Photoelectromotive Force of Ferroelectric
Liquid Crystals （3）
Shoichi SOTA
（Received August 31，1991）
The impact of ferroelectric liquid crystals in the field of flat display devices began about five years ago． Those liquid crystal are useful for sensors of photo， magnetic， ultrasonic， temperature， vibration and， etc．
In this paper， experimental results on the photoelectromotive force （photo E． M， F．） of the room−ternperature ferroelec−
tric liquid crystal cells with the alignment films for homeotropic and homogeneous and no alignment on molecular align−
ment of liquid crystal are reported． The materials used in this study are DOF−OOO6 and CS−1024 as liquid crystals， bril−
liant yellow， sudan皿，acidred， orange H as dyestuffs． The photo E． M． F， generated across a cell are continually re−
corded when an incident light of ultraviolet ray is illuminated，
Main results are as follows． The cells with CS−1024 generated the high photo E． M， F． and indicated the rapid rise re−
sponse time compared with the DOF−OOO6 eells． ln case of changing the alignment films， the cells with the homeotropic align皿ent．films shoWed the high photo E， M． F、 and the rapid response time on the rise and the fall characteristics com−
pared with other cells having the homogeneous alignment films or no alignment films．
1． lntroduction
Liquid−crystal devices such as multiplexed TN and STN．types and activematrix driven TN type have been widely used for， digital watch， personal compu−
ter， wotd processor， TV， and so forth． Since the dis−
coyery of bistable switching in a surface stabilized ferroelectric liquid crystal （SSFLC）， ．many new FLC materials has been synthesized to optimize the dis−
play device characteristics． ln recent
凾?≠窒刀C room−temperature ferroelectric liquid crystals are synthe−
sized for application to flat display panel， The high speed response in electro−optical switching and the memory effect due to bistability in molecular align−
ment are considered to b ?@utilized as a flat TV or a personal computer display panel． Moreover， ．room−
temperature ferroelectric liquid crystals are consi−
dered hopeful for application to sensors of phOto，
magnetic， ultrasonic， ultra sonic vibration， and
etc． 1−3ユ）
Photovoltaic effect is found on the nematic liquid crystal cells with asmmetry electrode glass only one side glass plate by T． KAMEI et al， 26 27） and is
reported on the nematic liquid crystal cells with the symmetry electrode glass mutually and doped with methyl red by S， SATO et al． 28） As a liquid crystal photosensor is required the equality performance compared with other devices of the photosensor， the cells with rapid response and the high value of the photoelectromotive force must be researched on wide range of the wavelength， materials of liquid crystals，
dyestuffs for dope， surface treatments of the elec−
trode glass substrates and other substrates excepted the ln2 03 coating glass． 33／48）
The author reported the photovoltaic effect of the ferrOelectric liquid crystal cells （CS−1011， ZLI−3489，
MBRA−9 and DOBAMBC） with the symmetry elec−
troC e． glas．s spb．＄trates mutually and doped with methyl yellow， sudan 1，sudan ll，nitro−p−chroloani−
line and orange II to the incident light of ultraviQlet rays and the photovoltaic effect of the cells is applic−
able as nematic liquid crystals． 5i 52＞ lt has been con−
