JP3584486B2 - Nematic liquid crystal composition and liquid crystal display device using the same - Google Patents

Description

【０００７】
（式中、Ｖ_ｔｈはしきい値電圧を、ｋは比例定数を、Ｋは弾性定数を、Δεは誘電異方性をそれぞれ表わす。）の関係から、誘電異方性の大きな液晶材料を用いて駆動電圧を低下させる方法が知られている。しかしながら、このような液晶材料は液晶材料の粘性を増加させる傾向を有するものが多いので、良好な応答特性を得ることを困難にさせる、あるいは各画素毎のキャパシタンス成分を増加させるものであり、表示可能な駆動周波数範囲を狭め、クロストーク現象を発生させる等の問題を有している。
【０００８】
一方、低電圧で駆動可能な従来の液晶材料の場合、一般的に、調製された初期あるいは加熱や紫外線照射による促進テスト後の抵抗値が低いことが知られている。この様な液晶材料の低い抵抗値は、時分割数の増大により表示画面のちらつきやコントラストの低下等を引き起こす原因となり、好ましくなかった。
【０００９】
更に、情報量の増加による暗い画質を補う目的で、ＳＴＮ−ＬＣＤにはバックライトを補助光源として利用することが一般的である。このために、バックライト方式のＳＴＮ−ＬＣＤに用いられる液晶材料には、耐熱性及び耐光性等の化学的安定性が新たに要求されている。
【００１０】
これらの要求特性に加えて、特にアクティブ・マトリクス方式においては、均一で高いコントラストを得るために、漏れ電流が小さく、高い電圧保持率を有することが重要である。この様な特性を得るために、例えば、下記のような化合物が用いられてきた。
【００１１】
【化６】

【００１２】
（式中、Ｒ^１０は直鎖状アルキル基を表わし、Ｘ^２は水素原子又はフッ素原子を表わす。）
しかしながら、このような化合物を用いても広い温度範囲、特に低温においてネマチック液晶性を保持することと、アクティブ・マトリクス方式に要求されるしきい値電圧を充分に低減させることを共に満足する組成物を調製することはできなかった。
【００１３】
更に加えて、均一で高いコントラストの液晶表示特性を得るために、液晶パネルの液晶層の厚みｄと液晶材料の複屈折率△ｎとの積△ｎ・ｄを０．４０〜０．５５（以下、このことをファーストミニマムと呼称する）の範囲に調整することが好ましいとされている。現在の液晶パネルの作製工程で行われている調光層の厚みｄは約４．５μｍ以上であることから、液晶材料の複屈折率△ｎを０．０７〜０．１０の範囲になるように調整することが要求されている。しかしながら、従来は液晶材料の複屈折率Δｎをこの範囲に調整しようとすると、それを用いて作製される表示装置のしきい値電圧Ｖ_ｔｈは逆に上昇してしまう傾向にあり、両者を同時に満足することは困難であった。
【００１４】
本発明が解決しようとする課題は、上記の問題に応えることにあり、特に広い温度範囲で液晶性を示し、しきい値電圧が低く、しかも充分に高い電圧保持率を有し、装置の設定条件に適した複屈折率Δｎを有する液晶組成物を提供し、更にこの液晶組成物を用い、フリッカが発生せず、コントラストに優れた液晶表示装置を提供することにある。
【００１５】
【課題を解決するための手段】
本発明は上記課題を解決するために、以下に示すネマチック液晶組成物を提供する。
【００１６】
まず、本発明の第１の液晶組成物として、（１）一般式（Ｉ）
【００１７】
【化７】

【００１８】
（式中、Ｒ^１は炭素原子数２〜７の直鎖状アルキル基を表わす。）
で表わされる化合物及び（２）一般式（ＩＩ）〜（ＩＩＩ）
【００１９】
【化８】

【００２０】
（式中、Ｒ^２は炭素原子数２〜７の直鎖状アルケニル基を表わし、Ｒ^３は炭素原子数２〜７の直鎖状アルキル基を表わす。）
で表わされる化合物からなる群から選ばれる化合物を含有することを特徴とするネマチック液晶組成物を提供する。
【００２１】
また、本発明の第２の液晶組成物として、（１）前述の一般式（Ｉ）で表わされる化合物及び（２）一般式（ＩＶ）〜（Ｖ）
【００２２】
【化９】

【００２３】
（式中、Ｒ^４はそれぞれ独立的に、炭素原子数２〜７の直鎖状アルキル基を表わす。）
で表わされる化合物からなる群から選ばれる化合物を含有することを特徴とするネマチック液晶組成物を提供する。
【００２４】
更に、本発明の第３の液晶組成物として、（１）前述の一般式（Ｉ）で表わされる化合物、（２）前述の一般式（ＩＩ）〜（ＩＩＩ）で表わされる化合物からなる群から選ばれる化合物及び（３）前述の一般式（ＩＶ）〜（Ｖ）で表わされる化合物からなる群から選ばれる化合物を含有することを特徴とするネマチック液晶組成物を提供する。
【００２５】
本発明は上記の第１〜第３の液晶組成物において、上記以外の成分として（Ａ）
一般式（ＶＩ）〜（ＸＩ）
【００２６】
【化１０】

【００２７】
（式中、Ｒ^５は炭素原子数２〜７の直鎖状アルケニル基を表わし、Ｒ^６はそれぞれ独立的に、炭素原子数２〜７の直鎖状アルキル基を表わし、Ｘ^１はそれぞれ独立的に、Ｈ又はＦを表わし、ｒは０又は１を表わす。）
で表わされる化合物からなる群から選ばれる１種又はそれ以上の化合物を含有することが好ましい。
【００２８】
ここで、本発明に係わる一般式（Ｉ）〜（ＸＩ）で表わされる化合物の代表的なものの例とその相転移温度を下記第１表に示す。下記表中、ｍ．ｐ．は結晶相から液晶相又は等方性液体相に相転移する温度を、ｃ．ｐ．は液晶相から等方性液体相に相転移する温度をそれぞれ表わす。また、各液晶化合物は、蒸留、カラム精製、再結晶等の方法を用いて不純物を除去し、十分精製したものを使用した。
【００２９】
【表１】

【００３０】
本発明の液晶組成物の特徴は、必須成分として前述の一般式（Ｉ）で表わされる化合物を含有する点にある。この一般式（Ｉ）で表わされる化合物は、誘電異方性が＋８前後と比較的小さいにも係わらず、液晶組成物の駆動電圧を低減させ、しかも高い電圧保持率を維持向上させる効果を有する。また、複屈折率Δｎが０．０６前後と極めて小さいので、前述のファーストミニマムの条件を満足するために用いられる装置に使用される液晶組成物を調製する上で優れた特性を有するものである。しかしながら、一般式（Ｉ）の化合物はスメクチック相を示し易いという欠点がある。例えば、一般式（Ｉ）の化合物のみからなる組成物（２−１）
【００３１】
【化１１】

【００３２】
は、ネマチック相の温度範囲が７７〜５６℃と非常に狭く、一般式（Ｉ）の化合物のみを用いて、特に低温で駆動可能なネマチック液晶組成物を調製することは困難であった。
【００３３】
本発明者等は、一般式（Ｉ）で表わされる化合物と種々の液晶化合物との組み合わせを検討した結果、本発明の第１〜第３の液晶組成物のように、一般式（ＩＩ）〜（ＩＩＩ）で表わされる化合物からなる群から選ばれる化合物及び／又は一般式（ＩＶ）〜（Ｖ）で表わされる化合物からなる群から選ばれる化合物を組み合わせて用いることにより、一般式（Ｉ）で表わされる化合物の優れた特性を損なうことなく、広い温度範囲で使用できるネマチック液晶組成物を調製できることを見い出した。
【００３４】
本発明の第１〜第３のネマチック液晶組成物においては、一般式（Ｉ）で表わされる化合物以外の化合物としては、一般式（ＩＩ）で表わされる化合物を含有することが好ましく、また、これに加えて、一般式（ＩＩＩ）で表わされる化合物及び／又は一般式（Ｖ）で表わされる化合物を含有することも好ましい。
【００３５】
前述の通り、本発明の第１〜第３の液晶組成物において、一般式（Ｉ）〜（Ｖ）で表わされる成分以外にも、（Ａ）一般式（ＶＩ）〜（ＸＩ）で表わされる化合物からなる群から選ばれる化合物を含有することが好ましい。
【００３６】
その中でも、（１）一般式（ＶＩ）〜（ＶＩＩ）で表わされる化合物からなる群から選ばれる化合物及び／又は（２）一般式（ＩＸ）〜（Ｘ）で表わされる化合物からなる群から選ばれる化合物を含有することが好ましく、例えば、具体的な組み合わせとしては以下のようなものを挙げることができる。
【００３７】
・（Ｉ）＋（ＩＩ）＋（ＶＩ）＋（ＶＩＩ）＋（Ｘ）
・（Ｉ）＋（ＩＩ）＋（ＶＩ）＋（ＶＩＩ）＋（ＩＸ）＋（Ｘ）
・（Ｉ）＋（ＩＩ）＋（ＩＩＩ）＋（ＶＩ）
・（Ｉ）＋（ＩＩ）＋（ＶＩＩ）
・（Ｉ）＋（ＩＩ）＋（ＩＩＩ）＋（Ｖ）＋（ＶＩＩＩ）＋（ＩＸ）＋（Ｘ）＋（ＸＩ）
【００３８】
本発明のネマチック液晶組成物で使用する一般式（ＩＩ）〜（ＸＩ）で表わされる各化合物は、組成物の電圧保持率を低下させることなく、駆動電圧を維持あるいは低減させる効果を有する。このような効果は、一般式（ＩＩ）〜（ＸＩ）の各化合物が、３，４，５−トリフルオロフェニル基又は３，４−ジフルオロフェニル基を有することによると考えられる。
【００３９】
この中でも一般式（ＩＩ）あるいは（ＶＩ）で表わされる化合物は、表示特性に重要な役割を果たす弾性定数比（Ｋ_３３／Ｋ_１１）を、用途に応じて調製する上で重要な化合物でもあり、ネマチック液晶組成物の粘性を低下させることもできる。従って、一般式（Ｉ）の化合物と組み合わせて用いることによって、広い温度範囲でネマチック相を示し、しかも高速応答性を有する液晶材料を容易に調製することができる。これらの一般式（ＩＩ）あるいは（ＶＩ）で表わされる化合物としては、特に下記のものが優れている。
【００４０】
【化１２】

