JP4887560B2

JP4887560B2 - Liquid crystal composition

Info

Publication number: JP4887560B2
Application number: JP2000340310A
Authority: JP
Inventors: 邦彦小谷; 正太郎川上; 佳孝斉藤; 貞夫竹原; 博之大西; 晴義高津
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2000-11-08
Filing date: 2000-11-08
Publication date: 2012-02-29
Anticipated expiration: 2020-11-08
Also published as: JP2002146354A

Description

【０００１】
【発明の属する技術分野】
本発明は電気光学的液晶表示材料として有用なネマチック液晶組成物及び、これを用いた液晶表示素子に関する。
【０００２】
【従来の技術】
液晶表示装置(LCD)は、電卓のディスプレイとして登場して以来、コンピューターの開発と歩みを同じくして、TN-LCD(捻れネマチック液晶表示装置)から、STN-LCDへと表示容量の拡大に対応してきた。STN-LCDは、シェファー(Scheffer)等［SID '85 Digest, 120頁(1985年)］、あるいは衣川等［SID '86 Digest, 122頁(1986年)］によって開発され、ワードプロセッサ、パーソナルコンピュータなどの高情報処理用の表示に広く普及しはじめている。最近、STN-LCDでの応答特性を改善する目的でアクティブ・アドレッシング駆動方式が提案されている。(Proc.12th International Display Research Conference p.503 1992年)また、携帯用端末表示(Personal Digital Assistance)ではより広い温度域で良好な表示特性が要求されている。この様な液晶材料として粘性が低く、駆動電圧が低くなおかつ広い温度範囲に対して一定値を保持することや、あるいは種々の時分割に対応した周波数範囲で駆動電圧が変動しないことが要求されている。しかし、表示素子に組み込んだときの応答速度やコントラストなどはまだ十分とは言えず、現在も新しい液晶化合物あるいは液晶組成物の提案がなされている。
【０００３】
上述のようにTN-LCDやSTN-LCDの重要な特性改善課題の一つにコントラストの向上がある。LCDの急速な用途拡大に伴い、室内で使用されるだけでなく、コンピューターの携帯端末ディスプレイ、車載用計器、屋外使用計測機のディスプレイのように、温度条件の過酷な屋外で使用されることが増加してきた。そのため、LCDが置かれる環境の温度変化による表示コントラストの低下、低温における応答速度の低下による表示品位の悪化が問題になってきている。また、屋外での使用では高い信頼性も求められるようになってきた。
【０００４】
周囲の温度変化によるLCD表示品位の低下の原因は、様々な要因が上げられるが、ネマティック液晶の弾性定数・誘電率などの温度変化と添加したカイラル物質の固有ピッチの温度変化に起因する閾値電圧Vthの温度変化を押されるため、カイラル物質の固有ピッチの温度変化を制御することにより閾値電圧の温度依存性を改善する提案(特開昭55-38869公報)はすでに知られており、母体液晶とカイラル物質の組み合わせによりその効果が変化する事や、カイラル量を増やすことによりレスポンス等の表示特性に悪影響を及ぼすことが問題になっていた。
しかし、液晶中に含まれるイオン性物質の易動度の温度変化により電流値が増加するため、液晶にかかる実効値電圧がイオンにより消費され、コントラスト及び信頼性を低下させることに起因する改善策は知られていない。この観点から、従来から広く用いられているエステル結合を有するΔεの大きい化合物の使用量を減らす必要があるが、それによって生じる閾値電圧の増加が問題になっていた。
【発明が解決しようとする課題】
本発明が解決しようとする課題は、上記問題の解決又は低減であり、特に閾値電圧、レスポンス等の液晶諸特性を悪化させることなく、Vthの温度依存性の小さい液晶組成物を提供することにあり、またこの液晶組成物を使用したコントラストの高い液晶表示素子を提供することにある。
【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、種々の液晶化合物を用いた液晶組成物を検討した結果以下の液晶組成物を見いだした。
【０００５】
発明1、第一成分として一般式(I)
【化１１】

(式中、R、R¹は炭素原子数1〜16のアルキル基またはアルコキシル基、炭素原子数2〜16のアルケニル基、炭素原子数3〜16のアルケニルオキシ基を表し、環Pはそれぞれ独立的にフッ素原子により置換されていてもよい1,4-フェニレン基、2-メチル-1,4-フェニレン基、3-メチル-1,4-フェニレン基、ナフタレン-2,6-ジイル基、フェナントレン-2,7-ジイル基、フルオレン-2,7-ジイル基、トランス-1,4-シクロヘキシレン基、1,2,3,4-テトラヒドロナフタレン-2,6-ジイル基、デカヒドロナフタレン-2,6-ジイル基、トランス-1,3-ジオキサン-2,5-ジイル基、ピリジン-2,5-ジイル基、ピリミジン-2,5-ジイル基、ピラジン-2,5-ジイル基またはピリダジン-2,5-ジイル基を表し、Lは単結合、-CH₂CH₂-、-(CH₂)₄-、-OCH₂-、-CH₂O-、-CH=CH-、-COO-または-C≡C-を表し、kは1、2もしくは3を表し、kが2もしくは3の場合、環Pはそれぞれ同じでも異なっていてもよい。)から選ばれる化合物を1種もしくは2種以上を含有し、
【０００６】
第二成分として一般式(II)、(III)
【化１２】

(式中、R²、R³及びR⁴はそれぞれ独立的にフッ素置換されていても良い炭素原子数1〜16のアルキル基またはアルコキシル基、炭素原子数2〜16のアルケニル基、炭素原子数3〜16のアルケニルオキシ基、または炭素原子数1〜10のアルコキシル基で置換された炭素原子数1〜12のアルキル基を表し、環A、環B、環C、環D及び環Eはそれぞれ独立的にフッ素原子により置換されていてもよい1,4-フェニレン基、2-メチル-1,4-フェニレン基、3-メチル-1,4-フェニレン基、フェナントレン-2,7-ジイル基、フルオレン-2,7-ジイル基、トランス-1,4-シクロヘキシレン基、1,2,3,4-テトラヒドロナフタレン-2,6-ジイル基、デカヒドロナフタレン-2,6-ジイル基、トランス-1,3-ジオキサン-2,5-ジイル基、ピリジン-2,5-ジイル基、ピリミジン-2,5-ジイル基、ピラジン-2,5-ジイル基またはピリダジン-2,5-ジイル基を表し、l及びmはそれぞれ独立的に0、1もしくは2を表し、Z¹、Z²、Z³及びZ⁴はそれぞれ独立的に単結合、-CH₂CH₂-、-(CH₂)₄-、-OCH₂-、-CH₂O-、-CH=CH-、-COO-または-C≡C-を表し、X²はシアノ基、フッ素原子、塩素原子、トリフルオロメトキシ基、トリフルオロメチル基、ジフルオロメトキシ基、水素原子、3,3,3-トリフルオロエトキシ基、R'または-OR'を表し、R'は炭素原子数1〜12の直鎖状アルキル基または、2〜12の直鎖状アルケニル基を表し、X¹、X³は水素原子、フッ素原子または塩素原子を表す。)から選ばれる化合物を1種もしくは2種以上を含有し、なお且つネマチック相上限温度が60℃以上であり、ネマチック下限温度が-20℃以下であり、屈折率の異方性(Δn)が0.07〜0.30の範囲であることを特徴とする液晶組成物に関する。
【０００７】
発明2、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、さらに一般式(II)もしくは一般式(III)の化合物の中から選んだ1種もしくは2種以上を含有し、選んだ化合物の含有率がそれぞれ5〜95質量%の範囲であることを特徴とする発明1記載の液晶組成物に関する。
【０００８】
発明3、一般式(II)の化合物として、環Aおよび環Bがトランス-1,4-シクロヘキシレン基であり、Z¹、Z²が単結合の一般式(II-a)
【化１３】