firmed that materials ．of liquid cryStals，・ kinds and consistency of dyestuffs and the temperature of cells affected the photoelecrtomotive force on the photo−
voltaic effect． The photoelectrQmotive force， the rise
and the fa11．time characteristics of．room−te正nperature ferroelectric liquid crystals （DOF−OOO6， CS−1024） are not reported as to combination of dyestuffs， aligning treatment．of the glass substrates with homeotropic and homogeneous aligning treatment．
The author has especially examined the difference of aligning treatment of the glass substrates for mol．ecular alignment of ferroelectric liquid crystal and of dyestuffs on the photoelectromotive force of the room−temperature．ferroelectric liquid crystal cells with DOF−OOO6 and CS−1024 in ．this study． The cells are fabricated by th6 ITO coated glass subs−
trates with the alignment films for homogeneous，
homeotrOpic ≠獅п@no alignrnent for molecul．ar align−
ment of liquid crystql and are illuminated by the in−
cident light of ultraviolet ray（253．7 n皿）．
2 ． Sample preparation and Measurements
Materials pf ferroelectric liquid crystals and dyestuffs used in this study are DOF−
OOO6 and CS−1024 （supplied from DAINI−
HON INKI Co．and CHISSO Co，） and bri｝liant yellow， sudan M， acid red， Orange ll．A sterilization lamp （253．7nm） is used as a in−
cident light source in this research．
QUARTZ
GLASS
MYLAR SPACER
with the alignment films for homeotropic or homogeneous or no alignment． Homeotropic alignment films are deposited on the ITO coated glass subs−
trates by a dipping method using the surface−actitre agent （FD−150，DAINIHON INKI Co）． Homogeneous align皿ent films are doie by rubbing of the electrode glass Substrates by the cotton to enhance a parallel configuration of rubbing direction， The cell area illu−
minated the incident light is about 1 X 1 cm2 and the cell thickness is 12 pt m which is hold by the ．mylar film as a spacer． Tabte 1 indicates the sample cells used in this experiment in combination of liquid crystal， dye．stuffs， aligning treatment and the spacer thick皿ess．
Table 1．Sample cells for experiments．
CELL mUM．＃
LIQUID
bRYSTAL DYESTUFFS ALIGNING sREATMENT
CELL sHICKNESS
＃1 DOF・0006 BRILLIANT YELLOW NO ALIGNMENT 12μm
＃2 POF−0006 SUDAN皿 NO ALIGNMENT 12μm
＃3 DOF．0006 ACID RED NO ALIGNMENT 12μm
＃4 DOF・0006 ORANGE H NO AL正GNMENT 12μm
＃5
CS・1024BRILLIANT YELLOW NO ALIGNMENT 12μm
＃6
CS．1024SUDAN皿 NO ALIGNMENT 12μm
＃7
CS−1024ACID RED NO ALIGNMENT 12μm
．＃8 CS・1024
ORANGE I NO ALIGNMENT 12μm
＃9
DOF・σ006HOMEOTROPIC AHGN． ユ2μm
＃10
DOF−0006 HOMOGENEOUS ALIGN． 12μm
＃11
DOF．0006 NO ALIGNMENT 12μm
＃12 CS−1024
HOMEOTROPIC ALIGN． 12μm
＃13 CS．1024
HQMOGENEOむS ALIGN． 12μrn
＃14 CS・1024
NO ALIGNMENT 12μm
LIQUID ln205
CRYSTAL NESA−COATING
Fig． 1 Top and cross sectional view of schematic repre−
sentation of a sandwich type liquid crystal cell．
Figure 1 illustrates the top and cross sectional view of schematic representation of a sandwich type ferroelectric liquid crystral celL Room−temperature ferroelectric liquid crystals are sandwiched between two conductive （ln2 03） ITO coated glass substrates
一．
Properties of ferroelectric liquid given belew．54， 55）
［DOF−OOO6］
1
D transition temperature （OC）：
一5 50．5 66
●
9臼つ﹂4
ユ．
2．
crystals are
71 C一一一一Sc ＊ 一一一一SA一一一N ＊ 一一一一I spontaneous polarization： 148 nC／cm2 （at 25℃）
tilt angle： 22．00 （at 25℃）
helical pitch：
11＃ m（at 25eC） in Sc＊ phase and 30 pt m（at 66 C） in N＊ phase
