JPH01225691A - Ferroelectric liquid crystal composition and ferroelectric liquid crystal display device - Google Patents
Ferroelectric liquid crystal composition and ferroelectric liquid crystal display deviceInfo
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- JPH01225691A JPH01225691A JP5192888A JP5192888A JPH01225691A JP H01225691 A JPH01225691 A JP H01225691A JP 5192888 A JP5192888 A JP 5192888A JP 5192888 A JP5192888 A JP 5192888A JP H01225691 A JPH01225691 A JP H01225691A
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- liquid crystal
- ferroelectric liquid
- phase
- crystal composition
- smectic
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- 239000005262 ferroelectric liquid crystals (FLCs) Substances 0.000 title claims description 51
- 239000000203 mixture Substances 0.000 title claims description 42
- 230000007704 transition Effects 0.000 claims abstract description 28
- 239000004990 Smectic liquid crystal Substances 0.000 claims abstract description 16
- 230000002269 spontaneous effect Effects 0.000 claims abstract description 14
- 230000001747 exhibiting effect Effects 0.000 claims abstract description 5
- 239000004973 liquid crystal related substance Substances 0.000 claims description 50
- 239000007788 liquid Substances 0.000 claims description 15
- 230000010287 polarization Effects 0.000 claims description 13
- 238000007562 laser obscuration time method Methods 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 6
- 238000000819 phase cycle Methods 0.000 abstract description 3
- 239000013078 crystal Substances 0.000 abstract 3
- 239000012071 phase Substances 0.000 description 27
- 239000000758 substrate Substances 0.000 description 14
- 230000004044 response Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 9
- 210000004027 cell Anatomy 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000004988 Nematic liquid crystal Substances 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 210000002858 crystal cell Anatomy 0.000 description 2
- 238000000113 differential scanning calorimetry Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 241000238876 Acari Species 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 210000003127 knee Anatomy 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
Landscapes
- Liquid Crystal (AREA)
- Liquid Crystal Substances (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は双安定性をもつ液晶に係わり、とくに強誘電性
液晶組成物及び強誘電性液晶表示装置に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to bistable liquid crystals, and more particularly to ferroelectric liquid crystal compositions and ferroelectric liquid crystal display devices.
従来の技術
近年液晶表示は、腕時計、電卓等だけでなく映 ′
像機器にも広く使われるようになり、液晶カラーテレビ
も市場に出始めている。現在カラー表示用液晶パネルは
ネマチ・ツク液晶を用いたものがその主流を占めている
。しかし、そのネマチック液晶の緒特性は理想的とは言
い難く多くの問題を含んでいる。強誘電性液晶はその速
い応答速度、メモリー性等ネマチック液晶にはない緒特
性を有しておりデイスプレィ装置への応用が考えられ多
方面から研究が進められている。(例えばオプトロニク
ス、1983、磁9)以下図面をみながら強誘電性液晶
について説明する。第4図は強誘電性液晶分子の模式図
である。強誘電性液晶は通常スメクチック液晶と呼ばれ
る層構造を有する液晶で、液晶分子は層法線方向に対し
てθだけ傾いた構造をとっている。また、通常強誘電性
液晶分子は、ラセミ体でない光学活性な液晶分子によっ
て構成されている。第5図に於て、7は液晶分子、8は
自発分極、9はCダイレクタ−1)0はコーン、1)は
層構造、12は層法線方向、13θは傾き角を示してい
る。第4図に示すように、強誘電性液晶分子は自発分極
を有しており、カイラルスメクチックC相に於ては、第
4図の円錐形8 (コーン)の外側を自由に動くことが
できる。層毎に分子長軸の方向は少しだけずれており全
体としてはねじれ構造をとっている。次に強誘電性液晶
の表示原理について述べる。第5図は強誘電性液晶の動
作原理図で有る。第5図(alは電圧無印加の状態、第
5図(b)は紙面裏から表方向に電圧を印加した場合、
第5図(C)は逆方向に電圧を印加した場合の動作原理
図である。14は層法線に対して分子長軸が+θ度度傾
た液晶分子、15は−θ度伸した液晶分子、16は紙面
表方向を向いている双極子モーメント、I7は紙面裏方
向を向いている双極子モーメント、18は2枚の偏光板
の方向である。強誘電性液晶を透明電極を有したガラス
基板に挾みそのパネルの厚を螺旋ピッチ以下にすると第
5図+alのように螺旋がほどけ層に対して分子が+6
度(頃いた領域と一θ度傾いた領域にわかれる。上下電
極間紙面頂から表方向に電圧を印加することにより第5
図(blのようにセル全体が+θ度度傾たユニフォーム
なモノドメインになる。また、逆電圧を印加すると第5
図fc)のようにセル全体が一θ度傾いたユニフォーム
なモノドメインになる。従って、電気光学効果による複