(式中、R⁵、R⁶はR²、R³と同じ意味を表し、環Fは1,4-フェニレン基またはトランス-1,4-シクロヘキシレン基を表し、nは0もしくは1を表す。)から選ばれる1種もしくは2種以上の化合物を含有することを特徴とする発明1又は2記載の液晶組成物に関する。
【０００９】
発明4、一般式(I)の含有率が5〜40質量%の範囲で、なお且つ第二成分として一般式(II-a)の化合物を1種もしくは2種以上を含有しその含有率が5〜95質量%の範囲であることを特徴とする発明3記載の液晶組成物に関する。
【００１０】
発明5、一般式(III)の化合物として、環Dがトランス-1,4-シクロヘキシレン基であり、Z³、Z⁴が単結合であり、m=1の一般式(III-a)
【化１４】

(式中、R⁷は炭素原子数1〜8のアルキル基または、2〜8のアルケニル基を表し、環Gは1,4-フェニレン基またはトランス-1,4-シクロヘキシレン基を表し、X⁵はシアノ基、フッ素原子、トリフルオロメトキシ基、ジフルオロメトキシ基を表し、X⁴、X⁶はそれぞれ独立的に水素原子またはフッ素原子を表す。)から選ばれる1種もしくは2種以上の化合物を含有することを特徴とする発明1〜4の何れかに記載の液晶組成物に関する。
【００１１】
発明6、一般式(I)の含有率が5〜40質量%の範囲で、なお且つ一般式(III-a)の化合物を1種もしくは2種以上を含有し、その含有率が5〜95質量%の範囲であることを特徴とする発明5記載の液晶組成物に関する。
【００１２】
発明7、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(II-b)
【化１５】

(式中、R⁸、R⁹はR²、R³と同じ意味を表し、rは0又は1を表す。)から選ばれる1種もしくは2種以上の化合物を含有し、その含有率が5〜60質量%の範囲であることを特徴とする発明1〜6の何れかに記載の液晶組成物に関する。
【００１３】
発明8、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(II-c)
【化１６】

(式中、R¹⁰、R¹¹はR²、R³と同じ意味を表す。)から選ばれる1種もしくは2種以上の化合物を含有しその含有率が5〜60質量%の範囲であることを特徴とする発明1〜6の何れかに記載の液晶組成物に関する。
【００１４】
発明9、一般式(I)の化合物を1種もしくは2種以上を含有しその含有率が5〜40質量%の範囲で、なお且つ一般式(II-b)の化合物を1種もしくは2種以上を含有しその含有率が5〜60質量%の範囲で、なお且つ一般式(II-c)の化合物を1種もしくは2種以上を含有しその含有率が5〜60質量%の範囲であることを特徴とする発明7又は8記載の液晶組成物に関する。
【００１５】
発明10、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なおかつ一般式(III-a)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(II-b)もしくは一般式(II-c)の化合物を1種もしくは2種以上を含有し、その含有率が5〜60質量%の範囲であることを特徴とする発明7〜9何れかに記載の液晶組成物に関する。
【００１６】
発明11、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(III-a)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(II-b)及び一般式(II-c)の化合物を1種もしくは2種以上を含有し、その含有率がそれぞれ5〜40質量%の範囲であることを特徴とする発明10記載の液晶組成物に関する。
【００１７】
発明12、一般式(III)もしくは(III-a)として一般式(III-b)
【化１７】

(式中、R¹²は炭素原子数1〜16のアルキル基または炭素原子数2〜8のアルケニル基を表す。)から選ばれる1種もしくは2種以上の化合物を含有し、その含有率が5〜40質量%の範囲であることを特徴とする発明1〜11の何れかに記載の液晶組成物に関する。
【００１８】
発明13、一般式(III)もしくは(III-a)として一般式(III-c)
【化１８】

(式中、R¹²は炭素原子数1〜16のアルキル基または炭素原子数2〜8のアルケニル基を表す。)から選ばれる1種もしくは2種以上の化合物を含有しその含有率が5〜40質量%の範囲であることを特徴とする発明1〜11の何れかに記載の液晶組成物に関する。
【００１９】
発明14、一般式(I)が、一般式(Ia)
【化１９】

(式中、R¹³、R¹⁴は炭素原子数1〜16のアルキル基またはアルコキシル基、環Qは、1,4-フェニレン基またはトランス-1,4-シクロヘキシレン基を表す。)から選ばれる1種もしくは2種以上の化合物を含有し、その含有率が5〜40質量%の範囲であることを特徴とする発明1〜13の何れかに記載の液晶組成物に関する。
【００２０】
発明15、さらに追加の成分として一般式(III)もしくは(III-a)として一般式(III-c)
【化２０】

(式中、R¹²は炭素原子数1〜16のアルキル基または炭素原子数2〜8のアルケニル基を表す。)から選ばれる1種もしくは2種以上の化合物を含有しその含有率が5〜40質量%であることを特徴とする発明14記載の液晶組成物に関する。
【００２１】
発明16、発明1〜15の何れかに記載の液晶組成物を用いた液晶表示素子に関する。
発明17、発明1〜15の何れかに記載の液晶組成物を用いた、ねじれ角が180°〜270°であることを特徴とする超捩れネマチック(STN)液晶表示素子に関する。
【発明の実施の形態】
以下に本発明の一例について説明する。
【００２２】
発明1において、第一成分として一般式(I)から選ばれる化合物、好ましくは式(Ia-a)または式(Ia-b)
【化２１】

を1種もしくは2種以上を含有するが、1種もしくは2種が好ましい。また、式中R、R¹は、炭素原子数1〜16のアルキル基、炭素原子数2〜16のアルケニル基もしくは炭素原子数3〜16のアルケニルオキシ基を表すが、いずれもアルキル基またはアルケニル基が好ましく、R¹においてはアルケニル基がより好ましく、式(a)または式(b)の構造がさらに好ましい。
【化２２】