［CS−1024］transition temperature （℃）：
一12 62 82 90
C一一一一Sc＊一一一一SA一一一一N＊一一一一I spontaneous polarization： T46．9 nC／cm2 （at 250C）
一118一
3． tilt angle： 25DO （at 25℃）
4 ． helical pitch：
20 pt m （at 25℃） in Sc＊ phase and 50 pt m （at 667C） in N＊ phase
One kind of dyestuffs is doped with concentration of 3 O／o in weight ratio to the ferroeiectric liquid crystais referring to performance of previous，
experiments．47 52） Figure 2 shQws the block diagram of the measurement systerri． The cells are illuminated by the incident light of ．ultraviolet ray and recorded the photo El ．M． F．， the rise and the fall time re−
sponse time． lllumination strength of the incident light is held at the constant o n 20 mw／em2 with refer−
ence to data of the fluorec ent lamp supplier． 53）
UL丁RA−
uIOLET
@TUBE
LIQUID
bRYSTAL
@CELL
ELEC−
sRONIC oOLY−
qECORDE
Fig．2Block diagram of the measure皿ent system，
Meas urements are perforrned by detection of the photoelectromotive force generated between quartz glass plates when the．．lttcident light of ultraviolet ray is illu面nated to the cells． Photo response of the cells by the turning the incident light on and off is re−
corded by the electronic polyrecorder from the be−
ginning of illumination． The recording time depends on individual material in period of 60−140 seconds in maximum． Time when the incident light is turned off is shown by the arrow marks in each figure．
Figure 3 shows the photoelectromotive force char−
acteristics on the cells doped with brilliant yellow or sudan皿．Table I stands for the maximum photo−
electromotive force， the rise and the fall tirpes on the cells doped with brilliant yellow， sudan皿，acid red ot Orange ［．
60
︵＞E︶ 0 0
4 2山O＜﹂﹁﹂O＞O卜O工匡
DOF−OOO6 ＋ L BRILLIANT YELLOist 2．SUDAN皿
1／
21
3． Experimental results
1 ． Photoelectromotive force on various dyestuffs 1 一 1． Photoelectromotive force characteristics on the cells using DOF−OOO6 liqUid crystaL Table皿．MaximuIh phOtoelectromotive force， the rise and the fall times on the cells with the DOF−OOe6 li−
quid crystal， （one kind dyestuffs doped）
O 40 80 120 140
TlME （S）
Fig．．3二：Photo E， M． F．．characteristics． of the cells with DOF−OOO6 liquld crystal． Dyestuffs are brilliant yellow and sudan皿．
︵＞E︶山O＜ト﹂O＞OトO工巳
40
20
DOF−OOO6 ＋
1． ACID RED 2． ORANGE l1
1／
2／
LIQUID
bRYSTAL DYESTUFFS MAXIMUM
gOTO E．M，F．（mV）
RISE
sIME（S）
FALL
sIME（S）
DOF−0006 BR茎LLIANT YELLOW ．．50 33．0 54．0
DOF−0006
SUDAN皿42 46．0 58．0
DOF−0006 ACIDRED 30 30．0 54．0
DOF−0006 ORANGE H
1946．0 53．0
O 40 80 ・ 120
TIME （S）
Fig． 4 Photo E． M， F． characteristics of the cells with DOF−OOO6 liquid crystal． Dyestuffs
are acid red and orange I工．The cell with brilliant yellow had the slightly high values of photovoltage but both of the cells with brilliant yellow and sudan M had not the big different photovol−
tage． The cell with brilliant yellow indi一
cated the periodic changing characteristjcs liked the nematic liquid crystal cells to performance of pre−
vious experiments．52）． The cell with sudan 皿 showed the photoelectromotive foree in−
creasing with the elapsed time of illumina−
tion of ultraviolet rays．
The rise response characteristics on the cell with sudan皿．ndicated little by little
increasing time， The fall time characteristics on both cells indicated the similar characteristics and scarce−
ly zero yoltage after 60 seconds from the incident
light off．
Figure 4 shows the photoelectromotive force char−
