JP4131296B2 - Nematic liquid crystal composition and liquid crystal display device using the same - Google Patents

Description

【００１１】
（式中、Ｒ、Ｒ’はアルキル基、アルコキシ基を表す。）の化合物が用いられてきた。しかし、依然として問題が残されたままである。具体的には、一般式（ａ-４）の化合物は、特に強い極性を有する化合物との相溶性において特異性があり、スメクチック相や結晶相が出現しやすい傾向を有しており、一般式（ａ-１）の化合物との溶解性に乏しいものである。
【００１２】
本発明が解決しようとする課題は、上記の問題を解決あるいはより改善することにあり、所望の複屈折率の大きさに対して、駆動可能な温度範囲が広く、応答性に優れたネマチック液晶組成物を提供することにあり、この液晶組成物を構成材料として用いた、電気光学特性の改善されたTN-LCD、STN-LCD、TFT-LCD等の液晶表示装置を提供することにある。
【００１３】
また、前述の光散乱形液晶表示においても、より速い応答性、より低い電圧駆動性、より高い調光層の抵抗値、あるいはより高いコントラスト比等の要求される表示特性を維持向上させると共に、メモリー現象を低減し、白濁性のより均一な表示、温度変化に対する改善された表示特性、応答特性を達成した光散乱形液晶表示装置を提供することにある。
【００１４】
【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、
１．液晶組成物が、一般式（I-1）
【００１５】
【化６】

【００１６】
（式中、Ｒ¹¹は炭素原子数１〜１０の直鎖状アルキル基、アルコキシ基又は炭素原子数２〜１０の直鎖状アルケニル基を表し、Ｒ¹²は炭素原子数２〜１０の直鎖状アルケニル基を表す。）で表される１種又は２種以上の化合物からなる液晶成分Ａを含有し、＋２以上の誘電率異方性を有する化合物からなる液晶成分Ｂを含有する液晶組成物であって、該液晶組成物が３以上の誘電率異方性であり、６０℃以上のネマチック相−等方性液体相転移温度であり、０℃以下の結晶相又はスメクチック相−ネマチック相転移温度であることを特徴とするネマチック液晶組成物。
２．前記液晶成分Ａが、一般式（I-1）におけるＲ¹¹がメチル基、エチル基、プロピル基又はブテニル基で表される化合物及び／又はＲ¹²がブテニル基で表される化合物を３０〜１００重量％含有することを特徴とする上記１記載のネマチック液晶組成物。
３．前記液晶成分Ａが、前記一般式（I-1）及び一般式（I-2）
【００１７】
【化７】

【００１８】
（式中、Ｒ¹³、Ｒ¹⁴は各々独立的に炭素原子数１〜１０の直鎖状アルキル基又はアルコキシ基を表す。）で表される化合物からなることを特徴とする上記１又は２記載のネマチック液晶組成物。
４．前記液晶組成物が、前記液晶成分Ａを１〜５０重量％含有することを特徴とする上記１、２又は３記載のネマチック液晶組成物。
５．前記液晶成分Ｂが、一般式（II-1）〜（II-4）
【００１９】
【化８】

【００２０】
（式中、Ｒ²¹〜Ｒ²⁴は各々独立的に炭素原子数２〜１０の直鎖状アルキル基、アルケニル基又はＣ_sＨ_2s+1-Ｏ-Ｃ_tＨ_2tを表し、ｓ及びｔは各々独立的に１〜５の整数を表し、Ｘ²¹〜Ｘ²⁴は各々独立的にフッ素原子、塩素原子、-ＯＣＦ₃、-ＯＣＨＦ₂、-ＣＦ₃又は-ＣＮを表し、Ｙ²¹〜Ｙ²⁸は各々独立的に水素原子又はフッ素原子を表し、Ｗ²¹〜Ｗ²⁴は各々独立的に水素原子又はフッ素原子を表し、Ｚ²¹〜Ｚ²³は各々独立的に単結合、-ＣＯＯ-、-Ｃ₂Ｈ₄-又は-Ｃ₄Ｈ₈-を表し、Ｚ²¹はまた-Ｃ≡Ｃ-又は-ＣＨ＝ＣＨ-であってもよく、Ｚ²⁴、Ｚ²⁵は各々独立的に単結合、-ＣＯＯ-、-Ｃ≡Ｃ-又は-ＣＦ＝ＣＦ-を表し、ｍ¹〜ｍ⁴は各々独立的に０又は１を表し、ｍ³＋ｍ⁴は０又は１であり、各化合物におけるシクロヘキサン環の水素原子（Ｈ）は重水素原子（Ｄ）により置換されていても良い。）で表される化合物群から選ばれる化合物を含有することを特徴とする上記１、２、３又は４記載のネマチック液晶組成物。
６．前記液晶成分Ｂが、前記一般式（II-1）〜（II-4）におけるＲ²¹〜Ｒ²⁴が炭素原子数２〜５のアルキル基又はアルケニル基である化合物及び／又はＸ²¹〜Ｘ²⁴がＦ、Ｃｌ、-ＯＣＦ₃又は-ＣＮである化合物を１０〜１００重量％含有することを特徴とする上記５記載のネマチック液晶組成物。
７．前記液晶成分Ｂが、前記一般式（II-1）の化合物におけるＺ²¹、Ｚ²²が各々独立的に単結合、-ＣＯＯ-、-Ｃ₂Ｈ₄-又は-Ｃ₄Ｈ₈-で表される化合物を１０〜１００重量％含有することを特徴とする上記５又は６記載のネマチック液晶組成物。
８．前記液晶成分Ｂが、前記一般式（II-2）の化合物におけるＺ²⁴が単結合、-ＣＯＯ-又は-Ｃ≡Ｃ-で表される化合物を１０〜１００重量％含有することを特徴とする上記５、６又は７記載のネマチック液晶組成物。
９．前記液晶成分Ｂが、前記一般式（II-3）の化合物におけるＺ²⁵が単結合又は-Ｃ≡Ｃ-で表される化合物を少なくとも１０重量％含有することを特徴とする上記５、６、７又は８記載のネマチック液晶組成物。
１０．前記液晶組成物が、前記液晶成分Ｂを１０〜９９重量％含有することを特徴とする上記１乃至９記載のネマチック液晶組成物。
１１．前記液晶組成物が、−２〜２の誘電率異方性を有する化合物からなる液晶成分Ｃを含有し、該液晶成分Ｃが、一般式（III-1）〜（III-4）
【００２１】
【化９】

【００２２】
（式中、Ｒ³¹〜Ｒ³⁴は各々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し、Ｒ³⁵〜Ｒ³⁸は各々独立的に炭素原子数１〜７の直鎖状アルキル基、アルコキシ基、アルケニル基、アルケニルオキシ基又はＣ_uＨ_2u+1-Ｏ-Ｃ_vＨ_2vを表し、ｕ及びｖは各々独立的に１〜５の整数を表し、Ｙ³¹は水素原子、フッ素原子又は-ＣＨ₃を表し、Ｙ³²及びＹ³³は各々独立的に水素原子又はフッ素原子を表し、Ｚ³¹〜Ｚ³⁴は各々独立的に単結合、-ＣＯＯ-、-Ｃ₂Ｈ₄-又は-Ｃ₄Ｈ₈-を表し、Ｚ³¹はまた-Ｃ≡Ｃ-又は-ＣＨ＝ＣＨ-であってもよく、Ｚ³⁵は単結合、-Ｃ≡Ｃ-、-ＣＯＯ-又は-ＣＦ＝ＣＦ-を表し、環Ａ³¹、環Ａ³²は各々独立的にシクロヘキサン環又はシクロヘキセン環を表し、環Ａ³³、環Ａ³⁴は各々独立的にシクロヘキサン環又はベンゼン環を表し、ｎ¹〜ｎ⁵は各々独立的に０又は１の整数を表し、ｎ⁴＋ｎ⁵は０又は１であり、各化合物におけるシクロヘキサン環の水素原子（Ｈ）は重水素原子（Ｄ）で置換されていても良い。）で表される化合物群から選ばれる化合物を１種又は２種以上含有することを特徴とする上記１乃至１０記載のネマチック液晶組成物。
１２．前記液晶成分Ｃが、前記一般式（III-1）の化合物において、Ｒ³¹が炭素原子数２〜５の直鎖状アルキル基又はアルケニル基を表し、Ｒ³⁵が炭素原子数１〜５の直鎖状アルキル基、アルコキシ基、アルケニル基、アルケニルオキシ基を表し、ｎ¹が０の場合、Ｚ³²が単結合又は-ＣＯＯ-で表される化合物及び／又はｎ¹が１の場合、環Ａ³¹がシクロヘキサン環を表し、Ｚ³¹、Ｚ³²が単結合で表される化合物を１０〜１００重量％含有することを特徴とする上記１１記載のネマチック液晶組成物。
１３．前記液晶成分Ｃが、前記一般式（III-2）の化合物において、Ｒ³²が炭素原子数２〜５の直鎖状アルキル基又はアルケニル基を表し、Ｒ³⁶が炭素原子数１〜５の直鎖状アルキル基、アルコキシ基、アルケニル基、アルケニルオキシ基を表し、ｎ²が０の場合、環Ａ³²がシクロヘキサン環又はシクロヘキセン環であり、Ｚ³³が単結合、-ＣＯＯ-又は-Ｃ₂Ｈ₄-で表される化合物及び／又はｎ²が１の場合、環Ａ³²がシクロヘキサン環であり、Ｚ³³が単結合又は-Ｃ₂Ｈ₄-で表される化合物を１０〜１００重量％含有することを特徴とする上記１１又は１２記載のネマチック液晶組成物。
１４．前記液晶成分Ｃが、前記一般式（III-3）の化合物において、Ｚ³⁵が-Ｃ≡Ｃ-で表される化合物を１０〜１００重量％含有することを特徴とする上記１１、１２又は１３記載のネマチック液晶組成物。
１５．前記液晶組成物が、前記液晶成分Ｃを多くとも７０重量％含有することを特徴とする上記１１、１２、１３又は１４記載のネマチック液晶組成物。
１６．前記液晶組成物が、４個の六員環を有したコア構造の化合物であって、該化合物の液晶相−等方性液体相転移温度が１００℃以上を有する化合物を1種又は２種以上含有することを特徴とする上記１乃至１５記載のネマチック液晶組成物。
１７．前記液晶組成物が、４〜３０の誘電率異方性であり、０．０８〜０．３３の複屈折率であり、６０℃〜１８０℃のネマチック相−等方性液体相転移温度であり、−２００℃〜０℃の結晶相、スメクチック相又はガラス相−ネマチック相転移温度であることを特徴とする上記１乃至１６記載のネマチック液晶組成物。１８．前記液晶組成物に、誘起螺旋ピッチが０．５〜１０００μｍとなる光学活性基を有する化合物を含有することを特徴とする上記１乃至１７記載のネマチック液晶組成物。
１９．上記１８記載のネマチック液晶組成物を用いたアクティブ・マトリクス、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。
２０．液晶層の厚みが１〜３０μｍであることを特徴とする上記１９記載の液晶表示装置。
２１．上記１乃至１８記載の液晶組成物及び透明性固体物質を含有する調光層を有する光散乱形液晶表示装置。
２２．前記調光層において、前記液晶組成物が連続層をなし、該連続層中に前記透明性固体物質が均一な三次元網目状構造を形成することを特徴とする上記２１記載の光散乱形液晶表示装置。
２３．前記透明性固体物質が、高分子形成性２官能性モノマー及び単官能性モノマーを含有した重合性組成物から形成されることを特徴とする上記２１又は２２記載の光散乱形液晶表示装置。
を前記課題の解決手段として見いだした。
【００２３】
【発明の実施の形態】
以下に、本発明のネマチック液晶組成物及びこれを用いた液晶表示素子の一例について説明する。尚、Ｈは水素原子を、Ｆはフッ素原子を、Ｃｌは塩素原子をそれぞれ表す。
【００２４】
本発明の液晶組成物は、一般式（I-1）で表される化合物からなる液晶成分Ａを必須成分として含有する。この液晶成分Ａは、より低い粘性でより大きい複屈折率を有し、より大きい弾性定数を有している。このため本発明の液晶組成物は、広い範囲で複屈折率や弾性定数を調整することが可能となり、例えば高速応答で駆動できるという特徴を有している。本発明の液晶組成物は、一般式（I-1）からなる液晶成分Ａを含有し、＋２以上の誘電率異方性を有する化合物からなる液晶成分Ｂを含有し、該液晶材料が３以上の誘電率異方性で、６０℃以上のネマチック相−等方性液体相転移温度で、０℃以下の結晶相又はスメクチック相−ネマチック相転移温度とさせることで、より速い応答特性を有することを見いだした。また、液晶成分Ａは、上記の他に、他の液晶材料と混合したとき、ネマチック相−等方性液体相転移温度を比較的高い温度に改善し、また相溶性に優れているので、表示温度範囲をより広くさせることができる。更に、誘電率異方性が−２〜＋２の範囲であり、より高い化学的安定性を有している。
【００２５】
この様な視点から、一般式（I-1）で表される化合物におけるより好ましい形態は、Ｒ¹¹がメチル基、エチル基、プロピル基又はブテニル基で表される化合物及び／又はＲ¹²がブテニル基で表される化合物であり、より具体的には式（I-3）〜（I-6）で表される化合物が好ましく、液晶成分Ａには、少なくとも１種以上の化合物を３０〜１００重量％含有するネマチック液晶組成物が好ましい。尚、各化合物は、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、充分精製したものを使用した。
【００２６】
【化１０】

【００２７】
液晶成分Ａとして一般式（I-1）の化合物を１種以上含有させることができるが、１種であっても上記の効果を得ることができる。一般式（I-1）で表される化合物を少なくとも１種以上含む液晶成分Ａを含有する本発明の液晶組成物は、これを構成材料として用いたTN-LCD、STN-LCD、TFT-LCD等の液晶表示装置を、より改善された電気光学特性にし、特に低温での応答性、急峻性駆動電圧の温度依存性をより好ましいものとさせる。
【００２８】
また、本発明における前記液晶成分Ａは、前記一般式（I-1）で表される化合物とともに一般式（I-2）で表される化合物を併用して構成することができ、より速い応答特性を有することを見いだした。この様な視点から、一般式（I-2）で表される化合物におけるより好ましい形態は、Ｒ¹³、Ｒ¹⁴がメチル基、エチル基又はプロピル基で表される化合物を含有すること好ましく、より具体的には一般式（I-7）〜（I-11）で表される化合物が好ましく、液晶成分Ａには、少なくとも１種以上の化合物を１〜９９重量％含有するネマチック液晶組成物が好ましい。
【００２９】
【化１１】