屈折または2色性を利用すれば±θ度度傾たユニフォー
ムな2つの状態により明暗を表すことができる。ところ
が、一般に有機配向膜のラビング法をもちいた場合この
ような理想的なユニフォーム間のスイッチングをする場
合は現在まで報告されておらず、第6図(a)に示すよ
うに基板上面では分子は+θ度度傾ており基板下面では
一θ度傾いておりその中間では分子が基板上面から下面
に+6度から一θ度ねじれたツイストの状態が安定であ
る。第6図において、19は上面基板、20は下面基板
、21は+θ傾いた液晶分子、22は一〇傾いた液晶分
子、23はコーン、24はCダイレクタ−を示す。第6
図(blにCダイレクタ−による表示を示した。分子は
基板にたいして一定角度のプレチルトをもっており、分
子のねじれが右か左かによって透過光量がことなってく
る。第7図の(8)〜(d)にプレティルトを考慮した
場合の可能なツイスト状態をCダイレクタ−による表示
で示した。第7図において25は上面基板、26は下面
基板、27はコーン、28はCダイレクタ−を示す。こ
れまでの報告によると有機配向膜のラビングによる配向
性を用いると、(al、 (b)間或いは(C1,fd
1間でのツイスト間スイッチングにより表示をおこなっ
ている。エム・ムラカミ、ニス・ミャケ、ティー・マス
ミ、ティー・アンド−、ニー・フカミ;プロシーディン
グ オブ ザ 6ス インターナショナル デイスプレ
ィ リサーチ コンフェレンス、 、 344(198
6) (M、 Mu r a kami、 S、
Mi y ake、 ToMasumt、T、And
o、A、Fukami;Proceedings o
fthe 5th InternationalD
isplay Re5each Confe−r
e n c e、 、 344 (1986) )こ
れを強誘電性液晶をデイスプレィデバイスに応用する場
合、液晶材料に要求されるモノとして以下の項目が挙げ
られる。Conventional technology In recent years, liquid crystal displays have been used not only in watches, calculators, etc.
It has become widely used in imaging equipment, and LCD color televisions are also starting to appear on the market. Currently, the majority of color display liquid crystal panels are those using nematic liquid crystals. However, the characteristics of the nematic liquid crystal are far from ideal and include many problems. Ferroelectric liquid crystals have characteristics not found in nematic liquid crystals, such as fast response speed and memory properties, and are being studied in a variety of fields for potential applications in display devices. (For example, Optronics, 1983, Magnetic 9) Ferroelectric liquid crystal will be explained below with reference to the drawings. FIG. 4 is a schematic diagram of ferroelectric liquid crystal molecules. A ferroelectric liquid crystal is usually a liquid crystal having a layered structure called a smectic liquid crystal, and the liquid crystal molecules have a structure tilted by θ with respect to the normal direction of the layers. Furthermore, ferroelectric liquid crystal molecules are usually composed of optically active liquid crystal molecules that are not racemic. In FIG. 5, 7 is a liquid crystal molecule, 8 is spontaneous polarization, 9 is a C director, 1) 0 is a cone, 1) is a layer structure, 12 is a layer normal direction, and 13θ is a tilt angle. As shown in Figure 4, ferroelectric liquid crystal molecules have spontaneous polarization, and in the chiral smectic C phase, they can move freely outside the cone 8 in Figure 4. . The direction of the long axis of the molecules deviates slightly from layer to layer, resulting in a twisted structure as a whole. Next, we will discuss the display principle of ferroelectric liquid crystal. FIG. 5 is a diagram showing the operating principle of a ferroelectric liquid crystal. Figure 5 (al is the state where no voltage is applied, Figure 5 (b) is when a voltage is applied from the back of the paper to the front,
FIG. 5(C) is a diagram showing the principle of operation when voltage is applied in the opposite direction. 14 is a liquid crystal molecule whose long axis of the molecule is tilted by +θ degrees with respect to the layer normal, 15 is a liquid crystal molecule that is elongated by -θ degrees, 16 is a dipole moment pointing toward the front of the paper, and I7 is a liquid crystal molecule facing toward the back of the paper. The dipole moment 18 is the direction of the two polarizing plates. When a ferroelectric liquid crystal is sandwiched between glass substrates with transparent electrodes and the thickness of the panel is made less than the helical pitch, the helix unravels as shown in Figure 5+al, and the molecules are +6 to the layer.