(構造式は右端で環に連結しているものとする。)
(b)が特に好ましい。
Rがアルケニル基の場合は、式(a)〜式(e)が好ましい。
【００２３】
さらに、第二成分として一般式(II)、(III)から選ばれる化合物を1種もしくは2種以上を含有するが、3種以上が好ましく、3種〜20種がさらに好ましく、5種〜15種が特に好ましく、その中に一般式(II)の化合物を少なくとも2種以上含むことがより好ましい。この液晶組成物はネマチック相上限温度が60℃以上であることを特徴とするが、70℃以上が好ましく、80℃以上が特に好ましい。また、Δnは0.07〜0.30の範囲であることを特徴とするが、0.08〜0.22が好ましい。R²、R³、R⁴はそれぞれ独立的にフッ素置換されていても良い炭素原子数1〜16のアルキル基またはアルコキシル基、炭素原子数2〜16のアルケニル基、炭素原子数3〜16のアルケニルオキシ基、または炭素原子数1〜10のアルコキシル基で置換された炭素原子数1〜12のアルキル基を表すが、炭素原子数1〜16のアルキル基、炭素原子数2〜16のアルケニル基が好ましく、炭素原子数1〜8のアルキル基、炭素原子数2〜8のアルケニル基がより好ましく、1〜5のアルキル基もしくはアルケニル基として式(a)〜(e)が特に好ましい。
【００２４】
環A、環B、環C、環D及び環Eはそれぞれ独立的にフッ素原子により置換されていてもよい1,4-フェニレン基、2-メチル-1,4-フェニレン基、3-メチル-1,4-フェニレン基、ナフタレン-2,6-ジイル基、フェナントレン-2,7-ジイル基、フルオレン-2,7-ジイル基、トランス-1,4-シクロヘキシレン基、1,2,3,4-テトラヒドロナフタレン-2,6-ジイル基、デカヒドロナフタレン-2,6-ジイル基、トランス-1,3ジオキサン-2,5-ジイル基、ピリジン-2,5-ジイル基、ピリミジン-2,5-ジイル基、ピラジン-2,5-ジイル基またはピリダジン-2,5-ジイル基を表すが、1,4-フェニレン基、トランス-1,4-シクロヘキシレン基が好ましく、環A、環B、環D、環Eにおいてはトランス-1,4-シクロヘキシレン基がより好ましく、環Cにおいては1,4-フェニレン基より好ましい。l、mはそれぞれ独立的に0、1もしくは2を表すが、0もしくは1が好ましい。Z¹、Z²、Z³、Z⁴はそれぞれ独立的に単結合、-CH₂CH₂-、-(CH₂)₄-、-OCH₂-、-CH₂O-、-COO-、-C=C-または-C≡C-表すが、Z¹、Z²においては単結合、-COO-、-C≡C-または-CH₂CH₂-が好ましく、単結合がより好ましい。Z³、Z⁴においては単結合、-COO-または-C≡C-が好ましく、単結合がより好ましい。X²はシアノ基、フッ素原子、塩素原子、トリフルオロメトキシ基、トリフルオロメチル基、ジフルオロメトキシ基、水素原子、3,3,3-トリフルオロエトキシ基、R'または-OR'を表し、R'は炭素原子数1〜12の直鎖状アルキル基または、2〜12の直鎖状アルケニル基を表すが、シアノ基、フッ素原子、トリフルオロメトキシ基、ジフルオロメトキシ基が好ましく、シアノ基、フッ素原子がより好ましく、フッ素原子が特に好ましい。X¹、X³は水素原子、フッ素原子または塩素原子を表すが、水素原子、フッ素原子が好ましく、フッ素原子が特に好ましい。
【００２５】
発明2において、一般式(I)の含有率は5〜40質量%であるが、5〜25質量%が好ましく、5〜20質量%が特に好ましく、一般式(II)もしくは一般式(III)の含有率は5〜95質量%であるが、15〜85質量%が好ましく、25〜85質量%が特に好ましい。
【００２６】
発明3において、一般式(II-a)のR⁵、R⁶はそれぞれ独立的にフッ素置換されていても良い炭素原子数1〜16のアルキル基またはアルコキシル基、炭素原子数2〜16のアルケニル基、炭素原子数3〜16のアルケニルオキシ基、または炭素原子数1〜10のアルコキシル基で置換された炭素原子数1〜12のアルキル基を表すが、炭素原子数1〜5のアルキル基もしくは炭素原子数2〜8のアルケニル基として式(a)〜(e)が特に好ましい。
【００２７】
発明4において、一般式(I)の化合物を1種もしくは2種以上を含有しその含有率が5〜40質量%の範囲で、なおかつ一般式(II-a)の化合物を1種もしくは2種以上を含有しその含有率が5〜95質量%の範囲であるが、一般式(I)の化合物を1種もしくは2種含有しその含有率は5〜25質量%が好ましく、5〜20質量%が特に好ましく、一般式(II-a)の化合物を2種以上含有しその含有率が5〜95質量%であることが好ましく、15〜85質量%が好ましく、25〜85質量%が特に好ましい。
【００２８】
発明6において、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なおかつ第二成分として一般式(III-a)の化合物を1種もしくは2種以上を含有し、その含有率が5〜95質量%の範囲であるが、一般式(I)の化合物を1種もしくは2種含有しその含有率は5〜25質量%が好ましく、5〜15質量%が特に好ましく、一般式(III-a)の化合物を2種以上含有しその含有率が5〜95質量%であることが好ましく、15〜85質量%が好ましく、25〜85質量%が特に好ましい。
【００２９】
発明7において、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なおかつ一般式(II-b)から選ばれる1種もしくは2種以上の化合物を含有し、その含有率が5〜60質量%の範囲であるが5〜25質量%が好ましい。式中R⁸、R⁹はそれぞれ独立的に炭素原子数1〜8のアルキル基または炭素原子数2〜8のアルケニル基を表すが、1〜5のアルキル基もしくはアルケニル基として式(a)〜(e)が特に好ましい。
【００３０】
発明8において、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なおかつ一般式(II-c)から選ばれる1種もしくは2種以上の化合物を含有し、その含有率が5〜60質量%の範囲であるが5〜25質量%が好ましい。式中R¹⁰、R¹¹はそれぞれ独立的に炭素原子数1〜8のアルキル基または炭素原子数2〜8のアルケニル基を表すが、1〜5のアルキル基もしくはアルケニル基として式(a)〜(e)が特に好ましい。
【００３１】
発明9において、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なおかつ一般式(II-b)から選ばれる1種もしくは2種以上の化合物を含有し、その含有率が5〜60質量%の範囲であるが5〜25質量%が好ましい。さらに一般式(II-c)から選ばれる1種もしくは2種以上の化合物を含有しその含有率が5〜60質量%の範囲であるが、5〜50質量%が好ましく5〜40質量%であることがより好ましい。式中R⁸、R⁹、R¹⁰、R¹¹はそれぞれ独立的に炭素原子数1〜8のアルキル基または炭素原子数2〜8のアルケニル基を表すが、1〜5のアルキル基もしくはアルケニル基として式(a)〜(e)が特に好ましい。
【００３２】
発明10において、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(III-a)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なおかつ一般式(II-b)もしくは一般式(II-c)の化合物を1種もしくは2種以上を含有し、その含有率が5〜60質量%の範囲であるが、一般式(I)の化合物を1種もしくは2種含有しその含有率が5〜20質量%の範囲であることが好ましく、一般式(III-a)の含有率が5〜35質量%の範囲であることが好ましく、5〜25質量%の範囲であることがより好ましく、一般式(II-b)もしくは一般式(II-c)の含有率が5〜55質量%の範囲であることが好ましく、5〜45質量%の範囲であることがより好ましい。
【００３３】
発明11において、一般式(I)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(III-a)の化合物を1種もしくは2種以上を含有し、その含有率が5〜40質量%の範囲で、なお且つ一般式(II-b)及び一般式(II-c)の化合物を1種もしくは2種以上を含有し、その含有率がそれぞれ5〜40質量%の範囲であるが、一般式(I)の化合物を1種もしくは2種含有しその含有率が5〜20質量%の範囲であることが好ましく、一般式(II-b)及び一般式(II-c)の化合物をそれぞれ1種以上含有しその含有率が5〜20質量%の範囲であり、更に一般式(III-a)の化合物を2種以上含有しその含有率が5〜25質量%の範囲であることが好ましい。
【００３４】
発明12において、一般式(III)もしくは一般式(III-a)として、一般式(III-b)から選ばれる1種もしくは2種以上の化合物を含有しその含有率が5〜40質量%の範囲であるが、一般式(III-b)の化合物を1〜10種含有しその含有率が5〜35質量%の範囲であることが好ましく、1〜5種を含有しその含有率が5〜30質量%の範囲であることがより好ましい。式中R¹²は炭素原子数1〜8のアルキル基または炭素原子数2〜8のアルケニル基を表すが、1〜5のアルキル基もしくはアルケニル基として式(a)〜(e)が特に好ましい。
【００３５】
発明13において、一般式(III)もしくは一般式(III-a)として、一般式(III-c)から選ばれる1種もしくは2種以上の化合物を含有しその含有率が5〜40質量%の範囲であるが、一般式(III-c)の化合物を1〜10種含有しその含有率が5〜35質量%の範囲であることが好ましく、1〜5種を含有しその含有率が5〜30質量%の範囲であることがより好ましい。式中R¹²は炭素原子数1〜8のアルキル基または炭素原子数2〜8のアルケニル基を表すが、アルケニル基が好ましく、その中で式(a)〜(e)が特に好ましい。
【００３６】
発明14において、一般式(I-a)を含有するが、その含有率が5〜40質量%の範囲であることが好ましく、5〜20質量%の範囲であることがより好ましい。
上記ネマチック液晶組成物はTN-LCDやSTN-LCDに有用であるがSTN-LCDに特に有用である。また、透過型あるいは反射型の液晶表示素子に用いることができる。本発明の液晶組成物は、上記の化合物以外に、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。
【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、以下の実施例及び比較例の組成物における「%」は『質量%』を意味する。
【００３７】
実施例中、測定した特性は以下の通りである。
T_N-I ：ネマチック相−等方性液体相転移温度（℃）
T→_N ：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）
Δε ：誘電異方性
Δn ：複屈折率
γ ：240°ツイストセルにて測定した輝度90%と10%での印加電圧の比
(急峻性)
dV／dT：閾値電圧の温度依存性
STN-LCD表示素子の作成は以下のように行った。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、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たツイスト角240°のSTN-LCD表示用セルに注入した。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=0.50となるように添加した。
化合物の記載に下記の略号を使用する。