【００３０】
一般式（I-1）の化合物とともに、一般式（I-2）で表される式（I-7）〜（I-11）の化合物を少なくとも１種以上含む液晶成分Ａを含有する本発明の液晶組成物は、これを構成材料として用いたTN-LCD、STN-LCD、TFT-LCD等の液晶表示装置を、より改善された電気光学特性にし、特に低温での応答性、急峻性駆動電圧の温度依存性をより好ましいものとさせる。
【００３１】
本発明の液晶組成物は、必須成分である液晶成分Ａに加えて、誘電率異方性が＋２以上の化合物からなる液晶成分Ｂから選ばれる化合物を１種又は２種以上を含有するものである。尚、本発明で述べる２より大きい誘電異方性を有する液晶化合物とは、以下の意義で用いる。液晶化合物の化学構造は棒状であり、中央部分が１個から４個の六員環を有したコア構造を有し、中央部分長軸方向の両端に位置する六員環が、液晶分子長軸方向に相当する位置で置換された末端基を有し、両端に存在する末端基の少なくとも一方が極性基であること、即ち例えば-ＣＮ、-ＯＣＮ、-ＮＣＳ、-Ｆ、-Ｃｌ、-ＮＯ₂、-ＣＦ₃、-ＯＣＦ₃、-ＯＣＨＦ₂である化合物である。これによって、液晶層の光学異方性を所定の値にすることができ、電気的に駆動可能となり、動作温度範囲を広くさせることができる。
【００３２】
液晶成分Ｂとして、誘電率異方性が＋２以上の化合物は、少なくとも１種以上を必要とし、３〜１５種の範囲が好ましい。また、誘電率異方性が＋８〜＋１３の化合物、＋１４〜＋１８の化合物、＋１８以上の化合物から適時選んで含有させることが好ましく、所定の駆動電圧や応答特性を得ることができる。この場合、＋８〜＋１３の誘電率異方性の化合物は多くとも１０種以下の範囲で混合することが好ましく、＋１４〜＋１８の化合物は多くとも８種以下の範囲で混合することが好ましく、＋１８以上の化合物は多くとも１０種以下の範囲で混合することが好ましい。液晶成分Ｂを上述の様に使用することは、表示特性の温度特性により好ましい効果を付与する。より具体的には、駆動電圧、急峻性に関わるコントラスト、応答性等の温度依存性をより好ましいものとする。
【００３３】
本発明の液晶成分Ｂとして、一般式（II-1）〜（II-4）で表される化合物から選ばれる化合物を１０〜１００重量％含有することが好ましい。一般式（II-1）〜（II-4）で表される化合物におけるより好ましい形態は、Ｒ²¹〜Ｒ²⁴が各々独立的に炭素原子数２〜５のアルキル基、アルケニル基で表される化合物及び／又はＸ²¹〜Ｘ²⁴がＦ、Ｃｌ、-ＯＣＦ₃又は-ＣＮで表される化合物を選択して、少なくとも１種以上含むことが好ましい。また、一般式（II-2）においてＺ²⁴が単結合、-ＣＯＯ-又は-Ｃ≡Ｃ-で表される化合物、一般式（II-3）においてＺ²⁵が単結合又は-Ｃ≡Ｃ-で表される化合物を含有することが好ましい。一般式（II-1）〜（II-4）で表される特に好ましいより具体的な化合物として、一般式（II-1a）〜（II-4d）を下記に示す。尚、各化合物は、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、充分精製したものを使用した。これらの化合物を含有した液晶成分Ｂは、必須成分の液晶成分Ａと良く混合する特徴を有し、特に駆動電圧の目的に応じた調製やその温度依存性の改善あるいは応答性の改善に有用である。特に、一般式（II-1a）〜（II-1h）、一般式（II-2a）〜（II-4d）の化合物はこの効果に優れており、１〜２５％と少量の含有率でもこの効果を得ることができる。
【００３４】
【化１２】

【００３５】
【化１３】

【００３６】
【化１４】

【００３７】
【化１５】

【００３８】
（式中、Ｒ²¹〜Ｒ²⁴、Ｘ²¹〜Ｘ²⁴、Ｙ²¹〜Ｙ²⁸、Ｗ²¹、Ｗ²²は前記におけると同じ意味を表す。）
更に好ましい形態について具体的に詳述する。
【００３９】
Ｒ²¹は炭素原子数が２〜５のアルキル基又はＣＨ₂=ＣＨ-(ＣＨ₂)_p(ｐ＝０、２）のアルケニル基である化合物が好ましく、一般式（II-1a）、（II-1d）の化合物がこの基を有することが好ましく、液晶成分Ｂにアルケニル基を有する化合物を少なくとも１種以上含有させることで、粘度や粘弾性を低減させることができる。同様に、Ｒ²²も炭素原子数２〜５のアルキル基、上述のアルケニル基である化合物が好ましく、一般式（II-2a）、（II-2d）、（II-2f）、（II-2g）の化合物がこの基を有することが好ましい。Ｘ²¹〜Ｘ²⁴はＦ、Ｃｌ、-ＯＣＦ₃、-ＣＮである化合物を多用することが好ましく、高速応答を重視する場合Ｘ²¹〜Ｘ²⁴がＦ、-ＯＣＦ₃である一般式（II-1a）、（II-1d）、（II-2a）、（II-2c）、（II-2d）、（II-2g）、（II-3a）の化合物を液晶成分Ｂに多用することが好ましく、より大きい複屈折率を必要とする場合はＸ²²〜Ｘ²⁴がＣｌ、-ＯＣＦ₃、-ＣＮである一般式（II-2a）〜（II-4d）の化合物を液晶成分Ｂに多用することが好ましく、より低い駆動電圧必要とする場合はＸ²¹が-ＣＮでＹ²¹がＨ又はＦである一般式（II-1a）〜（II-1g）の化合物、Ｘ²²がＦ、Ｃｌ、-ＣＮでＹ²³がＨ又はＦである一般式（II-2a）〜（II-2f）の化合物、Ｘ²³がＦ、Ｃｌ、-ＣＮでＹ²⁵がＦである一般式（II-3a）〜（II-3c）の化合物、Ｘ²⁴がＦ、Ｃｌ、-ＣＮでＹ²⁷がＦである一般式（II-4a）〜（II-4d）の化合物を液晶成分Ｂに多用することが好ましい。特に、アクティブ・マトリクス表示方式、TFT-LCD、MIM-LCD、IPSモードと組み合わせたスーパーＴＦＴやアクティブ・マトリクス技術を有した光散乱形液晶表示装置（例えば、液晶材料及び透明性固体物質を含有する調光層を有する表示装置）には、Ｘ²¹〜Ｘ²⁴がＦである化合物を多用することが好ましい。
一般式（II-1）〜（II-4）において、高速応答性を重視する場合Ｙ²¹〜Ｙ²⁸がＨ、及び／又はＷ²¹〜Ｗ²⁴がＨである化合物を多用することができ、駆動電圧の温度依存性を改善させる場合Ｙ²¹〜Ｙ²⁸がＦ、Ｗ²¹〜Ｗ²⁴がＦである化合物、特に好ましくはＹ²¹、Ｙ²³、Ｙ²⁵、Ｙ²⁷、Ｗ²¹〜Ｗ²⁴がＦである化合物を多用することが好ましく、このなかでＷ²¹及びＷ²²がＦの場合はＹ²⁴がＨである化合物を選択するとより相溶性を改善でき、一般式（II-3）の場合はＷ²³及び／又はＷ²⁴がＦである化合物を選択するとより相溶性を改善できる。一般式（II-1）において、Ｚ²¹とＺ²²の一方は単結合の化合物が好ましく、低温での応答性、相溶性を改善するには、単結合の化合物と-ＣＯＯ-、-Ｃ₂Ｈ₄-、-Ｃ₄Ｈ₈-の化合物を併用した液晶成分Ｂを用いることが好ましい。複屈折率がより大きいことを必要とする場合は、一般式（II-2）、（II-3）におけるＺ²⁴、Ｚ²⁵が-Ｃ≡Ｃ-の化合物、及び／又は一般式（II-4）におけるＸ²⁴がＣＮの化合物を液晶成分Ｂに多用することが好ましい。一般式（II-1）、（II-2）、（II-4）におけるｍ¹〜ｍ⁴が０の化合物と、一般式（II-1）、（II-2）におけるｍ¹、ｍ²が１の化合物、一般式（II-4）におけるｍ³＋ｍ⁴が１の化合物及び／又は一般式（II-3）の化合物との液晶成分Ｂでの混合比は、０〜１００から１００〜０の範囲で適時選ぶことができ、より高いネマチック相−等方性液体相転移温度を必要とする場合、一般式（II-1）、（II-2）におけるｍ¹、ｍ²が１の化合物、一般式（II-3）の化合物及び／又は一般式（II-4）におけるｍ³＋ｍ⁴が１の化合物を多用することが好ましい。一般式（II-1）、（II-2）のシクロヘキサン環中の水素原子（Ｈ）が重水素原子（Ｄ）で置換された化合物を用いることができるが、この化合物は液晶組成物の弾性定数の調整や配向膜に対応したプレチルト角の調整に有用であることから、重水素原子（Ｄ）で置換された化合物を少なくとも１種以上含有させることが好ましい。
【００４０】
上述してきた液晶成分Ｂの効果は、後述する液晶成分Ｃの含有率が非常に小さい場合においても得ることができる。駆動電圧を特に低くさせる目的のために、液晶成分Ｃの含有率を１０重量％以下にすることができる。この場合、液晶成分Ｃの粘性を可能な限り低くさせることが好ましく、駆動電圧の上昇がほとんどないか小さい範囲に止まり、応答速度の改善が効率的に得られる。例えば、液晶成分Ｃが少量の場合、この効果を液晶成分Ｂで達成させる方法として、一般式（II-1）〜（II-4）において、Ｘ²¹〜Ｘ²⁴がＦ、Ｃｌ、-ＯＣＦ₃である化合物又はＹ²¹〜Ｙ²⁴がＦである化合物又はＺ²⁴、Ｚ²⁵が-ＣＯＯ-、-Ｃ≡Ｃ-である化合物又はｍ¹が１である化合物の何れかの化合物を液晶成分Ｂに含有させることが好ましい。特に、一般式（II-1）〜（II-4）において、Ｘ²¹〜Ｘ²⁴がＦ、Ｃｌ、-ＯＣＦ₃、-ＣＮ、及び／又はＹ²¹〜Ｙ²³がＦである化合物は好ましい。
【００４１】
本発明の液晶組成物は、必須成分である液晶成分Ａ及び液晶成分Ｂに加えて、−２〜２の誘電率異方性を有する化合物からなる液晶成分Ｃを多くとも７０重量％含有させることが好ましい。本発明で述べる−２〜２の誘電率異方性を有する液晶化合物の好ましいものとしては、以下に示すものである。即ち、液晶化合物の化学構造は棒状であり、中央部分が１個から４個の六員環を有したコア構造を有し、中央部分長軸方向の両端に位置する六員環が、液晶分子長軸方向に相当する位置で置換された末端基を有し、両端に存在する末端基の両方が非極性基であること、即ち例えばアルキル基、アルコキシ基、アルコキシアルキル基、アルケニル基、アルケニルオキシ基、アルカノイルオキシ基である化合物である。液晶成分Ｃは、１種以上２０種以下の範囲で構成することが好ましく、２種以上１２種以下の範囲で構成することがより好ましい。
【００４２】
本発明の液晶成分Ｃとして、一般式（III-1）〜（III-4）で表される化合物から選ばれる化合物を１０〜１００重量％含有することが好ましい。一般式（III-1）〜（III-4）で表される特に好ましい化合物として、一般式（III-1a）〜（III-4e）を以下に示す。これらの化合物を含有した液晶成分Ｃは、一般式（I-1）の化合物を含有した液晶成分Ａと良く混合する特徴を有し、低温でのネマチック相を改善させるのに有用である。
【００４３】
【化１６】