It is divided into a tilted area and a 1θ degree tilted area.
As shown in the figure (bl), the entire cell becomes a uniform monodomain tilted by +θ degrees. Also, when a reverse voltage is applied, the fifth
As shown in Figure fc), the entire cell becomes a uniform monodomain tilted by 1θ degree. Therefore, by using birefringence or dichroism due to the electro-optic effect, brightness and darkness can be represented by two uniform states tilted by ±θ degrees. However, in general, there has been no report to date of such ideal uniform switching when using the rubbing method of an organic alignment film, and as shown in Figure 6(a), the molecules are It is tilted by +θ degree, and at the bottom surface of the substrate, it is tilted by 1θ degree, and in the middle, the molecule is stable in a twisted state in which it is twisted by +6 degrees to 1θ degree from the top surface of the substrate to the bottom surface. In FIG. 6, 19 is an upper substrate, 20 is a lower substrate, 21 is a +θ tilted liquid crystal molecule, 22 is a 10 tilted liquid crystal molecule, 23 is a cone, and 24 is a C director. 6th
Figure (bl) shows the display by the C director. The molecules have a pretilt of a certain angle with respect to the substrate, and the amount of transmitted light differs depending on whether the molecule is twisted to the right or left. (8) to ( In d), a possible twist state when pre-tilt is taken into account is shown by a C director. In Fig. 7, 25 is an upper substrate, 26 is a lower substrate, 27 is a cone, and 28 is a C director. According to previous reports, when the alignment by rubbing of an organic alignment film is used, the alignment between (al, (b)) or (C1, fd
Display is performed by switching between twists. M Murakami, Nis Myake, T Masumi, T & Fukami, Proceedings of the 6th International Display Research Conference, 344 (198)
6) (M, Murakami, S.
Mi yake, ToMasumt, T, And
o, A, Fukami; Proceedings o
fthe 5th InternationalD
isplay Re5each Confe-r
en ce, 344 (1986)) When applying this ferroelectric liquid crystal to a display device, the following items are required of the liquid crystal material.
(1)室温を含む広い温度範囲で強誘電性液晶相(例え
ばカイラルスメクチックC相)を示す。(1) Exhibits a ferroelectric liquid crystal phase (for example, chiral smectic C phase) over a wide temperature range including room temperature.
(2)強誘電性液晶の電界に対する応答速度τは、τ=
η/(Ps−E)
但し、η;粘度
Ps;自発分極
E;印加電場
で与えられる。この為、数μsecオーダーの高速応答
を実現するためには、大きな自発分極をもち且つ粘度が
低いことが必要である。(2) The response speed τ of the ferroelectric liquid crystal to the electric field is τ=
η/(Ps-E) where η; viscosity Ps; spontaneous polarization E; given by applied electric field. Therefore, in order to achieve a high-speed response on the order of several microseconds, it is necessary to have a large spontaneous polarization and a low viscosity.
(3) 先述したように、強誘電性液晶の光学応答は
、安定な2状[(bistable 5tate)に
より初めて実現される。(::1erkらによると、こ
の状態を実現するためには、セルギャップdを螺旋ピ・
ノチp以下にし螺旋をほどく必要がある。(3) As mentioned above, the optical response of a ferroelectric liquid crystal is first realized by a stable two-state [(bistable 5tate). (According to::1erk et al., in order to realize this state, the cell gap d must be
It is necessary to unwind the spiral by reducing the number to below p.
エヌ、ニー、クラーク、ニス、ティー、ラガヴアル;ア
プル、フィズ、レフト0、並 899 (1980)(
N、A、C1erk、S、T、Lagerw−a 1)
;Ap l 1.Phys、Le t t、 、36
899 (1980) ”)この為、セル作成上作成
容易なセルギャップの厚いセルを利用するためには、強
誘電性液晶の螺旋ピッチを長くする必要がある。N, Knee, Clark, Nis, T, Raghaval; Apple, Fizz, Left 0, Average 899 (1980) (
N, A, C1erk, S, T, Lagerw-a 1)
;Ap l 1. Phys, Let t, , 36
899 (1980)'') Therefore, in order to utilize a cell with a thick cell gap that is easy to fabricate, it is necessary to lengthen the helical pitch of the ferroelectric liquid crystal.
