JP3065048B2 - Liquid crystal electro-optical element - Google Patents
Liquid crystal electro-optical elementInfo
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- JP3065048B2 JP3065048B2 JP33103198A JP33103198A JP3065048B2 JP 3065048 B2 JP3065048 B2 JP 3065048B2 JP 33103198 A JP33103198 A JP 33103198A JP 33103198 A JP33103198 A JP 33103198A JP 3065048 B2 JP3065048 B2 JP 3065048B2
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はアクティブマトリク
ス方式の液晶電気光学素子に関する。The present invention relates to an active matrix type liquid crystal electro-optical element.
【０００２】[0002]
【従来の技術】従来のアクティブマトリクス方式の液晶
電気光学素子に於いて、配向材料としてはＦに示すよう
な構造の全芳香族系ポリイミドを用いていた。2. Description of the Related Art In a conventional active matrix type liquid crystal electro-optical element, a wholly aromatic polyimide having a structure shown by F is used as an alignment material.
【０００３】[0003]
【数６】 (Equation 6)
【０００４】また、液晶を構成する複数の液晶化合物の
うち△εが大きな液晶化合物はＣ、Ｄ、Ｅに示す末端基
を有する液晶化合物以外に、ＧやＨ等の末端基を有する
液晶化合物を用いるのが普通であった。A liquid crystal compound having a large Δε among a plurality of liquid crystal compounds constituting a liquid crystal is a liquid crystal compound having a terminal group such as G or H in addition to a liquid crystal compound having a terminal group represented by C, D or E. It was common to use.
【０００５】[0005]
【数７】 (Equation 7)
【０００６】[0006]
【数８】 (Equation 8)
【０００７】[0007]
【数９】 (Equation 9)
【０００８】[0008]
【数１０】 (Equation 10)
【０００９】[0009]
【数１１】 [Equation 11]
【００１０】[0010]
【発明が解決しようとする課題】しかし、従来のアクテ
ィブマトリクス方式の液晶電気光学素子には、静止画像
を長時間表示すると表示している画像が非点灯時にも残
ってしまう、いわゆる表示の焼き付きと呼ばれる現象が
発生し易かった。また、さらに長時間液晶表示セルを点
灯状態にしておくと表示むらが発生するという問題点が
あった。これらは、液晶になんらかの直流電圧が印加さ
れることにより、液晶中の不純物イオンが配向層に吸着
してセル内で分極が発生ために生じる現象である。これ
らの現象は、液晶電気光学素子の表示品位と信頼性を低
下させていた。However, in a conventional active matrix type liquid crystal electro-optical element, when a still image is displayed for a long period of time, the displayed image remains even when it is not turned on. The phenomenon called was easy to occur. Further, if the liquid crystal display cell is kept turned on for a longer time, there is a problem that display unevenness occurs. These are phenomena that occur when some DC voltage is applied to the liquid crystal, impurity ions in the liquid crystal are adsorbed on the alignment layer, and polarization occurs in the cell. These phenomena have reduced the display quality and reliability of the liquid crystal electro-optical element.
【００１１】本来液晶を駆動する為の電圧は交流信号の
はずであるが、実際にはＴＦＴのプッシュダウン、ソー
スラインと対向基板間の直流電圧の回り込み、カラーフ
ィルターの存在によるセルの非対称性等により液晶に印
加される電圧は完全交流にはならず、交流に近くとも僅
かな直流成分の電圧が液晶には印加される。The voltage for driving the liquid crystal should be an AC signal. However, actually, the push-down of the TFT, the sneak of DC voltage between the source line and the counter substrate, the asymmetry of the cell due to the presence of the color filter, etc. As a result, the voltage applied to the liquid crystal does not become a complete alternating current, but a voltage of a small DC component is applied to the liquid crystal even when the voltage is close to the alternating current.
【００１２】この直流電圧の大ききはスイッチング素子
の種類や構造により異なるが、直流電圧によって引き起
こされる、表示の焼き付きや表示むらの発生を完全に解
決することは従来困難であった。Although the magnitude of the DC voltage varies depending on the type and structure of the switching element, it has conventionally been difficult to completely solve the problem of display burn-in and display unevenness caused by the DC voltage.
【００１３】そこで本発明では、不純物イオン吸着の起
こりにくい配向膜と不純物イオンの取り込みが少ない液
晶を組み合わせて用いることにより、液晶表示素子の表
示の焼き付きや長時間連続駆動による表示むらの発生を
抑え信頼性を向上させること目的とするものである。Therefore, in the present invention, the use of a combination of an alignment film that is less likely to adsorb impurity ions and a liquid crystal that captures less impurity ions prevents the image sticking of the liquid crystal display element and the occurrence of display unevenness due to continuous driving for a long time. The purpose is to improve reliability.
【００１４】[0014]
【課題を解決するための手段】本発明の液晶電気光学素
子は、対向配置した一対の基板間に液晶組成物を挟持し
ており、少なくとも一方の前記基板にはスイッチング素
子を有し、且つ少なくとも一方の前記基板には配向膜が
形成されている液晶電気光学素子であって、前記配向膜
には下記Ｂで示される構造を有しており、前記液晶組成
物に含まれる電気二重層を形成する不純物イオンの量
は、シアノ基またはシアノ基とフッ素が付加した液晶化
合物を用いた液晶組成物に含まれる電気二重層を形成す
る不純物イオンの量に比べて少ないことを特徴とする。According to the liquid crystal electro-optical device of the present invention, a liquid crystal composition is sandwiched between a pair of opposed substrates, and at least one of the substrates has a switching element. One of the substrates is a liquid crystal electro-optical element having an alignment film formed thereon, wherein the alignment film has a structure represented by B below and forms an electric double layer contained in the liquid crystal composition. The amount of impurity ions to be formed is smaller than the amount of impurity ions forming an electric double layer contained in a liquid crystal composition using a liquid crystal compound in which a cyano group or a cyano group and fluorine are added.