【００４４】
【化１７】

【００４５】
【化１８】

【００４６】
（式中、Ｒ³¹〜Ｒ³⁸、Ｙ³¹〜Ｙ³³は前記におけると同じ意味を表す。）
液晶成分Ｃとして、一般式（III-1）〜（III-4）の化合物を含有することで、粘度や粘弾性を低減させることができ、比抵抗や電圧保持率が比較的高いという特徴を有する。液晶成分Ｃの粘度は、可能な限り低い粘度であることが好ましく、本発明の場合、４５ｃｐ以下が好ましく、３０ｃｐ以下がより好ましく、２０ｃｐ以下が更に好ましく、１５ｃｐ以下が特に好ましい。液晶成分Ｃとして、一般式（III-1）〜（III-4）のより好ましい化合物は、一般式（III-1a）〜（III-3a）、（III-3c）〜（III-3g）、（III-4a）、（III-4d）〜（III-4e）である。また、Ｒ³¹〜Ｒ³⁴が炭素原子数２〜５の直鎖状アルキル基又はＣＨ₂=ＣＨ-(ＣＨ₂)_q(ｑ＝０、２）のアルケニル基である化合物を少なくとも１種以上含有した液晶成分Ｃはより好ましい効果が得られる。更に特に、一般式（III-1a）、（III-1d）、（III-2a）の化合物、Ｙ³¹が水素原子である一般式（III-3c）〜（III-3f）の化合物及び／又はＲ³⁸がアルキル基である一般式（III-4a）の化合物は、３〜３０％と少量含有させてもこの効果を得ることができ、応答速度の改善に有用であり、例えばSTN-LCDに有用である。
【００４７】
上述した効果のために、液晶成分Ｃが含有すべきより好ましい化合物は、一般式（III-1）の化合物においては、Ｒ³¹が炭素原子数２〜５の直鎖状アルキル基又はアルケニル基を表し、Ｒ³⁵が炭素原子数１〜５の直鎖状アルキル基、アルコキシ基、アルケニル基、アルケニルオキシ基を表し、ｎ¹が０の場合、Ｚ³²が単結合又は-ＣＯＯ-であり、ｎ¹が１の場合、環Ａ³¹がシクロヘキサン環を表し、Ｚ³¹、Ｚ³²が単結合で表される化合物であり、一般式（III-2）の化合物においては、Ｒ³²が炭素原子数２〜５の直鎖状アルキル基又はアルケニル基を表し、Ｒ³⁶が炭素原子数１〜５の直鎖状アルキル基、アルコキシ基、アルケニル基、アルケニルオキシ基を表し、ｎ²が０の場合、環Ａ³²がシクロヘキサン環又はシクロヘキセン環であり、Ｚ³³が単結合、-ＣＯＯ-又は-Ｃ₂Ｈ₄-であり、ｎ²が１の場合、環Ａ³²がシクロヘキサン環であり、Ｚ³³が単結合又は-Ｃ₂Ｈ₄-で表される化合物である。
【００４８】
本発明の液晶成分Ｃは、一般式（III-1）、一般式（III-2）、一般式（III-3）、一般式（III-4）で表される化合物を各々単独で構成することもできるが、一般式（III-1）及び／又は（III-2）で表される化合物と一般式（III-3）及び／又は一般式（III-4）で表される化合物特にＺ³⁵が-Ｃ≡Ｃ-で表される化合物を併用することによって、液晶組成物の複屈折率を用途に応じて容易に最適化することができる。一般式（III-1）、一般式（III-2）の化合物、例えば一般式（III-1a）〜（III-2f）の化合物を多用することによって、複屈折率を減少させることができ、液晶表示装置の色むらの低減、視角特性の向上、コントラスト比の増加を容易に達成することができる。又、一般式（III-3）の化合物、例えば一般式（III-3a）〜（III-3h）の化合物、あるいは一般式（III-4）の化合物、例えば一般式（III-4a）〜（III-4e）の化合物を多用することで、複屈折率を増大させることができ、液晶層が１〜５μｍの薄い液晶表示素子の作製を可能とすることができる。
【００４９】
本発明の液晶組成物は、駆動電圧の大きさに対してより速い応答性を目的とする場合、以下のようにすることができる。中位の駆動電圧を目的とする場合は、本発明の液晶組成物の誘電率異方性が３〜１５の範囲であり、２０℃における粘性が８〜２０ｃ．ｐ．の範囲であることが好ましい。この場合、液晶成分Ｃのみの粘性が２５ｃ．ｐ．以下が好ましく、１５ｃ．ｐ．以下がより好ましく、１０ｃ．ｐ．以下が特に好ましい。又、特に低い駆動電圧を目的とする場合は、本発明の液晶組成物の誘電率異方性が１５〜３０の範囲にあることが好ましく、１８〜２８の範囲が特に好ましい。
【００５０】
現在、TN-LCD、STN-LCDあるいはTFT-LCDに用いられている配向膜は、ポリイミド系のものが多用されており、例えばLX1400、SE150、SE610、AL1051、AL3408等が使用されている。配向膜の仕様には、液晶表示特性、表示品位、信頼性、生産性が深く関係しており、液晶材料に対しては例えばプレチルト角特性が重要である。プレチルト角の大きさは、所望の液晶表示特性や均一な配向性を得るために、適時調整する必要がある。例えば、大きなプレチルト角の場合不安定な配向状態となりやすく、小さい場合充分な表示特性を満たされないこととなる。
【００５１】
本発明者らは、プレチルト角がより大きい液晶材料とより小さい液晶材料とに選別されることを見いだしており、これを応用することによって所望の液晶表示特性や均一な配向性を液晶材料から達成させることを見いだした。この技術は、本発明にも応用できる。例えば、液晶成分Ｂが一般式（II-1）〜（II-4）を含有する場合は以下のようになる。より大きいプレチルト角は、Ｒ²¹がアルケニル基、Ｘ²¹がＦ、Ｃｌ、-ＣＮ、Ｙ²¹、Ｙ²²がＦの化合物及び／又はＲ²¹がアルキル基、Ｘ²¹がＦ、Ｃｌ、-ＣＮ、Ｚ²²が-Ｃ₂Ｈ₄-、-Ｃ₄Ｈ₈-の化合物の含有率を多くさせることで得られ、より小さいプレチルト角は、Ｒ²¹がアルケニル基、Ｃ_sＨ_2s+1-Ｏ-Ｃ_tＨ_2t、Ｘ²¹がＦ、Ｙ²¹がＦ、Ｙ²²がＨの化合物及び／又はＺ²²が-ＣＯＯ-の化合物の含有率を多くさせることで得られる。一般式（II-1）、（II-2）におけるシクロヘキサン環の水素原子（Ｈ）を重水素原子（Ｄ）で置換した化合物の場合、置換位置によって異なり、プレチルト角の幅広い調整を可能にさせる。この様な効果は、例えばより大きいプレチルト角を得る場合、上述した化合物を液晶組成物総量に対して１０〜４０重量％あるいはそれ以上含有させることによってほぼ得ることができる。
【００５２】
本発明に関わる一般式（I-1）の化合物に関する類似技術は、例えば特開昭５４−８７６８８号公報で触れられており、例えば、一般式（a-3）の化合物を含有した混合物が示されている。また、一般式（a-1）、（a-2）の化合物を更に混合し、相溶性や応答特性に有用としている。しかし、特開昭５４−８７６８８号公報で開示されている組成物から一般式（a-3）の化合物を除くと、難溶性であり、改善策を必要としていた。また、本発明に関わる一般式（I-2）の化合物と例えば一般式（a-1）の化合物を含有した混合物の場合、０℃以上の結晶相又はスメクチック相−ネマチック相転移温度となり、充分な相溶性を得るのに困難であった。更にまた応答特性についても、例えばTN-LCDの応答特性は、６０msec以下、好ましくは５０msec以下、より好ましくは４０msec以下、特に好ましくは３０msec以下が現在要求されており、改善を必要としている。特に、一般式（a-3）の化合物は、応答特性を悪化させる傾向があり、新たな改善手段を必要としていた。
【００５３】
本発明は、上記の問題を解決したものであり、詳細には、例えば以下の各々の方策を見いだしたことによるものである。（１）液晶成分Ａの含有率を過度に多用せず、５０重量％以下にすること。（２）液晶成分Ｂを構成する化合物を、液晶成分Ａの含有率が特に多い場合、４種以上にすること。（３）シクロヘキサン環を有する化合物を、１種以上液晶成分Ｂに含有すること。この場合、一般式（II-1）の化合物がより好ましい結果を示した。（４）一般式（II-2）、（II-3）の化合物を用いた場合、一般式（II-1）の化合物を併用することが特に好ましい結果を示した。（５）液晶成分Ｃを構成する化合物を、液晶成分Ａの含有率が特に多い場合、含有すること。（６）液晶成分Ｂが一般式（II-2）、（II-3）の化合物を含有した場合、液晶成分Cを微量でも併用することが好ましい結果を示した。この場合、一般式（III-1）から（III-3）の化合物がより好ましい結果を示した。
【００５４】
本発明のネマチック液晶組成物における各液晶成分の含有量は以下のようにできる。液晶成分Ａは、１〜５０重量％の範囲であるが、３〜４０重量％の範囲が好ましく、３〜３０重量％の範囲がより好ましい。液晶成分Ｂは、１０〜９９重量％の範囲であるが、２５〜９０重量％の範囲が好ましく、２５〜８０重量％の範囲がより好ましい。液晶成分Ｃは、多くとも７０重量％の範囲であるが、３〜６５重量％の範囲が好ましく、５〜６０重量％の範囲がより好ましく、１０〜５５重量％の範囲が更に好ましい。一般式（I-1）、（I-2）で表される化合物の含有率は、単体で２０重量％以下が好ましく、それ以上は２種以上で構成することが好ましく、一般式（I-3）〜（I-11）で表される化合物の液晶成分Ａに対する含有率は、５０〜１００重量％の範囲であるが、７０〜１００重量％の範囲が好ましい。一般式（II-1）〜（II-4）で表される化合物あるいは一般式（II-1a）〜（II-4d）で表される化合物の含有率は、単体で３０重量％以下が好ましく、２５重量％以下が更に好ましく、それ以上は２種以上で構成することが好ましく、液晶成分Ｂに対する含有率は、１０〜１００重量％の範囲であるが、５０〜１００重量％の範囲が好ましく、７５〜１００重量％の範囲が更に好ましい。一般式（III-1）〜（III-4）で表される化合物あるいは一般式（III-1a）〜（III-4e）で表される化合物の含有率は、単体で３０重量％以下が好ましく、２５重量％以下が更に好ましく、それ以上は２種以上で構成することが好ましく、液晶成分Ｃに対する含有率は、１０〜１００重量％の範囲であるが、５０〜１００重量％の範囲が好ましく、７５〜１００重量％の範囲が更に好ましい。
【００５５】
結晶相又はスメクチック相−ネマチック相転移温度は、０℃以下であるが、好ましくは−１０℃以下、更に好ましくは−２０℃以下、特に好ましくは−３０℃以下である。ネマチック相−等方性液体相転移温度は、６０℃以上、好ましくは７０℃以上、更に好ましくは８０℃〜１３０℃の範囲である。本発明の液晶組成物は、誘電率異方性が３以上を必要とし、４〜３０の範囲が好ましく、高速応答性を重視する場合は４〜１６の範囲が、より低い駆動電圧を必要とする場合は１７〜３０の範囲が好ましい。より小さい或いは中位の複屈折率は、０．０９〜０．１８の範囲が好ましく、より大きい複屈折率は、０．１８〜０．３３の範囲が好ましい。この様なネマチック液晶組成物の特性は、アクティブ・マトリクス形、ツイスティッド・ネマチックあるいはスーパー・ツイスティッド・ネマチック液晶表示装置に用いるのに有用である。
【００５６】
上記ネマチック液晶組成物は、高速応答性のTN-LCDやSTN-LCDに有用であり、またカラーフィルター層を用いなくても、液晶層と位相差板の複屈折性でカラー表示をすることができる液晶表示素子に有用なものであり、透過型あるいは反射型の液晶表示素子の用いることができる。この液晶表示素子は、透明性電極層を有し少なくとも一方が透明である基板を有し、この基板間に前記ネマチック液晶組成物の分子をねじれた配向にさせ、目的に応じて３０°〜３６０°の範囲で選択することができ、９０°〜２７０°の範囲で選択することが好ましく、４５°〜１３５°の範囲または１８０°〜２６０°の範囲で選択することが特に好ましい。この為に、本発明の液晶組成物は、誘起螺旋ピッチが０．５〜１０００μｍとなる光学活性基を有する化合物を含有させることができる。透明性電極基板に設けられる配向膜によって得られるプレチルト角は、１°〜２０°の範囲で選択することが好ましく、ねじれ角が３０°〜１００°では１°〜４°のプレチルト角が好ましく、１００°〜１８０°では２°〜６°のプレチルト角が好ましく、１８０°〜２６０°では３°〜１２°のプレチルト角が好ましく、２６０°〜３６０°では６°〜２０°のプレチルト角が好ましい。
【００５７】
本発明の液晶組成物は、上記一般式（I-1）〜（III-4）で表される化合物以外にも、液晶組成物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いてもよい。しかしながら、これらの化合物を多量に用いることはネマチック液晶組成物の特性が低減することになるので、添加量は得られるネマチック液晶組成物の要求特性に応じて制限されるものである。
【００５８】
本発明者らは、上記液晶組成物が大きな複屈折率を有することから、透明性電極層を有する少なくとも一方が透明な２枚の基板間に挟持された調光層を有し、該調光層が液晶材料及び透明性固体物質を含有する光散乱形液晶表示にも、有利な光散乱特性による高いコントラストを具備させるのに有用であることを見いだした。
【００５９】
通常大きな複屈折率を有する液晶材料は、しばしば、誘起した結晶相あるいは一部が結晶化したスメクチック相が発現し、逆に液晶相が狭くなるという問題を有したり、大きな複屈折率及び広い温度で液晶相を示すが、アクティブ・マトリクス方式に必須の特段に高い電圧保持率を達成するには至らなかった。更に、光散乱形液晶表示を作製した場合、電圧無印加時の光透過率Ｔ０が、 作製した直後の値あるいは電圧印加後長期に放置させた値に比べ電圧印加状態から無印加状態に切り替えた直後の値のほうが大きくなってしまうメモリー現象が発現し、結果的に液晶表示のコントラストを悪化させることになり、単にフルオロトラン系の化合物を用いれば、好ましい結果に到るとは限らないのである。本発明の液晶組成物は、このような問題を回避したり、あるいは低減するに到ったものである。
【００６０】
また、本発明の液晶組成物は、透明性固体物質を形成させる高分子形成性化合物により高い相溶性を示す液晶材料であることを見い出したことにある。透明性固体物質は、高分子形成性化合物を重合させることにより形成することが好ましく、例えば、紫外線硬化型ビニル基を有する化合物を含有する紫外線硬化型樹脂組成物を液晶材料と混合した調光層形成材料を２枚の基板間に挟持した後、紫外線硬化型樹脂組成物を硬化させて作製する。高分子形成性化合物と液晶材料との相溶性がより高い場合、より広い温度域でより均一な溶液を得ることを可能とする。このような状態で高分子形成性化合物を硬化させると、片寄りが無いあるいは少ない状態で、光散乱性を有する調光層を作製することができ、駆動電圧やコントラスト比にムラの無い表示特性を得ると共に、白濁性のより均一な表示を達成した光散乱形液晶表示を提供できるのである。従って、より均一な光散乱特性を示す液晶表示あるいは比較的大型の液晶表示を真空注入法等を用いて作製するのに適した液晶材料を見い出したものである。
【００６１】
液晶材料は、アクティブ・マトリックス方式において必要な高い電圧保持率あるいは大きい複屈折率０．２００以上を得るために、シアノ基を有さない液晶化合物を用いることが好ましい。使用する液晶化合物としては、一般式（I-1）で表されるアジン系化合物、あるいは一般式（I-1）の化合物と併用して一般式（I-2）で表されるアジン系化合物を使用することが好ましく、これらのアジン系化合物は一般式（II-2）、（II-3）で表されるフルオロトラン系化合物と組み合わせることが好ましく、特に３つの環を有するフルオロトラン系化合物を必須成分として使用することがより好ましい。一般式（I-1）のアジン系化合物、あるいは一般式(I-1)及び一般式（I-2）のアジン系化合物を含有したことにより、特に応答性に改善効果があり、動画表示に有用な光散乱形液晶表示装置を提供することができる。また、より高い電圧保持率を有する液晶表示を調製するには、より高い比抵抗の液晶材料を用いることが好ましく、比抵抗としては１０¹¹Ω・ｃｍ以上が好ましく、１０¹²Ω・ｃｍ以上がより好ましく、１０¹³Ω・ｃｍ以上が最も好ましい。
【００６２】
本発明者らは特開平６−２２２３２０号公報において、液晶材料の物性値と液晶表示の表示特性との関係が次式（IV）で表されることを示した。
【００６３】
【数１】

【００６４】
なお、Ｖthはしきい値電圧を表し、¹Kii、²Kiiは弾性定数を表し、iiは11、22又は33を表し、△εは誘電率異方性を表し、＜ｒ＞は透明性固体物質界面の平均空隙間隔を表し、Ａは液晶分子に対する透明性固体物質のアンカリングエネルギーを表し、ｄは透明性電極を有する基板間の距離を表す。
【００６５】
この数式は、透明性固体界面が液晶分子に与える規制力が弾性定数¹KiiとアンカリングエネルギーＡの比によって変化することを意味しており、特にその効果が実際の平均空隙間隔＜ｒ＞より¹Kii／Ａの量だけ実質的に広げる作用を為し、従って効果的に駆動電圧を低減させることを示している。この関係は、本発明においても応用することができ、液晶材料を構成する液晶化合物によって液晶材料の誘電率異方性と弾性定数を選定することにより、低い電圧で駆動するより好ましい液晶表示を得ることができるものである。より具体的には、以下のようにすることが好ましい。透明性固体物質が高分子形成性化合物として２官能性モノマー及び単官能性モノマーを含有した重合性組成物から形成することにより、より優れた液晶表示の表示特性を得ることができる。高分子形成性化合物として２官能性モノマーと単官能性モノマーを組み合わせた組成物を用いることによって、高分子形成性化合物から透明性固体物質を形成する過程において、透明性固体物質の形状がより均一な構造を成し、液晶材料との界面の性質を操作できると考えられる。更に詳細には、前述した式（IV）における平均空隙間隔＜ｒ＞及びアンカリングエネルギーＡを優位にできる。このようにして、白濁性や透明性を維持したまま、駆動電圧を低減できるのである。更に又、例えば、前述した一般式（I）で表される化合物を含有した液晶材料は、高分子形成性化合物として２官能性モノマー及び単官能性モノマーを併用した重合性組成物を用いることで、メモリー現象を解消あるいは低減させることができる。
【００６６】
本発明で使用する液晶材料は、透明性電極層を有する２枚の基板間に液晶材料をマイクロカプセル化した液晶小滴を透明性固体物質中に分散させた表示にも有用なものであることが期待される。基板間に形成される透明性固体物質は、繊維状あるいは粒子状に分散するものでも、液晶材料を小滴状に分散させたフィルムのものでも良いが、三次元網目状の構造を有するものがより好ましい。また、液晶材料は連続層を形成することが好ましいが、液晶材料の無秩序な状態を形成することにより、光学的境界面を形成し、光の散乱を発現させる上で重要である。このような透明性固体物質から形成された三次元網目状構造の形状の平均径は、光の波長に比べて大きすぎたり、小さすぎる場合、光散乱性が衰える傾向にあるので、０．２〜２μｍの範囲が好ましい。また、調光層の厚みは、使用目的に応じ、２〜３０μｍの範囲が好ましく、５〜２０μｍの範囲が特に好ましい。
【００６７】
このようにして製造された本発明の液晶表示は、本発明者らが光散乱不透明状態と透明状態を利用する液晶表示を構成する液晶材料と透明性固体物質について鋭意検討し、液晶材料を構成する液晶化合物、高分子形成性化合物との相溶性及び重合性組成物の好ましい構成を見い出したことにより、より速い応答性、より低い電圧駆動性、より高い調光層の抵抗値、あるいはより高いコントラスト比等の表示特性を維持向上させると共に、メモリー現象を低減し、白濁性のより均一な表示を達成し、これにより、アクティブ・マトリクス方式に要求される特性を有するものである。また、本発明の液晶表示は、例えば、プロジェクション表示装置や直視型の携帯用端末表示（Personal Digital Assistance）として利用することができる。
【００６８】
【実施例】
以下、実施例を挙げて本発明を更に詳述するが、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。
【００６９】
組成物の化学的安定性は、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、１５０℃、１時間の加熱促進テストを行い、この液晶組成物の比抵抗あるいは電圧保持率を測定した。実施例中、測定した特性は以下の通りである。
【００７０】
Ｔ_N-I ： ネマチック相−等方性液体相転移温度（℃）
Ｔ→ _N ： 固体相又はスメクチック相−ネマチック相転移温度（℃）
Ｖth ： セル厚６μｍのTN-LCDを構成した時のしきい値電圧（Ｖ）
γ ： 飽和電圧（Ｖsat)とＶthの比
△ε ： 誘電異方性
△ｎ ： 複屈折率
η ： ２０℃での粘度（c.p.）
（実施例１）
【００７１】
【化１９】

