JP2004331848A - Liquid crystal orientation-controlling agent, method for orientating liquid crystalline molecule, liquid crystal composition and liquid crystal element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal orientation-controlling agent excellent in heat resistance and electric properties and readily vertically carrying out orientation control of a liquid crystalline material in a liquid crystal element such as liquid display and to provide a method for orientating the liquid crystalline molecule and to provide a liquid crystalline composition and the liquid crystal element using those. <P>SOLUTION: The liquid crystal orientation-controlling agent comprises a carbon cluster derivative represented by general formula (I) (R are each independently a substituent group containing totally two or more of hydrocarbon ring and/or heterocyclic ring or a vinyl group having a substituent group). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００１１】
（式中、Ｒは各々独立に、炭化水素環および／または複素環を合計で２個以上含有する置換基、あるいは置換基を有するビニル基を示す。）
本発明の第二の要旨は、前記一般式（Ｉ）において、Ｒが各々独立に、下記一般式（ＩＩ）または（ＩＩＩ）で表わされる炭素クラスター誘導体を含有する液晶配向制御剤に存する。
【００１２】
【化５】

【００１３】
（式中、Ｘ^１ およびＸ^２ はそれぞれ独立に、置換基を有していても良い４〜７員環である炭化水素環または複素環の、単環または２〜３縮合環からなる２価の連結基を表わし、
Ｙ^１およびＹ^２はそれぞれ独立に直接結合または鎖状で２価の連結基を表わし、
Ｘ^３ は置換基を有していても良い４〜７員環である炭化水素環または複素環の単環または２〜３縮合環からなる１価の基を示す。ａは０〜２の整数を示す。）
【００１４】
【化６】

【００１５】
（式中、Ｗ^１ は、
−ＣＨ＝ＣＨ−，―ＣＨ_２−Ｓｉ（ＣＨ_３）_２−，または―ＣＨ_２−Ｃ（ＣＨ_３）_２−を表わし、
Ｘ^４ およびＸ^５ はそれぞれ独立に、置換基を有していても良い４〜７員環である炭化水素環または複素環の、単環または２〜３縮合環からなる２価の連結基または直接結合を表わし、
Ｙ^３およびＹ^４はそれぞれ独立に直接結合または鎖状で２価の連結基を表わし、
Ｘ^６ は置換基を有していても良い４〜７員環である炭化水素環または複素環の、単環または２〜３縮合環からなる１価の基、あるいは置換基を有していても良い鎖状炭化水素基（但し、該炭化水素基における１以上のメチレン基は、−Ｏ−、−Ｓ−、または−ＣＯＯ−で置換されていてもよい）を示す。
ｂは０〜２の整数を示す。）
本発明の第三の要旨は、基板上または基板間に形成された、液晶性分子を含む液晶層における、該液晶分子を配向させる方法であって、該液晶層および／または該液晶層に隣接する層に前記一般式（Ｉ）で表される炭素クラスター誘導体を含有させ、該炭素クラスター誘導体の作用により液晶性分子の配向を制御することを特徴とする、液晶性分子の配向方法に存する。
【００１６】
本発明の第四の要旨は、前記一般式（Ｉ）で表される炭素クラスター誘導体、または該炭素クラスター誘導体をモノマーとする重合体を用いて形成された層を、液晶層に隣接して形成することにより、液晶性分子の配向を制御することを特徴とする、液晶性分子の配向方法に存する。
本発明の第五の要旨は、液晶性分子を含有する組成物中に、さらに前記一般式（Ｉ）で表される炭素クラスター誘導体を含有させ、該炭素クラスター誘導体の作用により液晶性分子の配向を制御することを特徴とする、液晶組成物に存する。
【００１７】
本発明の第六の要旨は、基板上に形成された液晶性分子を含有する液晶層および／または該液晶層に隣接する層に、前記一般式（Ｉ）で表される炭素クラスター誘導体を含有させ、該炭素クラスター誘導体の作用により液晶性分子を配向させてなる、液晶素子に存する。
なお、液晶性分子の配向方法、すなわち、界面分子配向機構は種々の原因の複合であるため（岡野光治、小林俊介編；「液晶＝応用編」培風館（１９８５年）、第５２頁〜第８３頁参照）、炭素クラスター誘導体の作用を詳細に論ずることは困難であるが、炭素クラスター誘導体分子の異方性、極性が配向に寄与していると推察している。すなわち、液晶層に本発明の炭素クラスター誘導体を添加した場合は、液晶組成物に炭素クラスター誘導体を添加して、液晶セルの一方からそれを注入することにより、基板上では炭素クラスター誘導体分子の極性により炭素クラスター誘導体が早く基板表面に吸着し、「クロマトグラフィ効果」により垂直配向が得られる。また、液晶層に隣接した層に本発明の炭素クラスター誘導体を添加した場合は、炭素クラスター誘導体分子の異方性、極性により液晶層の液晶性分子との排除体積最少効果や表面張力効果により垂直配向が得られる。
【００１８】
【発明の実施の形態】
本発明において、液晶配向制御剤（以下、単に「配向制御剤」と称することがある。）として用いられる炭素クラスター誘導体分子は、 ６０個の炭素原子から成るＣ_６０バックミンスターフラーレン（フラーレンＣ_６０）からなる炭素クラスター部位と、この炭素クラスター部位に置換される長さが１０Å以上、好ましくは長さ２０Å以上の置換基にて構成される。
【００１９】
長さ１０Å以上の置換基は、例えば４〜７員環である炭化水素環または複素環の、単環または２〜３縮合環を少なくとも２つ以上有する置換基や、置換基を有するビニル基により構成される。なお、ビニル基が有する置換基としては、４〜７員環である炭化水素環および／または複素環を含む基が好ましい。
本発明の炭素クラスター誘導体として具体的には、前述のように、下記一般式（Ｉ）で表される骨格を有し、Ｃ_６０Ｒ_５Ｈ（但し、Ｒは同一であっても異なっていてもよい）で表される化合物が挙げられる。
【００２０】
【化７】