(4)強誘電性液晶の配向状態は液晶材料の相系列によ
って異なる。相系列には以下のものがある。(4) The alignment state of the ferroelectric liquid crystal varies depending on the phase series of the liquid crystal material. The phase series includes the following:
■ I s o−*N*SmA−*SmC*■
I s o→SmA−3mC*■ r s
o−+N*−*SmC*■ Iso−esmc*
但し、Iso;等方性液体
N*;カイラルネマチ、り相
S m A iスメクチックA相
SmC*;カイラルスメクチックC相
従来はこの4つの相系列の中で■の相系列のものでかつ
N*相のらせんピッチの長いものがもっとも良好な配向
が得られ■のものはSmA相への転移時に■及び■のも
のはSmC*相への転移時に、変形が大きいために配向
膜れが生じる。■I s o-*N*SmA-*SmC*■
I s o→SmA-3mC*■ r s
o-+N*-*SmC*■ Iso-esmc* However, Iso: Isotropic liquid N*: Chiral nematic, liquid phase S m A i Smectic A phase SmC*; Chiral smectic C phase Conventionally, these four phase series Among them, the one with the phase series ■ and the N* phase with a long helical pitch gives the best orientation. , alignment film cracking occurs due to large deformation.
この為従来の強誘電性液晶組成物は■の相系列を示すも
のが殆どであった。For this reason, most conventional ferroelectric liquid crystal compositions exhibit a phase series of (1).
従来の強誘電性液晶は温度範囲のみならず応答速度の面
も実用レベルに達しているものは少なく又メモリー性、
闇値特性に関しても良好なユニフォーム間の転移を示す
高コントラストの得られる実用可能な液晶組成物は未だ
得られていないのが現状である。以下に従来の強誘電性
液晶材料の一例を示す。Few conventional ferroelectric liquid crystals have reached a practical level not only in terms of temperature range but also in terms of response speed.
At present, a practically usable liquid crystal composition that exhibits good uniform-to-uniform transition and high contrast with respect to dark value characteristics has not yet been obtained. An example of a conventional ferroelectric liquid crystal material is shown below.
転移温度
Iso −I N* −e SmA −*
SmC*75℃ 64℃ 57℃
融点
一1)’C
自発分極
1)nC/cm2
応答速度
300μsec (44VI)り印加時)チルト角
26゜
このような液晶組成物を用いた液晶表示装置では応答速
度も遅く有機配向膜のラビングによる配向性を用いたパ
ネルにおいては、前述のようにユニフォーム間の転移は
見られず、そのかわりにツイスト間転移を示すため表示
品位の点でも満足のいくものではなかった。Transition temperature Iso -I N* -e SmA -*
SmC*75℃ 64℃ 57℃ Melting point 1) 'C Spontaneous polarization 1) nC/cm2 Response speed 300 μsec (44VI) When applied) Tilt angle 26° In a liquid crystal display device using such a liquid crystal composition, the response speed is However, in panels using the late-rubbing orientation of an organic alignment film, no transition between uniforms is observed as described above, but instead a transition between twists is observed, which is unsatisfactory in terms of display quality. Ta.
発明が解決しようとする課題
しかしながら、従来の強誘電性液晶材料は、他の相系列
のもので良好な配向性をしめすものは殆ど無い為、相系
列がI s o−+N*−+SmA−3mC*のものが
殆どであった。この為有機配向膜のラビング法により配
向させた表示装置でユニフォーム間の転移を示すものが
全く無く良好な表示品位が得られないという課題を有し
ていた。Problems to be Solved by the Invention However, since there are almost no conventional ferroelectric liquid crystal materials with other phase series that exhibit good alignment, the phase series is Iso-+N*-+SmA-3mC. Most of them were *. For this reason, there has been a problem in that display devices aligned by rubbing an organic alignment film do not show any transition between uniforms, making it impossible to obtain good display quality.
課題を解決するための手段
上記課題を解決する為に本発明の強誘電性液晶組成物お
よび強誘電性液晶表示装置は相系列が■s o−4Sm
A−”SmC*でありかつ等方性液体がらSmA相への
転移の際に前転移現象を伴う強誘電性液晶組成物であり
、この液晶組成物をもちいることにより、良好な配向が
容易に得られ、有機配向膜のラビング法を用いた液晶表
示装置においテj、ニフォーム間の転移を示し、高いコ
ントラストの表示が得られるものである。Means for Solving the Problems In order to solve the above problems, the ferroelectric liquid crystal composition and ferroelectric liquid crystal display device of the present invention have a phase series of ■s o-4Sm.