【化２３】

例えば、以下に示すように略号を用いる。
【化２４】

【００３８】
(実施例1、実施例2、比較例1)
ネマチック液晶組成物No.1、No.2を調製し、この組成物の諸特性を測定した結果を比較例1と共に表1に示す。
【表１】

実施例1では、比較例1中の4-Ph-Z-Ph-O2と5-Ph-Z-Ph-O1を一般式(I)の化合物である3-Cy-VO-Np-2に置換することにより、実施例2では3-Ph-VO-Np-2に置換することにより、それぞれ実施例1、2を作製した。結果、Δεがほとんど変わらないにもかかわらず比較例1に比べ閾値電圧Vthの低下を得ることができ、閾値電圧の温度依存性dV／dTは、低温領域(0〜25℃)においても、高温領域(25〜40℃)においても改善されていることがわかる。
【００３９】
(実施例3)
240°ツイストのSTN-LCD表示セルにそれぞれ比較例1と実施例1の液晶組成物を注入し、STN特性を比較したがTNと同様に実施例1の液晶組成物を注入した方が、閾値電圧の温度依存性dV／dTが低減された。
【発明の効果】
本発明の液晶材料の組み合わせによって、温度依存性が良く、かつ、応答速度が速い誘電率異方性の高い液晶組成物が得られた。また、この組成物を液晶表示素子として用いた場合、閾値電圧が低く優れたものであった。この液晶ディスプレイはSTNおよびTN-LCDとして非常に有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nematic liquid crystal composition useful as an electro-optical liquid crystal display material and a liquid crystal display element using the same.
[0002]
[Prior art]
The liquid crystal display (LCD) has been used as a calculator display, and it has been the same as the development of computers to support the expansion of display capacity from TN-LCD (twisted nematic liquid crystal display) to STN-LCD. I have done it. STN-LCD was developed by Scheffer et al. [SID '85 Digest, 120 (1985)] or Kinugawa et al. [SID '86 Digest, 122 (1986)]. Widely used in displays for high information processing. Recently, an active addressing drive system has been proposed for the purpose of improving the response characteristics of STN-LCD. (Proc. 12th International Display Research Conference p.503 1992) In addition, in portable terminal display (Personal Digital Assistance), good display characteristics are required in a wider temperature range. As such a liquid crystal material, it is required that the viscosity is low, the driving voltage is low and a constant value is maintained over a wide temperature range, or that the driving voltage does not fluctuate in a frequency range corresponding to various time divisions. Yes. However, the response speed and contrast when incorporated in a display element are still not sufficient, and new liquid crystal compounds or liquid crystal compositions have been proposed.
[0003]
As described above, one of the important characteristics improvement issues of TN-LCD and STN-LCD is the improvement of contrast. With the rapid expansion of LCD applications, it is not only used indoors but also used outdoors with severe temperature conditions, such as computer mobile terminal displays, in-vehicle instruments, and displays used outdoors. It has increased. For this reason, display contrast deterioration due to temperature changes in the environment where the LCD is placed, and display quality deterioration due to low response speed at low temperatures, are becoming problems. In addition, high reliability has been required for outdoor use.
[0004]
There are various causes for the deterioration of LCD display quality due to ambient temperature changes, but the threshold voltage is caused by temperature changes such as the elastic constant and dielectric constant of the nematic liquid crystal and the temperature change of the intrinsic pitch of the added chiral substance. Since the temperature change of Vth is pushed, a proposal to improve the temperature dependence of the threshold voltage by controlling the temperature change of the natural pitch of the chiral substance (Japanese Patent Laid-Open No. 55-38869) is already known, and the matrix liquid crystal It has been a problem that the effect changes depending on the combination of the chiral substance and that the display characteristics such as response are adversely affected by increasing the amount of chiral substance.
However, since the current value increases due to the temperature change of the mobility of the ionic substance contained in the liquid crystal, the effective value voltage applied to the liquid crystal is consumed by the ions, and the improvement measures are caused by lowering the contrast and reliability. Is not known. From this point of view, it is necessary to reduce the amount of a compound having a large Δε having an ester bond that has been widely used in the past, but the increase in threshold voltage caused thereby has been a problem.
[Problems to be solved by the invention]
The problem to be solved by the present invention is to solve or reduce the above-mentioned problems, and in particular, to provide a liquid crystal composition having a small Vth temperature dependency without deteriorating liquid crystal characteristics such as threshold voltage and response. Another object of the present invention is to provide a liquid crystal display element having a high contrast using the liquid crystal composition.
[Means for Solving the Problems]
The present invention has found the following liquid crystal compositions as a result of studying liquid crystal compositions using various liquid crystal compounds in order to solve the above problems.
[0005]
Invention 1, General Formula (I) as the first component
Embedded image