【００２１】
（式中、Ｒは各々独立に、炭化水素環および／または複素環を合計で２個以上含有する置換基、あるいは置換基を有するビニル基を示す。）
Ｒは、上記定義を満たし、本発明の趣旨を逸脱しない限り特に制限はないが、前述のように、例えば各々独立に、下記一般式（ＩＩ）または一般式（ＩＩＩ）で表わされる構造が挙げられる。
【００２２】
【化８】

【００２３】
（式中、Ｘ^１ およびＸ^２ はそれぞれ独立に、置換基を有していても良い４〜７員環である炭化水素環または複素環の、単環または２〜３縮合環からなる２価の連結基を表わし、
Ｙ^１およびＹ^２はそれぞれ独立に直接結合または鎖状で２価の連結基を表わし、
Ｘ^３ は置換基を有していても良い４〜７員環である炭化水素環または複素環の単環または２〜３縮合環からなる１価の基を示す。ａは０〜２の整数を示す。）
【００２４】
【化９】

【００２５】
（式中、Ｗ^１ は、
−ＣＨ＝ＣＨ−，―ＣＨ_２−Ｓｉ（ＣＨ_３）_２−，または―ＣＨ_２−Ｃ（ＣＨ_３）_２−を表わし、
Ｘ^４ およびＸ^５ はそれぞれ独立に、置換基を有していても良い４〜７員環である炭化水素環または複素環の、単環または２〜３縮合環からなる２価の連結基または直接結合を表わし、
Ｙ^３およびＹ^４はそれぞれ独立に直接結合または鎖状で２価の連結基を表わし、
Ｘ^６ は置換基を有していても良い４〜７員環である炭化水素環または複素環の、単環または２〜３縮合環からなる１価の基、あるいは置換基を有していても良い鎖状炭化水素基（但し、該炭化水素基における１以上のメチレン基は、−Ｏ−、−Ｓ−、または−ＣＯＯ−で置換されていてもよい）を示す。ｂは０〜２の整数を示す。）
前記一般式（ＩＩ）および前記一般式（ＩＩＩ）のＸ^１ 〜Ｘ^５ における炭化水素環または複素環としてはそれぞれ独立に、例えば、
【００２６】
【化１０】