A-"SmC* is a ferroelectric liquid crystal composition with a pre-transition phenomenon during the transition from an isotropic liquid to an SmA phase. By using this liquid crystal composition, good alignment is easily achieved. In a liquid crystal display device using a rubbing method of an organic alignment film, a transition between tej and niform can be obtained, and a display with high contrast can be obtained.
作用
一般にI s o−=SmA→SmC*の相系列を示す
液晶組成物はN*相が無い為等方性液体がらSmA相へ
の転移の際に全くランダムな状態から分子長軸の規制及
び層方向の規制が同時に起きる為変形が急激すぎる。こ
の為良好な配向状態が得られない。ところが本発明の液
晶組成物は等方性液体からSmA層への転移の際に前転
移現象(プレトランジション)と呼ばれる現象が起り、
等方性液体のランダムな状態のなかにサイボタクチツク
なりラスターが生じる。この為、SmA層への転移はこ
のサイボタクチツククラスターからの転移になる為前述
のような急激な変形はなく転移が緩やかになり良好な配
向が得られる。又、N*相が無い為、SmC*相への転
移後の配向状態は有機配向膜のラビング法に特有のジグ
ザグディスクリネイションと呼ばれるディスクリも殆ど
無く、また自発分極も20n C/ c m 2以上と
大きく、さらにはチルト角も20°以上と大きい為、ツ
イスト間転移ではなく良好なユニフォーム間のスイッチ
ングが観測される。又、この液晶組成物を用いることに
より良好な配向状態をもち優れた表示品位をもつ液晶表
示装置が容易に得られる。Function Generally speaking, liquid crystal compositions exhibiting a phase sequence of Iso-=SmA→SmC* do not have an N* phase, so during the transition from an isotropic liquid to an SmA phase, the molecular long axis is regulated and the molecular long axis changes from a completely random state. The deformation is too rapid because the layer direction regulation occurs at the same time. For this reason, a good orientation state cannot be obtained. However, in the liquid crystal composition of the present invention, a phenomenon called pretransition occurs during the transition from the isotropic liquid to the SmA layer.
Cybotic ticks or rasters occur in the random state of an isotropic liquid. Therefore, since the transition to the SmA layer is from this cytotactic cluster, there is no rapid deformation as described above, and the transition is gradual, resulting in good orientation. In addition, since there is no N* phase, the orientation state after the transition to the SmC* phase has almost no discrepancy called zigzag disclination, which is specific to the rubbing method of organic alignment films, and the spontaneous polarization is 20n C/cm. Since the tilt angle is large at 2 or more and the tilt angle is also large at 20° or more, good uniform-to-uniform switching is observed instead of twist-to-twist transition. Further, by using this liquid crystal composition, a liquid crystal display device having a good alignment state and excellent display quality can be easily obtained.
実施例 以下本発明の一実施例を図面を用いて説明する。Example An embodiment of the present invention will be described below with reference to the drawings.
最初に本実施例において、その強誘電性液晶材料の応答
測定に用いた液晶セルの構造を第3図に示す。ここで、
lは偏光板、2はガラス基板、3は透明電極、4は有機
配向膜にラビング処理を施した有機膜、5は液晶、6は
対向基板間を密着させるためのシール剤を表している。First, FIG. 3 shows the structure of a liquid crystal cell used to measure the response of the ferroelectric liquid crystal material in this example. here,
1 is a polarizing plate, 2 is a glass substrate, 3 is a transparent electrode, 4 is an organic film obtained by rubbing an organic alignment film, 5 is a liquid crystal, and 6 is a sealant for bringing the opposing substrates into close contact.
このような構造のセルに強誘電性液晶材料を封入しその
応答特性及び自発分極、闇値特性を測定した。自発分極
については三角波法を用いて測定を行った。A ferroelectric liquid crystal material was sealed in a cell with such a structure, and its response characteristics, spontaneous polarization, and dark value characteristics were measured. Spontaneous polarization was measured using the triangular wave method.
又、相転移温度については、偏光顕微鏡によるtext
ure観察及び示差走査熱量計(D S C)により測
定を行った。In addition, regarding the phase transition temperature, the text
Measurements were performed by ure observation and differential scanning calorimetry (DSC).
実施例1
用いた強誘電性液晶組成物の、Ps、チルト角、転移温
度、応答速度、闇値特性等を測定した。結果を以下に示
す。Example 1 Ps, tilt angle, transition temperature, response speed, dark value characteristics, etc. of the ferroelectric liquid crystal composition used were measured. The results are shown below.