【００７２】
からなるネマチック液晶組成物（2-1）を調製し、この組成物の諸特性を測定した。結果は以下の通りであった。
Ｔ_N-I ： １１８．１ ℃
Ｔ→ _N ： −１２． ℃
Ｖth ： ２．７７ Ｖ
γ ： １．１３
△ε ： ４．０
△ｎ ： ０．１４４
η ： ２１．４ ｃ．ｐ．
テスト前の比抵抗 ： ６．１×１０¹¹ Ω・ｃｍ
加熱促進テスト後の比抵抗 ： ５．２×１０¹¹ Ω・ｃｍ
テスト前の電圧保持率 ： ９８．４％
加熱促進テスト後電圧保持率 ： ９７．９％
このネマチック液晶組成物は、文献『高速液晶技術』（６３頁、(株)シーエムシー社出版）中に示された液晶表示の光学的急峻性の限界値である１．１２に近い値を示しており、従って、この液晶組成物は高時分割駆動に有用であることが理解できる。
【００７３】
このネマチック液晶組成物は加熱促進テスト後の比抵抗や電圧保持率が高いことから、熱に安定であることが理解できる。また、この組成物を基本的な構成材料とする新たな本発明のネマチック液晶組成物を作製し、これを用いたアクティブ・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。更に同様にして、この組成物を基本的な構成材料とする他の本発明のネマチック液晶組成物を作製し、これをツイスティッド・ネマチック及びスーパー・ツイスティッド・ネマチック液晶表示装置を作製したところ、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。
【００７４】
上記ネマチック液晶組成物（2-1）は、下記母体液晶（b-1）に一般式（I-1）を混合したものである。この母体液晶（b-1）の諸特性を測定した。結果は以下の通りであった。
【００７５】
【化２０】

【００７６】
Ｔ_N-I ： １１６．７ ℃
Ｔ→ _N ： ＋１１． ℃
Ｖth ： ２．１４ Ｖ
γ ： １．２３
△ε ： ４．８
△ｎ ： ０．０９０
η ： １９．８ ｃ．ｐ．
特性を比較すると、本発明の液晶組成物は、複屈折率がより大きく、ネマチック相の温度範囲がより広く、飽和電圧としきい値電圧の比がより小さく、より好ましい結果であった。
（実施例２）
【００７７】
【化２１】

【００７８】
からなるネマチック液晶組成物（2-2）を調製し、この組成物の諸特性を測定した。結果は以下の通りであった。
Ｔ_N-I ： １０１．１ ℃
Ｔ→ _N ： −７０． ℃
Ｖth ： ２．１９ Ｖ
△ε ： ７．８
△ｎ ： ０．１７２
このネマチック液晶組成物にカイラル物質「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610」（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240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、高時分割特性に優れ、速応答性が改善されたSTN-LCD表示特性を示す液晶表示装置が得られた。なお、カイラル物質はカイラル物質の添加による混合液晶の固有らせんピッチＰと表示用セルのセル厚ｄが、Δｎ・ｄ＝０．８５、ｄ／Ｐ＝０．５３となるように添加した。
【００７９】
ツイスト角240度のSTN-LCD表示特性
Ｖth ： ２．４０ Ｖ
γ ： １．０２４
応答（τr=τd）： １５．６ｍｓｅｃ（スタティック駆動）
（実施例３）
【００８０】
【化２２】

【００８１】
からなるネマチック液晶組成物（2-3）を調製し、この組成物の諸特性を測定した。結果は以下の通りであった。
Ｔ_N-I ： １０１．７ ℃
Ｔ→ _N ： −３０． ℃
Ｖth ： ２．１６ Ｖ
△ε ： ５．７
△ｎ ： ０．１６７
このネマチック液晶組成物にカイラル物質「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610」（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240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、高時分割特性に優れ、速応答性が改善されたSTN-LCD表示特性を示す液晶表示装置が得られた。なお、カイラル物質はカイラル物質の添加による混合液晶の固有らせんピッチＰと表示用セルのセル厚ｄが、Δｎ・ｄ＝０．８５、ｄ／Ｐ＝０．５１となるように添加した。
【００８２】
ツイスト角240度のSTN-LCD表示特性
Ｖth ： ２．４６ Ｖ
γ ： １．０２４
応答（τr=τd）： １９．０ｍｓｅｃ（スタティック駆動）
（実施例４）
【００８３】
【化２３】

【００８４】
からなるネマチック液晶組成物（2-4）を調製し、この組成物の諸特性を測定した。結果は以下の通りであった。
Ｔ_N-I ： ８３．８ ℃
Ｔ→ _N ： −３１． ℃
Ｖth ： １．８９ Ｖ
γ ： １．１４
△ε ： ７．０
△ｎ ： ０．１７２
このネマチック液晶組成物にカイラル物質「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610」（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240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、高時分割特性に優れ、速応答性が改善されたSTN-LCD表示特性を示す液晶表示装置が得られた。なお、カイラル物質はカイラル物質の添加による混合液晶の固有らせんピッチＰと表示用セルのセル厚ｄが、Δｎ・ｄ＝０．８５、ｄ／Ｐ＝０．５１となるように添加した。
【００８５】
ツイスト角240度のSTN-LCD表示特性

（実施例５）
【００８６】
【化２４】

【００８７】
からなるネマチック液晶組成物（2-5）を調製し、この組成物の諸特性を測定した。結果は以下の通りであった。
Ｔ_N-I ： ９５．４ ℃
Ｔ→ _N ： −１０． ℃
Ｖth ： ２．４８ Ｖ
γ ： １．１５
△ε ： ４．７
△ｎ ： ０．２９０
このネマチック液晶組成物を用いて、セル厚ｄが１．７μｍのTN-LCDを構成してその表示特性を測定したところ、しきい値電圧が２．２０Ｖ、応答速度が１．２ｍｓｅｃを示す液晶表示装置が得られた。
【００８８】
また、このネマチック液晶組成物の複屈折率の波長分散を測定したところ、光の波長６５０ｎｍに対する４００ｎｍでの比が１．１５以上であった。この液晶材料は、光の波長の違いによってより大きな位相差が現れていることから、カラーフィルター層を用いないでカラー表示を行う、液晶と位相差板の複屈折性を利用した新規反射型カラー液晶表示方式に有用なものである。
（実施例６）
以下、ネマチック液晶組成物（2-5）を用いた光散乱形液晶表示について更に詳細に説明する。しかしながら、本発明はこれらの実施例に限定されるものではない。
【００８９】
液晶材料として液晶組成物（2-5）を８０％、高分子形成性化合物として「ＨＸ−２２０」（日本化薬社製）を１３．８６％、ラウリルアクリレートを５．９４％、重合開始剤として２−ヒドロキシ−２−メチル−１−フェニルプロパン−１−オンを０．２％の比率で混合し、均一溶液の調光層形成材料を作製した。この調光層形成材料を、平均粒径１０μｍのスペーサーが介在した２枚のＩＴＯ電極ガラス基板を用いて作製した大きさ５０×５０mmの空セルに、均一溶液の転移温度より１０℃高い温度の下で真空注入した。これを、均一溶液の転移温度より３℃高い温度に保持しながら、メタルハライドランプ（８０Ｗ／cm２)の下を３．５ｍ／分の速度で通過させ、５００ｍＪ／cm２に相当するエネルギーの紫外線を照射して高分子形成化合物を硬化させて、液晶材料と透明性固体物質から成る調光層を有する液晶デバイスを得た。得られた液晶デバイスについて、基板間に形成された硬化物の断面を走査型電子顕微鏡を用いて観察したところ、ポリマーから成る三次元ネットワーク構造の透明性固体物質が認められた。
【００９０】
得られた光散乱形液晶表示の特性は、従来の光散乱形液晶デバイスと比較して、広い動作温度範囲を示し、動画有利な応答性を有し、高コントラストでかつ均一でむらのない表示特性を有しており、広告板等の装飾表示板や時計等の表示装置、又はプロジェクション表示装置等に有用なものであった。
【００９１】
【発明の効果】
本発明のネマチック液晶組成物は、複屈折率Δｎが大きく、広い温度範囲でネマチック相を示し、応答特性の改善効果に優れ、また、電圧保持率が高く、化学的安定性が高いことが明らかである。従って、本発明のネマチック液晶組成物は、アクティブ・マトリクス形、ツイスティッド・ネマチックあるいはスーパー・ツイスティッド・ネマチック液晶表示装置に用いることができる。また、液晶層と位相差板の複屈折性でカラー表示をする液晶表示素子を提供することができる。特に、大きな複屈折率により液晶層の厚みｄを低減でき応答特性を改善でき、特に情報量の多い表示特性を提供できる。さらに、液晶材料及び透明性固体物質を含有する調光層を有する光散乱形液晶表示にも有用装置を提供できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nematic liquid crystal composition useful as an electro-optical display material and a liquid crystal display device using the same.
[0002]
[Prior art]
A typical liquid crystal display element is a TN-LCD (twisted nematic liquid crystal display element), which is used in watches, calculators, electronic notebooks, pocket computers, word processors, personal computers, and the like. On the other hand, with the increase in processing information of OA equipment, STN (Super-Sheffer) (Scheffer et al. [SID '85 Digest, p.120 1985), Kinugawa et al [SID '86 Digest, p.122 1986]) Twisted nematic) -LCDs have been developed and are beginning to gain widespread use in displays for high-information processing such as portable terminals, word processors, and personal computers.
[0003]
Recently, active addressing drive method [Proc.12th IDRC p.503 1992] and multi-line addressing drive method [SID'92 Digest, p.232 1992] have been proposed for the purpose of improving response characteristics of STN-LCD. . As such a liquid crystal material, the elastic constant ratio K₃₃/ K₁₁Is around 1.5 and the dielectric anisotropy and viscosity are relatively small, and in particular, those having a high birefringence are required. Also, for the purpose of achieving brighter display and higher contrast ratio, a new reflective color liquid crystal display system that uses the birefringence of liquid crystal and retardation plate instead of the color filter layer [TVJ Technical Report vol. 14 No10.p.51 1990] and a liquid crystal display device having a reflective surface with a small paraboloid on the substrate electrode side has been proposed. As a liquid crystal material suitable for this, a birefringence characteristic that causes a larger phase difference due to a difference in wavelength of light and an optical characteristic of a birefringence index that maintains high contrast even at a wide viewing angle are required. Furthermore, a liquid crystal display device having a wider operating temperature is required for display applications such as miniaturization, portability, and increase in the number of pixels. As a liquid crystal material suitable for this, the elastic constant K₁₁Is 10. -25. In this range, a material that is chemically stable, can efficiently reduce the response speed, and has a wider nematic temperature is required. As described above, there is a need for comprehensively optimizing individual physical properties of liquid crystal materials, and proposals for new liquid crystal compounds or liquid crystal compositions are still required.
[0004]
Furthermore, because of its excellent display quality, active matrix liquid crystal display devices are put on the market for portable terminals, liquid crystal televisions, projectors, computers, and the like. In the active matrix display method, TFT (thin film transistor) or MIM (metal insulator metal) is used for each pixel, and high voltage holding ratio is regarded as important in this method. In addition, Kondo et al. Have proposed a super TFT [Asia Display '95 Digest, p.707 1995] combined with the IPS mode in order to obtain a wider viewing angle characteristic. (Hereinafter, these active matrix display type liquid crystal display elements are generically referred to as TFT-LCDs.) In order to cope with such display elements, new liquid crystal compounds or liquid crystal compositions such as those disclosed in Japanese Patent Laid-Open No. No. 312949 and Japanese Patent Publication No. 5-501735 have been proposed.
[0005]
A liquid crystal display element in which liquid crystal droplets are dispersed in a polymer is known as a bright and high-contrast liquid crystal device that does not require a polarizing plate or alignment treatment. JP-A-58-501631 and U.S. Pat. No. 4,435,047 propose gelatin, gum arabic, polyvinyl alcohol, and the like as encapsulating materials. Besides these, for example, JP-A-61-502128 This is known in Japanese Patent Laid-Open No. 62-2231. These have the problems of optimizing the coincidence between the individual refractive index of the liquid crystal material and the refractive index of the polymer, and requiring a high voltage of 25 V or more to obtain sufficient transparency.
[0006]
U.S. Pat. No. 5,304,323 and JP-A-1-198725 are techniques that enable low voltage drivability, high contrast, and time-division drivability required for liquid crystal display. A liquid crystal display element having a structure in which a polymer substance is distributed in a three-dimensional network in the continuous layer is disclosed.
[0007]
As a liquid crystal material related to this purpose, for example, European Patent No. 359,146 discloses a method for optimizing the birefringence and dielectric anisotropy of a liquid crystal material, and JP-A-6-222320 discloses a liquid crystal material. The technique etc. which specify the elastic constant of are shown. Japanese Patent Application Laid-Open Nos. 5-339573 and 6-123866 disclose that the contrast in projection display is about 40 by using a fluoro compound. However, required characteristics, high resistance value, excellent voltage holding ratio, low driving voltage, strong light scattering, large contrast ratio, fast response speed, good temperature characteristics, etc. There are problems in satisfying everything and new proposals are still being made.
[0008]
[Problems to be solved by the invention]
In order to improve the liquid crystal display characteristics as described above, a liquid crystal material having a desired birefringence is required. There is also a need for higher chemical stability of liquid crystal materials, lower viscosity, fast response of liquid crystal displays and wider characteristics of the driving temperature range. The technology relating to the compound of the general formula (I-1) and the similar compounds related to the present invention is described in, for example, JP-A No. 54-87688, and a mixture containing the compound of the general formula (I-1). This knowledge has not yet been fully reported. In addition, the properties and mixtures of liquid crystal materials with the desired birefringence, dielectric anisotropy, elastic constant, etc. useful for TN-LCDs, STN-LCDs, and light-scattering liquid crystal displays as described above are still reported. It has not been.
[0009]
More specifically, when a liquid crystal material having a high birefringence is required, as a liquid crystal material having higher chemical stability, lower viscosity, and wider nematic temperature characteristics, for example, the following general formula (a- 1) to (a-4)
[0010]
[Chemical formula 5]