【００２７】
などが挙げられる。中でも、Ｘ^１およびＸ^４としては好ましくは、各々独立に
【００２８】
【化１１】

【００２９】
などが挙げられ、さらに好ましくは、
【００３０】
【化１２】

【００３１】
が挙げられる。ａ＝１の場合のＸ^２、およびｂ＝１の場合のＸ^５として好ましくは、各々独立に、
【００３２】
【化１３】

【００３３】
が挙げられる。Ｙ^１〜Ｙ^４としては各々独立に、例えば、
−ＣＯＯ−，−ＯＣＯ−，−ＯＣＨ_２−，−ＣＨ＝Ｎ−，−ＣＨ＝ＣＨ−，
−Ｃ≡Ｃ−，−Ｏ−，−ＣＯＳ−，−ＣＯＮＨ−，−Ｎ＝Ｎ−，または直接結合がなど挙げられ、好ましくは、
−ＣＯＯ−，−ＯＣＯ−，−ＯＣＨ_２−，
Ｘ^１ とＸ^２ あるいはＸ^１ とＸ^３が直接結合するもの（Ｙ^１が直接結合であり、ａが１または０である場合に相当）、
Ｘ^４ とＸ^５ あるいはＸ^４ とＸ^６が直接結合するもの（Ｙ^２が直接結合であり、ｂが１または０である場合に相当）
が挙げられ、さらに好ましくは、−ＯＣＯ−が挙げられる。
【００３４】
Ｘ^３およびＸ^６が炭化水素環または複素環である場合の例としては、例えば、
【００３５】
【化１４】