転移温度
Iso −+ SmA −SmC*65℃
53℃
自発分極
40nC/cm2
チルト角
24゜
応答速度
30μsec
又、第1図ta+にこの強誘電性液晶組成物の等方性液
体からSmA相への転移時のDSCの熱量曲線を示し、
第1図(blに従来よりしられているIs。Transition temperature Iso −+ SmA −SmC *65℃
53°C Spontaneous polarization 40nC/cm2 Tilt angle 24°Response speed 30μsec In addition, Fig. 1 ta+ shows the DSC calorific value curve during the transition of this ferroelectric liquid crystal composition from an isotropic liquid to an SmA phase.
FIG. 1 (Is conventionally known as bl.
−3m A −+ S m C*の相系列を示す強誘電
性液晶組成物の熱量曲線を示す。ここで第1図(a)の
液晶組成物は等方性液体、N*相、SmA相の3重臨界
点(リフシソツボインド)の液晶組成物であり第1図t
b+の液晶組成物は3重臨界点をもたない液晶組成物で
ある。図からも明らがなように第1図fatの液晶組成
物は等方性液体からSmA相への転移ピークの直前にベ
ースラインのずれ、つまり緩やかな発熱現象がみられる
。ところが、第1図(blの従来の液晶組成物はベース
ラインのずれは認められない。このことより明らかに第
1図(alの液晶組成物はSmA相に転移する直前に前
転移現象(プレトランジション)があるが第1図(b)
の液晶組成物は前転移現象はない液晶組成物である。こ
れらの液晶組成物を2.5μmの有機配向膜のラビング
をほどこしたセルにいれ配向状態を観察すると、第1図
+alの液晶組成物は非常に良好な配向状態を示すが、
第1図(blの液晶組成物は液晶分子に一軸性は失われ
良好な配向状態は得られなかった。Fig. 3 shows a calorific value curve of a ferroelectric liquid crystal composition exhibiting a phase series of -3mA-+SmC*. Here, the liquid crystal composition in FIG. 1(a) is a triple critical point liquid crystal composition of an isotropic liquid, an N* phase, and an SmA phase.
The b+ liquid crystal composition is a liquid crystal composition that does not have a triple critical point. As is clear from the figure, in the liquid crystal composition of FIG. 1 fat, a shift in the baseline, that is, a gradual heat generation phenomenon is observed just before the peak of the transition from the isotropic liquid to the SmA phase. However, in the conventional liquid crystal composition shown in FIG. 1 (bl), no deviation of the baseline is observed. From this, it is clear that the liquid crystal composition shown in FIG. Figure 1(b)
The liquid crystal composition is a liquid crystal composition that does not have a pre-transition phenomenon. When these liquid crystal compositions were placed in a cell rubbed with a 2.5 μm organic alignment film and the alignment state was observed, the liquid crystal composition shown in Figure 1+al showed a very good alignment state;
In the liquid crystal composition shown in FIG. 1 (bl), the liquid crystal molecules lost their uniaxiality and a good alignment state could not be obtained.
第2図にこれらの強誘電性液晶組成物の闇値特性を示す
。第2図において(01は闇値特性測定時に用いた印加
波形を示し、Vrはリセットパルス、■tは実際の闇値
特性評価パルス、Vnは非選択パルスを示す。又、第2
図Tal、 (b)において、○は評価電圧印加直後の
最大輝度を示す。×は評価電圧印加後1000ライン走
査後のメモリー状態の輝度を示す。第2図falは第1
図(a)の液晶組成物の闇値特性を示すが、良好なユニ
フォームからユニフォームへの急峻な闇値特性を示す。FIG. 2 shows the dark value characteristics of these ferroelectric liquid crystal compositions. In FIG. 2, (01 indicates the applied waveform used when measuring the dark value characteristics, Vr indicates the reset pulse, ■t indicates the actual dark value characteristic evaluation pulse, and Vn indicates the non-selection pulse.
In Figure Tal, (b), ◯ indicates the maximum brightness immediately after application of the evaluation voltage. × indicates the brightness of the memory state after 1000 line scans after application of the evaluation voltage. Figure 2 fal is the first
The dark value characteristics of the liquid crystal composition shown in FIG.