【００４１】
また、一般式（ＩＩＩ）〜（Ｖ）で表わされる化合物は、液晶組成物の駆動電圧を低減させるという効果を有するものの、これらの化合物を用いて低温までネマチック相を示す液晶組成物を調製することは困難であった。特に一般式（Ｖ）の化合物は他の液晶化合物に比べて相溶性の点で劣っており、従来この化合物は例えば一般式（２−２）〜（２−４）
【００４２】
【化１３】

【００４３】
（式中、Ｒ^１１はアルキル基を表わし、Ｘ^３はＦ、ＯＣＦ_３、ＯＣＨＦ_２又はＣＦ_３を表わし、Ｘ^４及びＸ^５はそれぞれ独立的に、Ｈ又はＦを表わし、Ｘ^６はＯＣＦ_３、ＯＣＨＦ_２又はＣＦ_３を表わし、ｓは０又は１を表わす。）で表わされる化合物と組み合わせて用いることが必須であった。しかしながら、この様な手段を用いても依然として前述のような問題は十分に解決されていなかった。
【００４４】
この一般式（ＩＩＩ）〜（Ｖ）で表わされる化合物について、例えば、特表平５−５００６８１号公報には、上記一般式（２−２）の化合物と、本発明に関わる一般式（ＩＩＩ）〜（Ｖ）あるいは（ＶＩＩ）の化合物とを混合した液晶組成物に関する記載があり、この混合比は１：４〜１：１が良く、一般式（２−２）の化合物の含有量は４０％以上であることが更に好適であるとの記載がある。しかしながら、このような組成物は、ネマチック相−等方性液体相転移温度Ｔ_Ｎ−Ｉが８０℃以下と低いか、あるいはＴＮ−ＬＣＤを構成したときのしきい値電圧Ｖ_ｔｈが１．５Ｖ以上と高くなるなど、現在要求されている特性を満足するものは得られていないのが現状であった。更に、一般式（２−２）の化合物の含有量が多いために、蒸気圧温度特性が悪化し、液晶表示パネルの作製工程における液晶注入条件が厳しくなる、あるいは注入ムラを発生させる等、新たな問題を発生させてしまい、実用的ではなかった。
【００４５】
また、例えば特表平５−５００８３０号公報には、上記一般式（２−４）の化合物と本発明に関わる一般式（ＩＩＩ）〜（Ｖ）あるいは（ＶＩＩ）の化合物とを混合した液晶組成物に関する記載があり、この混合比は１：４〜１：１が良く、一般式（２−４）の化合物の含有量は４０％以上であることが更に好適であるとの記載がある。しかしながら、このような組成物も、低温でのネマチック相を改善させるために、実際には一般式（２−４）の化合物の含有量が多いために、上述と同様に、Ｔ_Ｎ−ＩあるいはＶ_ｔｈに対する要求特性を満足するものは得られていないのが現状であった。更に、複屈折率△ｎが０．１２以上と大きいものを用いた場合、ファーストミニマム（△ｎ・ｄ＝０．５）の条件を満たすためには、セル厚ｄを約４μｍあるいはそれ以下にする必要があり、液晶表示パネルの作製工程における均一なセル作製条件が厳しくなる、あるいは表示ムラを発生させる等新たな問題を発生させてしまい、実用的ではなかった。
【００４６】
これに対して、本発明では一般式（Ｉ）の化合物と組み合わせて用いることにより、上述のような問題点を解決することができ、個々の化合物が有する優れた特性を損なうことなく、低温まで広い温度範囲で駆動できる優れた組成物を得ることができる。
【００４７】
このような効果は、例えば、以下の例からも明らかである。
一般式（Ｖ）の化合物のみからなる組成物（２−５）
【００４８】
【化１４】

【００４９】
は７１〜４４℃の範囲でネマチック相を示す。また一般式（Ｖ）の化合物及び一般式（ＶＩＩ）の化合物からなる組成物（２−６）
【００５０】
【化１５】

【００５１】
は８５〜３３℃の範囲でネマチック相を示し、成分数が増えてもネマチック相の温度範囲、特に下限温度はあまり低下していない。しかしながら、本発明の必須成分である一般式（Ｉ）の化合物と一般式（Ｖ）の化合物を混合して得られる組成物（２−７）
【００５２】
【化１６】

【００５３】
は７４〜１８℃の範囲でネマチック相を示し、一般式（Ｉ）の化合物と一般式（ＶＩＩ）の化合物を混合して得られる組成物（２−８）
【００５４】
【化１７】

【００５５】
は８９〜０℃の範囲でネマチック相を示し、低温側に大きくネマチック相が拡大している。
また、一般式（Ｉ）の化合物及び一般式（ＩＩ）の化合物を混合して得られる組成物（２−９）
【００５６】
【化１８】

【００５７】
は８３〜１５℃の範囲でネマチック相を示し、一般式（Ｉ）の化合物、一般式（ＩＩ）の化合物及び一般式（ＶＩ）の化合物を混合して得られる組成物（２−１０）
【００５８】
【化１９】

【００５９】
は９０〜−３０℃の範囲でネマチック相を示し、一般式（Ｉ）の化合物及び一般式（ＶＩ）の化合物を混合して得られる組成物（２−１１）
【００６０】
【化２０】

【００６１】
は９６〜−２０℃の範囲でネマチック相を示し、いずれもネマチック相の上限温度は高く、しかもネマチック相の温度範囲は低温側に大きく拡大していることが明らかである。
【００６２】
従って、一般式（Ｉ）で表わされる化合物と一般式（ＩＩ）〜（ＸＩ）で表わされる化合物を組み合わせて用いることにより、更に広い温度範囲、特に低温側でも使用できるネマチック液晶組成物を得られることが明らかである。
【００６３】
比較例３
実施例１において、ＭＣＴＣの添加量を０．５９５ｇに、ＢＨＴＣＡの添加量を０．６５０ｇに替えた以外は実施例１と同じ操作を繰り返し、テトラカルボン酸成分としてＭＣＴＣ４５％およびＢＨＴＣＡ５５％を含むポリイミドを合成した。このポリマーはＮＭＰ、γ−ブチロラクトン、ＤＭＦなどの一般極性溶媒に容易に溶解した。
【００６４】
しかしながら、本発明の液晶組成物は、一般式（Ｉ）〜（ＩＩＩ）又は（Ｖ）で表わされる３，４，５−トリフルオロフェニル基を有する化合物と、一般式（ＩＶ）、（ＶＩ）又は（ＶＩＩ）で表わされる３，４−ジフルオロフェニル基を有する化合物との混合比が１：１以上であっても、あるいは３，４，５−トリフルオロフェニル基を有する化合物の総含有量が５０重量％以上であっても、上記の例示からも明らかなように、広い温度範囲で使用できるネマチック液晶組成物を調製できる。
【００６５】
本発明の第１〜第３のネマチック液晶組成物に用いることができる（Ａ）一般式（ＶＩ）〜（ＸＩ）で表わされる化合物は、上述のような特性を維持向上する効果をそれぞれ有する。
【００６６】
詳しくは、一般式（ＶＩ）〜（ＸＩ）で表わされる化合物は、液晶組成物の複屈折率（△ｎ）を０．０７〜０．１０の範囲に最適化することができ、これにより液晶表示装置の視角特性の向上、コントラスト比の増加等の効果が得られる。また、組成物のネマチック相温度範囲を高温側及び低温側に拡大させる効果を有し、液晶表示装置の駆動可能な温度範囲を更に拡大することができる。
【００６７】
これらの化合物のうち、一般式（ＶＩＩＩ）、（ＩＸ）あるいは（ＸＩ）の化合物は−（ＣＨ_２）_４−あるいは−（ＣＨ_２）_２−の連結基を有し、前述の一般式（Ｉ）〜（ＶＩＩ）の化合物からなる液晶組成物との相溶性にも優れている。更に、一般式（ＩＸ）で表わされる化合物は、一般式（ＶＩＩＩ）においてｒ＝０である化合物に比べ、蒸気圧温度特性にも優れており、本発明の液晶組成物において、一般式（ＩＸ）の化合物を多用しても、液晶表示パネルの作製工程における液晶注入条件を緩和することができ、大型液晶パネルの作製工程における注入ムラを低減させるという特徴も有する。
【００６８】
また、本発明の第１〜第３の液晶組成物は、（Ｂ）一般式（ＸＩＩ）〜（ＸＶＩ）
【００６９】
【化２１】