(In the formula, R and R ^{1 each} represent an alkyl group or alkoxyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or an alkenyloxy group having 3 to 16 carbon atoms, and each ring P is independent. 1,4-phenylene group, 2-methyl-1,4-phenylene group, 3-methyl-1,4-phenylene group, naphthalene-2,6-diyl group, phenanthrene optionally substituted by fluorine atom -2,7-diyl group, fluorene-2,7-diyl group, trans-1,4-cyclohexylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, decahydronaphthalene-2 , 6-diyl group, trans-1,3-dioxane-2,5-diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-diyl group or pyridazine- 2,5-diyl group, L is a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —CH═CH—, —COO— or -C≡C-, k represents 1, 2 or 3, k When is 2 or 3, the rings P may be the same or different from each other.) Containing one or more compounds selected from
[0006]
General formula (II), (III) as the second component
Embedded image

(Wherein R ² , R ³ and R ⁴ are each independently a fluorine-substituted alkyl group or alkoxyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or the number of carbon atoms. Represents an alkyl group having 1 to 12 carbon atoms substituted with an alkenyloxy group having 3 to 16 carbon atoms or an alkoxyl group having 1 to 10 carbon atoms, and ring A, ring B, ring C, ring D and ring E are each 1,4-phenylene group optionally substituted by a fluorine atom, 2-methyl-1,4-phenylene group, 3-methyl-1,4-phenylene group, phenanthrene-2,7-diyl group, Fluorene-2,7-diyl group, trans-1,4-cyclohexylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group, trans- 1,3-dioxane-2,5-diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-diyl group or Represents Dajin 2,5-diyl group, l and m represent each independently 0, 1 or ^{^{2, Z 1, Z 2,}} Z 3 and Z ⁴ are each independently a single bond, -CH ₂ CH _{_{2 -, - (CH 2)}} 4 -, - OCH 2 -, - CH 2 O -, - CH = CH -, - represents COO- or -C≡C-, X ² is a cyano group, a fluorine atom, chlorine Represents an atom, a trifluoromethoxy group, a trifluoromethyl group, a difluoromethoxy group, a hydrogen atom, a 3,3,3-trifluoroethoxy group, R ′ or —OR ′, and R ′ is a straight chain having 1 to 12 carbon atoms. A linear alkyl group or a linear alkenyl group of 2 to 12, wherein X ¹ and X ³ each represent a hydrogen atom, a fluorine atom or a chlorine atom). The nematic phase upper limit temperature is 60 ° C. or higher, the nematic lower limit temperature is −20 ° C. or lower, and the refractive index anisotropy (Δn) is in the range of 0.07 to 0.30. About.
[0007]
Invention 2, containing one or more compounds of general formula (I) in the range of 5 to 40% by mass, and among the compounds of general formula (II) or general formula (III) The present invention relates to a liquid crystal composition according to invention 1, wherein the liquid crystal composition comprises one or more selected from the above, and the content of the selected compound is in the range of 5 to 95% by mass.
[0008]
Invention 3, as a compound of general formula (II), ring A and ring B are trans-1,4-cyclohexylene groups, and Z ¹ and Z ² are single bonds, general formula (II-a)
Embedded image

(Wherein R ⁵ and R ⁶ represent the same meaning as R ² and R ³ , ring F represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and n represents 0 or 1) 3. A liquid crystal composition according to invention 1 or 2, which comprises one or more compounds selected from the group consisting of:
[0009]
Invention 4, the content of the general formula (I) is in the range of 5 to 40% by mass, and the compound of the general formula (II-a) as the second component contains one or more, the content is The present invention relates to the liquid crystal composition according to invention 3, which is in the range of 5 to 95% by mass.
[0010]
Invention 5, as a compound of general formula (III), ring D is a trans-1,4-cyclohexylene group, Z ³ and Z ⁴ are single bonds, and m = 1 of general formula (III-a)
Embedded image

(Wherein R ⁷ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, ring G represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and ⁵ represents a cyano group, a fluorine atom, a trifluoromethoxy group, or a difluoromethoxy group, and X ⁴ and X ⁶ each independently represent a hydrogen atom or a fluorine atom.) The liquid crystal composition according to any one of inventions 1 to 4, wherein the composition is contained.
[0011]
Invention 6, the content of the general formula (I) is in the range of 5 to 40% by mass, and contains one or more compounds of the general formula (III-a), the content is 5 to 95 The liquid crystal composition according to the invention 5 is characterized by being in the range of mass%.
[0012]
Invention 7, containing one or more compounds of general formula (I) in the range of 5-40% by mass, and general formula (II-b)
Embedded image

(Wherein R ⁸ and R ⁹ represent the same meaning as R ² and R ³ , r represents 0 or 1), and the content is 5 or more. The liquid crystal composition according to any one of inventions 1 to 6, which is in a range of ˜60 mass%.
[0013]
Invention 8, containing one or more compounds of general formula (I), the content is in the range of 5-40% by mass, and general formula (II-c)
Embedded image