【数２】 (Equation 2)
【００１５】[0015]
【数１２】 (Equation 12)
【００１６】[0016]
【数１３】 (Equation 13)
【００１７】[0017]
【００１８】[0018]
【００１９】[0019]
【００２０】[0020]
【００２１】[0021]
【００２２】また、前記スイッチング素子としては、ｐ
ｏｌｙ−Ｓｉ ＴＦＴ、ａ−ＳｉＴＦＴやＭＩＭなどの
２端子素子のいずれかを用いることを特徴とする。The switching element may include p
It is characterized by using any one of two-terminal elements such as an poly-Si TFT, a-Si TFT, and MIM.
【００２３】[0023]
【作用】液晶セル中の液晶に印加される信号は基本的に
交流となるように設計されるのが普通である。The signal applied to the liquid crystal in the liquid crystal cell is usually designed to be basically an alternating current.
【００２４】しかし、スイツチング素子の特性、構造上
の問題やセルの非対称性等の影響で実際に液晶に印加さ
れる電圧は、完全交流ではなく、僅かながらも直流電圧
が存在する。セル内の液晶に直流電圧が印加されると液
晶中の不純物イオンが配向膜に吸着し電気二重層が形成
される。この電気二重層の形成は液晶層に印加されてい
る直流電圧を完全にキャンセルするまで進行する。セル
に印加される電圧がＯＦＦになり同時に直流電圧が小さ
くなると、今度は電気二重層の直流電圧が液晶層に印加
されることになる。この電気二重層により液晶に電圧が
印加される状態が表示の焼き付きである。However, the voltage actually applied to the liquid crystal due to the characteristics of the switching element, structural problems, and the asymmetry of the cell is not a perfect alternating current but a slight DC voltage. When a DC voltage is applied to the liquid crystal in the cell, impurity ions in the liquid crystal are adsorbed on the alignment film to form an electric double layer. The formation of the electric double layer proceeds until the DC voltage applied to the liquid crystal layer is completely cancelled. When the voltage applied to the cell is turned off and the DC voltage is reduced at the same time, the DC voltage of the electric double layer is applied to the liquid crystal layer. The state in which a voltage is applied to the liquid crystal by the electric double layer is image burn-in.
【００２５】この表示の焼き付きは、配向層に吸着した
不純物イオンが熱エネルギー等により配向層の界面を離
れ液晶層のバルクに分散して電気二重層による電位が十
分小さくなると消滅する。This burn-in of the display disappears when the impurity ions adsorbed on the alignment layer leave the interface of the alignment layer due to thermal energy or the like and are dispersed in the bulk of the liquid crystal layer, so that the potential of the electric double layer becomes sufficiently small.
【００２６】さらに、長時間液晶を駆動すると配向層の
界面に不純物イオンの吸着と脱離を繰り返えされる。Further, when the liquid crystal is driven for a long time, adsorption and desorption of impurity ions at the interface of the alignment layer are repeated.
【００２７】不純物イオンが配向層の界面に吸着してか
ら脱離するまでに要する時間を緩和時間とすると長時間
吸着と脱離を繰り返すと必然的に緩和時間の長い不純物
イオンの吸着が多くなる。If the time required from the time when the impurity ions are adsorbed at the interface of the alignment layer to the time when they are desorbed is set as the relaxation time, if the adsorption and desorption are repeated for a long time, the adsorption of the impurity ions having a long relaxation time will inevitably increase. .
【００２８】この緩和持間の長い不純物イオンの吸着は
セル内に分極を生じ液晶に所望の信号を印加させること
を阻害するようになる。この緩和時間の長い不純物イオ
ンの吸着は、表示むらとなり観察される。The adsorption of the impurity ions having a long relaxation time causes polarization in the cell and hinders application of a desired signal to the liquid crystal. The adsorption of the impurity ions having a long relaxation time causes display unevenness and is observed.
【００２９】液晶中の不純物イオンの配向層への吸着
は、ジャパニーズ ジャーナル オブアプライド フィ
ジクス２７（１９８７）Ｌ１０９２でＭＡＤＡ等が報告
しているように、液晶セルのＣ−Ｖ特性のヒステリシス
幅の測定を行うことで評価することが可能である。The adsorption of the impurity ions in the liquid crystal onto the alignment layer can be measured by measuring the hysteresis width of the CV characteristic of the liquid crystal cell as reported by MADA et al. In Japanese Journal of Applied Physics 27 (1987) L1092. It is possible to evaluate by doing.
【００３０】表１−１と表１−２に液晶のヒステリシス
幅の測定結果を示す。Tables 1-1 and 1-2 show the measurement results of the hysteresis width of the liquid crystal.