【００７０】
（式中、Ｒ^７はそれぞれ独立的に、炭素原子数２〜７の直鎖状アルキル基又はアルケニル基を表わし、Ｒ^８はそれぞれ独立的に、炭素原子数２〜７の直鎖状アルキル基、アルケニル基、アルコキシ基又はアルケニルオキシ基を表わし、Ｒ^９はそれぞれ独立的に、炭素原子数２〜７の直鎖状アルキル基を表わす。）
で表わされる化合物からなる群から選ばれる化合物を含有してもよい。
【００７１】
その中でも特に一般式（ＸＩＩ）で表わされる化合物を含有することが好ましく、一般式（Ｉ）、（ＩＩ）、（ＶＩ）、（ＩＸ）、（Ｘ）及び（ＸＩＩ）で表わされる化合物を含有する液晶組成物が特に好ましい。
【００７２】
この一般式（ＸＩＩ）〜（ＸＶＩ）で表わされる化合物は、液晶組成物のネマチック相の温度範囲を特に低温側に拡大し得るものである。また、これらの化合物はネマチック液晶組成物の粘性を低下させることもできるので、広い温度範囲で高速応答性を有する液晶材料を得ることができる。特に一般式（ＸＩＩ）あるいは（ＸＩＩＩ）で表わされる化合物はこのような効果を得るのに非常に適している。
【００７３】
更に、本発明の液晶組成物は、一般式（Ｉ）〜（ＸＶＩ）の化合物に加えて、液晶組成物の他の特性を改善するために、液晶化合物として認識される通常のネマチック液晶、スメクチック液晶、コレステリック液晶などを含有してもよい。
【００７４】
本発明の液晶組成物における一般式（Ｉ）で表わされる化合物の含有量は、３〜６０重量％の範囲にあることが好ましい。また、（２）一般式（ＩＩ）〜（ＩＩＩ）で表わされる化合物からなる群から選ばれる化合物の含有量は、総量で３〜５０重量％の範囲にあることが好ましく、このとき、各化合物の含有量は、一般式（ＩＩ）で表わされる化合物を０〜２５重量％の範囲で、且つ一般式（ＩＩＩ）で表わされる化合物を０〜３０重量％の範囲で含有することがより好ましい。
【００７５】
また、（３）一般式（ＩＶ）〜（Ｖ）で表わされる化合物からなる群から選ばれる化合物の含有量は、総量で３〜４０重量％の範囲にあることが好ましく、このとき、各化合物の含有量は、一般式（ＩＶ）で表わされる化合物を０〜３０重量％の範囲で、一般式（Ｖ）で表わされる化合物を３〜３０重量％の範囲で含有することが好ましい。
【００７６】
一般式（ＶＩ）〜（ＶＩＩ）で表わされる化合物を含有する場合は、その含有量が総量で３〜５５重量％の範囲にあることが好ましく、このとき、各化合物の含有量は、各々０〜３５重量％の範囲にあることが好ましい。また、一般式（ＶＩＩＩ）〜（ＸＩ）で表わされる化合物を含有する場合は、その含有量が総量で３〜３５重量％の範囲にあることが好ましく、このとき、各化合物の含有量はね各々０〜２０重量％の範囲にあることが好ましい。また、一般式（ＸＩＩ）〜（ＸＶＩ）で表わされる化合物からなる群から選ばれる化合物を含有する場合は、総量で３〜２５重量％の範囲で含有することが好ましく、特に一般式（ＸＩＩ）の化合物を３〜２５重量％の範囲で含有することが好ましい。
【００７７】
本発明の液晶組成物は、その使用目的に応じて、例えば以下のような組成で用いることが好ましい。
液晶組成物の結晶相又はスメクチック相−ネマチック相転移温度Ｔ→_Ｎを特に低くする目的には、（１）一般式（Ｉ）の化合物及び（２）一般式（ＩＩ）〜（ＩＶ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましく、よりＴ→_Ｎを低下させる目的には、（３）一般式（ＶＩ）〜（ＶＩＩ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましく、更に（４）一般式（ＩＸ）〜（ＸＩ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましい。
【００７８】
液晶組成物のネマチック相−等方性液体相転移温度Ｔ_Ｎ−Ｉを高くし、且つ結晶相又はスメクチック相−ネマチック相転移温度Ｔ→_Ｎを低くする目的には、（１）一般式（Ｉ）の化合物及び（２）一般式（ＩＩ）〜（ＩＶ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましく、更に（３）一般式（Ｘ）〜（ＸＩ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましい。
【００７９】
液晶表示のしきい値電圧Ｖ_ｔｈを低くする目的には、（１）一般式（Ｉ）の化合物、（２）一般式（ＩＩ）〜（ＩＩＩ）の化合物からなる群から選ばれる化合物及び（３）一般式（Ｖ）の化合物を組み合わせて用いることが好ましく、更に（４）一般式（ＩＸ）〜（ＸＩ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましい。
【００８０】
液晶表示の応答特性を速くする目的には、（１）一般式（Ｉ）の化合物、（２）一般式（ＩＩ）の化合物及び（３）一般式（ＶＩ）の化合物を組み合わせて用いることが好ましく、更に一般式（４）一般式（ＸＩＩ）〜（ＸＶＩ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましい。
【００８１】
液晶組成物の複屈折率△ｎを０．０７〜０．０８の範囲に調整する目的には、（１）一般式（Ｉ）の化合物、（２）一般式（ＩＩＩ）〜（Ｖ）の化合物からなる群から選ばれる化合物及び（３）一般式（ＶＩＩ）の化合物を組み合わせて用いることが好ましく、液晶組成物の複屈折率△ｎを０．０８〜０．１０の範囲に調整する目的には、（１）一般式（Ｉ）の化合物、（２）一般式（ＩＩ）の化合物及び（３）一般式（ＶＩ）の化合物を組み合わせて用いることが好ましく、更に一般式（４）一般式（Ｘ）〜（ＸＩ）の化合物からなる群から選ばれる化合物を組み合わせて用いることが好ましい。
【００８２】
この様にして得られる本発明の液晶組成物は、後述の実施例にも示したように、ネマチック相−等方性液体相転移温度（Ｔ_Ｎ−Ｉ）が８０〜１００℃の範囲にあり、しかもしきい値電圧（Ｖ_ｔｈ）が１．２〜１．６Ｖの範囲にあるものが得られ、あるいはネマチック相−等方性液体相転移温度（Ｔ_Ｎ−Ｉ）が１００〜１２０℃の範囲にあり、しかもしきい値電圧（Ｖ_ｔｈ）が１．６〜２．０Ｖの範囲にあるものが得られ、これらのネマチック液晶組成物は、結晶相又はスメクチック相−ネマチック相転移温度（Ｔ→_Ｎ）が−１０℃以下であり、複屈折率△ｎが０．０７〜０．１０の範囲にあり、誘電異方性（△ε）は＋６〜９にあるという非常に実用的であり、要求される特性をほぼ満足するものが得られた。
【００８３】
また、本発明のネマチック液晶組成物は、後述の実施例にも示したように、加熱促進テスト、紫外線照射促進テストを行ったところ、各促進テスト後も９８％以上の高い電圧保持率を有することや、化学的にも非常に安定で高い抵抗値を有することが確認された。
【００８４】
よって、このようなネマチック液晶組成物を用いた液晶表示装置も非常に優れた特性を有するものであり、本発明は前述の種々のネマチック液晶組成物を用いた液晶表示装置をも提供する。
【００８５】
本発明の液晶表示装置、特にアクティブ・マトリクス形液晶表示装置あるいはツイスティッド・ネマチック又はスーパー・ツイスティッド・ネマチック液晶表示装置は、広い温度範囲で液晶性を示し、しきい値電圧が低く、しかも充分に高い電圧保持率を示す。特にアクティブ・マトリクス液晶表示装置においては、フリッカが発生せずコントラストにも優れ、ＴＮ−ＬＣＤやＳＴＮ−ＬＣＤ液晶表示装置は、広範な駆動周波数で表示可能であることが確認された。
【００８６】
【実施例】
以下、実施例を挙げて本発明を詳述するが、本発明はこれらの実施例に限定されるものではない。また、以下の実施例の組成物における「％」は『重量％』を意味する。
【００８７】
なお、組成物の比抵抗は、液晶組成物２ｇをアンプル管に入れ、真空脱気後、窒素置換の処理をして封入し、１８０℃、１時間の加熱促進テスト、及び１０時間の紫外線照射促進テスト「ＳＵＮＴＥＳＴ」（オリジナルハナウ社製）を行った後の液晶組成物の比抵抗を測定した。
【００８８】
また、実施例中、測定した特性の各記号の意味は以下の通りである。
Ｔ_Ｎ−Ｉ ： ネマチック相−等方性液体相転移温度（℃）
Ｔ→_Ｎ ： 結晶相又はスメクチック相−ネマチック相転移温度（℃）
Ｖ_ｔｈ ： パネル液晶層の厚みをｄとし、ファーストミニマム△ｎ・ｄ＝０．５のＴＮ−ＬＣＤを構成した時のしきい値電圧（Ｖ）
△ε ： 誘電異方性
△ｎ ： 複屈折率
τｒ＝τｄ： 電圧無印加状態から電圧を印加して光が透過する状態になるまでの立ち上がり時間τｒ、と電圧印加状態から電圧を除いて光が透過しなくなるまでの立ち下がり時間τｄが等しくなる応答時間（ ｍｓｅｃ）
【００８９】
（実施例１）
【００９０】
【化２２】