[0011]
A compound of the formula (wherein R and R 'each represents an alkyl group or an alkoxy group) has been used. However, problems still remain. Specifically, the compound of the general formula (a-4) is specific in compatibility with a compound having a particularly strong polarity, and has a tendency that a smectic phase or a crystalline phase tends to appear. It is poor in solubility with the compound (a-1).
[0012]
The problem to be solved by the present invention is to solve or improve the above-mentioned problem, and a nematic liquid crystal having a wide drivable temperature range and excellent responsiveness with respect to a desired birefringence size. The object of the present invention is to provide a composition, and to provide a liquid crystal display device such as TN-LCD, STN-LCD, TFT-LCD and the like having improved electro-optical characteristics using the liquid crystal composition as a constituent material.
[0013]
Also, in the above-described light scattering type liquid crystal display, while maintaining and improving required display characteristics such as faster responsiveness, lower voltage drivability, higher light control layer resistance, or higher contrast ratio, It is an object of the present invention to provide a light scattering type liquid crystal display device that reduces memory phenomenon and achieves more uniform display of white turbidity, improved display characteristics with respect to temperature changes, and response characteristics.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, the present invention
1. The liquid crystal composition has the general formula (I-1)
[0015]
[Chemical 6]

[0016]
(Wherein R¹¹Represents a linear alkyl group having 1 to 10 carbon atoms, an alkoxy group or a linear alkenyl group having 2 to 10 carbon atoms;¹²Represents a straight-chain alkenyl group having 2 to 10 carbon atoms. A liquid crystal composition comprising a liquid crystal component A composed of one or two or more compounds represented by formula (I) and a liquid crystal component B comprising a compound having a dielectric anisotropy of +2 or more, wherein the liquid crystal The composition has a dielectric anisotropy of 3 or more, a nematic phase-isotropic liquid phase transition temperature of 60 ° C. or higher, and a crystal phase or smectic phase-nematic phase transition temperature of 0 ° C. or lower. A nematic liquid crystal composition.
2. The liquid crystal component A is R in the general formula (I-1)¹¹Wherein R is a methyl group, an ethyl group, a propyl group or a butenyl group and / or R¹²2. The nematic liquid crystal composition as described in 1 above, wherein 30 to 100% by weight of a compound represented by a butenyl group is contained.
3. The liquid crystal component A comprises the general formula (I-1) and the general formula (I-2)
[0017]
[Chemical 7]

[0018]
(Wherein R¹³, R¹⁴Each independently represents a linear alkyl group or alkoxy group having 1 to 10 carbon atoms. 3. The nematic liquid crystal composition according to 1 or 2 above, which comprises a compound represented by
4). 4. The nematic liquid crystal composition according to 1, 2, or 3, wherein the liquid crystal composition contains 1 to 50% by weight of the liquid crystal component A.
5. The liquid crystal component B is represented by the general formulas (II-1) to (II-4)
[0019]
[Chemical 8]

[0020]
(Wherein R^{twenty one}~ R^{twenty four}Are each independently a linear alkyl group, alkenyl group or C 2 -C 10_sH_{2s + 1}-OC_tH_2tS and t each independently represents an integer of 1 to 5,^{twenty one}~ X^{twenty four}Are each independently a fluorine atom, a chlorine atom, -OCF_Three, -OCHF₂, -CF_ThreeOr -CN, Y^{twenty one}~ Y²⁸Each independently represents a hydrogen atom or a fluorine atom;^{twenty one}~ W^{twenty four}Each independently represents a hydrogen atom or a fluorine atom;^{twenty one}~ Z^{twenty three}Are each independently a single bond, -COO-, -C₂H_Four-Or-C_FourH₈-Represents Z^{twenty one}May also be -C≡C- or -CH = CH-^{twenty four}, Z^{twenty five}Each independently represents a single bond, —COO—, —C≡C— or —CF═CF—, m¹~ M^FourEach independently represents 0 or 1, m^Three+ M^FourIs 0 or 1, and the hydrogen atom (H) of the cyclohexane ring in each compound may be substituted by a deuterium atom (D). 5. The nematic liquid crystal composition according to the above 1, 2, 3 or 4, which comprises a compound selected from the group of compounds represented by
6). The liquid crystal component B is R in the general formulas (II-1) to (II-4).^{twenty one}~ R^{twenty four}Wherein X is an alkyl or alkenyl group having 2 to 5 carbon atoms and / or X^{twenty one}~ X^{twenty four}Is F, Cl, -OCF_Three6. The nematic liquid crystal composition according to 5 above, which contains 10 to 100% by weight of a compound which is —CN.
7. The liquid crystal component B is Z in the compound of the general formula (II-1).^{twenty one}, Z^{twenty two}Are each independently a single bond, -COO-, -C₂H_Four-Or-C_FourH₈7. The nematic liquid crystal composition as described in 5 or 6 above, which comprises 10 to 100% by weight of a compound represented by-.
8). The liquid crystal component B is Z in the compound of the general formula (II-2)^{twenty four}8. The nematic liquid crystal composition according to 5, 6, or 7, wherein the compound contains 10 to 100% by weight of a compound represented by a single bond, —COO— or —C≡C—.
9. The liquid crystal component B is Z in the compound of the general formula (II-3).^{twenty five}9. The nematic liquid crystal composition according to 5, 6, 7 or 8, wherein the compound contains at least 10% by weight of a compound represented by a single bond or —C≡C—.
10. 10. The nematic liquid crystal composition as described in any one of 1 to 9 above, wherein the liquid crystal composition contains 10 to 99% by weight of the liquid crystal component B.
11. The liquid crystal composition contains a liquid crystal component C composed of a compound having a dielectric anisotropy of −2 to 2, and the liquid crystal component C is represented by the general formulas (III-1) to (III-4)
[0021]
[Chemical 9]