【００３１】[0031]
【表１】 [Table 1]
【００３２】このヒステリシス幅の定義は、１００ｍＶ
／ｓｅｃのｓｃａｎｒａｔｅで±１０ＶのＣ−Ｖ特性の
測定を行い、図１に示すように得られたたＣ−Ｖ特性の
最小容量ＣMINからＣMINと最大容量ＣMAXの変化分△Ｃ
＝（ＣMAX−ＣMIN）の１０％の容量変化起こる電圧をＶ
ｌ、Ｖ２、Ｖ３、Ｖ４を用いて（Ｖ１＋Ｖ２−Ｖ３−Ｖ
４）／２をヒステリシス幅とした。The definition of the hysteresis width is 100 mV
The CV characteristic of ± 10 V was measured at a scan rate of / sec, and as shown in FIG. 1, the change ΔC between the minimum capacitance CMIN and the maximum capacitance CMAX of the CV characteristic obtained as shown in FIG.
= (CMAX-CMIN) 10% of the capacitance change voltage is V
1, V2, V3, and V4 (V1 + V2-V3-V
4) / 2 was defined as the hysteresis width.
【００３３】液晶Ｉは△εが＋３以上の液晶化合物に末
端基がフッ素あるいはジフッ素の液晶のみを用いた混合
液晶である。The liquid crystal I is a mixed liquid crystal using only a liquid crystal having a terminal group of fluorine or difluorine in a liquid crystal compound having Δε of +3 or more.
【００３４】液晶ＩＩは△εが＋３以上の液晶化合物に
末端基がフッ素あるいはジフッ素の液晶のみを用いた混
合液晶で液晶Ｉとは異なる液晶である。The liquid crystal II is a mixed liquid crystal using a liquid crystal compound having Δ △ of +3 or more and a terminal group of only fluorine or difluorine and different from the liquid crystal I.
【００３５】液晶ＩＩＩは△εが＋３以上の液晶化合物
に末端基がフッ素あるいはジフッ素の液晶化合物のみを
用いた混合液晶で液晶Ｉ、液晶ＩＩとは異なる液晶であ
る。The liquid crystal III is a mixed liquid crystal using a liquid crystal compound having Δ △ of at least +3 and a liquid crystal compound having a terminal group of fluorine or difluorine, which is different from the liquid crystals I and II.
【００３６】液晶ＩＶは△εが＋３以上の液晶化合物に
末端基がフッ素あるいはジフッ素あるいはトリフルオロ
メトキシ基の液晶化合物のみを用いた混合液晶である。The liquid crystal IV is a mixed liquid crystal using a liquid crystal compound having Δ △ of +3 or more and only a liquid crystal compound having a terminal group of fluorine, difluorine or trifluoromethoxy group.
【００３７】液晶Ｖは△εが＋３以上の液晶化合物に末
端基がフッ素あるいはジフッ素の液晶化合物の他にシア
ノ基を持つ液晶化合物を含む混合液晶である。The liquid crystal V is a mixed liquid crystal containing a liquid crystal compound having a △ ε of +3 or more and a liquid crystal compound having a cyano group in addition to a liquid crystal compound having a terminal group of fluorine or difluorine.
【００３８】液晶ＶＩは△εが＋３以上の液晶化合物に
末端基がフッ素あるいはジフッ素の液晶液晶化合物の他
にシアノ基を持つ液晶材料を含む混合液晶で液晶Ｖとは
異なる液晶である。The liquid crystal VI is a liquid crystal compound different from the liquid crystal V, which is a mixed liquid crystal containing a liquid crystal compound having a terminal group of fluorine or difluorine and a liquid crystal material having a cyano group in addition to a liquid crystal compound having Δ △ of +3 or more.
【００３９】液晶ＶＩＩは△εが＋３以上の液晶化合物
に末端基がフッ素あるいはジフッ素の液晶化合物の他に
シアノ基を持つ液晶化合物を含む混合液晶で液晶Ｖ、液
晶ＶＩとは異なる液晶である。The liquid crystal VII is a mixed liquid crystal containing a liquid crystal compound having Δ △ of not less than +3 and a liquid crystal compound having a cyano group in addition to a liquid crystal compound having a terminal group of fluorine or difluorine and different from the liquid crystal V and the liquid crystal VI. .
【００４０】液晶ＶＩＩＩは△εが＋３以上の液晶化合
物に末端基にシアノ基をもつ液晶化合物のみを用いた混
合液晶である。The liquid crystal VIII is a mixed liquid crystal using only a liquid crystal compound having a cyano group as a terminal group in a liquid crystal compound having Δ △ of +3 or more.
【００４１】液晶ＩＸは△εが＋３以上の液晶化合物に
末端基にシアノ基とフッ素の付加した液晶化合物とフッ
素の付加した液晶化合物を用いた混合液晶である。The liquid crystal IX is a mixed liquid crystal using a liquid crystal compound having Δ △ of +3 or more and a liquid crystal compound having a cyano group and fluorine added to a terminal group and a liquid crystal compound having fluorine added.
【００４２】液晶Ｉ、液晶ＩＩ、液晶ＩＩＩ、液晶ＩＶ
などの液晶組成物のヒステリシス幅は液晶Ｖ、液晶Ｖ
Ｉ、液晶ＶＩＩ、液晶ＶＩＩＩ、液晶ＩＸのヒステリシ
ス幅と比較してはるかに小さな値を示した。Liquid crystal I, liquid crystal II, liquid crystal III, liquid crystal IV
The hysteresis width of a liquid crystal composition such as liquid crystal V and liquid crystal V
I, the liquid crystal VII, the liquid crystal VIII, and the liquid crystal IX showed much smaller values than the hysteresis width.