【００９１】
からなるネマチック液晶組成物（３−１）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ８２．０ ℃
Ｔ→_Ｎ ： −３２．０ ℃
Ｖ_ｔｈ ： １．３７ Ｖ
△ε ： ９．２
△ｎ ： ０．０７６
テスト前の比抵抗 ： ７．５×１０^１３Ω ｃｍ
加熱促進テスト後比抵抗 ： ５．６×１０^１３Ω ｃｍ
紫外線照射促進テスト後比抵抗： ３．０×１０^１３Ω ｃｍ
テスト前の電圧保持率 ： ９９．６％（測定温度８０℃）
加熱促進テスト後電圧保持率 ： ９８．７％（測定温度８０℃）
紫外線照射促進テスト後電圧保持率： ９８．３％（測定温度８０℃）
【００９２】
このネマチック液晶組成物（３−１）を構成材料とするアクティブ・マトリクス液晶表示装置を作製したところ、漏れ電流が小さくフリッカの発生しない優れたものであることが確認できた。
【００９３】
（実施例２）
【００９４】
【化２３】

【００９５】
からなるネマチック液晶組成物（３−２）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ８５．７ ℃
Ｔ→_Ｎ ： −２５．０ ℃
Ｖ_ｔｈ ： １．４２ Ｖ
Δε ： ７．４
Δｎ ： ０．０７４
【００９６】
（実施例３）
【００９７】
【化２４】

【００９８】
からなるネマチック液晶組成物（３−３）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ９３．２ ℃
Ｔ→_Ｎ ： −３０．０ ℃
Ｖ_ｔｈ ： １．６０ Ｖ
△ε ： ７．２
△ｎ ： ０．０８０
【００９９】
（実施例４）
【０１００】
【化２５】

【０１０１】
からなるネマチック液晶組成物（３−４）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ９２．１ ℃
Ｔ→_Ｎ ：＜−７０．０ ℃
Ｖ_ｔｈ ： １．５８ Ｖ
△ε ： ６．５
△ｎ ： ０．０８４
【０１０２】
（実施例５）
【０１０３】
【化２６】

【０１０４】
からなるネマチック液晶組成物（３−５）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： １１９．３ ℃
Ｔ→_Ｎ ：＜−７０．０ ℃
Ｖ_ｔｈ ： １．６３ Ｖ
△ε ： ７．３
△ｎ ： ０．０９１
τｒ＝τｄ： ２９．０ ｍｓｅｃ
【０１０５】
（実施例６）
【０１０６】
【化２７】

【０１０７】
からなるネマチック液晶組成物（３−６）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： １２４．５ ℃
Ｔ→_Ｎ ：＜−７０．０ ℃
Ｖ_ｔｈ ： ２．００ Ｖ
△ε ： ７．０
△ｎ ： ０．０９３
テスト前の比抵抗 ： ７．０×１０^１３Ω ｃｍ
加熱促進テスト後比抵抗 ： ５．８×１０^１３Ω ｃｍ
紫外線照射促進テスト後比抵抗： ２．７×１０^１３Ω ｃｍ
テスト前の電圧保持率 ： ９９．８％
加熱促進テスト後電圧保持率 ： ９８．６％
紫外線照射促進テスト後電圧保持率： ９７．５％
【０１０８】
このネマチック液晶組成物（３−６）を構成材料とするアクティブ・マトリクス液晶表示装置を作製したところ、漏れ電流が小さくフリッカの発生しない優れたものであることが確認できた。
【０１０９】
（実施例７）
【０１１０】
【化２８】

【０１１１】
からなるネマチック液晶組成物（３−７）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ９８．６ ℃
Ｔ→_Ｎ ：＜−７０．０ ℃
Ｖ_ｔｈ ： １．７３ Ｖ
△ε ： ６．０
△ｎ ： ０．０８７
テスト前の比抵抗 ： ７．２×１０^１３Ω ｃｍ
加熱促進テスト後比抵抗 ： ５．５×１０^１３Ω ｃｍ
紫外線照射促進テスト後比抵抗： ３．２×１０^１３Ω ｃｍ
テスト前の電圧保持率 ： ９９．０％
加熱促進テスト後電圧保持率 ： ９７．８％
紫外線照射促進テスト後電圧保持率： ９７．３％
【０１１２】
このネマチック液晶組成物（３−７）を構成材料とするアクティブ・マトリクス液晶表示装置を作製したところ、漏れ電流が小さくフリッカの発生しない優れたものであることが確認できた。
【０１１３】
また、このネマチック液晶組成物（３−７）にカイラル物質「Ｓ−８１１」（メルク社製）を添加して混合液晶を調製した。一方、対向する平面透明電極上に「サンエバー１５０」（日産化学社製）の有機膜をラビングして配向膜を形成し、ツイスト角２２０度のＳＴＮ−ＬＣＤ表示用セルを作製した。上記の混合液晶をこのセルに注入して液晶表示装置を構成し、表示特性を測定した。その結果、しきい値電圧が低く、高時分割特性に優れ、表示画面のちらつきやクロストーク現象が改善されたＳＴＮ−ＬＣＤ表示特性を示す液晶表示装置が得られた。
【０１１４】
（実施例８）
【０１１５】
【化２９】

【０１１６】
からなるネマチック液晶組成物（３−８）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ８３．０ ℃
Ｖ_ｔｈ ： １．２９ Ｖ
△ε ： ８．６
△ｎ ： ０．０７６
【０１１７】
（実施例９）
【０１１８】
【化３０】

【０１１９】
からなるネマチック液晶組成物（３−９）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ８４．３ ℃
Ｖ_ｔｈ ： １．３０ Ｖ
△ε ： ８．８
△ｎ ： ０．０７７
【０１２０】
（実施例１０）
【化３１】

【０１２１】
からなるネマチック液晶組成物（３−１０）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ８９．３ ℃
Ｔ→_Ｎ ： −４５．０ ℃
Ｖ_ｔｈ ： １．４８ Ｖ
△ε ： ７．９
△ｎ ： ０．０８８
【０１２２】
（実施例１１）
【０１２３】
【化３２】

【０１２４】
からなるネマチック液晶組成物（３−１１）を調製し、この組成物の諸特性を測定したところ、結果は以下の通りであった。
Ｔ_Ｎ−Ｉ ： ８３．３ ℃
Ｔ→_Ｎ ：＜−７０．０ ℃
Ｖ_ｔｈ ： １．３２ Ｖ
△ε ： ８．７
△ｎ ： ０．０８２
【０１２５】
【発明の効果】
本発明のネマチック液晶組成物は、広い温度範囲でネマチック相を示し、しきい値電圧が低く、高い電圧保持率を有し、しかも化学的安定性が高い。従って、これを用いた本発明の液晶表示装置は、表示画面のちらつき、クロストーク現象を改善することができ、情報量の多いＴＮ−ＬＣＤ、ＳＴＮ−ＬＣＤあるいはアクティブ・マトリクス方式において良好な駆動特性及び表示特性が得られる。[0001]
[Industrial applications]
The present invention relates to a nematic liquid crystal composition useful as an electro-optical display material and a liquid crystal display using the same.
[0002]
[Prior art]
A typical liquid crystal display device is a TN-LCD (twisted nematic liquid crystal display device), which is used in watches, calculators, electronic organizers, pocket computers, word processors, personal computers, and the like. On the other hand, with the increase in the processing information of the OA device, the amount of information displayed on one screen is increasing, and Scheffer et al. [SID '85 Digest, 120, p. '86 Digest, p. 122 (1986)], STN (Super Twisted Nematic) -LCD has been developed and has begun to be widely used for display for high information processing such as word processors and personal computers.
[0003]
Further, due to its excellent display quality, active matrix type liquid crystal display devices are being marketed as being promising in display application fields such as liquid crystal televisions, projector displays, and computers. In the active matrix display system, a switching element such as a TFT (thin film transistor) or MIM (metal insulator metal) is used for each pixel, and this system has a small leakage current, that is, a high voltage holding ratio. That is important. Therefore, a new liquid crystal compound or liquid crystal composition has been proposed to cope with such a display element.
[0004]
[Problems to be solved by the invention]
The TN-LCD and the STN-LCD have problems such as chemical stability of a liquid crystal material, low-voltage drivability and response characteristics of a liquid crystal display device.
[0005]
For example, a STN-LCD having a large amount of information such as a word processor and a personal computer requires good driving characteristics with a high time division number. However, an increase in the time division number causes an increase in driving voltage, which greatly affects a driving circuit. give. As one way to reduce this,
[0006]
(Equation 1)