acteristics on the cells doped with acid red or orange U．The photovOltage on both of the cells stood． for a Iittle value of voltage compared with the celis with brilliant yellow．or sudan皿．The rise time of photo一 electromotive force had little by．little．i口creasing characteristics from the incident light en． The fa11 times on both cells indicated the si皿ilar characteris・
tics showing the cells with brilliant yellow and sudan 皿 in figure 3．
Table巫．Maximu皿photoelectromotive force， the rise and the fall times on the cells with the CS−1024 li−
quid crysital． （one kind dyestuffs doped）
LIQUID
bRYSTAL DYESTUFFS MAXIMUM
gOTO E．M．F．（mV）
RISE
sIME（S）
FALLsIME（S）
CS4024 BRILLIANT YELLOW
6223．5． 34．5
CS−1024 SUDAN皿 51
16．0 29．0
CS−1024
ACIDRED 25 8．0 36．5
CS−1024
ORANGE H
179．0 19．5
1 一 2 ． Photoelectromotive force characteristics on the ce11s using CS−1024 liquid crystal．
60
0 ∩暫
4 ハ∠
︵﹀∈︶山O＜ト﹂O＞OトO工旺
1 ！ CS−1024 ＋ 1． BRtLLIANT YELLOW
2SUDAN皿
2 I
Figure 5 shows the photoelectromotive force char−
acteristics on the cells doped with brilliant yellow or sudan 皿．Table 皿 stands for the maximunl photoelectromotive force， the rise and the fall times on the cell doped with． brilliant yellow， sudan M，
acid red and orange ll ．
The photoelectromotive force on both of the cells generated the two or three times values of
DOF−OOO6 cells indicated the figures ・3 and 4 and the rise response tim． ?@on the cells with sudan皿 had．
the tapid responsibility and indicated half fu11 of time compared with DOFmOOO6 cells． The cell with brilliant yellow indicated the large periodic changing characteristics compared with DOF−OOO6 cells and changing width on the photovoltage varied from 40 to 60mV during form 20 to 40 seconds．
The fall time characteristics showed the similar curve and the fall time had a little short titne com一
30
@ 20 ． 10︵﹀∈︶山O＜ト﹂O＞O↑O工巳
CS−1024 ＋
1． ACID RED
Z ORANGE g
1／
2！
Fig．
O ・ 20 40 60 80
TlME （S）
5 Photo E． M． F． characteristics of the cells with CS−1024 liquid crystal， Dyestuffs are brilliant yel−
Iow and sudan皿．
o 20 40 60
TIME （S）
80
Fig． 6 Photo E． M． F． characteristics of the cells with CS 1024 liquid crystal． Dyestuffs are acid red and orange a．
一120一
pared with the cells with brilliafit yellow， The au−
thor understood that the cells with CSnt・1024 had the large photoelectromotive． force and the rapid re−
sponse time．
Figure 6 shows the photoelectromotive force characteristics oR the cells doped・
with acid red and orange ll． The photo E． M． F． generated as much as the cells with DOF OOO6 doped with acid red or
orange 1 b浮煤@the rise response time indicated the rapid response time by three or four times． The fall time on ．the cells with orange fi indicated the quick fallresponse characteristics and the cells with acid red showed the similar characteristics compared with the DOF−OOO6 cells．
2． Photoelectromotive force on the lng treatment
2−L
Table 1V ． Maximum photoelectromotive force， the rise and the fall times on the cells with the DOF−OOO6 li−
quid crystal aligning with all kinds of alignment
films for rnolecular alignment． ．
LIQUID bRYSTAL
ALIGNING
sREATMENT
MAXIMUM gOTO EM．F．（mV）
RISE
slME（S）
FALL
s工ME（S）
DOF−0006 NO ALIGNMENT
1546．5 57．Q
DOF−0006 HOMEOTROPIC ALI． 80 2．0 44．5
DOF−00D6 HOMOGENEOUS ALI．
322．0 16．5
cells with align一
PhotoelectrQmotive f．orce on the cells with DOF−OOO6 liquid crystal，
80
60
@ 40︵﹀∈︶山O＜トJO＞O↑O工
20