(Wherein R ¹⁰ and R ¹¹ represent the same meaning as R ² and R ³ ), and contain one or more compounds selected from the group, and the content thereof is in the range of 5 to 60% by mass. The invention relates to a liquid crystal composition according to any one of inventions 1 to 6.
[0014]
Invention 9, containing one or more compounds of general formula (I) in the range of 5-40% by mass, and one or two compounds of general formula (II-b) In the range of 5 to 60% by mass, and containing one or more compounds of general formula (II-c), the content of which is in the range of 5 to 60% by mass. The present invention also relates to the liquid crystal composition according to invention 7 or 8.
[0015]
Invention 10, containing one or more compounds of general formula (I) in the range of 5 to 40% by mass, and one or two compounds of general formula (III-a) The content is in the range of 5-40% by mass, and contains one or more compounds of general formula (II-b) or general formula (II-c), the content The liquid crystal composition according to any one of inventions 7 to 9, wherein the ratio is in the range of 5 to 60% by mass.
[0016]
Invention 11, containing one or more compounds of general formula (I) in the range of 5-40% by mass, and one or two compounds of general formula (III-a) Containing at least one species, the content of which is in the range of 5-40% by mass, and containing one or more compounds of general formula (II-b) and general formula (II-c), The liquid crystal composition according to invention 10 is characterized in that the content is in the range of 5 to 40% by mass.
[0017]
Invention 12, General Formula (III-b) as General Formula (III) or (III-a)
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(Wherein R ¹² represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms), and the content thereof is 5 or more. The liquid crystal composition according to any one of inventions 1 to 11, which is in the range of ˜40 mass%.
[0018]
Invention 13, General Formula (III-c) as General Formula (III) or (III-a)
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(Wherein R ¹² represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms), and the content thereof is 5 to 5 The liquid crystal composition according to any one of inventions 1 to 11, which is in a range of 40% by mass.
[0019]
Invention 14, General Formula (I) is General Formula (Ia)
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(Wherein R ¹³ and R ¹⁴ represent an alkyl group or alkoxyl group having 1 to 16 carbon atoms, and ring Q represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group). The liquid crystal composition according to any one of inventions 1 to 13, wherein the liquid crystal composition contains one or more compounds and has a content of 5 to 40% by mass.
[0020]
Invention 15, and as an additional component, general formula (III) or (III-a) as general formula (III-c)
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(Wherein R ¹² represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms), and the content thereof is 5 to 5 The liquid crystal composition according to invention 14 is characterized by being 40% by mass.
[0021]
The present invention relates to a liquid crystal display device using the liquid crystal composition according to any one of inventions 16 and 1-15.
The present invention relates to a super twisted nematic (STN) liquid crystal display element using the liquid crystal composition according to any one of inventions 17 and 1 to 15 and having a twist angle of 180 ° to 270 °.
DETAILED DESCRIPTION OF THE INVENTION
An example of the present invention will be described below.
[0022]
In the invention 1, the compound selected from the general formula (I) as the first component, preferably the formula (Ia-a) or the formula (Ia-b)
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1 type or 2 types or more, but 1 type or 2 types are preferable. In the formula, R and R ^{1 each} represents an alkyl group having ^{1 to} 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or an alkenyloxy group having 3 to 16 carbon atoms. A group is preferred, and in R ¹ , an alkenyl group is more preferred, and a structure of the formula (a) or the formula (b) is more preferred.
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(The structural formula shall be connected to the ring at the right end.)
(b) is particularly preferred.
When R is an alkenyl group, the formulas (a) to (e) are preferable.
[0023]
Furthermore, it contains one or more compounds selected from general formulas (II) and (III) as the second component, preferably 3 or more, more preferably 3 to 20 and more preferably 5 to 15 Species are particularly preferred, and it is more preferred that at least two kinds of compounds of the general formula (II) are contained therein. The liquid crystal composition has a nematic phase upper limit temperature of 60 ° C. or higher, preferably 70 ° C. or higher, particularly preferably 80 ° C. or higher. In addition, Δn is characterized by being in the range of 0.07 to 0.30, preferably 0.08 to 0.22. R ² , R ³ , and R ⁴ each independently may be fluorine-substituted alkyl group or alkoxyl group having 1 to 16 carbon atoms, alkenyl group having 2 to 16 carbon atoms, or 3 to 16 carbon atoms Represents an alkenyloxy group or an alkyl group having 1 to 12 carbon atoms substituted with an alkoxyl group having 1 to 10 carbon atoms, but an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 16 carbon atoms Are more preferable, an alkyl group having 1 to 8 carbon atoms and an alkenyl group having 2 to 8 carbon atoms are more preferable, and formulas (a) to (e) are particularly preferable as an alkyl group or alkenyl group having 1 to 5 carbon atoms.
[0024]
Ring A, Ring B, Ring C, Ring D and Ring E are each independently a 1,4-phenylene group, 2-methyl-1,4-phenylene group, 3-methyl- 1,4-phenylene group, naphthalene-2,6-diyl group, phenanthrene-2,7-diyl group, fluorene-2,7-diyl group, trans-1,4-cyclohexylene group, 1,2,3, 4-tetrahydronaphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group, trans-1,3-dioxane-2,5-diyl group, pyridine-2,5-diyl group, pyrimidine-2, 5-diyl group, pyrazine-2,5-diyl group or pyridazine-2,5-diyl group, preferably 1,4-phenylene group or trans-1,4-cyclohexylene group, ring A, ring B In Ring D and Ring E, a trans-1,4-cyclohexylene group is more preferable, and in Ring C, a 1,4-phenylene group is more preferable. l and m each independently represents 0, 1 or 2, with 0 or 1 being preferred. Z ¹ , Z ² , Z ³ and Z ⁴ are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —COO—, — C═C— or —C≡C— is represented. In Z ¹ and Z ² , a single bond, —COO—, —C≡C— or —CH ₂ CH ₂ — is preferable, and a single bond is more preferable. Z ³ and Z ⁴ are preferably a single bond, —COO— or —C≡C—, and more preferably a single bond. X ² represents a cyano group, a fluorine atom, a chlorine atom, a trifluoromethoxy group, a trifluoromethyl group, a difluoromethoxy group, a hydrogen atom, a 3,3,3-trifluoroethoxy group, R ′ or —OR ′, and R 'Represents a linear alkyl group having 1 to 12 carbon atoms or a linear alkenyl group having 2 to 12 carbon atoms, preferably a cyano group, a fluorine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, a fluorine atom An atom is more preferable and a fluorine atom is particularly preferable. X ¹ and X ³ represent a hydrogen atom, a fluorine atom or a chlorine atom, preferably a hydrogen atom or a fluorine atom, and particularly preferably a fluorine atom.
[0025]
In the invention 2, the content of the general formula (I) is 5 to 40% by mass, preferably 5 to 25% by mass, particularly preferably 5 to 20% by mass, the general formula (II) or the general formula (III). The content of is from 5 to 95 mass%, preferably from 15 to 85 mass%, particularly preferably from 25 to 85 mass%.
[0026]
In Invention 3, R ⁵ and R ⁶ in the general formula (II-a) are each independently an alkyl or alkoxyl group having 1 to 16 carbon atoms and alkenyl having 2 to 16 carbon atoms, which may be substituted with fluorine. Group, an alkenyloxy group having 3 to 16 carbon atoms, or an alkyl group having 1 to 12 carbon atoms substituted with an alkoxyl group having 1 to 10 carbon atoms, but an alkyl group having 1 to 5 carbon atoms or As the alkenyl group having 2 to 8 carbon atoms, the formulas (a) to (e) are particularly preferred.
[0027]
In the invention 4, the compound of the general formula (I) contains one or more compounds, the content thereof is in the range of 5 to 40% by mass, and one or two compounds of the general formula (II-a) The content is in the range of 5 to 95% by mass, but one or two compounds of the general formula (I) are contained, and the content is preferably 5 to 25% by mass, and 5 to 20% by mass. % Is particularly preferred, containing two or more compounds of the general formula (II-a), the content of which is preferably 5 to 95% by weight, preferably 15 to 85% by weight, particularly 25 to 85% by weight preferable.
[0028]
In the invention 6, the compound of the general formula (I) contains one or more compounds of the general formula (I), the content is in the range of 5 to 40% by mass, and the compound of the general formula (III-a) as the second component 1 or 2 or more types, the content is in the range of 5 to 95% by mass, but contains one or two compounds of general formula (I), the content is 5 to 25% by mass Preferably, 5 to 15% by mass is particularly preferable, it contains two or more compounds of the general formula (III-a), the content is preferably 5 to 95% by mass, preferably 15 to 85% by mass, 25 ˜85% by weight is particularly preferred.
[0029]
In the invention 7, one or two or more compounds selected from the general formula (II-b) are contained in the range of 5 to 40% by mass of the compound of the general formula (I). It contains more than one kind of compound, and its content is in the range of 5 to 60% by mass, preferably 5 to 25% by mass. In the formula, R ⁸ and R ⁹ each independently represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and as the alkyl group or alkenyl group having 1 to 5 carbon atoms, formulas (a) to (e) is particularly preferred.
[0030]
In the invention 8, the compound of the general formula (I) contains one or two or more, the content is in the range of 5 to 40% by mass, and one or two selected from the general formula (II-c) It contains more than one kind of compound, and its content is in the range of 5 to 60% by mass, preferably 5 to 25% by mass. In the formula, R ¹⁰ and R ¹¹ each independently represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and the formula (a) to (e) is particularly preferred.
[0031]
In the invention 9, the compound of the general formula (I) contains one or more compounds, the content is in the range of 5 to 40% by mass, and one or two selected from the general formula (II-b) It contains more than one kind of compound, and its content is in the range of 5 to 60% by mass, preferably 5 to 25% by mass. Furthermore, it contains one or more compounds selected from general formula (II-c), and the content thereof is in the range of 5 to 60% by mass, preferably 5 to 50% by mass, and 5 to 40% by mass. More preferably. In the formula, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ each independently represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, but an alkyl group or alkenyl group having 1 to 5 carbon atoms. Are particularly preferred as formulas (a) to (e).
[0032]
In invention 10, the compound of general formula (I) contains one or more compounds, the content is in the range of 5 to 40% by mass, and one compound of general formula (III-a) or Containing two or more, the content of which is in the range of 5 to 40% by mass, and containing one or more compounds of general formula (II-b) or general formula (II-c), The content is in the range of 5 to 60% by mass, but preferably contains one or two compounds of the general formula (I) and the content is in the range of 5 to 20% by mass. The content of -a) is preferably in the range of 5 to 35% by mass, more preferably in the range of 5 to 25% by mass, of the general formula (II-b) or the general formula (II-c) The content is preferably in the range of 5 to 55% by mass, and more preferably in the range of 5 to 45% by mass.
[0033]
In invention 11, one or more compounds of the general formula (I) are contained, the content thereof is in the range of 5 to 40% by mass, and one or more compounds of the general formula (III-a) Containing two or more, the content is in the range of 5 to 40% by mass, and contains one or more compounds of general formula (II-b) and general formula (II-c), Each content is in the range of 5 to 40% by mass, but preferably contains one or two compounds of general formula (I) and the content is in the range of 5 to 20% by mass. Each containing at least one compound of (II-b) and general formula (II-c), the content of which is in the range of 5 to 20% by mass, and further two or more compounds of general formula (III-a) The content is preferably in the range of 5 to 25% by mass.
[0034]
In the invention 12, the general formula (III) or the general formula (III-a) contains one or more compounds selected from the general formula (III-b), and the content thereof is 5 to 40% by mass. It is preferable that the content of the compound of the general formula (III-b) is 1 to 10 and the content thereof is in the range of 5 to 35% by mass, the content is 1 to 5 and the content is 5 More preferably, it is in the range of ˜30% by mass. In the formula, R ¹² represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and the formulas (a) to (e) are particularly preferable as the alkyl group or alkenyl group having 1 to 5 carbon atoms.
[0035]
In Invention 13, as general formula (III) or general formula (III-a), one or more compounds selected from general formula (III-c) are contained, and the content thereof is 5 to 40% by mass. It is preferable that the content of the compound of the general formula (III-c) is 1 to 10 and the content is in the range of 5 to 35% by mass, the content is 1 to 5 and the content is 5 More preferably, it is in the range of ˜30% by mass. In the formula, R ¹² represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, preferably an alkenyl group, among which formulas (a) to (e) are particularly preferable.
[0036]
In invention 14, although it contains general formula (Ia), the content is preferably in the range of 5 to 40% by mass, more preferably in the range of 5 to 20% by mass.
The nematic liquid crystal composition is useful for TN-LCD and STN-LCD, but is particularly useful for STN-LCD. Further, it can be used for a transmissive or reflective liquid crystal display element. The liquid crystal composition of the present invention may contain a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal and the like in addition to the above compounds.
【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 and comparative examples means “mass%”.
[0037]
In the examples, the measured characteristics are as follows.
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 6μm is constructed
Δε: Dielectric anisotropy Δn: Birefringence index γ: Ratio of applied voltage at 90% luminance and 10% measured with 240 ° twist cell
(Steepness)
dV / dT: Temperature dependence of threshold voltage
The STN-LCD display element was created as follows. A chiral substance `` S-811 '' (Merck) was added to the nematic liquid crystal composition to prepare a mixed liquid crystal, and an organic film of `` Sunever 610 '' (Nissan Chemical) was rubbed on the opposing flat transparent electrode. Then, it was injected into an STN-LCD display cell having a twist angle of 240 ° on which an alignment film was formed. 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 = 0.50 by adding the chiral material.
The following abbreviations are used in the description of compounds.