【００４３】この結果から、△εが＋３以上の液晶化合
物に末端基がフッ素あるいはジフッ素あるいはトリフル
オロメトキシ基を有する液晶化合物のみを用いた混合液
晶は、電気二重層を形成する不純物イオンの量がシアノ
基やシアノ基とフッ素の付加した液晶化合物を用いた混
合液晶に比べて少ないことがわかった。From these results, it can be seen that a mixed liquid crystal using only a liquid crystal compound having a terminal group of fluorine, difluorine or trifluoromethoxy group in a liquid crystal compound having Δε of +3 or more has a low impurity ion forming an electric double layer. Was smaller than that of a mixed liquid crystal using a liquid crystal compound in which a cyano group or a cyano group and fluorine were added.
【００４４】次に、液晶材料に△εが＋３以上の液晶化
合物に末端基がフッ素あるいはジフッ素の液晶化合物の
みを用いた混合液晶を用いて、配向膜の材料を変えたと
き不純物イオンの配向膜に形成する電気二重層によるセ
ル内の分極電圧の測定を行った。Next, when the material of the alignment film is changed by using a liquid crystal material in which only a liquid crystal compound having a terminal group of fluorine or difluorine is used as a liquid crystal compound having Δ △ of +3 or more as a liquid crystal material, the orientation of impurity ions is changed. The polarization voltage in the cell was measured by the electric double layer formed on the film.
【００４５】この測定は、５０℃の高温槽内で評価用液
晶セルに５Ｖの直流電圧を１００時間印加した後に２５
℃の温度で同様のＣ−Ｖ特性の測定を行った。Ｃ−Ｖ特
性はセル内に電気二重層による内部分極が生じているた
め図２に示すようＣ−Ｖカーブの対称軸が０Ｖから大き
くずれる。この対称のずれを分極電圧として定義した。
分極電圧は、先ほどのＶｌ、Ｖ２、Ｖ３、Ｖ４を用いる
と（Ｖｌ＋Ｖ２＋Ｖ３＋Ｖ４）／４で定義した。配向膜
の材料を変えたときの分極電圧の測定結果を表２に示
す。In this measurement, a DC voltage of 5 V was applied to a liquid crystal cell for evaluation in a high-temperature bath at 50 ° C. for 100 hours, and then 25 minutes.
Similar CV characteristics were measured at a temperature of ° C. In the CV characteristic, the symmetry axis of the CV curve deviates greatly from 0 V as shown in FIG. 2 because internal polarization occurs due to the electric double layer in the cell. This symmetry shift was defined as polarization voltage.
The polarization voltage was defined as (Vl + V2 + V3 + V4) / 4 using Vl, V2, V3, and V4. Table 2 shows the measurement results of the polarization voltage when the material of the alignment film was changed.
【００４６】[0046]
【表２】 [Table 2]
【００４７】配向膜ＩはＡに示す構造を持つ脂環族／芳
香族系ポリイミドである。The alignment film I is an alicyclic / aromatic polyimide having the structure shown in A.
【００４８】[0048]
【数１７】 [Equation 17]
【００４９】配向膜ＩＩはＢに示す構造を持つ脂環族／
芳香族系ポリイミドである。The alignment film II has an alicyclic group having the structure shown in B /
It is an aromatic polyimide.
【００５０】[0050]
【数１８】 (Equation 18)
【００５１】配向膜ＩＩＩはＦに示す構造を持つ全芳香
族系ポリイミドである。The alignment film III is a wholly aromatic polyimide having a structure shown by F.
【００５２】[0052]
【数１９】 [Equation 19]
【００５３】表２から配向膜Ｉと配向膜ＩＩは配向膜Ｉ
ＩＩ、配向膜ＩＶ、配向膜Ｖや配向膜ＶＩと比較して、
分極電圧が著しく小さい。これは、配向膜Ｉと配向膜Ｉ
Ｉは、不純物イオンが吸着しても短時間で脱離が起こる
ためである。From Table 2, it can be seen that the alignment films I and II
II, alignment film IV, alignment film V and alignment film VI,
The polarization voltage is extremely low. This is because the alignment film I and the alignment film I
I is because desorption occurs in a short time even if impurity ions are adsorbed.
【００５４】これらの結果から液晶を構成する液晶化合
物で△εが＋３以上の液晶化合物の全てがＣ〜Ｅに示す
末端基From these results, all of the liquid crystal compounds constituting the liquid crystal having Δε of +3 or more show the terminal groups represented by CE.
【００５５】[0055]
【数２０】 (Equation 20)
【００５６】[0056]
【数２１】 (Equation 21)
【００５７】[0057]
【数２２】 (Equation 22)
【００５８】のいずれかを有することを特徴とする混合
液晶とＡあるいはＢに示す構造の有機膜配向膜ＩＶはＪ
に示す構造を持つ全芳香族系のポリイミドである。The mixed liquid crystal having one of the above and the organic film alignment film IV having the structure shown in A or B is
This is a wholly aromatic polyimide having the structure shown in FIG.