一方第2図(blは第1図(blの液晶組成物の闇値特
性を示すが(alのように良好な闇値特性はしめさす、
ツイスト間のなまった闇値特性を示す。又、このような
液晶組成物を用いて作成した液晶表示装置は良好な表示
品位を示すものであった。又、このような前転移現象を
示す液晶組成物で自発分極が20n C/ c m 2
以上でチルト角が20°以上のものはこの実施例と同様
良好な配向が容易に得られ、ユニフォーム間の良好な配
向が得られた。On the other hand, although FIG. 2 (bl shows the dark value characteristics of the liquid crystal composition in FIG. 1 (bl), it shows good dark value characteristics like (al),
Indicates the dark value characteristic between twists. Moreover, a liquid crystal display device made using such a liquid crystal composition showed good display quality. In addition, a liquid crystal composition exhibiting such a pre-transition phenomenon has a spontaneous polarization of 20nC/cm2.
As described above, when the tilt angle was 20° or more, good alignment was easily obtained as in this example, and good alignment between uniforms was obtained.
発明の効果
以上のように本発明は相系列が等方性液体−8m A−
4S m C*であり且つ等方性液体→SmAへの転移
時に前転移現象を示す強誘電性液晶組成物であり有機膜
のラビング法を施した表示装置で良好な配向が容易に得
られ、ユニフォーム間のスイッチングを示し、この強誘
電性液晶組成物を用いた強誘電性液晶表示装置は高いコ
ントラストを示し、優れた表示品位を示すものである。Effects of the Invention As described above, the present invention provides an isotropic liquid with a phase series of -8mA-
It is a ferroelectric liquid crystal composition which is 4S m C* and exhibits a pre-transition phenomenon during the transition from isotropic liquid to SmA, and can easily obtain good alignment in a display device subjected to an organic film rubbing method. A ferroelectric liquid crystal display device using this ferroelectric liquid crystal composition exhibits uniform switching and exhibits high contrast and excellent display quality.
第1図は本発明の実施例1における等方性液体からSm
A相への転移時のDSCの特性図、第2図は本発明の実
施例1に於ける闇値特性の特性図、第3図は強誘電性液
晶セルの構成図、第4図は強誘電性液晶の模式図、第5
図は強誘電性液晶の動作原理を示した模式図、第6図は
ツイスト状態の模式図、第7図はツイスト間スイッチン
グの説明図である。
l・・・・・・偏光板、2・・・・・・上下のガラス基
板、3・・・・・・透明電極、4・・・・・・配向処理
を施した有機配向膜、5・・・・・・強誘電性液晶相、
6・・・・・・対抗基板間を密着させるためのシール材
、7・・・・・・強誘電性液晶分子、8・・・・・・自
発分極、9・・・・・・Cダイレクタ−1)0・・・・
・・コーン、1)・・・・・・層、12・・・・・・層
法線、13・・・・・・分子の層法線に対する傾き角θ
、14・・・・・・層法線に対して分子の長軸が十〇傾
いた液晶分子、15・・・・・・層法線に対して分子の
長軸が−θ傾いた液晶分子、16・・・・・・紙面裏方
向を向いている双極子モーメント、17・・・・・・紙
面裏方向を向いている双極子モーメント、18・・・・
・・2枚の偏光板の方向、19・・・・・・上面基板、
2゜・・・・・・下面基板、21・・・・・・+θ傾い
た液晶分子、22・・・・・・−θ傾いた液晶分子、−
23・・・・・・コーン、24・・・・・・Cダイレク
タ−125・・・・・・上面基板、26・・・・・・下
面基板、27・・・・・・コーン、28・・・・・・C
ダイレクタ−0”代理人の氏名 弁理士 中尾敏男 は
か1名第1図
(a)
(b)第2図
詳涌電圧Vt
洋 イ遍シ 1遺= 圧 Vt
第3図
第4図
I
第5図Figure 1 shows Sm from the isotropic liquid in Example 1 of the present invention.
FIG. 2 is a characteristic diagram of the dark value characteristic in Example 1 of the present invention, FIG. 3 is a configuration diagram of a ferroelectric liquid crystal cell, and FIG. Schematic diagram of dielectric liquid crystal, 5th
The figure is a schematic diagram showing the operating principle of a ferroelectric liquid crystal, FIG. 6 is a schematic diagram of a twisted state, and FIG. 7 is an explanatory diagram of switching between twists. 1... Polarizing plate, 2... Upper and lower glass substrates, 3... Transparent electrode, 4... Organic alignment film subjected to alignment treatment, 5... ...ferroelectric liquid crystal phase,
6... Seal material for adhering opposing substrates, 7... Ferroelectric liquid crystal molecules, 8... Spontaneous polarization, 9... C director -1) 0...