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For example, abbreviations are used as shown below.
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[0038]
(Example 1, Example 2, Comparative Example 1)
Table 1 shows the results of preparing nematic liquid crystal compositions No. 1 and No. 2 and measuring various properties of the compositions together with Comparative Example 1.
[Table 1]

In Example 1, 4-Ph-Z-Ph-O2 and 5-Ph-Z-Ph-O1 in Comparative Example 1 were replaced with 3-Cy-VO-Np-2, which is a compound of general formula (I) Thus, in Example 2, Examples 1 and 2 were produced by substituting 3-Ph-VO-Np-2, respectively. As a result, it is possible to obtain a decrease in threshold voltage Vth compared to Comparative Example 1 even though Δε hardly changes. It can be seen that the region (25 to 40 ° C.) is improved.
[0039]
(Example 3)
The liquid crystal compositions of Comparative Example 1 and Example 1 were injected into a 240 ° twisted STN-LCD display cell, respectively. The STN characteristics were compared, but the liquid crystal composition of Example 1 was injected as in the case of TN. The voltage temperature dependence dV / dT was reduced.
【Effect of the invention】
By the combination of the liquid crystal materials of the present invention, a liquid crystal composition having a high dielectric anisotropy having a high temperature dependency and a high response speed was obtained. Moreover, when this composition was used as a liquid crystal display element, the threshold voltage was low and excellent. This liquid crystal display is very useful as STN and TN-LCD.