【００５９】[0059]
【数２３】 (Equation 23)
【００６０】配向膜ＶはＫに示す構造を持つ脂環族／芳
香族系のポリイミドである。The alignment film V is an alicyclic / aromatic polyimide having a structure represented by K.
【００６１】[0061]
【数２４】 (Equation 24)
【００６２】配向膜ＶＩはＬに示す構造を持つ全脂環族
系のポリイミドである。The alignment film VI is an all-alicyclic polyimide having the structure shown by L.
【００６３】[0063]
【数２５】 (Equation 25)
【００６４】[0064]
【数２６】 (Equation 26)
【００６５】[0065]
【数２７】 [Equation 27]
【００６６】を配向膜として組み合わせて用いると液晶
層に直流電圧が印加されても不純物イオンの配向層界面
への吸着による電気二重層の形成がより少なくなるた
め、従来の液晶と配向膜のを用いた液晶表示セルと比較
して、表示の焼き付きや長時間連続駆動による表示むら
の発生が起こりにくい信頼性の高い液晶表示セルが得ら
れることがわかる。When a liquid crystal layer is used in combination with an alignment layer, even if a DC voltage is applied to the liquid crystal layer, the formation of an electric double layer due to the adsorption of impurity ions at the interface between the alignment layers is reduced. It can be seen that a highly reliable liquid crystal display cell which is less likely to cause display burn-in and display unevenness due to long-time continuous driving as compared with the liquid crystal display cell used is obtained.
【００６７】以下、実施例により本発明の詳細を示す。Hereinafter, the present invention will be described in detail with reference to examples.
【００６８】[0068]
【発明の実施の形態】（実施例１）本発明の第１の実施
例として、画素数３２０×２２０個でｐｏｌｙ−Ｓｉ
ＴＦＴを用いた対角１インチのビュウファインダー用の
液晶電気光学素子を作成した。(Embodiment 1) As a first embodiment of the present invention, the number of pixels is 320 × 220 and poly-Si
A 1-inch diagonal liquid crystal electro-optical element for a viewfinder using a TFT was prepared.
【００６９】配向膜は、γ−プチルラクトンに溶解させ
たＡに示す構造の脂環族／芳香族ポリイミドを、スピン
コート法により液晶電気光学素子を構成する基板に塗布
１５０℃で１時間焼成して形成した。The alignment film is formed by applying an alicyclic / aromatic polyimide having a structure shown in A dissolved in γ-butyl lactone to a substrate constituting a liquid crystal electro-optical element by a spin coating method, followed by firing at 150 ° C. for 1 hour. Formed.
【００７０】[0070]
【数２８】 [Equation 28]
【００７１】液晶は、複数の液晶化合物から構成された
混合液晶を用いた。この液晶を構成する液晶化合物のな
かで、△εが＋３以上の液晶化合物はすべてＣに示す末
端基かＤに示す末端基のどちらかを有する液晶化合物で
あった。この液晶の△εは＋３．９、△ｎは０．０８０
であった。As the liquid crystal, a mixed liquid crystal composed of a plurality of liquid crystal compounds was used. Among the liquid crystal compounds constituting the liquid crystal, all of the liquid crystal compounds having Δε of +3 or more were liquid crystal compounds having either a terminal group represented by C or a terminal group represented by D. Δ 液晶 of this liquid crystal is +3.9 and Δn is 0.080.
Met.
【００７２】[0072]
【数２９】 (Equation 29)
【００７３】[0073]
【数３０】 [Equation 30]
【００７４】セル厚は△ｎｄが０．４０μｍになるよう
に５．０μｍに設定した。The cell thickness was set to 5.0 μm so that Δnd became 0.40 μm.
【００７５】この液晶電気光学素子と従来の液晶電気光
学素子の信頼性テストの結果、従来の液晶電気光学素子
はウインドウパターンを１分間点灯後消灯したとき表示
の焼き付きがみられたのに対して本発明の液晶電気光学
素子は２４時間点灯表示しても表示の焼き付きはみられ
なかった。また、５０℃の高温槽内で通電エージングを
行った結果、従来の液晶電気光学素子は５００時間以内
に５０％以上の表示不良が発生したのに対して、本発明
の液晶電気光学素子は１０００時間エージングしても表
示不良の発生率は１０％以下であった。本発明の液晶電
気光学素子はきわめて高い信頼性が得られた。As a result of a reliability test of this liquid crystal electro-optical element and the conventional liquid crystal electro-optical element, display sticking was observed when the window pattern was turned on for 1 minute and then turned off. The liquid crystal electro-optical element of the present invention did not show any image sticking even after being lit for 24 hours. In addition, as a result of conducting current aging in a high-temperature chamber at 50 ° C., the conventional liquid crystal electro-optical element exhibited a display failure of 50% or more within 500 hours, whereas the liquid crystal electro-optical element of the present invention had a display defect of 1000%. Even after time aging, the occurrence rate of display failure was 10% or less. The liquid crystal electro-optical device of the present invention has extremely high reliability.
【００７６】（実施例２）本発明の第２の実施例とし
て、画素数４８０×４４０個でｐｏｌｙ−Ｓｉ ＴＦＴ
を用いた対角２インチのライトバルブ用の液晶電気光学
素子を作成した。(Embodiment 2) As a second embodiment of the present invention, a poly-Si TFT having 480 × 440 pixels is used.
A 2 inch diagonal liquid crystal electro-optical element for a light valve was prepared using the above method.