【００３６】
などが挙げられ、好ましくは、
【００３７】
【化１５】

【００３８】
などが挙げられ、さらに好ましくは、
【００３９】
【化１６】

【００４０】
などが挙げられる。ここで、上記各構造中、ｃはＺ^１基の数を表し、通常０〜３程度である。またｃが２以上の場合、一つのＸ^３またはＸ^６における複数個のＺ^１は、同一であっても異なっていてもよい。
Ｚ^１としては、フッ素原子、塩素原子等のハロゲン原子；シアノ基；ニトロ基；メチル基、エチル基、ｎ−プロピル基、ｎ−ドデシル基、ｎ−テトラデシル基、ｎ−ペンタデシル基、ｎ−ヘキサデシル基、ｎ−オクタデシル基等の炭素数１〜２０のアルキル基；ジフルオロメチル基、トリフルオロエチル基、ペンタフルオロペンチル基等の炭素数１〜１２のアルキル基にフッ素原子等のハロゲン原子が置換されたハロゲン置換アルキル基；メトキシ基、エトキシ基、ｎ−プロポキシ基など上記アルキル基に対応した炭素数１〜２０のアルコキシ基；トリフルオロエトキシ基、ジフルオロエトキシ基等の炭素数１〜１２のアルコキシ基にフッ素原子等のハロゲン原子が置換されたハロゲン置換アルコキシ基；メトキシメチル基、メトキシエチル基、メトキシブチル基、エトキシメチル基、エトキシエチル基又はエトキシブチル基等の炭素数２〜２０のアルコキシアルキル基；―Ｏ（Ｃ_ｋＨ_２ｋＯ）_ｎ（ｋ＝１〜３、ｎ＝２〜２０）で表されるポリアルキレンオキシド基；ビニル基、アリル基、１−プロペニル基、１−ブテニル基、２−ブテニル基等の炭素数１〜２０の直鎖状もしくは分枝状のアルケニル基；メトキシカルボニル基、エトキシカルボニル基等の炭素数１〜２０の直鎖状もしくは分枝状のカルボン酸エステル基；メチルチオ基、エチルチオ基、ｎ−プロピルチオ等の炭素数１〜２０のアルキルチオ基が挙げられる。更に、これらのアルキル基、アルコキシ基、アルコキシアルキル基、ポリアルキレンオキシド基、アルケニル基、カルボン酸エステル基はエポキシ基、アクリル基、ビニル基などの重合性基、特にラジカル反応性の重合性基で置換されていても良い。またＺ^１の例としては、ここに挙げた基を置換基として有するポリオルガノシロキサン基も挙げられる。
【００４１】
置換基Ｚ^１のうち好ましいものとしては炭素数１０〜２０の直鎖状アルコキシ基が挙げられ、さらに好ましくは炭素数１２〜１８の直鎖状アルコキシ基が挙げられる。置換基Ｚ^１の数ｃに特に制限はなく、前述したように、通常０〜３個程度であればよいが、置換基Ｒ全体における炭化水素環および複素環の数が２の場合、ｃ＝２が好ましい。
【００４２】
Ｘ^６が鎖状の炭化水素基（但し、該炭化水素基における１以上のメチレン基は、−Ｏ−、−Ｓ−、または−ＣＯＯ−で置換されていてもよい）である場合、例えばメチル基、エチル基、ｎ−プロピル基、ｎ−ドデシル基、ｎ−テトラデシル基、ｎ−ペンタデシル基、ｎ−ヘキサデシル基、ｎ−オクタデシル基などの炭素数１〜２０の直鎖又は分岐置換基を有していてもよいアルキル基；ジフルオロメチル基、トリフルオロエチル基、ペンタフルオロペンチル基等の炭素数１〜１２のアルキル基にフッ素原子等のハロゲン原子が置換されたハロゲン置換アルキル基；メトキシ基、エトキシ基、ｎ−プロポキシ基など上記アルキル基に対応した炭素数１〜２０のアルコキシ基；トリフルオロエトキシ基、ジフルオロエトキシ基等の炭素数１〜１２のアルコキシ基にフッ素原子等のハロゲン原子が置換されたハロゲン置換アルコキシ基；メトキシメチル基、メトキシエチル基、メトキシブチル基、エトキシメチル基、エトキシエチル基又はエトキシブチル基等の炭素数２〜２０のアルコキシアルキル基；―Ｏ（Ｃ_ｋＨ_２ｋＯ）_ｎ（ｋ＝１〜３、ｎ＝２〜２０）で表されるポリアルキレンオキシド基；ビニル基、アリル基、１−プロペニル基、１−ブテニル基、２−ブテニル基等の炭素数１〜２０の直鎖状もしくは分枝状のアルケニル基；メトキシカルボニル基、エトキシカルボニル基等の炭素数１〜２０の直鎖状もしくは分枝状のカルボン酸エステル基；メチルチオ基、エチルチオ基、ｎ−プロピルチオ等の炭素数１〜２０のアルキルチオ基、などを表す。これらはＺ^１基として前述した基で置換されていてもよい。
【００４３】
Ｘ^６としては、上記炭化水素環基、複素環基、および鎖状炭化水素基（但し、該炭化水素基における１以上のメチレン基は、−Ｏ−、−Ｓ−、または−ＣＯＯ−で置換されていてもよい）のうち、置換基を有していてもよい炭化水素環基または複素環基が好ましい。置換基を有していてもよい炭化水素環基および複素環基のうち、好ましいものは前述の通りである。
【００４４】
一般式（Ｉ）におけるＲとして好ましくは、一般式（ＩＩ）で表される場合であり、より好ましくは式（ＩＩ）におけるａ＝０であり、式（ＩＩ）中の炭化水素環基および複素環基の数が２個である場合である。
なお、一化合物中の５個のＲは、同一であっても異なっていてもよいが、合成が容易である点からは全て同じであることが好ましい。
【００４５】
前記一般式（Ｉ）で表される炭素クラスター誘導体において、置換基Ｒの具体例を下記［表１］に示すが、これに限定されるものではない。
【００４６】
【表１】