[0007]
(Where V_thRepresents a threshold voltage, k represents a proportional constant, K represents an elastic constant, and Δε represents dielectric anisotropy. According to the relationship (1), there is known a method of lowering the driving voltage using a liquid crystal material having a large dielectric anisotropy. However, such liquid crystal materials often have a tendency to increase the viscosity of the liquid crystal material, which makes it difficult to obtain good response characteristics, or increases the capacitance component of each pixel. There is a problem that the possible driving frequency range is narrowed and a crosstalk phenomenon occurs.
[0008]
On the other hand, in the case of a conventional liquid crystal material that can be driven at a low voltage, it is generally known that the resistance value is low at the initial stage of preparation or after an accelerated test by heating or irradiation with ultraviolet rays. Such a low resistance value of the liquid crystal material is not preferable because it causes flickering of the display screen and a decrease in contrast due to an increase in the number of time divisions.
[0009]
Further, in order to compensate for dark image quality due to an increase in the amount of information, STN-LCDs generally use a backlight as an auxiliary light source. For this reason, a liquid crystal material used for a backlight type STN-LCD is required to have new chemical stability such as heat resistance and light resistance.
[0010]
In addition to these required characteristics, especially in the active matrix system, it is important to have a small leakage current and a high voltage holding ratio in order to obtain a uniform and high contrast. In order to obtain such properties, for example, the following compounds have been used.
[0011]
Embedded image

[0012]
(Where R¹⁰Represents a linear alkyl group;²Represents a hydrogen atom or a fluorine atom. )
However, a composition that satisfies both the nematic liquid crystallinity in a wide temperature range, particularly at a low temperature, and the sufficient reduction of the threshold voltage required for an active matrix system even when such a compound is used. Could not be prepared.
[0013]
In addition, in order to obtain uniform and high-contrast liquid crystal display characteristics, the product Δnd of the thickness d of the liquid crystal layer of the liquid crystal panel and the birefringence Δn of the liquid crystal material is set to 0.40 to 0.55 ( Hereinafter, this is referred to as a first minimum). Since the thickness d of the light control layer performed in the current manufacturing process of the liquid crystal panel is about 4.5 μm or more, the birefringence Δn of the liquid crystal material is set to be in the range of 0.07 to 0.10. Adjustment is required. However, conventionally, when it is attempted to adjust the birefringence Δn of the liquid crystal material to this range, the threshold voltage V of a display device manufactured using the same is adjusted._thOn the contrary, it was difficult to satisfy both at the same time.
[0014]
The problem to be solved by the present invention is to respond to the above-mentioned problems. In particular, the present invention exhibits liquid crystallinity over a wide temperature range, has a low threshold voltage, has a sufficiently high voltage holding ratio, and has a device setting. An object of the present invention is to provide a liquid crystal composition having a birefringence index Δn suitable for the conditions, and to provide a liquid crystal display device which does not generate flicker and has excellent contrast by using the liquid crystal composition.
[0015]
[Means for Solving the Problems]
The present invention provides the following nematic liquid crystal composition to solve the above problems.
[0016]
First, as the first liquid crystal composition of the present invention, (1) general formula (I)
[0017]
Embedded image

[0018]
(Where R¹Represents a linear alkyl group having 2 to 7 carbon atoms. )
And (2) compounds represented by the general formulas (II) to (III):
[0019]
Embedded image

[0020]
(Where R²Represents a linear alkenyl group having 2 to 7 carbon atoms;³Represents a linear alkyl group having 2 to 7 carbon atoms. )
A nematic liquid crystal composition comprising a compound selected from the group consisting of compounds represented by the formula:
[0021]
Further, as the second liquid crystal composition of the present invention, (1) the compound represented by the aforementioned general formula (I) and (2) the general formulas (IV) to (V)
[0022]
Embedded image

[0023]
(Where R⁴Each independently represents a linear alkyl group having 2 to 7 carbon atoms. )
A nematic liquid crystal composition comprising a compound selected from the group consisting of compounds represented by the formula:
[0024]
Further, the third liquid crystal composition of the present invention includes (1) a compound represented by the aforementioned general formula (I), and (2) a compound represented by the aforementioned general formulas (II) to (III). A nematic liquid crystal composition comprising a compound selected and (3) a compound selected from the group consisting of compounds represented by formulas (IV) to (V) described above is provided.
[0025]
The present invention relates to the first to third liquid crystal compositions described above, in which (A)
General formulas (VI) to (XI)
[0026]
Embedded image

[0027]
(Where R⁵Represents a linear alkenyl group having 2 to 7 carbon atoms;⁶Each independently represents a linear alkyl group having 2 to 7 carbon atoms;¹Each independently represents H or F, and r represents 0 or 1. )
It is preferable to contain one or more compounds selected from the group consisting of the compounds represented by
[0028]
Here, typical examples of the compounds represented by the general formulas (I) to (XI) according to the present invention and their phase transition temperatures are shown in Table 1 below. In the table below, m. p. Is a temperature at which a phase transition from a crystal phase to a liquid crystal phase or an isotropic liquid phase is performed; c. p. Represents a temperature at which a phase transition from a liquid crystal phase to an isotropic liquid phase is performed. In addition, each liquid crystal compound used was sufficiently purified by removing impurities by a method such as distillation, column purification, and recrystallization.
[0029]
[Table 1]

[0030]
The feature of the liquid crystal composition of the present invention resides in that it contains the compound represented by the general formula (I) as an essential component. The compound represented by the general formula (I) has the effect of reducing the driving voltage of the liquid crystal composition and maintaining and improving the high voltage holding ratio, despite the relatively small dielectric anisotropy of around +8. . Further, since the birefringence Δn is as extremely small as about 0.06, it has excellent characteristics in preparing a liquid crystal composition used in a device used to satisfy the above-mentioned first minimum requirements. . However, the compound of the formula (I) has a disadvantage that it tends to exhibit a smectic phase. For example, a composition (2-1) consisting only of the compound of the general formula (I)
[0031]
Embedded image

[0032]
Has a very narrow temperature range of the nematic phase of 77 to 56 ° C., and it has been difficult to prepare a nematic liquid crystal composition which can be driven at a low temperature, particularly using only the compound of the general formula (I).
[0033]
The present inventors have studied combinations of the compound represented by the general formula (I) with various liquid crystal compounds, and as a result, as in the first to third liquid crystal compositions of the present invention, By using a compound selected from the group consisting of the compounds represented by (III) and / or a compound selected from the group consisting of the compounds represented by the general formulas (IV) to (V) in combination, the compound represented by the general formula (I) It has been found that a nematic liquid crystal composition that can be used in a wide temperature range can be prepared without impairing the excellent properties of the compound represented.
[0034]
In the first to third nematic liquid crystal compositions of the present invention, the compound other than the compound represented by the general formula (I) preferably contains a compound represented by the general formula (II). In addition, it is also preferable to contain a compound represented by the general formula (III) and / or a compound represented by the general formula (V).
[0035]
As described above, in the first to third liquid crystal compositions of the present invention, in addition to the components represented by general formulas (I) to (V), (A) represented by general formulas (VI) to (XI). It preferably contains a compound selected from the group consisting of compounds.
[0036]
Among them, (1) a compound selected from the group consisting of compounds represented by the general formulas (VI) to (VII) and / or (2) a compound selected from the group consisting of compounds represented by the general formulas (IX) to (X) It is preferable to include the following compounds, for example, specific combinations include the following.
[0037]
・ (I) + (II) + (VI) + (VII) + (X)
(I) + (II) + (VI) + (VII) + (IX) + (X)
・ (I) + (II) + (III) + (VI)
・ (I) + (II) + (VII)
(I) + (II) + (III) + (V) + (VIII) + (IX) + (X) + (XI)
[0038]
The compounds represented by the general formulas (II) to (XI) used in the nematic liquid crystal composition of the present invention have an effect of maintaining or reducing the driving voltage without lowering the voltage holding ratio of the composition. Such an effect is considered to be due to the fact that each compound of the general formulas (II) to (XI) has a 3,4,5-trifluorophenyl group or a 3,4-difluorophenyl group.
[0039]
Among them, the compound represented by the general formula (II) or (VI) has an elastic constant ratio (K) which plays an important role in display characteristics.₃₃/ K₁₁Is also an important compound for preparing according to the application, and can also reduce the viscosity of the nematic liquid crystal composition. Therefore, when used in combination with the compound of the general formula (I), a liquid crystal material exhibiting a nematic phase in a wide temperature range and having high-speed response can be easily prepared. As the compounds represented by the general formula (II) or (VI), the following compounds are particularly excellent.
[0040]
Embedded image

[0041]
Although the compounds represented by the general formulas (III) to (V) have an effect of reducing the driving voltage of the liquid crystal composition, a liquid crystal composition exhibiting a nematic phase up to a low temperature is prepared using these compounds. It was difficult. In particular, the compound of the general formula (V) is inferior in compatibility with other liquid crystal compounds, and conventionally, this compound has, for example, the general formulas (2-2) to (2-4)
[0042]
Embedded image