【００７７】配向膜は、実施例１と同じ方法で形成し
た。液晶は、複数の液晶化合物から構成された混合液晶
を用いた。この液晶を構成する液晶化合物のなかで、△
εが＋３以上の液晶化合物はすべてＣに示す末端基か、
Ｄに示す末端基か、あるいはＥに示す末端基のいずれか
を有する液晶化合物であった。この液晶の△εは＋６．
８、△ｎは０．０８８であった。The alignment film was formed in the same manner as in Example 1. As the liquid crystal, a mixed liquid crystal composed of a plurality of liquid crystal compounds was used. Among the liquid crystal compounds constituting this liquid crystal,
All the liquid crystal compounds having ε of +3 or more are terminal groups represented by C,
It was a liquid crystal compound having either the terminal group shown in D or the terminal group shown in E. Δ △ of this liquid crystal is +6.
8, Δn was 0.088.
【００７８】[0078]
【数３１】 (Equation 31)
【００７９】[0079]
【数３２】 (Equation 32)
【００８０】[0080]
【数３３】 [Equation 33]
【００８１】セル厚は△ｎｄが０．４０μｍになるよう
に４．５μｍに設定した。The cell thickness was set to 4.5 μm so that Δnd became 0.40 μm.
【００８２】この液晶電気光学素子と従来の液晶電気光
学素子の信頼性テストの結果、従来の液晶電気光学素子
はウインドウパターンを１分間点打後消灯したとき表示
の焼き付きがみられたのに対して本発明の液晶電気光学
素子は２４時間点灯表示しても表示の焼き付きはみられ
なかった。また、５０℃の高温槽内で通電エージングを
行った結果、従来の液晶電気光学素子は５００時間以内
に５０％以上の表示不良が発生したのに対して、本発明
の液晶電気光学素子は１０００時間エージングしても表
示不良の発生率は１０％以下であった。本発明の液晶電
気光学素子はきわめて高い信頼性が得られた。As a result of a reliability test of the liquid crystal electro-optical element and the conventional liquid crystal electro-optical element, display burn-in was observed in the conventional liquid crystal electro-optical element when the window pattern was struck for one minute and then turned off. Thus, the liquid crystal electro-optical element of the present invention showed no display burn-in even after being lit for 24 hours. In addition, as a result of conducting current aging in a high-temperature chamber at 50 ° C., the conventional liquid crystal electro-optical element exhibited a display failure of 50% or more within 500 hours, whereas the liquid crystal electro-optical element of the present invention had a display defect of 1000%. Even after time aging, the occurrence rate of display failure was 10% or less. The liquid crystal electro-optical device of the present invention has extremely high reliability.
【００８３】（実施例３）本発明の第３の実施例とし
て、画素数６４０×４００×３個でＭＩＭを用いた対角
１０インチのラップトップ・コンピューターのディスプ
レイ用の液晶電気光学素子を作成した。Embodiment 3 As a third embodiment of the present invention, a liquid crystal electro-optical element for a display of a 10-inch diagonal laptop computer using MIM with 640 × 400 × 3 pixels is prepared. did.
【００８４】配向膜は、実施例１、実施例２と同じ方法
で形成した。液晶は、複数の液晶化合物から構成された
混合液晶を用いた。この液晶を構成する液晶化合物のな
かで、△εが＋３以上の液晶化合物はすベてＤに示す末
端基を有する液晶化合物であった。また、この液晶はエ
ステル系の液晶化合物を全く含まなかった。この液晶の
△εは＋３．２、△ｎは０．０８８であった。The alignment film was formed in the same manner as in Examples 1 and 2. As the liquid crystal, a mixed liquid crystal composed of a plurality of liquid crystal compounds was used. Among the liquid crystal compounds constituting the liquid crystal, all the liquid crystal compounds having Δε of +3 or more were the liquid crystal compounds having the terminal group shown by D. This liquid crystal did not contain any ester-based liquid crystal compound. Δ △ of this liquid crystal was +3.2 and Δn was 0.088.
【００８５】[0085]
【数３４】 (Equation 34)
【００８６】セル厚は△ｎｄが０．４０μｍになるよう
に４．５μｍに設定した。The cell thickness was set to 4.5 μm so that Δnd became 0.40 μm.
【００８７】この液晶電気光学素子と従来の液晶電気光
学素子の信頼性テストの結果、従来の液晶電気光学素子
はウインドウパターンを１分間点灯後消灯したとき表示
の焼き付きがみられたのに対して本発明の液晶電気光学
素子は４８時間点灯表示しても表示の焼き付きはみられ
なかった。また、５０℃の高温槽内で通電エージングを
行った結果、従来の液晶電気光学素子は１０００時間以
内に４０％以上の表示不良が発生したのに対して、本発
明の液晶電気光学素子は１０００時間エージングしても
表示不良の発生率は５％以下であった。本発明の液晶電
気光学素子はきわめて高い信頼性が得られた。As a result of a reliability test of this liquid crystal electro-optical element and a conventional liquid crystal electro-optical element, the conventional liquid crystal electro-optical element showed image sticking when the window pattern was turned on for 1 minute and then turned off. In the liquid crystal electro-optical element of the present invention, no burn-in of the display was observed even when the display was lit for 48 hours. In addition, as a result of conducting current aging in a high-temperature bath at 50 ° C., the conventional liquid crystal electro-optical element had a display failure of 40% or more within 1000 hours, whereas the liquid crystal electro-optical element of the present invention had a display defect of 1000%. Even after time aging, the rate of occurrence of display defects was 5% or less. The liquid crystal electro-optical device of the present invention has extremely high reliability.