Claims

General formula (I) as the first component

(In the formula, R and R ^{1 each} represent an alkyl group or alkoxyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or an alkenyloxy group having 3 to 16 carbon atoms, and each ring P is independent. 1,4-phenylene group, 2-methyl-1,4-phenylene group, 3-methyl-1,4-phenylene group or trans-1,4-cyclohexylene group which may be optionally substituted by a fluorine atom. represents, L is a single _{_{bond, -CH 2 CH 2 -, -}} (CH 2) 4 -, - OCH 2 -, - CH 2 O -, - CH = CH- or -COO- the stands, k is 1, 2 Or in the case where k is 2 or 3, the rings P may be the same or different from each other. A compound selected from the group consisting of one or more compounds and a general formula (III) as a third component

Wherein R ² , R ³ and R ⁴ are each independently an alkyl group or alkoxyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or an alkenyloxy group having 3 to 16 carbon atoms. Or an alkyl group having 1 to 12 carbon atoms substituted with an alkoxyl group having 1 to 10 carbon atoms, and ring A, ring B, ring C, ring D and ring E are each independently substituted with a fluorine atom. 1,4-phenylene group, 2-methyl-1,4-phenylene group, 3-methyl-1,4-phenylene group, phenanthrene-2,7-diyl group, fluorene-2,7-diyl Group, trans-1,4-cyclohexylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group, trans-1,3-dioxane-2 , 5-diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-diyl group or pyridazine-2,5-diyl group, l and m each independently represent 0, 1 or 2, Z ¹ , Z ² , Z ³ and Z ⁴ are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —CH═CH—, —COO— or —C≡C—, wherein X ² is a cyano group, a fluorine atom, a chlorine atom, a trifluoromethoxy group, or a trifluoromethyl group. Represents a difluoromethoxy group, a hydrogen atom or a 3,3,3-trifluoroethoxy group , and X ¹ and X ³ each represents a hydrogen atom, a fluorine atom or a chlorine atom.) And the nematic phase upper limit temperature is 60 ° C. or higher, the nematic lower limit temperature is −20 ° C. or lower, and the refractive index anisotropy (Δn) is in the range of 0.07 to 0.30. Liquid crystal composition.

One or more compounds of the general formula (I) are contained, the content is in the range of 5 to 40% by mass, and further selected from the compounds of the general formula (II) and general formula (III), respectively. 2. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more kinds, and the content of the selected compound is in the range of 5 to 95% by mass.

As a compound of general formula (II), ring A and ring B are trans-1,4-cyclohexylene groups, and Z ¹ and Z ² are single bonds.

(Wherein R ⁵ and R ⁶ represent the same meaning as R ² and R ³ , ring F represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and n represents 0 or 1) 3. The liquid crystal composition according to claim 1, wherein the liquid crystal composition comprises one or more compounds selected from.

The content of the general formula (I) is in the range of 5 to 40% by mass, and the second component contains one or more compounds of the general formula (II-a), and the content is 15 to 85 4. The liquid crystal composition according to claim 3, wherein the liquid crystal composition is in a range of mass%.

As a compound of general formula (III), ring D is a trans-1,4-cyclohexylene group, Z ³ and Z ⁴ are single bonds, and m = 1, general formula (III-a)

(Wherein R ⁷ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, ring G represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and ⁵ represents a cyano group, a fluorine atom, a trifluoromethoxy group, or a difluoromethoxy group, and X ⁴ and X ⁶ each independently represent a hydrogen atom or a fluorine atom.) 5. The liquid crystal composition according to any one of claims 1 to 4, which is contained.

The content of the general formula (I) is in the range of 5 to 40% by mass, and one or more compounds of the general formula (III-a) are contained, and the content is 15 to 85 % by mass. 6. The liquid crystal composition according to claim 5, wherein the liquid crystal composition is in a range.

1 type or 2 types or more of the compound of general formula (I), the content rate is the range of 5-40 mass%, and also general formula (II-b)

(Wherein R ⁸ and R ⁹ represent the same meaning as R ² and R ³ , r represents 0 or 1), and the content is 5 or more. 7. The liquid crystal composition according to claim 1, wherein the liquid crystal composition is in a range of ˜60% by mass.

1 type or 2 types or more of the compound of general formula (I), the content rate is the range of 5-40 mass%, and also general formula (II-c)

(Wherein R ¹⁰ and R ¹¹ represent the same meaning as R ² and R ³ ), and contain one or more compounds selected from the group, and the content thereof is in the range of 5 to 60% by mass. The liquid crystal composition according to claim 1, wherein:

Contains one or more compounds of general formula (I), the content of which is in the range of 5-40% by mass, and contains one or more compounds of general formula (II-b) The content is in the range of 5 to 60% by mass, and the compound of general formula (II-c) contains one or more compounds, and the content is in the range of 5 to 60% by mass. 9. The liquid crystal composition according to claim 7, wherein the liquid crystal composition is characterized in that

Contains one or more compounds of general formula (I), the content of which is in the range of 5 to 40% by mass, and contains one or more compounds of general formula (III-a) And the content thereof is in the range of 5 to 40% by mass, and contains one or more compounds of the general formula (II-b) or general formula (II-c), and the content is 5 10. The liquid crystal composition according to claim 7, wherein the liquid crystal composition is in the range of ˜60 mass%.

1 type or 2 types or more of the compound of general formula (I) is contained in the range of 5-40 mass%, and 1 type or 2 types or more of compounds of general formula (III-a) are contained. Containing, in the range of 5 to 40% by mass, and containing one or more compounds of general formula (II-b) and general formula (II-c), the content is 11. The liquid crystal composition according to claim 10, wherein the range is 5 to 40% by mass.

General formula (III-b) as general formula (III) or (III-a)

(Wherein R ¹² represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms), and the content thereof is 5 or more. 12. The liquid crystal composition according to claim 1, which is in a range of ˜40% by mass.

General formula (III-c) as general formula (III) or (III-a)

(Wherein R ¹² represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms), and the content thereof is 5 to 5 12. The liquid crystal composition according to claim 1, wherein the liquid crystal composition is in a range of 40% by mass.

General formula (I) is general formula (Ia)

(Wherein R ¹³ and R ¹⁴ represent an alkyl group or alkoxyl group having 1 to 16 carbon atoms, and ring Q represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group). 14. The liquid crystal composition according to any one of claims 1 to 13, wherein the liquid crystal composition contains one or more compounds and has a content of 5 to 40% by mass.

Furthermore, as an additional component, the general formula (III-c) as general formula (III) or (III-a)

(Wherein R ¹² represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms), and the content thereof is 5 to 5 15. The liquid crystal composition according to claim 14, wherein the liquid crystal composition is 40% by mass.

A liquid crystal display device using the liquid crystal composition according to claim 1.

A super twisted nematic (STN) liquid crystal display element using the liquid crystal composition according to claim 1 and having a twist angle of 180 ° to 270 °.