[0043]
(Where R¹¹Represents an alkyl group; X³Is F, OCF₃, OCHF₂Or CF₃And X⁴And X⁵Each independently represents H or F;⁶Is OCF₃, OCHF₂Or CF₃And s represents 0 or 1. ) Was indispensable. However, even if such a means is used, the above-mentioned problem has not been sufficiently solved.
[0044]
With respect to the compounds represented by the general formulas (III) to (V), for example, JP-A-5-500681 discloses a compound represented by the general formula (2-2) and a compound represented by the general formula (III) related to the present invention. To (V) or (VII), the mixture ratio is preferably 1: 4 to 1: 1 and the content of the compound of the general formula (2-2) is 40. % Is more preferable. However, such compositions have a nematic phase-isotropic liquid phase transition temperature T_NIIs as low as 80 ° C. or lower, or the threshold voltage V when a TN-LCD is formed._thAt present, such as 1.5 V or higher, satisfying the characteristics required at present has not been obtained. Further, since the content of the compound of the general formula (2-2) is large, the vapor pressure-temperature characteristics are deteriorated, the liquid crystal injection conditions in the manufacturing process of the liquid crystal display panel are strict, or the injection unevenness is generated. Problems occurred and were not practical.
[0045]
Also, for example, Japanese Patent Application Laid-Open No. 5-500830 discloses a liquid crystal composition obtained by mixing the compound of the general formula (2-4) with the compound of the general formulas (III) to (V) or (VII) according to the present invention. It is described that the mixing ratio is preferably 1: 4 to 1: 1 and the content of the compound of the general formula (2-4) is more preferably 40% or more. However, such a composition also has a high content of the compound of the general formula (2-4) in order to improve the nematic phase at a low temperature, and thus, as described above,_NIOr V_thAt present, there has not been obtained any material that satisfies the characteristics required for the above. Further, when a birefringence Δn of as large as 0.12 or more is used, in order to satisfy the condition of the first minimum (Δn · d = 0.5), the cell thickness d is reduced to about 4 μm or less. In such a case, the uniform cell manufacturing conditions in the manufacturing process of the liquid crystal display panel become severe, or a new problem such as display unevenness occurs, which is not practical.
[0046]
On the other hand, in the present invention, the above-mentioned problems can be solved by using the compound of the general formula (I) in combination with the compound of the general formula (I). An excellent composition that can be driven in a wide temperature range can be obtained.
[0047]
Such an effect is apparent from, for example, the following example.
Composition (2-5) consisting only of compound of general formula (V)
[0048]
Embedded image

[0049]
Shows a nematic phase in the range of 71 to 44 ° C. Further, a composition (2-6) comprising a compound of the general formula (V) and a compound of the general formula (VII)
[0050]
Embedded image

[0051]
Shows a nematic phase in the range of 85 to 33 ° C., and the temperature range of the nematic phase, particularly the lower limit temperature, does not decrease so much even when the number of components increases. However, the composition (2-7) obtained by mixing the compound of the general formula (I) and the compound of the general formula (V), which are essential components of the present invention.
[0052]
Embedded image

[0053]
Shows a nematic phase in the range of 74 to 18 ° C, and is a composition (2-8) obtained by mixing a compound of the general formula (I) and a compound of the general formula (VII).
[0054]
Embedded image

[0055]
Shows a nematic phase in the range of 89 ° C. to 0 ° C., and the nematic phase greatly expands toward the low temperature side.
Further, a composition (2-9) obtained by mixing a compound of the general formula (I) and a compound of the general formula (II)
[0056]
Embedded image

[0057]
Shows a nematic phase in the range of 83 to 15 ° C, and is obtained by mixing a compound of the general formula (I), a compound of the general formula (II) and a compound of the general formula (VI) (2-10)
[0058]
Embedded image

[0059]
Shows a nematic phase in the range of 90 to -30 ° C, and is obtained by mixing the compound of the general formula (I) and the compound of the general formula (VI) (2-11)
[0060]
Embedded image

[0061]
Shows a nematic phase in the range of 96 to -20 ° C., and it is clear that the maximum temperature of the nematic phase is high in all cases, and that the temperature range of the nematic phase is greatly expanded to a lower temperature side.
[0062]
Therefore, by using the compound represented by the general formula (I) and the compounds represented by the general formulas (II) to (XI) in combination, it is possible to obtain a nematic liquid crystal composition which can be used in a wider temperature range, especially in a lower temperature range. It is clear that.
[0063]
Comparative Example 3
A polyimide containing 45% of MCTC and 55% of BHTCA as a tetracarboxylic acid component was repeated by repeating the same operation as in Example 1 except that the addition amount of MCTC was changed to 0.595 g and the addition amount of BHTCA was changed to 0.650 g. Was synthesized. This polymer was easily dissolved in common polar solvents such as NMP, γ-butyrolactone, DMF and the like.
[0064]
However, the liquid crystal composition of the present invention comprises a compound having a 3,4,5-trifluorophenyl group represented by the general formulas (I) to (III) or (V) and a compound represented by the general formulas (IV) and (VI) Or even if the mixing ratio with the compound having a 3,4-difluorophenyl group represented by (VII) is 1: 1 or more, or the total content of the compound having a 3,4,5-trifluorophenyl group is Even when the content is 50% by weight or more, a nematic liquid crystal composition that can be used in a wide temperature range can be prepared as is clear from the above examples.
[0065]
The compounds (A) represented by the general formulas (VI) to (XI) which can be used in the first to third nematic liquid crystal compositions of the present invention have the effects of maintaining and improving the above-described properties, respectively.
[0066]
Specifically, the compounds represented by the general formulas (VI) to (XI) can optimize the birefringence (Δn) of the liquid crystal composition in the range of 0.07 to 0.10. Effects such as improvement of the viewing angle characteristics of the display device and increase of the contrast ratio can be obtained. Further, the composition has the effect of expanding the nematic phase temperature range of the composition to the high temperature side and the low temperature side, and can further expand the temperature range in which the liquid crystal display device can be driven.
[0067]
Among these compounds, the compound of the general formula (VIII), (IX) or (XI) is-(CH₂)₄-Or- (CH₂)₂And has excellent compatibility with the liquid crystal composition comprising the compounds of the aforementioned general formulas (I) to (VII). Furthermore, the compound represented by the general formula (IX) is more excellent in the vapor pressure temperature characteristic than the compound in which r = 0 in the general formula (VIII), and the compound represented by the general formula (IX) in the liquid crystal composition of the present invention. Even when the compound of the above) is frequently used, the liquid crystal injection conditions in the manufacturing process of the liquid crystal display panel can be relaxed, and the injection unevenness in the manufacturing process of the large liquid crystal panel can be reduced.
[0068]
In addition, the first to third liquid crystal compositions of the present invention can be obtained by: (B) General formulas (XII) to (XVI)
[0069]
Embedded image