DOF−OOO6
1． HOMEOTROPIC ALIGNMENT TREATMENT 2．HOMOGENEOUS AしIGNMENT TREATMENT 3． NO ALIGNMENT TREATMENT
1
2！
3！
o 20
40 60 80 100 120TIME （S）
Fig． 7 Photo E． M． F． characteristics of the cells with DOF＋OOO6 liquid crystal cells with homeotropic，
homogeneous or no alignment films．
Figure 7 shows the photoelectromotive force char−
acteristics on the cells with homeotropic，
homogeneOus or no alignment films for molecular alignment， Table IV stands for the maximurn photo−
electromotive force， the rise and the fall times on the cells with all kinds of the alignment films for molecular alignment of room−temperature liquid
crystal．
The cell with homeotropic alignrnent indicated the high photo E， M． F， compared with the cells having homogen．eous or no alignment films． The cells with homogeneous or no alignment films generated 15 mV or 3 mV．， but this values spoke for the lo ver voltage and were considered the cells having the worse photo E． M． F． characteristics． The phbto E． M． F， on the cells with homeotropic alignment film had the over shoot characteristics and indicated the fixed values after 40 seconds from the incident light on．
The cell with homogeneous alignment film had the latest value of the photo E． M． F． but the author had not been understanding the reason why they had the latest value of the photo E． M． F．．
As for the response time on the photo E． M． F．， the cells with homeotroPic aligRment film had the rapid rise and fall times characteristics compared with other cells． Both of the cells withhomogeneous and no alignment films had the．longest rise and．fall ti皿es characteristics．on the photo E． M． F， and they were not suitable for a liquid crystal photo sensor．
2一 2． ・Photoelectromotive force on the cells with CS−1024 liquid crystal．
Fiqure 8 shows the photoelectromotive force char−
acteristics on the cells liked on figure 6． Table V
stands for the maximum photeelectromotive force，
the rise and the fall times on the cells liked table 1V．
The cells with homeotropic alignment film indi−
cated the similar characteristic liked the ce11s with DOF−OOO6 pointed out the fiquire 7． Both of the cells with homogeneous and no alig 獅高?獅煤@films indicated 19 and 12 mV on the photo E． M． F． and tbis．values stood for the lower photo E． M． F． liked the DOF−OOO6 cells．with homogeneods and rio ≠撃奄№獅高?獅
films． The photo E． M． F． dn the cells with homogeneous alignment film had the over shoot char一
160
20 1
︵﹀∈︶ 80
国O＜ト﹂O＞OトQ工巳
40
csrlo24．
・剛E。TR。PIC牛御子，
2． HOMQGENEOUS ALIGNMENT
TREATMENT
5． NO ALIGNMENT TREATMENT
L1
21
3」
acteristics liked the DOF−OOO6 cells and indicated the fixed values after 30 seconds from the incident light on． Anyhow the cells with homeotropic align−
ment films considered the cells having the over shoot characteristics and thus results were not understood to 06cur those cells for what reason．
The rise and the fall times on the cell with homeot−
ropic alignment films on the photo response charac−
teristics showed the rapid response in spite of the high photb E． M． F．， Both of the cells with homogeneous and no alignment films showed the
almost equality response time on the rise and the fall characteristics． Comparing 狽??@ali gnment treatment on the photo E． M， F．， the cells ．with homeotropic treatment generated the high photo E． M． F． Com−
pared with the cells having homogeneous or nQ align−
ing treatment．
100