[0022]
(Wherein R³¹~ R³⁴Each independently represents a linear alkyl group or alkenyl group having 2 to 7 carbon atoms;³⁵~ R³⁸Are each independently a linear alkyl group having 1 to 7 carbon atoms, alkoxy group, alkenyl group, alkenyloxy group or C_uH_{2u + 1}-OC_vH_2vU and v each independently represent an integer of 1 to 5, Y³¹Is a hydrogen atom, a fluorine atom or —CH_ThreeY³²And Y³³Each independently represents a hydrogen atom or a fluorine atom;³¹~ Z³⁴Are each independently a single bond, -COO-, -C₂H_Four-Or-C_FourH₈-Represents Z³¹May also be -C≡C- or -CH = CH-³⁵Represents a single bond, —C≡C—, —COO— or —CF═CF—, and ring A³¹, Ring A³²Each independently represents a cyclohexane ring or a cyclohexene ring;³³, Ring A³⁴Each independently represents a cyclohexane ring or a benzene ring, and n¹~ N^FiveEach independently represents an integer of 0 or 1, n^Four+ N^FiveIs 0 or 1, and the hydrogen atom (H) of the cyclohexane ring in each compound may be substituted with a deuterium atom (D). 11. The nematic liquid crystal composition as described in any one of 1 to 10 above, which comprises one or more compounds selected from the group of compounds represented by formula (1):
12 In the compound of the general formula (III-1), the liquid crystal component C is R³¹Represents a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, R³⁵Represents a linear alkyl group having 1 to 5 carbon atoms, an alkoxy group, an alkenyl group, an alkenyloxy group, and n¹Z is 0³²Wherein n is a single bond or —COO— and / or n¹Is 1, ring A³¹Represents a cyclohexane ring, Z³¹, Z³²12. The nematic liquid crystal composition according to 11 above, wherein the compound contains 10 to 100% by weight of a compound represented by a single bond.
13. In the compound of the general formula (III-2), the liquid crystal component C is R³²Represents a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, R³⁶Represents a linear alkyl group having 1 to 5 carbon atoms, an alkoxy group, an alkenyl group, an alkenyloxy group, and n²Is 0, ring A³²Is a cyclohexane ring or a cyclohexene ring, and Z³³Is a single bond, -COO- or -C₂H_Four-And / or n²Is 1, ring A³²Is a cyclohexane ring and Z³³Is a single bond or -C₂H_Four13. The nematic liquid crystal composition according to 11 or 12 above, which contains 10 to 100% by weight of a compound represented by-.
14 In the compound of the general formula (III-3), the liquid crystal component C is Z³⁵14. The nematic liquid crystal composition according to 11, 12, or 13, wherein the compound contains 10 to 100% by weight of a compound represented by —C≡C—.
15. 15. The nematic liquid crystal composition as described in 11, 12, 13 or 14, wherein the liquid crystal composition contains at most 70% by weight of the liquid crystal component C.
16. The liquid crystal composition is a compound having a core structure having four six-membered rings, and the compound has one or more compounds having a liquid crystal phase-isotropic liquid phase transition temperature of 100 ° C. or higher. 16. The nematic liquid crystal composition as described in 1 to 15 above, which is contained.
17. The liquid crystal composition has a dielectric anisotropy of 4 to 30, a birefringence of 0.08 to 0.33, and a nematic phase-isotropic liquid phase transition temperature of 60 ° C. to 180 ° C. The nematic liquid crystal composition according to any one of 1 to 16 above, which has a crystal phase, a smectic phase, or a glass phase-nematic phase transition temperature of -200 ° C to 0 ° C. 18. 18. The nematic liquid crystal composition as described in any one of 1 to 17 above, wherein the liquid crystal composition contains a compound having an optically active group having an induced helical pitch of 0.5 to 1000 μm.
19. 19. An active matrix, twisted nematic or super twisted nematic liquid crystal display device using the nematic liquid crystal composition as described in 18 above.
20. 20. The liquid crystal display device as described in 19 above, wherein the liquid crystal layer has a thickness of 1 to 30 μm.
21. 19. A light-scattering liquid crystal display device having a light control layer containing the liquid crystal composition according to 1 to 18 and a transparent solid material.
22. 22. The light-scattering liquid crystal according to 21 above, wherein in the light control layer, the liquid crystal composition forms a continuous layer, and the transparent solid substance forms a uniform three-dimensional network structure in the continuous layer. Display device.
23. The light-scattering liquid crystal display device as described in 21 or 22 above, wherein the transparent solid material is formed from a polymerizable composition containing a polymer-forming bifunctional monomer and a monofunctional monomer.
Was found as a solution to the above problem.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the nematic liquid crystal composition of the present invention and a liquid crystal display device using the same will be described. H represents a hydrogen atom, F represents a fluorine atom, and Cl represents a chlorine atom.
[0024]
The liquid crystal composition of the present invention contains, as an essential component, a liquid crystal component A composed of a compound represented by formula (I-1). The liquid crystal component A has a lower viscosity, a higher birefringence, and a higher elastic constant. For this reason, the liquid crystal composition of the present invention can adjust the birefringence and the elastic constant in a wide range, and can be driven with a high-speed response, for example. The liquid crystal composition of the present invention contains a liquid crystal component A composed of the general formula (I-1), a liquid crystal component B composed of a compound having a dielectric anisotropy of +2 or more, and the liquid crystal material contains 3 or more With a dielectric anisotropy of 60 ° C or higher, a nematic phase-isotropic liquid phase transition temperature of 0 ° C or lower and a crystal phase or smectic phase-nematic phase transition temperature of 0 ° C or lower have faster response characteristics. I found. In addition to the above, the liquid crystal component A, when mixed with other liquid crystal materials, improves the nematic phase-isotropic liquid phase transition temperature to a relatively high temperature and is excellent in compatibility. The temperature range can be made wider. Furthermore, dielectric anisotropy is in the range of -2 to +2, and it has higher chemical stability.
[0025]
From such a viewpoint, a more preferable form of the compound represented by the general formula (I-1) is R¹¹Wherein R is a methyl group, an ethyl group, a propyl group or a butenyl group and / or R¹²Is a compound represented by a butenyl group, and more specifically, compounds represented by formulas (I-3) to (I-6) are preferable. In the liquid crystal component A, at least one compound is 30 A nematic liquid crystal composition containing ˜100% by weight is preferred. In addition, each compound removed the impurity using methods, such as distillation, column refinement | purification, and recrystallization, and used what was fully refined | purified.
[0026]
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[0027]
One or more compounds of the general formula (I-1) can be contained as the liquid crystal component A, but the above-described effects can be obtained even with one compound. The liquid crystal composition of the present invention containing the liquid crystal component A containing at least one compound represented by the general formula (I-1) includes TN-LCD, STN-LCD, TFT-LCD using this as a constituent material The liquid crystal display device is made to have more improved electro-optical characteristics, and in particular, the responsiveness at a low temperature and the temperature dependence of the steep driving voltage are made more preferable.
[0028]
In addition, the liquid crystal component A in the present invention can be constituted by using a compound represented by the general formula (I-2) together with a compound represented by the general formula (I-1), and thus a faster response. Found to have characteristics. From such a viewpoint, a more preferable form of the compound represented by the general formula (I-2) is R¹³, R¹⁴Preferably contains a compound represented by a methyl group, an ethyl group or a propyl group, more specifically, compounds represented by the general formulas (I-7) to (I-11) are preferred. Is preferably a nematic liquid crystal composition containing 1 to 99% by weight of at least one compound.
[0029]
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[0030]
The present invention contains a liquid crystal component A containing at least one compound of formulas (I-7) to (I-11) represented by formula (I-2) together with the compound of formula (I-1) This liquid crystal composition makes liquid crystal display devices such as TN-LCD, STN-LCD, TFT-LCD, etc. using this as a constituent material more improved electro-optic characteristics, especially at low temperature response and steep drive The temperature dependence of the voltage is made more preferable.
[0031]
The liquid crystal composition of the present invention contains one or more compounds selected from the liquid crystal component B comprising a compound having a dielectric anisotropy of +2 or more in addition to the essential component liquid crystal component A. is there. The liquid crystal compound having a dielectric anisotropy larger than 2 described in the present invention is used in the following meaning. The chemical structure of the liquid crystal compound is rod-shaped, the central part has a core structure with one to four six-membered rings, and the six-membered rings located at both ends in the central part major axis direction are the major axes of the liquid crystal molecules Having a terminal group substituted at a position corresponding to the direction, and at least one of the terminal groups present at both ends is a polar group, that is, for example, —CN, —OCN, —NCS, —F, —Cl, —NO₂, -CF_Three, -OCF_Three, -OCHF₂It is a compound which is. As a result, the optical anisotropy of the liquid crystal layer can be set to a predetermined value, can be electrically driven, and the operating temperature range can be widened.
[0032]
As the liquid crystal component B, a compound having a dielectric anisotropy of +2 or more needs at least one kind, and a range of 3 to 15 kinds is preferable. In addition, it is preferable that the dielectric anisotropy is selected from a compound having a dielectric anisotropy of +8 to +13, a compound of +14 to +18, a compound of +18 or more, and a predetermined driving voltage and response characteristics can be obtained. In this case, it is preferable that the compounds having dielectric anisotropy of +8 to +13 are mixed in a range of at most 10 or less, and the compounds of +14 to +18 are preferably mixed in a range of at most 8 or less, +18 The above compounds are preferably mixed in a range of at most 10 kinds. The use of the liquid crystal component B as described above gives a more favorable effect due to the temperature characteristics of the display characteristics. More specifically, temperature dependency such as drive voltage, contrast related to steepness, and responsiveness is more preferable.
[0033]
The liquid crystal component B of the present invention preferably contains 10 to 100% by weight of a compound selected from the compounds represented by the general formulas (II-1) to (II-4). A more preferable form of the compounds represented by the general formulas (II-1) to (II-4) is R^{twenty one}~ R^{twenty four}Are each independently an alkyl group having 2 to 5 carbon atoms, a compound represented by an alkenyl group and / or X^{twenty one}~ X^{twenty four}Is F, Cl, -OCF_ThreeAlternatively, it is preferable to select at least one compound selected from -CN. In general formula (II-2), Z^{twenty four}Is a single bond, —COO— or —C≡C—, Z in the general formula (II-3)^{twenty five}Preferably contains a single bond or a compound represented by -C≡C-. General preferred formulas (II-1a) to (II-4d) are shown below as particularly preferred more specific compounds represented by the general formulas (II-1) to (II-4). In addition, each compound removed the impurity using methods, such as distillation, column refinement | purification, and recrystallization, and used what was fully refined | purified. The liquid crystal component B containing these compounds has a characteristic of being well mixed with the essential liquid crystal component A, and is particularly useful for the preparation according to the purpose of the driving voltage and for improving the temperature dependency or the response. is there. In particular, the compounds represented by the general formulas (II-1a) to (II-1h) and the general formulas (II-2a) to (II-4d) are excellent in this effect. An effect can be obtained.
[0034]
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[0035]
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[0036]
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[0037]
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[0038]
(Wherein R^{twenty one}~ R^{twenty four}, X^{twenty one}~ X^{twenty four}, Y^{twenty one}~ Y²⁸, W^{twenty one}, W^{twenty two}Represents the same meaning as described above. )
Further preferred embodiments will be specifically described in detail.
[0039]
R^{twenty one}Is an alkyl group having 2 to 5 carbon atoms or CH₂= CH- (CH₂)_pA compound that is an alkenyl group of (p = 0, 2) is preferable, a compound of the general formulas (II-1a) and (II-1d) preferably has this group, and the compound having an alkenyl group in the liquid crystal component B By containing at least one kind, viscosity and viscoelasticity can be reduced. Similarly, R^{twenty two}Is preferably an alkyl group having 2 to 5 carbon atoms or the above-mentioned alkenyl group, and compounds of the general formulas (II-2a), (II-2d), (II-2f) and (II-2g) are preferred. It preferably has a group. X^{twenty one}~ X^{twenty four}Is F, Cl, -OCF_ThreeIt is preferable to use a large amount of a compound that is -CN, and when high-speed response is important X^{twenty one}~ X^{twenty four}Is F, -OCF_ThreeA compound of the general formula (II-1a), (II-1d), (II-2a), (II-2c), (II-2d), (II-2g), (II-3a) It is preferable to use a large amount of B, and when a higher birefringence is required, X^{twenty two}~ X^{twenty four}Is Cl, -OCF_ThreeIt is preferable to use a large amount of the compounds of the general formulas (II-2a) to (II-4d), which are —CN, as the liquid crystal component B.^{twenty one}Is -CN and Y^{twenty one}A compound of the general formulas (II-1a) to (II-1g) in which is H or F, X^{twenty two}Is Y for F, Cl, -CN^{twenty three}A compound of the general formulas (II-2a) to (II-2f) wherein X is H or F, X^{twenty three}Is Y for F, Cl, -CN^{twenty five}A compound of the general formulas (II-3a) to (II-3c) wherein X is F, X^{twenty four}Is Y for F, Cl, -CN²⁷It is preferable to frequently use the compounds of the general formulas (II-4a) to (II-4d) in which F is F for the liquid crystal component B. In particular, a light-scattering liquid crystal display device (for example, containing a liquid crystal material and a transparent solid substance) having a super TFT combined with an active matrix display method, TFT-LCD, MIM-LCD, IPS mode, or active matrix technology Display device having a light control layer)^{twenty one}~ X^{twenty four}It is preferable to frequently use a compound in which F is F.
In general formulas (II-1) to (II-4), when high-speed response is important Y^{twenty one}~ Y²⁸Is H and / or W^{twenty one}~ W^{twenty four}When a compound in which H is H can be used extensively and the temperature dependency of the driving voltage is improved, Y^{twenty one}~ Y²⁸Is F, W^{twenty one}~ W^{twenty four}Wherein F is F, particularly preferably Y^{twenty one}, Y^{twenty three}, Y^{twenty five}, Y²⁷, W^{twenty one}~ W^{twenty four}It is preferable to frequently use a compound in which F is F.^{twenty one}And W^{twenty two}Y if is F^{twenty four}If a compound in which H is H can be selected, the compatibility can be further improved.^{twenty three}And / or W^{twenty four}When the compound in which F is F is selected, the compatibility can be further improved. In the general formula (II-1), Z^{twenty one}And Z^{twenty two}One of them is preferably a single bond compound, and in order to improve the response and compatibility at low temperatures, a single bond compound and -COO-, -C₂H_Four-, -C_FourH₈It is preferable to use liquid crystal component B in which a compound of-is used in combination. When it is necessary to have a higher birefringence, Z in the general formulas (II-2) and (II-3)^{twenty four}, Z^{twenty five}Is a compound of —C≡C— and / or X in the general formula (II-4)^{twenty four}Is preferably used in the liquid crystal component B. M in the general formulas (II-1), (II-2) and (II-4)¹~ M^FourIn the general formulas (II-1) and (II-2)¹, M²Is a compound of formula 1, m in the general formula (II-4)^Three+ M^FourThe mixing ratio in the liquid crystal component B with the compound of formula 1 and / or the compound of the general formula (II-3) can be appropriately selected in the range of 0-100 to 100-0, and a higher nematic phase isotropic In the general formula (II-1) and (II-2)¹, M²Is a compound of general formula (II-3) and / or m in general formula (II-4)^Three+ M^FourIt is preferable to use a large number of compounds having the formula (1). A compound in which the hydrogen atom (H) in the cyclohexane ring of the general formulas (II-1) and (II-2) is substituted with a deuterium atom (D) can be used. Since it is useful for adjusting the constant and adjusting the pretilt angle corresponding to the alignment film, it is preferable to contain at least one compound substituted with a deuterium atom (D).
[0040]
The effect of the liquid crystal component B described above can be obtained even when the content of the liquid crystal component C described later is very small. For the purpose of reducing the driving voltage in particular, the content of the liquid crystal component C can be 10% by weight or less. In this case, it is preferable to reduce the viscosity of the liquid crystal component C as much as possible, and the drive voltage hardly increases or stays in a small range, so that the response speed can be improved efficiently. For example, when the amount of the liquid crystal component C is small, as a method of achieving this effect with the liquid crystal component B, in general formulas (II-1) to (II-4),^{twenty one}~ X^{twenty four}Is F, Cl, -OCF_ThreeA compound or Y^{twenty one}~ Y^{twenty four}A compound wherein Z is F or Z^{twenty four}, Z^{twenty five}A compound in which is —COO—, —C≡C— or m¹It is preferable that the liquid crystal component B contains any one of the compounds in which is 1. In particular, in the general formulas (II-1) to (II-4), X^{twenty one}~ X^{twenty four}Is F, Cl, -OCF_Three, -CN, and / or Y^{twenty one}~ Y^{twenty three}A compound in which is F is preferred.
[0041]
The liquid crystal composition of the present invention contains at least 70% by weight of liquid crystal component C composed of a compound having a dielectric anisotropy of −2 to 2 in addition to liquid crystal component A and liquid crystal component B which are essential components. Is preferred. Preferred examples of the liquid crystal compound having a dielectric anisotropy of −2 to 2 described in the present invention are as follows. That is, the chemical structure of the liquid crystal compound is rod-shaped, the central portion has a core structure having 1 to 4 six-membered rings, and the six-membered rings positioned at both ends in the central portion major axis direction are liquid crystal molecules. It has a terminal group substituted at a position corresponding to the major axis direction, and both terminal groups present at both ends are nonpolar groups, that is, for example, an alkyl group, an alkoxy group, an alkoxyalkyl group, an alkenyl group, an alkenyloxy Group, an alkanoyloxy group. The liquid crystal component C is preferably composed of 1 or more and 20 or less, more preferably 2 or more and 12 or less.
[0042]
The liquid crystal component C of the present invention preferably contains 10 to 100% by weight of a compound selected from the compounds represented by the general formulas (III-1) to (III-4). As particularly preferred compounds represented by general formulas (III-1) to (III-4), general formulas (III-1a) to (III-4e) are shown below. The liquid crystal component C containing these compounds has a feature of being well mixed with the liquid crystal component A containing the compound of the general formula (I-1), and is useful for improving a nematic phase at a low temperature.
[0043]
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[0044]
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[0045]
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[0046]
(Wherein R³¹~ R³⁸, Y³¹~ Y³³Represents the same meaning as described above. )
As the liquid crystal component C, by containing the compounds of the general formulas (III-1) to (III-4), the viscosity and viscoelasticity can be reduced, and the specific resistance and voltage holding ratio are relatively high. Have. The viscosity of the liquid crystal component C is preferably as low as possible. In the present invention, it is preferably 45 cp or less, more preferably 30 cp or less, still more preferably 20 cp or less, and particularly preferably 15 cp or less. As the liquid crystal component C, more preferable compounds of the general formulas (III-1) to (III-4) are represented by the general formulas (III-1a) to (III-3a), (III-3c) to (III-3g), (III-4a) and (III-4d) to (III-4e). R³¹~ R³⁴Is a linear alkyl group having 2 to 5 carbon atoms or CH₂= CH- (CH₂)_qThe liquid crystal component C containing at least one compound that is an alkenyl group of (q = 0, 2) has a more preferable effect. More particularly, compounds of the general formulas (III-1a), (III-1d), (III-2a), Y³¹Is a hydrogen atom and the compounds of general formulas (III-3c) to (III-3f) and / or R³⁸The compound of the general formula (III-4a) in which is an alkyl group can obtain this effect even when contained in a small amount of 3 to 30%, and is useful for improving the response speed, for example, useful for STN-LCD. is there.
[0047]
Because of the effects described above, a more preferable compound that the liquid crystal component C should contain is R in the compound of the general formula (III-1).³¹Represents a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, R³⁵Represents a linear alkyl group having 1 to 5 carbon atoms, an alkoxy group, an alkenyl group, an alkenyloxy group, and n¹Z is 0³²Is a single bond or —COO— and n¹Is 1, ring A³¹Represents a cyclohexane ring, Z³¹, Z³²Is a compound represented by a single bond, and in the compound of the general formula (III-2), R³²Represents a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, R³⁶Represents a linear alkyl group having 1 to 5 carbon atoms, an alkoxy group, an alkenyl group, an alkenyloxy group, and n²Is 0, ring A³²Is a cyclohexane ring or a cyclohexene ring, and Z³³Is a single bond, -COO- or -C₂H_Four-And n²Is 1, ring A³²Is a cyclohexane ring and Z³³Is a single bond or -C₂H_FourIt is a compound represented by-.
[0048]
The liquid crystal component C of the present invention comprises each of compounds represented by general formula (III-1), general formula (III-2), general formula (III-3), and general formula (III-4) alone. The compound represented by the general formula (III-1) and / or (III-2) and the compound represented by the general formula (III-3) and / or the general formula (III-4), particularly Z³⁵By using together a compound represented by —C≡C—, the birefringence of the liquid crystal composition can be easily optimized depending on the application. The birefringence can be reduced by using many compounds of general formula (III-1) and general formula (III-2), for example, compounds of general formulas (III-1a) to (III-2f), The liquid crystal display device can be easily reduced in color unevenness, improved viewing angle characteristics, and increased contrast ratio. In addition, compounds of general formula (III-3), such as compounds of general formulas (III-3a) to (III-3h), or compounds of general formula (III-4), such as compounds of general formula (III-4a) to (III) By frequently using the compound of III-4e), the birefringence can be increased, and a thin liquid crystal display device having a liquid crystal layer of 1 to 5 μm can be produced.
[0049]
The liquid crystal composition of the present invention can be configured as follows when it is intended to have a faster response to the magnitude of the driving voltage. When aiming at a medium driving voltage, the liquid crystal composition of the present invention has a dielectric anisotropy in the range of 3 to 15 and a viscosity at 20 ° C. of 8 to 20 c. p. It is preferable that it is the range of these. In this case, the viscosity of only the liquid crystal component C is 25 c. p. The following are preferred, 15c. p. More preferred is 10c. p. The following are particularly preferred: When a particularly low driving voltage is intended, the dielectric anisotropy of the liquid crystal composition of the present invention is preferably in the range of 15 to 30, particularly preferably in the range of 18 to 28.
[0050]
Currently, polyimide-based alignment films are frequently used for TN-LCD, STN-LCD, or TFT-LCD, and for example, LX1400, SE150, SE610, AL1051, AL3408, etc. are used. The specifications of the alignment film are closely related to liquid crystal display characteristics, display quality, reliability, and productivity. For example, pretilt angle characteristics are important for liquid crystal materials. The size of the pretilt angle needs to be adjusted in a timely manner in order to obtain desired liquid crystal display characteristics and uniform orientation. For example, when the pretilt angle is large, an unstable alignment state is likely to be obtained, and when the angle is small, sufficient display characteristics are not satisfied.
[0051]
The present inventors have found that a liquid crystal material having a larger pretilt angle is selected and a liquid crystal material having a smaller pretilt angle, and by applying this, desired liquid crystal display characteristics and uniform alignment are achieved from the liquid crystal material. I found out that This technique can also be applied to the present invention. For example, when the liquid crystal component B contains general formulas (II-1) to (II-4), it is as follows. A larger pretilt angle is R^{twenty one}Is an alkenyl group, X^{twenty one}Is F, Cl, -CN, Y^{twenty one}, Y^{twenty two}Is a compound of F and / or R^{twenty one}Is an alkyl group, X^{twenty one}Is F, Cl, -CN, Z^{twenty two}-C₂H_Four-, -C_FourH₈-Is obtained by increasing the content of the compound, the smaller pretilt angle is R^{twenty one}Is an alkenyl group, C_sH_{2s + 1}-OC_tH_2t, X^{twenty one}Is F, Y^{twenty one}Is F, Y^{twenty two}Is a compound of H and / or Z^{twenty two}Can be obtained by increasing the content of the compound of —COO—. In the case of a compound in which the hydrogen atom (H) of the cyclohexane ring in the general formulas (II-1) and (II-2) is substituted with a deuterium atom (D), it varies depending on the substitution position and allows a wide adjustment of the pretilt angle. . Such an effect can be substantially obtained by, for example, containing the above-described compound in an amount of 10 to 40% by weight or more based on the total amount of the liquid crystal composition when obtaining a larger pretilt angle.
[0052]
A similar technique relating to the compound of the general formula (I-1) relating to the present invention is described in, for example, JP-A No. 54-87688. For example, a mixture containing the compound of the general formula (a-3) is shown. Has been. Further, the compounds of the general formulas (a-1) and (a-2) are further mixed to make them useful for compatibility and response characteristics. However, when the compound of the general formula (a-3) is removed from the composition disclosed in Japanese Patent Application Laid-Open No. 54-87688, it is poorly soluble and needs to be improved. Further, in the case of a mixture containing the compound of the general formula (I-2) and the compound of the general formula (a-1) related to the present invention, the crystal phase or smectic phase-nematic phase transition temperature of 0 ° C. or higher is sufficient. It was difficult to obtain a good compatibility. Furthermore, as for the response characteristics, for example, the response characteristics of TN-LCD are currently required to be 60 msec or less, preferably 50 msec or less, more preferably 40 msec or less, particularly preferably 30 msec or less, and improvement is required. In particular, the compound of the general formula (a-3) has a tendency to deteriorate the response characteristics, and requires a new improvement means.
[0053]
The present invention solves the above-described problems, and in detail, for example, is based on the discovery of the following measures. (1) The content of the liquid crystal component A is not excessively used and is 50% by weight or less. (2) When the content rate of the liquid crystal component A is particularly large, the compound constituting the liquid crystal component B should be four or more. (3) The liquid crystal component B contains at least one compound having a cyclohexane ring. In this case, the compound of the general formula (II-1) showed a more preferable result. (4) When the compounds of the general formulas (II-2) and (II-3) were used, it was particularly preferable to use the compound of the general formula (II-1) together. (5) The compound constituting the liquid crystal component C is contained when the content of the liquid crystal component A is particularly large. (6) When the liquid crystal component B contains the compounds of the general formulas (II-2) and (II-3), it was shown that the liquid crystal component C was preferably used in combination even in a trace amount. In this case, the compounds of general formulas (III-1) to (III-3) showed more preferable results.
[0054]
The content of each liquid crystal component in the nematic liquid crystal composition of the present invention can be as follows. The liquid crystal component A is in the range of 1 to 50% by weight, preferably 3 to 40% by weight, and more preferably 3 to 30% by weight. The liquid crystal component B is in the range of 10 to 99% by weight, preferably in the range of 25 to 90% by weight, and more preferably in the range of 25 to 80% by weight. The liquid crystal component C is at most 70% by weight, preferably 3 to 65% by weight, more preferably 5 to 60% by weight, and still more preferably 10 to 55% by weight. The content of the compounds represented by the general formulas (I-1) and (I-2) is preferably 20% by weight or less as a single substance, and more than that is preferably composed of two or more. The content of the compounds represented by 3) to (I-11) with respect to the liquid crystal component A is in the range of 50 to 100% by weight, but preferably in the range of 70 to 100% by weight. The content of the compounds represented by the general formulas (II-1) to (II-4) or the compounds represented by the general formulas (II-1a) to (II-4d) is preferably 30% by weight or less alone. 25% by weight or less is more preferable, and more than that is preferably composed of two or more, and the content with respect to the liquid crystal component B is in the range of 10 to 100% by weight, preferably in the range of 50 to 100% by weight. The range of 75 to 100% by weight is more preferable. The content of the compounds represented by the general formulas (III-1) to (III-4) or the compounds represented by the general formulas (III-1a) to (III-4e) is preferably 30% by weight or less alone. 25% by weight or less is more preferable, and more than that is preferably composed of two or more, and the content with respect to the liquid crystal component C is in the range of 10 to 100% by weight, preferably in the range of 50 to 100% by weight. The range of 75 to 100% by weight is more preferable.
[0055]
The crystal phase or smectic phase-nematic phase transition temperature is 0 ° C. or lower, preferably −10 ° C. or lower, more preferably −20 ° C. or lower, particularly preferably −30 ° C. or lower. The nematic phase-isotropic liquid phase transition temperature is 60 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. to 130 ° C. The liquid crystal composition of the present invention requires a dielectric anisotropy of 3 or more, preferably in the range of 4-30, and in the case where high-speed response is important, the range of 4-16 requires a lower driving voltage. When it does, the range of 17-30 is preferable. The smaller or middle birefringence is preferably in the range of 0.09 to 0.18, and the larger birefringence is preferably in the range of 0.18 to 0.33. Such a characteristic of the nematic liquid crystal composition is useful for use in an active matrix type, twisted nematic or super twisted nematic liquid crystal display device.
[0056]
The nematic liquid crystal composition is useful for responsive TN-LCDs and STN-LCDs, and can display colors with the birefringence of the liquid crystal layer and the retardation plate without using a color filter layer. It is useful for a liquid crystal display element that can be used, and a transmissive or reflective liquid crystal display element can be used. This liquid crystal display element has a substrate having a transparent electrode layer and at least one of which is transparent, and the molecules of the nematic liquid crystal composition are twisted between the substrates, depending on the purpose, from 30 ° to 360 °. The range can be selected in the range of 90 °, preferably in the range of 90 ° to 270 °, particularly preferably in the range of 45 ° to 135 ° or in the range of 180 ° to 260 °. For this purpose, the liquid crystal composition of the present invention can contain a compound having an optically active group with an induced helical pitch of 0.5 to 1000 μm. The pretilt angle obtained by the alignment film provided on the transparent electrode substrate is preferably selected in the range of 1 ° to 20 °, and when the twist angle is 30 ° to 100 °, a pretilt angle of 1 ° to 4 ° is preferable. A pretilt angle of 2 ° to 6 ° is preferable at 100 ° to 180 °, a pretilt angle of 3 ° to 12 ° is preferable at 180 ° to 260 °, and a pretilt angle of 6 ° to 20 ° is preferable at 260 ° to 360 °. .
[0057]
In addition to the compounds represented by the above general formulas (I-1) to (III-4), the liquid crystal composition of the present invention is generally recognized as a liquid crystal compound in order to improve the properties of the liquid crystal composition. Nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal and the like may be contained. However, when these compounds are used in a large amount, the characteristics of the nematic liquid crystal composition are reduced, so that the addition amount is limited depending on the required characteristics of the obtained nematic liquid crystal composition.
[0058]
Since the liquid crystal composition has a large birefringence, the present inventors have a light control layer in which at least one of the transparent electrode layers is sandwiched between two transparent substrates, and the light control It has been found that the light scattering liquid crystal display in which the layer contains a liquid crystal material and a transparent solid substance is also useful for providing high contrast due to advantageous light scattering properties.
[0059]
Liquid crystal materials that usually have a large birefringence often have the problem that an induced crystal phase or a smectic phase that is partially crystallized, and conversely the liquid crystal phase becomes narrow, Although the liquid crystal phase is exhibited at a temperature, a particularly high voltage holding ratio essential for the active matrix method has not been achieved. Furthermore, when a light-scattering liquid crystal display was manufactured, the light transmittance T0 when no voltage was applied was switched from the voltage application state to the no-application state compared to the value immediately after the production or the value left for a long time after the voltage application. The memory phenomenon that the value immediately after becomes larger appears, and as a result, the contrast of the liquid crystal display is deteriorated, and if a fluorotolane compound is simply used, a preferable result is not necessarily achieved. . The liquid crystal composition of the present invention has been able to avoid or reduce such problems.
[0060]
In addition, the liquid crystal composition of the present invention has been found to be a liquid crystal material exhibiting high compatibility with a polymer-forming compound that forms a transparent solid substance. The transparent solid substance is preferably formed by polymerizing a polymer-forming compound. For example, a light control layer in which an ultraviolet curable resin composition containing a compound having an ultraviolet curable vinyl group is mixed with a liquid crystal material After the forming material is sandwiched between two substrates, the ultraviolet curable resin composition is cured. When the compatibility between the polymer-forming compound and the liquid crystal material is higher, a more uniform solution can be obtained in a wider temperature range. When the polymer-forming compound is cured in such a state, a light-modulating layer having light scattering properties can be produced with little or no deviation, and display characteristics without unevenness in driving voltage and contrast ratio. In addition, it is possible to provide a light scattering type liquid crystal display that achieves a more uniform display of white turbidity. Therefore, a liquid crystal material suitable for manufacturing a liquid crystal display showing more uniform light scattering characteristics or a relatively large liquid crystal display using a vacuum injection method or the like has been found.
[0061]
As the liquid crystal material, it is preferable to use a liquid crystal compound having no cyano group in order to obtain a high voltage holding ratio or a large birefringence of 0.200 or more necessary in the active matrix system. The liquid crystal compound used is an azine compound represented by general formula (I-1) or an azine compound represented by general formula (I-2) in combination with a compound of general formula (I-1). These azine compounds are preferably combined with the fluorotolane compounds represented by the general formulas (II-2) and (II-3), and in particular, the fluorotolane compounds having three rings Is more preferably used as an essential component. By including the azine compound of general formula (I-1), or the azine compound of general formula (I-1) and general formula (I-2), there is an effect of improving responsiveness in particular, and it is possible to display moving images. A useful light-scattering liquid crystal display device can be provided. In order to prepare a liquid crystal display having a higher voltage holding ratio, it is preferable to use a liquid crystal material having a higher specific resistance.¹¹Ω · cm or more is preferable 10¹²More preferably, it is Ω · cm or more.¹³Most preferable is Ω · cm or more.
[0062]
In the Japanese Patent Application Laid-Open No. 6-222320, the present inventors have shown that the relationship between the physical property value of the liquid crystal material and the display characteristics of the liquid crystal display is represented by the following formula (IV).
[0063]
[Expression 1]