【００４７】
【表２】

【００４８】
なお、［表１］に示される化合物は、本発明の実施例に記載の方法や特開平１０−１６７９９４号公報、特開平１１−２５５５０９号公報、特願２００１−３４４６１６などに記載の方法、またはこれらに準ずる公知の方法にて製造できる。
本発明の炭素クラスター誘導体を含有する液晶配向制御剤は、例えばトルエン、クロロホルム、クロロベンセンなどの溶媒に炭素クラスター誘導体と、必要に応じて後述する任意成分などを溶解させた後、スピンコートやバーコートなどの公知の塗布方法により塗布・乾燥することにより、配向制御層を形成することができる。この配向制御層は、液晶性分子を含有する液晶層に隣接して設けることにより、液晶層に含まれる液晶性分子を配向させることが出来るため、後述する各種用途に供することが可能である。また、前記炭素クラスター誘導体を含有する配向制御剤を塗布した基板に、紫外線等の放射性を照射したり、加熱することにより、該炭素クラスター誘導体を重合させ、重合体（２量体やそれ以上の多量体）としてもよい。
【００４９】
本発明の液晶配向制御剤、およびこれを用いて形成される配向制御層は、前記炭素クラスター誘導体を複数種含有していても良く、また本発明の趣旨を逸脱しない範囲で、該炭素クラスター誘導体以外の配向制御剤を含有していても良い。更に、各種添加剤を含んでいても良い。各種添加剤には、各種バインダー樹脂、導電性ポリマーなど配向制御層が光電荷発生層としても機能するためのドナー性物質、官能性重合基を有するモノマーなどの添加剤が挙げられる。
【００５０】
本発明の配向制御剤、および該配向制御剤を用いて形成された配向制御層における炭素クラスター誘導体の濃度は、配向制御機能の発現に支障のない範囲で適宜選択される。具体的には、該誘導体自身の溶剤への溶解性、他の各種添加剤成分の種類や濃度により、各々適正な範囲が決まるが、通常は０．１から１０重量％程度、好ましくは０．５〜３重量％程度である。
【００５１】
本発明の配向制御層により配向制御される液晶層は、液晶表示用のネマチック相、コレステリック相、スメクチック相、ディスコチック相などの公知の相を示す低分子液晶や主鎖型高分子系液晶、側鎖型高分子系液晶、重合性モノマー液晶などの高分子液晶の他、光空間変調素子などの液晶性物質を用いた液晶光学素子や、液晶性物質を配向させた有機半導体素子、有機太陽電池、有機エレクトロルミネッセンス素子などにも使用することができる。
【００５２】
本発明の液晶組成物は、液晶性分子を含む組成物に、前記一般式（Ｉ）で表される炭素クラスター誘導体を含有させることにより、配向制御機能を発現することができる。該組成物における液晶相の種類としては、ネマチック相、コレステリック相、スメクチック相、ディスコチック相などの公知の相を示す低分子液晶や主鎖型高分子系液晶、側鎖型高分子系液晶、重合性モノマー液晶などの高分子液晶等を使用することができる。
【００５３】
公知の液晶性物質（液晶性分子）を用いる場合、具体的には日本学術振興会第１４２委員会編；「液晶デバイスハンドブック」日本工業新聞社（１９８９年）、第１５２頁〜第１９２頁および液晶便覧編集委員会編； 「液晶便覧」丸善株式会社（２０００年） 、第２６０頁〜第３３０頁に記載されているようなビフェニル系、フェニルシクロヘキサン系、フェニルピリミジン系、シクロヘキシルシクロヘキサン系などの各種低分子系の化合物または混合物を使用することができる。また、液晶便覧編集委員会編； 「液晶便覧」丸善株式会社（２０００年）、第３６５頁〜第４１５頁に記載されているような高分子系化合物または混合物を使用することができる。
【００５４】
本発明の液晶組成物には、カイラルドーパントや二色性色素やポリマー、重合剤、増感剤、紫外線吸収剤、安定剤などの各種添加剤を液晶組成物の配向性を損なわない範囲で含んでいても良い。
本発明の液晶組成物における、前記炭素クラスター誘導体の含有量としては、液晶性物質に対して通常０．１〜５重量％、炭素クラスター誘導体の液晶性物質へ対する溶解性や炭素クラスター誘導体の可視光吸収強度などから好ましくは０．５〜３重量％である。
【００５５】
本発明の液晶組成物は、液晶性物質と炭素クラスター誘導体および必要に応じて添加される各種添加剤を振盪などの操作により混合、溶解させることによって容易に得ることができる。
本発明において、例えば液晶表示素子に用いられる液晶組成物における、液晶性分子として好ましい液晶性物質としては、棒状（ロッド状）の分子形状を有するネマチック液晶およびスメクチック液晶、盤状（ディスク状）の分子形状を有するディスコチック液晶、これらの分子をメソゲン基として有する高分子液晶が挙げられ、より好ましくは下記に例示されるものが挙げられるが、本発明は何ら以下のものに限定されるものではない。
【００５６】
【化１７】

