectric Liquid Crystals in a Cell with Dipping Polyethylene Glycol Films
the present， it may safely state that these aligning iilms by the dipping method are excellent aligning films on many points of practical use because of the easy fabrication
of the aligning ．iilms and the suitability for mass produgtion．
As the study in quest of the good aligning charqcteptstlcs cell i＄ hoped to the aligning treatment of the electrode glass substrates for molecular alignrnent． Author makes an ef−
fort the development of the． good aligning cell．
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