【００８８】（実施例４）本発明の第４の実施例とし
て、画素数３２０×２２０個でｐｏｌｙ−Ｓｉ ＴＦＴ
を用いた対角１インチのビュウファインダー用の液晶電
気光学素子を作成した。(Embodiment 4) As a fourth embodiment of the present invention, a poly-Si TFT having 320 × 220 pixels is used.
A 1 inch diagonal liquid crystal electro-optical element for a viewfinder was prepared using the above method.
【００８９】配向膜は、Ｎ−メチルピロリドンの溶解さ
せたＢに示す構造の脂環族／芳香族ポリイミドを、スピ
ンコート法により液晶電気光学素子を構成する基板に塗
布１５０℃で１時間焼成して形成した。The alignment film is formed by applying an alicyclic / aromatic polyimide having a structure shown in B in which N-methylpyrrolidone is dissolved to a substrate constituting a liquid crystal electro-optical element by spin coating at 150 ° C. for 1 hour. Formed.
【００９０】[0090]
【数３５】 (Equation 35)
【００９１】液晶は、複数の液晶化合物から構成された
混合液晶を用いた。この液晶を構成する液晶化合物のな
かで、△εが＋３以上の液晶化合物はすべてＣに示す末
端基かＤに示す末端基のどちらかを有する液晶化合物で
あった。この液晶の△εは＋３．９、△ｎは０．０８０
であった。As the liquid crystal, a mixed liquid crystal composed of a plurality of liquid crystal compounds was used. Among the liquid crystal compounds constituting the liquid crystal, all of the liquid crystal compounds having Δε of +3 or more were liquid crystal compounds having either a terminal group represented by C or a terminal group represented by D. Δ 液晶 of this liquid crystal is +3.9 and Δn is 0.080.
Met.
【００９２】[0092]
【数３６】 [Equation 36]
【００９３】[0093]
【数３７】 (37)
【００９４】セル厚は△ｎｄが０．４０μｍになるよう
に５．０μｍに設定した。The cell thickness was set to 5.0 μm so that Δnd became 0.40 μm.
【００９５】この液晶電気光学素子と従来の液晶電気光
学素子の信頼性テストの結果、従来の液晶電気光学素子
はウインドウパターンを１分間点灯後消灯したとき表示
の焼き付きがみられたのに対して本発明の液晶電気光学
素子は２４時間点灯表示しても表示の焼き付きはみられ
なかった。また、５０℃の高温槽内で通電エージングを
行った結果、従来の液晶電気光学素子は５００時間以内
に５０％以上の表示不良が発生したのに対して、本発明
の液晶電気光学素子は１０００時間エージングしても表
示不良の発生率は１０％以下であった。本発明の液晶電
気光学素子はきわめて高い信頼性が得られた。As a result of a reliability test of this liquid crystal electro-optical element and a conventional liquid crystal electro-optical element, the conventional liquid crystal electro-optical element showed image sticking when the window pattern was turned on for 1 minute and then turned off. The liquid crystal electro-optical element of the present invention did not show any image sticking even after being lit for 24 hours. In addition, as a result of conducting current aging in a high-temperature chamber at 50 ° C., the conventional liquid crystal electro-optical element exhibited a display failure of 50% or more within 500 hours, whereas the liquid crystal electro-optical element of the present invention had a display defect of 1000%. Even after time aging, the occurrence rate of display failure was 10% or less. The liquid crystal electro-optical device of the present invention has extremely high reliability.
【００９６】（実施例５）本発明の第２の実施例とし
て、画素数４８０×４４０個でｐｏｌｙ−Ｓｉ ＴＦＴ
を用いた対角２インチのライトバルブ用の液晶電気光学
素子を作成した。(Embodiment 5) As a second embodiment of the present invention, a poly-Si TFT having 480 × 440 pixels is used.
A 2 inch diagonal liquid crystal electro-optical element for a light valve was prepared using the above method.
【００９７】配向膜は、実施例４と同じ方法で形成し
た。液晶は、複数の液晶化合物から構成された混合液晶
を用いた。この液晶を構成する液晶化合物のなかで、△
εが＋３以上の液晶化合物はすべてＣに示す末端基か、
Ｄに示す末端基か、あるいはＥに示す末端基のいずれか
を有する液晶化合物であった。The alignment film was formed in the same manner as in Example 4. As the liquid crystal, a mixed liquid crystal composed of a plurality of liquid crystal compounds was used. Among the liquid crystal compounds constituting this liquid crystal,
All the liquid crystal compounds having ε of +3 or more are terminal groups represented by C,
It was a liquid crystal compound having either the terminal group shown in D or the terminal group shown in E.
【００９８】この液晶の△εは＋６．８、△ｎは０．０
８８であった。Δ 液晶 of this liquid crystal is +6.8, Δn is 0.0
88.
【００９９】[0099]
【数３８】 (38)
【０１００】[0100]
【数３９】 [Equation 39]
【０１０１】[0101]
【数４０】 (Equation 40)
【０１０２】セル厚は△ｎｄが０．４０μｍになるよう
に４．５μｍに設定した。The cell thickness was set to 4.5 μm so that Δnd became 0.40 μm.