[0070]
(Where R⁷Each independently represents a linear alkyl group or alkenyl group having 2 to 7 carbon atoms;⁸Each independently represents a linear alkyl group, alkenyl group, alkoxy group or alkenyloxy group having 2 to 7 carbon atoms;⁹Each independently represents a linear alkyl group having 2 to 7 carbon atoms. )
And a compound selected from the group consisting of compounds represented by
[0071]
Among them, it is particularly preferable to contain a compound represented by the general formula (XII), and to contain a compound represented by the general formulas (I), (II), (VI), (IX), (X) and (XII). Liquid crystal compositions are particularly preferred.
[0072]
The compounds represented by the general formulas (XII) to (XVI) can extend the temperature range of the nematic phase of the liquid crystal composition to a lower temperature side. Further, since these compounds can also reduce the viscosity of the nematic liquid crystal composition, a liquid crystal material having high-speed response in a wide temperature range can be obtained. Particularly, the compound represented by the general formula (XII) or (XIII) is very suitable for obtaining such an effect.
[0073]
Furthermore, in addition to the compounds of the general formulas (I) to (XVI), the liquid crystal composition of the present invention may be used in order to improve other properties of the liquid crystal composition. Liquid crystals, cholesteric liquid crystals and the like may be contained.
[0074]
The content of the compound represented by formula (I) in the liquid crystal composition of the present invention is preferably in the range of 3 to 60% by weight. Further, (2) the content of the compound selected from the group consisting of the compounds represented by the general formulas (II) to (III) is preferably in the range of 3 to 50% by weight in total, and at this time, each compound More preferably, the compound represented by the general formula (II) is contained in the range of 0 to 25% by weight, and the compound represented by the general formula (III) is contained in the range of 0 to 30% by weight.
[0075]
Further, (3) the content of the compound selected from the group consisting of the compounds represented by the general formulas (IV) to (V) is preferably in the range of 3 to 40% by weight in total, and at this time, each compound Is preferably in the range of 0 to 30% by weight of the compound represented by the general formula (IV) and in the range of 3 to 30% by weight of the compound represented by the general formula (V).
[0076]
When the compound represented by any of the general formulas (VI) to (VII) is contained, its content is preferably in the range of 3 to 55% by weight, and at this time, the content of each compound is 0%. It is preferably in the range of ~ 35% by weight. When the compound represented by any of the general formulas (VIII) to (XI) is contained, its content is preferably in the range of 3 to 35% by weight in total. Each is preferably in the range of 0 to 20% by weight. When a compound selected from the group consisting of compounds represented by the general formulas (XII) to (XVI) is contained, the compound is preferably contained in a total amount of 3 to 25% by weight, and particularly preferably the general formula (XII) Is preferably contained in the range of 3 to 25% by weight.
[0077]
The liquid crystal composition of the present invention is preferably used, for example, in the following composition according to the intended use.
Crystalline or smectic-nematic phase transition temperature T →_NIn particular, for the purpose of lowering the value, it is preferable to use a combination of a compound selected from the group consisting of (1) a compound of the general formula (I) and (2) a compound of the general formulas (II) to (IV). →_NFor the purpose of lowering the value, it is preferable to use a combination of compounds selected from the group consisting of (3) compounds of the general formulas (VI) to (VII), and (4) a compound of the general formulas (IX) to (XI) It is preferable to use a combination of compounds selected from the group consisting of compounds.
[0078]
Nematic phase-isotropic liquid phase transition temperature T of liquid crystal composition_NIAnd the crystal phase or the smectic phase-nematic phase transition temperature T →_NFor the purpose of lowering the value, it is preferable to use a combination of a compound selected from the group consisting of (1) a compound of the general formula (I) and (2) a compound of the general formulas (II) to (IV). ) It is preferable to use a combination of compounds selected from the group consisting of compounds of general formulas (X) to (XI).
[0079]
Liquid crystal display threshold voltage V_th(1) a compound of the general formula (I), (2) a compound selected from the group consisting of the compounds of the general formulas (II) to (III), and (3) a compound of the general formula (V) Are preferably used in combination, and more preferably (4) a compound selected from the group consisting of compounds represented by formulas (IX) to (XI) is used in combination.
[0080]
For the purpose of speeding up the response characteristics of the liquid crystal display, a combination of (1) the compound of the general formula (I), (2) the compound of the general formula (II) and (3) the compound of the general formula (VI) is used. More preferably, it is preferable to use a combination of compounds selected from the group consisting of compounds of the general formulas (4) and (XII) to (XVI).
[0081]
In order to adjust the birefringence Δn of the liquid crystal composition in the range of 0.07 to 0.08, (1) the compound of the general formula (I), (2) the compound of the general formula (III) to (V) It is preferable to use a combination of a compound selected from the group consisting of compounds and (3) the compound of the general formula (VII), and to adjust the birefringence Δn of the liquid crystal composition to a range of 0.08 to 0.10. It is preferable to use a combination of (1) a compound of the general formula (I), (2) a compound of the general formula (II) and (3) a compound of the general formula (VI). It is preferable to use a combination of compounds selected from the group consisting of compounds of formulas (X) to (XI).
[0082]
The liquid crystal composition of the present invention thus obtained has a nematic phase-isotropic liquid phase transition temperature (T_NI) Is in the range of 80 to 100 ° C. and the threshold voltage (V_th) In the range of 1.2 to 1.6 V, or a nematic phase-isotropic liquid phase transition temperature (T_NI) Is in the range of 100 to 120 ° C. and the threshold voltage (V_thIs obtained in the range of 1.6 to 2.0 V, and these nematic liquid crystal compositions have a crystalline phase or a smectic phase-nematic phase transition temperature (T →_N) Is −10 ° C. or lower, the birefringence Δn is in the range of 0.07 to 0.10, and the dielectric anisotropy (Δε) is in the range of +6 to 9, which is very practical. What almost satisfied the required characteristics was obtained.
[0083]
Further, the nematic liquid crystal composition of the present invention was subjected to a heating acceleration test and an ultraviolet irradiation acceleration test, as shown in Examples described later, and had a high voltage holding ratio of 98% or more after each acceleration test. In addition, it was confirmed that it was very stable chemically and had a high resistance value.
[0084]
Therefore, a liquid crystal display device using such a nematic liquid crystal composition also has very excellent characteristics, and the present invention also provides a liquid crystal display device using the above-described various nematic liquid crystal compositions.
[0085]
The liquid crystal display device of the present invention, in particular, an active matrix type liquid crystal display device or a twisted nematic or super twisted nematic liquid crystal display device exhibits liquid crystallinity over a wide temperature range, has a low threshold voltage, and has a sufficient Shows a high voltage holding ratio. In particular, in an active matrix liquid crystal display device, flicker does not occur and the contrast is excellent, and it has been confirmed that a TN-LCD or STN-LCD liquid crystal display device can display a wide range of driving frequencies.
[0086]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. Further, “%” in the compositions of the following examples means “% by weight”.
[0087]
The specific resistance of the composition was determined by placing 2 g of the liquid crystal composition in an ampoule tube, degassing in vacuum, treating with nitrogen replacement, sealing the mixture, heating at 180 ° C. for 1 hour, and irradiating with ultraviolet light for 10 hours The specific resistance of the liquid crystal composition after the accelerated test “SUNEST” (manufactured by Original Hanau) was measured.
[0088]
In the examples, the meaning of each symbol of the measured characteristics is as follows.
T_NI    : Nematic phase-isotropic liquid phase transition temperature (℃)
T →_N    : Crystalline phase or smectic phase-nematic phase transition temperature (° C)
V_th    : Threshold voltage (V) when TN-LCD with first minimum Δn · d = 0.5, where d is the thickness of the panel liquid crystal layer
Δε: dielectric anisotropy
Δn: birefringence
τr = τd: The rise time τr from when no voltage is applied to when a voltage is applied and the light is transmitted is equal to the fall time τd when the voltage is not applied and the light is not transmitted except for the voltage. Response time (msec)
[0089]
(Example 1)
[0090]
Embedded image

[0091]
Was prepared, and various properties of the composition were measured. The results were as follows.
T_NI      : 82.0 ° C
T →_N      : -32.0 ° C
V_th      : 1.37 V
Δε: 9.2
Δn: 0.076
Specific resistance before test: 7.5 × 10^ThirteenΩ cm
Specific resistance after heating acceleration test: 5.6 × 10^ThirteenΩ cm
Specific resistance after UV irradiation acceleration test: 3.0 × 10^ThirteenΩ cm
Voltage holding ratio before test: 99.6% (measuring temperature 80 ° C)
Voltage holding ratio after heating acceleration test: 98.7% (measuring temperature 80 ° C)
Voltage holding ratio after UV irradiation acceleration test: 98.3% (measuring temperature 80 ° C)
[0092]
When an active matrix liquid crystal display device using the nematic liquid crystal composition (3-1) as a constituent material was manufactured, it was confirmed that the device was excellent in that the leakage current was small and flicker did not occur.
[0093]
(Example 2)
[0094]
Embedded image

[0095]
Was prepared, and various properties of the composition were measured. The results were as follows.
T_NI        : 85.7 ° C
T →_N    : -25.0 ° C
V_th      : 1.42 V
Δε: 7.4
Δn: 0.074
[0096]
(Example 3)
[0097]
Embedded image

[0098]
Was prepared, and various properties of the composition were measured. The results were as follows.
T_NI      : 93.2 ° C
T →_N      : -30.0 ° C
V_th      : 1.60 V
Δε: 7.2
Δn: 0.080
[0099]
(Example 4)
[0100]
Embedded image

[0101]
Was prepared, and various characteristics of the composition were measured. The results were as follows.
T_NI      : 92.1 ° C
T →_N      : <-70.0 ° C
V_th      : 1.58 V
Δε: 6.5
Δn: 0.084
[0102]
(Example 5)
[0103]
Embedded image

[0104]
Was prepared, and various characteristics of the composition were measured. The results were as follows.
T_NI      : 119.3 ° C
T →_N      : <-70.0 ° C
V_th      : 1.63 V
Δε: 7.3
Δn: 0.091
τr = τd: 29.0 msec
[0105]
(Example 6)
[0106]
Embedded image

[0107]
Was prepared, and various properties of the composition were measured. The results were as follows.
T_NI      : 124.5 ° C
T →_N      : <-70.0 ° C
V_th      : 2.00 V
Δε: 7.0
Δn: 0.093
Specific resistance before test: 7.0 × 10^ThirteenΩ cm
Specific resistance after heating acceleration test: 5.8 × 10^ThirteenΩ cm
Specific resistance after UV irradiation acceleration test: 2.7 × 10^ThirteenΩ cm
Voltage holding ratio before test: 99.8%
Voltage holding ratio after heating acceleration test: 98.6%
Voltage retention after UV irradiation acceleration test: 97.5%
[0108]
When an active matrix liquid crystal display device using the nematic liquid crystal composition (3-6) as a constituent material was manufactured, it was confirmed that the device was excellent in that the leakage current was small and flicker did not occur.
[0109]
(Example 7)
[0110]
Embedded image

[0111]
Was prepared, and various properties of the composition were measured. The results were as follows.
T_NI      : 98.6 ° C
T →_N      : <-70.0 ° C
V_th      : 1.73 V
Δε: 6.0
Δn: 0.087
Specific resistance before test: 7.2 × 10^ThirteenΩ cm
Specific resistance after heating acceleration test: 5.5 × 10^ThirteenΩ cm
Specific resistance after UV irradiation acceleration test: 3.2 × 10^ThirteenΩ cm
Voltage holding ratio before test: 99.0%
Voltage holding ratio after heating acceleration test: 97.8%
Voltage holding ratio after UV irradiation acceleration test: 97.3%
[0112]
When an active matrix liquid crystal display device using the nematic liquid crystal composition (3-7) as a constituent material was produced, it was confirmed that the device was excellent in that the leakage current was small and flicker did not occur.
[0113]
Further, a chiral substance “S-811” (manufactured by Merck) was added to the nematic liquid crystal composition (3-7) to prepare a mixed liquid crystal. On the other hand, an organic film of “Sun Ever 150” (manufactured by Nissan Chemical Industries, Ltd.) was rubbed on the opposed flat transparent electrode to form an alignment film, and a STN-LCD display cell having a twist angle of 220 ° was manufactured. The mixed liquid crystal was injected into this cell to construct a liquid crystal display, and the display characteristics were measured. As a result, a liquid crystal display device having a low threshold voltage, excellent high time division characteristics, and exhibiting STN-LCD display characteristics with improved display screen flicker and crosstalk was obtained.
[0114]
(Example 8)
[0115]
Embedded image