4． Conclusions
o
20 40 60 80TjME （S）
Fig． 8 Photo E． M． F， characteristics of the cells with CS−1024 Liquid crystal cells with homeotropic，
homogeneous or no alignment films，
Table V．Maximu皿photoelectromotive force， the rise and the fall times on the cells with the CS−1024 li−
quid crystal aligning with all kinds of align皿ent films for rnolecular alignment．
LIQUID bRYSTAL
ALIGNING
sREATMENT MAXIMUM gOTO E．MF．（mV）
RISE
sIME（S） FALL
sIME（S）
CS−1024 NO ALIGNMENT
196．0 26φ0
CS−1024 HOMEOTROPIC ALI． 150 10．0 25．0
CS−1024 HOMOGENEOUS ALI．
1214．0 16．0
Photovoltaic effect on the room−temperatute fer−
roelectric liquid crystal cells doped with one kind of
dyestuffs or treated with homeotropic or
homogeneous alignment were exarnined in regard to the photoelectromotive force characteristics and the rise and the fall times response． The photoelectromo−
tive force and the rise and the fall tiMe characteris−
tics Were considerably affected with the ．combipation of dyestuffs and aligning treatment for molecular alignment，
The results are summarized as follow＄． Consi，dering the photo E． M． F．， the cells with brilliant yellow re−
corded the highest values of the photo E． M． F．． Con−
cerning the rise response time， the cells with acid red indicated the comparatively rapid response char−
acteristics． ln general the cells with CS−1024 gener−
ated the high photo E． M． F， and indicated the rapid response time on ． the rise response characteristics compared with the DOF−QOO6 cells． Concerning the al ignment treatment for molecular align−
ment， the photo E． M． F． of the cells with the homeotropic alignment films had the sN7 times larger than the cells with the homogeneous or no alignment films． The
一122一
author has not been understanding the reason why the cell with homogeneous alignment film had the low value of the photo E， M． F．． As for the incident light response time， the cells with homeottopic align−
ment films indicated the rapid response time on the rise and the fall response characteristics．
Studies in quest of high values of the photo E． M， F．
and rapid response to the irradiation ．of the incident light is hoped to the combination of dyestuffs， align−
ing treatment of the electrode glass substrates for
．molecular alignment and the construction on cell fab−
rication．
References
1）
2）
3．）
4）
5）
6）
7）
8）
9）．
10）
11）
12）
13）
H． Maeda， C． M． Gomes， M， Yoshida， B． Y，
Zhang； proc． of the 9th lnternational Display
．research Conf．， 89， 344．
C． Escher， H． R． Dubai， T． Harada； Proc． of the gth lnternational Display research Conf．， 89，
348．
S． S． Bawa， Kanchan Saxena and Subhas Chandra； Jpn． J． Appl． Phys．， Vol． 28， No． 4 （1989） 662．
G， W， Gray； Proc． of the 5th Liquid Crystal Seminar （Merck Japan Limited） ，1991， 6．
M． S． Lee， J． S． Tzeng， Y． C． Chen； Jpn， J． Appl．
Phys．， Vol． 28， No． 6 （1989） 1008，
Bernard J． Lehner； Proceedings of IEEE， Vol，
59 （1971−11） 1566．
A． Sasaki； Basic and Applications of Liquid Crystal Electronics， （1971） 81， OHM， Co．．
S， Matstumoto； Liquid Crystal Electronics， P，
86， OHM Co，．
Martin Schadt， FranS Leenhouts； 」． Appl．
Phys．， Lett．， 50−6 （1987） 236．
T． J． Scheffer， J． Nehring； J． Appl． Phys． Lett．，
45−10 （1984−11） 1021．
Y． Oqchi， Y． Takanishi， H． Takezoe， A． Fuku−
da； Jpn． J． Appl． Phys．， Vol． 28，12 （1989）
2547．
Y． Ouchi， H． Takezoe， A． fukuda； Jpn， J． Appl，
Phys．， Vol． 28， No． 3 （1989） L487．
A． Sasaki； Oyou Buturi， 50 （1981−11） 1261．