【０１０３】この液晶電気光学素子と従来の液晶電気光
学素子の信頼性テストの結果、従来の液晶電気光学素子
はウインドウパターンを１分間点灯後消灯したとき表示
の焼き付きがみられたのに対して本発明の液晶電気光学
素子は２４時間点灯表示しても表示の焼き付きはみられ
なかった。また、５０℃の高温槽内で通電エージングを
行った結果、従来の液晶電気光学素子は５００時間以内
に５０％以上の表示不良が発生したのに対して、本発明
の液晶電気光学素子は１０００時間エージングしても表
示不良の発生率は１０％以下であった。本発明の液晶電
気光学素子はきわめて高い信頼性が得られた。As a result of a reliability test of the liquid crystal electro-optical element and the conventional liquid crystal electro-optical element, display burn-in was observed in the conventional liquid crystal electro-optical element when the window pattern was turned on for 1 minute and then turned off. The liquid crystal electro-optical element of the present invention did not show any image sticking even after being lit for 24 hours. In addition, as a result of conducting current aging in a high-temperature chamber at 50 ° C., the conventional liquid crystal electro-optical element exhibited a display failure of 50% or more within 500 hours, whereas the liquid crystal electro-optical element of the present invention had a display defect of 1000%. Even after time aging, the occurrence rate of display failure was 10% or less. The liquid crystal electro-optical device of the present invention has extremely high reliability.
【０１０４】以上実施例を述べたが、本発明は以上の実
施例のようなＴＮ（ツイステッドネマチック）モードの
液晶表示素子のみならず、ＳＴＮ（スーパーツイステッ
ドネマチック）モードなど他の液晶表示モードの液晶電
気光学素子に応用が可能である。Although the embodiments have been described above, the present invention is not limited to the TN (twisted nematic) mode liquid crystal display device as in the above embodiments, but also to other liquid crystal display modes such as STN (super twisted nematic) mode. It can be applied to electro-optical elements.
【０１０５】[0105]
【発明の効果】以上述べたように本発明によれば、不純
物イオンが吸着しにくい配向膜と、電気二重層を形成す
る不純物イオンの量が少ない液晶組成物とを組み合わせ
ることによって、配向膜に吸着する不純物イオンの量を
抑制することが可能となり、その結果、電気二重層が形
成されにくくなるので、表示の焼き付き又は表示むらの
ない液晶電気光学素子が実現する。As described above, according to the present invention, by combining an alignment film in which impurity ions are not easily adsorbed and a liquid crystal composition having a small amount of impurity ions forming an electric double layer, the alignment film can be formed. Since the amount of adsorbed impurity ions can be suppressed, and as a result, an electric double layer is hardly formed, a liquid crystal electro-optical element having no display burn-in or display unevenness is realized.
【図１】液晶セルのＣ−Ｖ特性の測定で現れるヒステリ
シスを表す図である。FIG. 1 is a diagram showing hysteresis appearing in measurement of CV characteristics of a liquid crystal cell.
【図２】液晶セルのＣ−Ｖ特性の測定で現れる、液晶セ
ル内の内部分極によるＣ−Ｖカーブの対称軸のずれを表
す図である。FIG. 2 is a diagram showing deviation of a symmetric axis of a CV curve due to internal polarization in the liquid crystal cell, which appears in measurement of the CV characteristic of the liquid crystal cell.
Claims (1)
を挟持しており、少なくとも一方の前記基板にはスイッ
チング素子を有し、且つ少なくとも一方の前記基板には
配向膜が形成されている液晶電気光学素子であって、 前記配向膜には下記Ｂで示される構造を有しており、 前記液晶組成物に含まれる電気二重層を形成する不純物
イオンの量は、シアノ基またはシアノ基とフッ素が付加
した液晶化合物を用いた液晶組成物に含まれる電気二重
層を形成する不純物イオンの量に比べて少ないことを特
徴とする液晶電気光学素子。Ｂ 【数１】 1. A liquid crystal composition is sandwiched between a pair of substrates arranged opposite to each other, a switching element is provided on at least one of the substrates, and an alignment film is formed on at least one of the substrates. In a liquid crystal electro-optical element, the alignment film has a structure represented by B below, and the amount of impurity ions forming an electric double layer included in the liquid crystal composition is a cyano group or a cyano group. A liquid crystal electro-optical element characterized in that the liquid crystal composition has a smaller amount of impurity ions forming an electric double layer contained in a liquid crystal composition using a liquid crystal compound to which fluorine has been added. B (Equation 1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33103198A JP3065048B2 (en) | 1998-11-20 | 1998-11-20 | Liquid crystal electro-optical element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33103198A JP3065048B2 (en) | 1998-11-20 | 1998-11-20 | Liquid crystal electro-optical element |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10800690A Division JP2949770B2 (en) | 1990-04-24 | 1990-04-24 | Liquid crystal electro-optical element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11249147A JPH11249147A (en) | 1999-09-17 |
| JP3065048B2 true JP3065048B2 (en) | 2000-07-12 |
Family
ID=18239060
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33103198A Expired - Lifetime JP3065048B2 (en) | 1998-11-20 | 1998-11-20 | Liquid crystal electro-optical element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3065048B2 (en) |
-
1998
- 1998-11-20 JP JP33103198A patent/JP3065048B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11249147A (en) | 1999-09-17 |
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