[0116]
Was prepared, and various properties of the composition were measured. The results were as follows.
T_NI      : 83.0 ° C
V_th      : 1.29 V
Δε: 8.6
Δn: 0.076
[0117]
(Example 9)
[0118]
Embedded image

[0119]
Was prepared, and various characteristics of the composition were measured. The results were as follows.
T_NI      : 84.3 ° C
V_th      : 1.30 V
Δε: 8.8
Δn: 0.077
[0120]
(Example 10)
Embedded image

[0121]
Was prepared, and various properties of the composition were measured. The results were as follows.
T_NI      : 89.3 ° C
T →_N      : -45.0 ° C
V_th      : 1.48 V
Δε: 7.9
Δn: 0.088
[0122]
(Example 11)
[0123]
Embedded image

[0124]
Was prepared, and various characteristics of the composition were measured. The results were as follows.
T_NI      : 83.3 ° C
T →_N      : <-70.0 ° C
V_th      : 1.32 V
Δε: 8.7
Δn: 0.082
[0125]
【The invention's effect】
The nematic liquid crystal composition of the present invention exhibits a nematic phase in a wide temperature range, has a low threshold voltage, has a high voltage holding ratio, and has high chemical stability. Therefore, the liquid crystal display device of the present invention using the same can improve the flickering of the display screen and the crosstalk phenomenon, and has good driving characteristics in a TN-LCD, STN-LCD or an active matrix system having a large amount of information. And display characteristics.

Claims (35)

(1) General formula (I)

(Wherein, R ¹ represents a linear alkyl group having 2 to 7 carbon atoms); and (2) compounds represented by the general formulas (II) to (III):

(Wherein, R ² represents a straight-chain alkenyl group having 2 to 7 carbon atoms, and R ³ represents a straight-chain alkyl group having 2 to 7 carbon atoms). Liquid crystal composition characterized by containing a compound to be prepared. 2. The nematic liquid crystal composition according to claim 1, comprising a compound represented by the general formula (II). 3. The nematic liquid crystal composition according to claim 2, comprising a compound represented by the general formula (III). (1) The compound represented by the general formula (I) according to claim 1 and (2) the general formulas (IV) to (V)

(Wherein, R ⁴ independently represents a linear alkyl group having 2 to 7 carbon atoms.) A nematic liquid crystal composition comprising a compound selected from the group consisting of compounds represented by the formula: object. The compound according to claim 1, wherein (1) a compound represented by the general formula (I), (2) a compound selected from the group consisting of compounds represented by the general formulas (II) to (III), and (3) A nematic liquid crystal composition comprising a compound selected from the group consisting of compounds represented by formulas (IV) to (V). 6. The nematic liquid crystal composition according to claim 5, comprising a compound represented by the general formula (II) according to claim 1 and a compound represented by the general formula (V) according to claim 4. The compound represented by the general formula (I) according to claim 1, the compound represented by the general formula (II) and the compound represented by the general formula (V) according to claim 4. Nematic liquid crystal composition. A compound comprising the compound represented by the general formula (II), the compound represented by the general formula (III) and the compound represented by the general formula (V) according to claim 4. The nematic liquid crystal composition according to the above. The compound represented by the general formula (I), the compound represented by the general formula (II), the compound represented by the general formula (III) and the compound represented by the general formula (V) according to claim 4 The nematic liquid crystal composition according to claim 8, wherein the composition comprises: General formulas (VI) to (XI)

(Wherein, R ⁵ represents a linear alkenyl group having 2 to 7 carbon atoms, R ⁶ each independently represents a linear alkyl group having 2 to 7 carbon atoms, and X ¹ represents each independently Wherein H represents F or F, and r represents 0 or 1.) 7. A compound selected from the group consisting of compounds represented by the following formulas: 1, 2, 3, 4, 5, 6 Or the nematic liquid crystal composition according to 8. A compound comprising a compound selected from the group consisting of compounds represented by general formulas (VI) to (VII) and a compound selected from the group consisting of compounds represented by general formulas (IX) to (X). Item 11. A nematic liquid crystal composition according to item 10. A compound represented by the general formula (II) according to claim 1, a compound represented by the general formula (VI), a compound represented by the general formula (VII) and a compound represented by the general formula (X) according to claim 10. The nematic liquid crystal composition according to claim 11, which is contained. The compound represented by the general formula (I) according to claim 1, the compound represented by the general formula (II), the compound represented by the general formula (VI) according to claim 10, the compound represented by the general formula (VII) and The nematic liquid crystal composition according to claim 12, comprising a compound represented by the general formula (X). A compound represented by the general formula (I) according to claim 1, a compound represented by the general formula (II), a compound represented by the general formula (VI) according to claim 10, a compound represented by the general formula (VII), The nematic liquid crystal composition according to claim 11, comprising a compound represented by the general formula (IX) and a compound represented by the general formula (X). The nematic liquid crystal composition according to claim 10, comprising the compound represented by the general formula (VI) according to claim 10. The compound represented by the general formula (I), the compound represented by the general formula (II), the compound represented by the general formula (III) and the compound represented by the general formula (VI) according to claim 10 The nematic liquid crystal composition according to claim 15, wherein the composition comprises: The nematic liquid crystal composition according to claim 10, comprising a compound represented by the general formula (VII). The compound represented by the general formula (I) according to claim 1, the compound represented by the general formula (II), or the compound represented by the general formula (VII) according to claim 10. Nematic liquid crystal composition. The nematic liquid crystal composition according to claim 10, further comprising a compound selected from the group consisting of compounds represented by formulas (VIII) to (XI). A compound represented by the general formula (VIII), the compound represented by the general formula (IX), the compound represented by the general formula (X) and the compound represented by the general formula (XI) according to claim 10. The nematic liquid crystal composition according to claim 19, wherein A compound represented by the general formula (I), a compound represented by the general formula (II), a compound represented by the general formula (III) according to claim 1, a compound represented by the general formula (V) according to claim 4, A compound represented by the general formula (VIII), the compound represented by the general formula (IX), the compound represented by the general formula (X) and the compound represented by the general formula (XI) according to claim 10. 21. The nematic liquid crystal composition according to claim 20, wherein General formulas (XII) to (XVI)

(Wherein, R ⁷ independently represents a linear alkyl group or alkenyl group having 2 to 7 carbon atoms, and R ⁸ each independently represents a linear alkyl group having 2 to 7 carbon atoms. , An alkenyl group, an alkoxy group or an alkenyloxy group, and R ⁹ each independently represents a linear alkyl group having 2 to 7 carbon atoms.) 21. The nematic liquid crystal composition according to claim 1, wherein the nematic liquid crystal composition is used. 23. The nematic liquid crystal composition according to claim 22, comprising a compound represented by the general formula (XII). A compound represented by the general formula (II) according to claim 1, a compound represented by the general formula (VI) according to claim 10, a compound represented by the general formula (IX), a compound represented by the general formula (X) and The nematic liquid crystal composition according to claim 22, comprising the compound represented by the general formula (XII) according to claim 21. A compound represented by the general formula (I) according to claim 1, a compound represented by the general formula (II), a compound represented by the general formula (VI) according to claim 10, a compound represented by the general formula (IX), 25. The nematic liquid crystal composition according to claim 24, comprising a compound represented by formula (X) and a compound represented by formula (XII) according to claim 21. 26. The nematic liquid crystal composition according to claim 1, wherein the content of the compound represented by the general formula (I) according to claim 1 is in a range of 3 to 60% by weight. 27. The nematic liquid crystal according to claim 26, wherein the total amount of the compounds selected from the group consisting of the compounds represented by formulas (II) and (III) according to claim 1 is in the range of 3 to 50% by weight. Composition. The content of the compound represented by the general formula (II) according to claim 1 is in the range of 0 to 25% by weight, and the content of the compound represented by the general formula (III) according to claim 1 is 0% by weight. 28. The nematic liquid crystal composition according to claim 27, wherein the composition is in a range of from 30% by weight to 30% by weight. The content of a compound selected from the group consisting of compounds represented by the general formulas (IV) to (V) according to claim 4 is in a range of 3 to 40% by weight in total. 29. The nematic liquid crystal composition according to 27 or 28. 30. The nematic liquid crystal composition according to claim 29, wherein the content of the compound represented by formula (V) according to claim 4 is in the range of 3 to 30% by weight. The content of the compound selected from the group consisting of the compounds represented by the general formulas (VI) to (VII) according to claim 10 is in a range of 3 to 55% by weight in total. 31. The nematic liquid crystal composition according to 27, 28, 29 or 30. The content of a compound selected from the group consisting of compounds represented by the general formulas (XII) to (XVI) according to claim 22 is in a range of 3 to 25% by weight in total. 32. The nematic liquid crystal composition according to 27, 28, 29, 30 or 31. The nematic liquid crystal composition according to claim 32, wherein the content of the compound represented by the general formula (XII) according to claim 22 is in a range of 3 to 25% by weight. An active matrix type liquid crystal display using the nematic liquid crystal composition according to any one of claims 1 to 33. 34. A twisted nematic or super twisted nematic liquid crystal display using the nematic liquid crystal composition according to claim 1.