14）
15）
16）
17）
18）
19）
20）
21）
22）
23）・
24）
25）
26）
27），
28）
29）
30）
31）
32）
33）
34）
35）
R． B． MEYER； LE JOURNAL DE PHYSOUE，
LETTERS， TOME，36 （1975−3） 69
B． 1． Ostrovkii， A． Z． Rabinovich et al； Fer−
roelectric， VoL 24 （1980） 309．
A． Hallsdy， M． Nitson et al； Mol． Cryst． Lett．
82 （1982） 61，
R． Duke， G． Durand et al； Mol． Cryst． Liq．
Cryst． Vol． 75 （1981） 249．
S． Matu．moto； Liquid Crystal Electfonics；
（1961・） 62， OHM． Co．，
K， Yoshino， M． Ozaki； Jpn． S Aool． Phys．， vol，
27， No． 2．（1988）． L127，
S． Kobayashi， K． Nakaya et al； SID 88 Digest
45．S． Kobayashi； K． NakaYa et al； Jpn． J． Appl．
Phys，， Vol． 27， No． 4 （1988） L475．
S． Kobayashi， K． Nakaya et al； Jpn． 」． Appl，
Phys．， Vol． 2
V， No． 4 （1988） L477，
H． Takezoe， A． Fukuda et al； Jpn． J． Appi．
Phys．， Vol， 27， No． 5 （1988） L729．
S， Sota， T． lshibashi， A． Sasaki； Extended Ab−
stracts （The ・15th Liquid Crystal Meeting，
1989） The Chemical Society of Japan， 283．
K． Yoshino； High Speed Liquid Crystal Tech−
niques， （1986） 84， CMC， Co．，
Noel A， Clark： Sven T． Lagerwall； Appl． Phys．
Lett．， Vol． 36， No， 11 （1980） 899．
K． Sato， K． Kato， T． Uchida； Proc． of the 9th Interinational Display reseqrch Cbnf，， 89， 392，
S． Sota， T． lshibashi， A． Sasaki； Proc． of the gth lnternational Display research ConL， 89 356．
．M． Johno， Y． Ouchi， H． Takezoe； Jpn． J Appl，
Phys．， VoL 29． No， 1 （i990） Llll．
M． Johno， Y． Ouchi， H． Take2pe； Jpn． J， ApPl．
Phys．， Vol． 29， No． 1 （1990） Llll．
K． Yatuzuka， A． Watanabe； Jpn， J． Appl．，
Phys．， Vol． 22， No． 2 （1983） L76．
E， O． Fostef； J． Chem． Phys． 37 （1962） 1021．
E． O． Foster； 」． Chem． Phys．．40 （1964） 86．
E． O． Foster； J． Chem． Phys， 40 （1964） 91．
Y． Kiuchi， S． Sato et al； J． Appl． Phys．， （1987）
107．
36）
37）
38）
39）
40）
41）
42）
43）
44）
Y，Katayama；Denshigijutu， （1987）ユ3， Nik−
kan lndustry Newspaper， Co．，
S． Kurita； J． Appl． Phys．， Extended Abstracts
（The 27th Spring Meeting，1973）；The Japan Society of Applied Physics， 4．
S． Sato， T， Nose et al； Extended Abstracts
（The 48th AutuMn Meeting， 1987） The Japan Society of Applied Physics， 107．
S． Sato， T． Nose et al； Extended Abstracts
（The 35th Spring Meeting， 1988） The Japan Society of Applied Physics， 172．
M． Sugimura， H． Sonomura et al； Extended Abstracts （The 35th Spring Meeting， 1988）
The Japan Society of Applied Physics， 172．
K． Toda， N． Watanabe； Sharp TechRical Re−
ports， VoL39， （1988） 67．
S． Sato； Liquid Crystal and Applicatioris，
（1094） 128， Sangyou Tosho， Co．．
S． Sato； Extende Abstracts （The 5th Liquid Crystal Meeting， 1980） The Chemical Society of Japan， 124．
S，．Matumoto； Liquid Crystal Electronics，
45）
46）
47）
48）
49）
50）
51）
52）
53）
54）
55）
（1961） 129， OHM Co．．
A． Fukuda， H． Takezoe； J． 」 Appl． Phys．， 54−5
（S−60−5） 412．
K． Okano， S． Kobayashi； Liquid Crystal，
（1985） 204， Baifukan Co．．
S。So亡a， K． Kaneko；Bulletin of Tsuyama National college of Technology， No， 23 （1985）
113．
S． Sota； Bulletin of Tsuyarna National CQIIege of Technology， No． 24 （1986） 93．
S． Sota； Bulletin・ of Tsuyama National College of Technology， No． 25 （1987） 133．
S． Sota； Bulletin ，of T＄uyama National College of Technology， No． 26 （1988） 55．
S． Sota； Bulletin of Tsuyama National College of Technology， No． 27 （1989） 66．
S． Sota； Bulletin of Tsuyama National College of Technology， No． 28 （1989）． 69．
MATUSHITA DENKISANGYO Co． Catalogue．
DAINJHON INKI Co． Catalogue．
CHISSO Co． Catalogue．
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