[0064]
Vth represents a threshold voltage,¹Kii,²Kii represents an elastic constant, ii represents 11, 22 or 33, Δε represents a dielectric anisotropy, <r> represents an average gap distance at the interface of the transparent solid material, and A represents a transparent to liquid crystal molecule Represents the anchoring energy of the conductive solid material, and d represents the distance between the substrates having transparent electrodes.
[0065]
This formula shows that the regulating force that the transparent solid interface gives to the liquid crystal molecules is the elastic constant¹It means that it changes depending on the ratio of Kii and anchoring energy A.¹It shows that the effect of expanding substantially by the amount of Kii / A is made, and thus the drive voltage is effectively reduced. This relationship can also be applied in the present invention. By selecting the dielectric anisotropy and elastic constant of the liquid crystal material according to the liquid crystal compound constituting the liquid crystal material, a more preferable liquid crystal display driven at a low voltage is obtained. It is something that can be done. More specifically, the following is preferable. By forming the transparent solid material from a polymerizable composition containing a bifunctional monomer and a monofunctional monomer as a polymer-forming compound, it is possible to obtain more excellent liquid crystal display characteristics. By using a composition comprising a bifunctional monomer and a monofunctional monomer as the polymer-forming compound, the shape of the transparent solid material is more uniform in the process of forming the transparent solid material from the polymer-forming compound. It can be considered that the properties of the interface with the liquid crystal material can be manipulated. More specifically, the average gap interval <r> and anchoring energy A in the above-described formula (IV) can be made dominant. In this way, the drive voltage can be reduced while maintaining the cloudiness and transparency. Furthermore, for example, the liquid crystal material containing the compound represented by the general formula (I) described above can be obtained by using a polymerizable composition in which a bifunctional monomer and a monofunctional monomer are used in combination as a polymer-forming compound. The memory phenomenon can be eliminated or reduced.
[0066]
The liquid crystal material used in the present invention is also useful for display in which liquid crystal droplets in which a liquid crystal material is microencapsulated between two substrates having a transparent electrode layer are dispersed in a transparent solid substance. There is expected. The transparent solid substance formed between the substrates may be dispersed in the form of fibers or particles, or may be a film in which liquid crystal material is dispersed in droplets, but has a three-dimensional network structure. More preferred. In addition, the liquid crystal material preferably forms a continuous layer, but is important in forming an optical interface by forming a disordered state of the liquid crystal material to express light scattering. If the average diameter of the shape of the three-dimensional network structure formed from such a transparent solid material is too large or too small compared to the wavelength of light, the light scattering property tends to decrease. A range of ˜2 μm is preferred. The thickness of the light control layer is preferably in the range of 2 to 30 μm, particularly preferably in the range of 5 to 20 μm, depending on the purpose of use.
[0067]
In the liquid crystal display of the present invention thus manufactured, the present inventors have intensively studied the liquid crystal material and the transparent solid substance constituting the liquid crystal display utilizing the light scattering opaque state and the transparent state, and configured the liquid crystal material. The liquid crystal compound, the compatibility with the polymer-forming compound, and the preferable constitution of the polymerizable composition, the faster response, the lower voltage driving performance, the higher resistance value of the light control layer, or the higher The display characteristics such as contrast ratio are maintained and improved, the memory phenomenon is reduced, and more uniform display of white turbidity is achieved, thereby having the characteristics required for the active matrix system. The liquid crystal display of the present invention can be used as, for example, a projection display device or a direct-viewing portable terminal display (Personal Digital Assistance).
[0068]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples. Further, “%” in the compositions of the following examples means “% by weight”.
[0069]
The chemical stability of the composition is as follows. 2 g of the liquid crystal composition is placed in an ampule tube, vacuum degassed and nitrogen-substituted, sealed, and subjected to a heating acceleration test at 150 ° C. for 1 hour. Specific resistance or voltage holding ratio was measured. In the examples, the measured characteristics are as follows.
[0070]
T_NI  : Nematic phase-isotropic liquid phase transition temperature (° C)
T→ _N  : Solid phase or smectic phase-nematic phase transition temperature (° C)
Vth: threshold voltage (V) when a TN-LCD with a cell thickness of 6 μm is constructed
γ: Ratio of saturation voltage (Vsat) to Vth
Δε: Dielectric anisotropy
Δn: birefringence
η: Viscosity at 20 ° C. (c.p.)
Example 1
[0071]
Embedded image

[0072]
A nematic liquid crystal composition (2-1) comprising: was prepared, and various properties of the composition were measured. The results were as follows.
T_NI  : 118.1 ° C
T→ _N  : -12. ℃
Vth: 2.77 V
γ: 1.13
Δε: 4.0
Δn: 0.144
η: 21.4 c. p.
Specific resistance before test: 6.1 × 10¹¹  Ω · cm
Specific resistance after heating acceleration test: 5.2 × 10¹¹  Ω · cm
Voltage holding ratio before test: 98.4%
Voltage holding ratio after heating acceleration test: 97.9%
This nematic liquid crystal composition exhibits a value close to 1.12 which is the limit value of the optical steepness of the liquid crystal display shown in the document “High-speed liquid crystal technology” (page 63, published by CMC Co., Ltd.). Therefore, it can be understood that this liquid crystal composition is useful for high time division driving.
[0073]
Since this nematic liquid crystal composition has a high specific resistance and voltage holding ratio after the heating acceleration test, it can be understood that it is stable to heat. In addition, a new nematic liquid crystal composition of the present invention having this composition as a basic constituent material was produced, and an active matrix liquid crystal display device using the composition was produced. As a result, the leakage current was small and flicker was not generated. It was confirmed that In the same manner, another nematic liquid crystal composition of the present invention having the composition as a basic constituent material was produced, and a twisted nematic and a super twisted nematic liquid crystal display device were produced from the composition. It was confirmed that it was excellent without flicker.
[0074]
The nematic liquid crystal composition (2-1) is a mixture of the following base liquid crystal (b-1) with the general formula (I-1). Various characteristics of the base liquid crystal (b-1) were measured. The results were as follows.
[0075]
Embedded image

[0076]
T_NI  : 116.7 ° C
T→ _N  : +11. ℃
Vth: 2.14 V
γ: 1.23
Δε: 4.8
Δn: 0.090
η: 19.8 c. p.
Comparing the characteristics, the liquid crystal composition of the present invention had a larger birefringence, a wider temperature range of the nematic phase, a smaller ratio of saturation voltage and threshold voltage, and more favorable results.
(Example 2)
[0077]
Embedded image