... Cone, 1) ... Layer, 12 ... Layer normal, 13 ... Tilt angle θ of the molecule with respect to the layer normal
, 14... Liquid crystal molecules whose long axis of the molecule is tilted by 10 degrees with respect to the layer normal, 15... Liquid crystal molecule whose long axis of the molecule is tilted by -θ with respect to the layer normal , 16...Dipole moment facing toward the back of the page, 17...Dipole moment pointing toward the back of the page, 18...
...Direction of the two polarizing plates, 19...Top substrate,
2゜・・・Lower substrate, 21・・・+θ tilted liquid crystal molecules, 22・・・−θ tilted liquid crystal molecules, −
23...Cone, 24...C director-125...Top board, 26...Bottom board, 27...Cone, 28...・・・・・・C
Director-0” Name of agent Patent attorney Toshio Nakao Figure 1 (a)
(b) Figure 2 Voltage Vt Figure 3 Voltage Vt Figure 3 Figure 4 I Figure 5
Claims (7)
ラルスメクチックC相のすべての相系列を示し、等方性
液体からスメクチックA相への転移時に前転移現象を伴
うことを特徴とする強誘電性液晶組成物。(1) It shows all phase series from the high temperature side: isotropic liquid, smectic A phase, and chiral smectic C phase, and is characterized by being accompanied by a pre-transition phenomenon at the time of transition from isotropic liquid to smectic A phase. Dielectric liquid crystal composition.
ることを特徴とする請求項第(1)項記載の強誘電性液
晶組成物。(2) The ferroelectric liquid crystal composition according to claim (1), wherein the ferroelectric liquid crystal composition has a tilt angle of 20° or more.
2以上であることを特徴とする請求項第(1)項記載の
強誘電性液晶組成物。(3) Spontaneous polarization of ferroelectric liquid crystal composition is 20 nC/cm
2. The ferroelectric liquid crystal composition according to claim 1, wherein the ferroelectric liquid crystal composition is 2 or more.
ラルスメクチックC相のすべての相系列を示し、等方性
液体からスメクチックA相への転移時に前転移現象を伴
う強誘電性液晶組成物をもちいることを特徴とする強誘
電性液晶表示装置。(4) A ferroelectric liquid crystal composition exhibiting all phase series from the high temperature side: isotropic liquid, smectic A phase, and chiral smectic C phase, and accompanied by a pre-transition phenomenon during the transition from the isotropic liquid to the smectic A phase. A ferroelectric liquid crystal display device characterized by using.
性液晶組成物をもちいることを特徴とする請求項第(4
)項記載の強誘電性液晶表示装置。(5) A ferroelectric liquid crystal composition having a tilt angle of 20° or more is used.
) A ferroelectric liquid crystal display device according to item 2.
ある強誘電性液晶組成物をもちいることを特徴とする請
求項第(4)項記載の強誘電性液晶表示装置。(6) A ferroelectric liquid crystal display device according to claim (4), characterized in that a ferroelectric liquid crystal composition having a spontaneous polarization of 20 nC/cm2 or more is used.
によることを特徴とする請求項第(4)項、第(5)項
または第(6)項のいずれかに記載の強誘電性液晶表示
装置。(7) The ferroelectric liquid crystal according to any one of claims (4), (5), and (6), wherein the alignment treatment of the liquid crystal display device is performed by rubbing an organic alignment film. Display device.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5192888A JPH01225691A (en) | 1988-03-04 | 1988-03-04 | Ferroelectric liquid crystal composition and ferroelectric liquid crystal display device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5192888A JPH01225691A (en) | 1988-03-04 | 1988-03-04 | Ferroelectric liquid crystal composition and ferroelectric liquid crystal display device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH01225691A true JPH01225691A (en) | 1989-09-08 |
Family
ID=12900538
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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JP5192888A Pending JPH01225691A (en) | 1988-03-04 | 1988-03-04 | Ferroelectric liquid crystal composition and ferroelectric liquid crystal display device |
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JP (1) | JPH01225691A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5318951A (en) * | 1990-10-01 | 1994-06-07 | Sharp Kabushiki Kaisha | Method for fabricating oxide superconducting coatings |
-
1988
- 1988-03-04 JP JP5192888A patent/JPH01225691A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5318951A (en) * | 1990-10-01 | 1994-06-07 | Sharp Kabushiki Kaisha | Method for fabricating oxide superconducting coatings |
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