[0078]
A nematic liquid crystal composition (2-2) was prepared and various properties of the composition were measured. The results were as follows.
T_NI  : 101.1 ° C
T→ _N  : -70. ℃
Vth: 2.19 V
Δε: 7.8
Δn: 0.172
A chiral substance “S-811” (manufactured by Merck) was added to the nematic liquid crystal composition to prepare a mixed liquid crystal. On the other hand, an organic film of “Sunever 610” (manufactured by Nissan Chemical Industries, Ltd.) was rubbed on the opposing planar transparent electrode to form an alignment film, and an STN-LCD display cell having a twist angle of 240 degrees was produced. The mixed liquid crystal was injected into this cell to constitute a liquid crystal display device, and the display characteristics were measured. As a result, a liquid crystal display device exhibiting STN-LCD display characteristics with excellent time-sharing characteristics and improved quick response was obtained. The chiral material was added so that the inherent helical pitch P of the mixed liquid crystal and the cell thickness d of the display cell were Δn · d = 0.85 and d / P = 0.53.
[0079]
STN-LCD display characteristics with twist angle of 240 degrees
Vth: 2.40 V
γ: 1.024
Response (τr = τd): 15.6 msec (static drive)
(Example 3)
[0080]
Embedded image

[0081]
A nematic liquid crystal composition (2-3) was prepared and various properties of this composition were measured. The results were as follows.
T_NI  : 101.7 ° C
T→ _N  : -30. ℃
Vth: 2.16 V
Δε: 5.7
Δn: 0.167
A chiral substance “S-811” (manufactured by Merck) was added to the nematic liquid crystal composition to prepare a mixed liquid crystal. On the other hand, an organic film of “Sunever 610” (manufactured by Nissan Chemical Industries, Ltd.) was rubbed on the opposing planar transparent electrode to form an alignment film, and an STN-LCD display cell having a twist angle of 240 degrees was produced. The mixed liquid crystal was injected into this cell to constitute a liquid crystal display device, and the display characteristics were measured. As a result, a liquid crystal display device exhibiting STN-LCD display characteristics with excellent time-sharing characteristics and improved quick response was obtained. The chiral material was added so that the intrinsic helical pitch P of the mixed liquid crystal and the cell thickness d of the display cell were Δn · d = 0.85 and d / P = 0.51.
[0082]
STN-LCD display characteristics with twist angle of 240 degrees
Vth: 2.46 V
γ: 1.024
Response (τr = τd): 19.0 msec (static drive)
Example 4
[0083]
Embedded image

[0084]
A nematic liquid crystal composition (2-4) comprising the following was prepared, and various properties of the composition were measured. The results were as follows.
T_NI  : 83.8 ° C
T→ _N  : -31. ℃
Vth: 1.89 V
γ: 1.14
Δε: 7.0
Δn: 0.172
A chiral substance “S-811” (manufactured by Merck) was added to the nematic liquid crystal composition to prepare a mixed liquid crystal. On the other hand, an organic film of “Sunever 610” (manufactured by Nissan Chemical Industries, Ltd.) was rubbed on the opposing planar transparent electrode to form an alignment film, and an STN-LCD display cell having a twist angle of 240 degrees was produced. The mixed liquid crystal was injected into this cell to constitute a liquid crystal display device, and the display characteristics were measured. As a result, a liquid crystal display device exhibiting STN-LCD display characteristics with excellent time-sharing characteristics and improved quick response was obtained. The chiral material was added so that the intrinsic helical pitch P of the mixed liquid crystal and the cell thickness d of the display cell were Δn · d = 0.85 and d / P = 0.51.
[0085]
STN-LCD display characteristics with twist angle of 240 degrees

(Example 5)
[0086]
Embedded image

[0087]
A nematic liquid crystal composition (2-5) was prepared and various properties of this composition were measured. The results were as follows.
T_NI  : 95.4 ° C
T→ _N  : -10. ℃
Vth: 2.48 V
γ: 1.15
Δε: 4.7
Δn: 0.290
Using this nematic liquid crystal composition, a TN-LCD having a cell thickness d of 1.7 μm was constructed and its display characteristics were measured. As a result, a liquid crystal showing a threshold voltage of 2.20 V and a response speed of 1.2 msec. A display device was obtained.
[0088]
Further, when the wavelength dispersion of the birefringence of the nematic liquid crystal composition was measured, the ratio at 400 nm to the light wavelength of 650 nm was 1.15 or more. Since this liquid crystal material has a larger phase difference due to the difference in the wavelength of light, a new reflective color that uses the birefringence of liquid crystal and phase difference plate to perform color display without using a color filter layer This is useful for a liquid crystal display system.
(Example 6)
Hereinafter, the light scattering liquid crystal display using the nematic liquid crystal composition (2-5) will be described in more detail. However, the present invention is not limited to these examples.
[0089]
80% liquid crystal composition (2-5) as a liquid crystal material, 13.86% "HX-220" (manufactured by Nippon Kayaku Co., Ltd.) as a polymer-forming compound, 5.94% lauryl acrylate, polymerization initiator As a result, 2-hydroxy-2-methyl-1-phenylpropan-1-one was mixed at a ratio of 0.2% to prepare a light control layer forming material in a uniform solution. This light-control layer forming material was placed in a 50 × 50 mm empty cell produced using two ITO electrode glass substrates with spacers having an average particle diameter of 10 μm, and a temperature 10 ° C. higher than the transition temperature of the uniform solution. Under vacuum injection. While maintaining this at a temperature 3 ° C. higher than the transition temperature of the homogeneous solution, it is passed under a metal halide lamp (80 W / cm 2) at a speed of 3.5 m / min and irradiated with ultraviolet rays having an energy equivalent to 500 mJ / cm 2. Then, the polymer-forming compound was cured to obtain a liquid crystal device having a light control layer composed of a liquid crystal material and a transparent solid substance. With respect to the obtained liquid crystal device, a cross section of the cured product formed between the substrates was observed using a scanning electron microscope, and a transparent solid substance having a three-dimensional network structure composed of a polymer was observed.
[0090]
The characteristics of the obtained light-scattering type liquid crystal display show a wide operating temperature range, have a favorable response to moving images, and have high contrast, uniform and uniform display compared to conventional light-scattering type liquid crystal devices. It has characteristics and is useful for a decorative display board such as an advertising board, a display device such as a clock, or a projection display device.
[0091]
【The invention's effect】
The nematic liquid crystal composition of the present invention has a large birefringence Δn, exhibits a nematic phase in a wide temperature range, is excellent in response characteristic improvement effect, has a high voltage holding ratio, and has high chemical stability. It is. Therefore, the nematic liquid crystal composition of the present invention can be used for an active matrix type, twisted nematic or super twisted nematic liquid crystal display device. Further, it is possible to provide a liquid crystal display element that performs color display with the birefringence of the liquid crystal layer and the retardation plate. In particular, the thickness d of the liquid crystal layer can be reduced by a large birefringence, the response characteristics can be improved, and display characteristics with a large amount of information can be provided. Furthermore, a useful apparatus can be provided also for the light-scattering type liquid crystal display which has a light control layer containing a liquid crystal material and a transparent solid substance.

Claims (22)

The liquid crystal composition has the general formula (I-1)

(In the formula, R ¹¹ represents a linear alkyl group having 1 to 10 carbon atoms, an alkoxy group, or a linear alkenyl group having 2 to 10 carbon atoms, and R ¹² represents a linear chain having 2 to 10 carbon atoms. A liquid crystal component A composed of one or two or more compounds represented by formula (1), a liquid crystal component B composed of a compound having a dielectric anisotropy of +2 or more, and -2. A liquid crystal component C comprising a compound having a dielectric anisotropy of ˜2, and the liquid crystal component C is represented by the general formulas ( III-1 ) to ( III-4 )

(In the formula, R ^{31 to} R ³⁴ each independently represents a linear alkyl group or alkenyl group having 2 to 7 carbon atoms, and R ^{35 to} R ³⁸ are each independently a straight chain having 1 to 7 carbon atoms. chain alkyl group, alkoxy group, alkenyl group, alkenyloxy group or _{C u H 2u + 1 - O} - C v represents H _2v, u and v are each independently an integer of 1 to 5, Y ³¹ is hydrogen atom, a fluorine atom or a - represents CH 3, Y ³² and Y ³³ are each independently represent a hydrogen atom or a fluorine atom, Z ³¹ to Z ³⁴ each independently represents a single bond, - COO -, - C ₂ H ₄ - or - C ₄ H ₈ - represents, Z ³¹ also - C [identical to] C - or - CH = CH - a a at best, Z ³⁵ is a single bond, - C≡C -, - COO - or - CF = CF - represents, ring a ^31, ring a ³² are each independently represent a cyclohexane ring or a cyclohexene ring, ring a ^33, ring a ³⁴ are each independently Cyclohexane represents a ring or a benzene ring, n ¹ ~n ⁵ each independently represent an integer of 0 or 1, n ⁴ + n ⁵ is 0 or 1, the hydrogen atom of the cyclohexane ring in the compound (H) is deuterium atom (D) may be substituted. the compound selected from the group consisting of compounds represented by) a liquid crystal composition you containing one or more, the liquid crystal composition is 3 or more A nematic liquid crystal composition having a dielectric anisotropy, a nematic phase-isotropic liquid phase transition temperature of 60 ° C. or higher, and a crystal phase or smectic phase-nematic phase transition temperature of 0 ° C. or lower. . 30 to 100 in which the liquid crystal component A is a compound in which R ¹¹ in the general formula (I-1) is a methyl group, an ethyl group, a propyl group, or a butenyl group and / or a compound in which R ¹² is a butenyl group. 2. The nematic liquid crystal composition according to claim 1, wherein the nematic liquid crystal composition is contained by weight%. The liquid crystal component A comprises the general formula (I-1) and the general formula (I-2)

(Wherein R ¹³ and R ¹⁴ each independently represents a linear alkyl group or an alkoxy group having 1 to 10 carbon atoms). The nematic liquid crystal composition described. 4. The nematic liquid crystal composition according to claim 1, wherein the liquid crystal composition contains 1 to 50% by weight of the liquid crystal component A. The liquid crystal component B is represented by the general formulas (II-1) to (II-4)

(Wherein R ^{21 to} R ²⁴ each independently represents a linear alkyl group having 2 to 10 carbon atoms, an alkenyl group, or C _s H _{2s + 1} —OC _t H _2t , and s and t are each independently X ^{21 to} X ²⁴ each independently represents a fluorine atom, a chlorine atom, —OCF ₃ , —OCHF ₂ , —CF ₃ or —CN, and Y ^{21 to} Y ²⁸ each represents an integer of 1 to 5 Independently represents a hydrogen atom or a fluorine atom, W ^{21 to} W ²⁴ each independently represents a hydrogen atom or a fluorine atom, and Z ^{21 to} Z ²³ each independently represents a single bond, —COO—, —C ₂ H; ₄ - or -C ₄ H ₈ - represents may be Z ²¹ is also -C≡C- or -CH = CH- and, Z ^24, Z ²⁵ are each independently a single bond, -COO-, —C≡C— or —CF═CF—, each of m ^{1 to} m ⁴ independently represents 0 or 1, m ³ + m ⁴ is 0 or 1, and a hydrogen atom of a cyclohexane ring in each compound ( H It claims 1 to 4 nematic liquid crystal composition according to characterized in that it contains a compound selected from the group consisting of compounds represented by which may be optionally.) Replaced by deuterium atoms (D). The liquid crystal component B is a compound in which R ^{21 to} R ²⁴ in the general formulas (II-1) to (II-4) are an alkyl group or an alkenyl group having 2 to 5 carbon atoms and / or X ^{21 to} X ^24. but F, Cl, -OCF ₃ or nematic liquid crystal composition according to claim 5, wherein a -CN, compound, characterized in that it contains 10 to 100 wt%. In the liquid crystal component B, Z ²¹ and Z ²² in the compound of the general formula (II-1) are each independently represented by a single bond, —COO—, —C ₂ H ₄ — or —C ₄ H ₈ —. The nematic liquid crystal composition according to claim 5 or 6, characterized by containing 10 to 100% by weight of a compound. The liquid crystal component B contains 10 to 100% by weight of a compound in which Z ²⁴ in the compound of the general formula (II-2) is a single bond, —COO— or —C≡C—. The nematic liquid crystal composition according to claim 5, 6 or 7. 7. The liquid crystal component B contains at least 10% by weight of a compound in which Z ²⁵ in the compound of the general formula (II-3) is a single bond or —C≡C—. 7. A nematic liquid crystal composition according to 7 or 8. 10. The nematic liquid crystal composition according to claim 1, wherein the liquid crystal composition contains 10 to 99% by weight of the liquid crystal component B. In the compound of the general formula (III-1), R ³¹ represents a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, and R ³⁵ is a straight chain having 1 to 5 carbon atoms. A chain alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, when n ¹ is 0, a compound where Z ³² is a single bond or —COO— and / or when n ¹ is 1, ring A ³¹ represents a cyclohexane ring, Z ^31, Z ³² is a nematic liquid crystal composition according to claim 1, characterized in that it contains 10 to 100 wt% of the compound represented by a single bond. In the compound of the general formula (III-2), R ³² represents a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, and R ³⁶ is a straight chain having 1 to 5 carbon atoms. Represents a chain alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, and when n ² is 0, ring A ³² is a cyclohexane ring or a cyclohexene ring, Z ³³ is a single bond, —COO— or —C ₂ H _{When the} compound represented by 4- and / or n ² is 1, ring A ³² is a cyclohexane ring, and Z ³³ contains a single bond or a compound represented by —C 2 H ₄ — in an amount of 10 to 100% by weight. The nematic liquid crystal composition according to claim 11 . Said liquid crystal component C, in said compound of general formula (III-3), according to claim 11 or 12 wherein the Z ³⁵ contains 10 to 100 wt% of the compound represented by -C≡C- Nematic liquid crystal composition. The nematic liquid crystal composition according to claim 11 , wherein the liquid crystal composition contains at most 70 wt% of the liquid crystal component C. The liquid crystal composition is a compound having a core structure having four six-membered rings, and the compound has one or more compounds having a liquid crystal phase-isotropic liquid phase transition temperature of 100 ° C. or higher. The nematic liquid crystal composition according to claim 1, which is contained. The liquid crystal composition has a dielectric anisotropy of 4 to 30, a birefringence of 0.08 to 0.33, and a nematic phase-isotropic liquid phase transition temperature of 60 ° C. to 180 ° C. The nematic liquid crystal composition according to any one of claims 1 to 15 , which has a crystal phase, a smectic phase, or a glass phase-nematic phase transition temperature of -200 ° C to 0 ° C. The nematic liquid crystal composition according to any one of claims 1 to 16 , wherein the liquid crystal composition contains a compound having an optically active group having an induced helical pitch of 0.5 to 1000 µm. An active matrix, twisted nematic or super twisted nematic liquid crystal display device using the nematic liquid crystal composition according to claim 17 . The liquid crystal display device according to claim 18 , wherein the liquid crystal layer has a thickness of 1 to 30 μm. A light-scattering liquid crystal display device comprising a light control layer containing the liquid crystal composition according to claim 1 and a transparent solid substance. 21. The light scattering type according to claim 20 , wherein in the light control layer, the liquid crystal composition forms a continuous layer, and the transparent solid material forms a uniform three-dimensional network structure in the continuous layer. Liquid crystal display device. The light-scattering liquid crystal display device according to claim 20 or 21, wherein the transparent solid substance is formed from a polymerizable composition containing a polymer-forming bifunctional monomer and a monofunctional monomer.