【００５７】
（上記各式中、Ｒ^ａは炭素数１〜１０のアルキル基、アルコキシ基、アルコキシアルキル基、またはアルケニル基を表わし、Ｒ^ｂはシアノ基；フッ素原子、塩素原子などのハロゲン原子；フッ素原子、塩素原子などのハロゲン原子を置換基として有する炭素数１〜１０の置換アルキル基、置換アルコキシ基、置換アルコキシアルキル基、または置換アルケニル基；炭素数１〜１０のアルキル基、アルコキシ基、アルコキシアルキル基、またはアルケニル基を表わす。また、上記各式中におけるベンゼン環またはシクロヘキサン環はシアノ基、フッ素原子、または塩素原子により置換されていても良い。）
さらにＶＡ方式などの液晶表示素子において好ましくは、分子の側方位にフッ素が置換された誘電異方性が負の液晶が挙げられる。
本発明の炭素クラスター誘導体を含有する配向制御剤、および炭素クラスター誘導体を含む液晶組成物は、液晶セルへの注入により液晶セルの基板表面に付着し、垂直配向が得られる。また、より均一な配向を得るために、配向制御剤および／または液晶組成物注入済みの液晶セルを加熱、エージング処理してもよい。
【００５８】
さらに、液晶配向後のセルに、紫外線などの放射線を照射して、炭素クラスター誘導体を重合させ、重合体（多量体）を形成してもよい。
ただ、液晶組成物を基板間（液晶セル内）に注入して使用する場合、炭素クラスター誘導体への放射線照射処理は、通常、液晶組成物のセルへの注入後に行われる。この場合、液晶セル基板による放射線の吸収により、重合化が効率よく行われない可能性があること、また放射線による液晶材料の劣化が生じるおそれがあるため注意が必要である。従って、放射線照射処理を行う場合、炭素クラスター誘導体は、液晶層に隣接した配向制御層に含有させることが好ましい。また、液晶層に隣接して形成された配向制御層に、炭素クラスター誘導体を含有させた場合には、配向の熱安定性の観点から紫外線処理を施すことが好ましい。
【００５９】
本発明は炭素クラスター誘導体は、例えば液晶素子の製造プロセスの簡略化の観点では、予め配向層を形成する必要がないので液晶層に添加した方が好ましい。一方、広視野角化などの表示品位の観点では、液晶層に隣接した層（配向制御層）に含有させた方が、ＭＶＡ方式などのマルチドドメイン処理による後処理工程が加えられるため好ましい。
【００６０】
本発明は、ＶＡ方式などの液晶表示素子のほか、液晶便覧編集委員会編； 「液晶便覧」丸善株式会社（２０００年）、第５１１頁〜第５１５頁に記載されているような空間光変調器や日本学術振興会第１４２委員会編；「液晶デバイスハンドブック」日本工業新聞社（１９８９年）、第６３３頁〜第６３４頁に記載されているような液晶ライトバルブなどの各種素子に使用することができる。この場合、素子構成などにより炭素クラスター誘導体が配向制御の他に光導電機能を併せ持つことも可能である。
【００６１】
このようにして得られた本発明の炭素クラスター誘導体からなる配向制御剤および炭素クラスター誘導体を含有する組成物は優れた配向制御能と電気的、化学的安定性などの各種特性を有し、各種液晶表示素子、液晶光学素子や光電変換素子等に応用できる。
【００６２】
なお、液晶性分子の配向機構、すなわち基板界面における液晶性分子の配向メカニズムは種々の要因の複合であるため、本発明の配向制御剤を用いた素子の構成や製造プロセスの種類・方法により、配向制御剤の好ましい範囲を限定することは困難であるが、配向の強さに関係する液晶性分子との相互作用は、公知の界面活性剤やシラン化剤による化学吸着（配向処理）の事例からも、炭素数が１０〜２０程度の末端基があることが重要と思われる。但し、単にフレキシブルな基が炭素クラスターＣ_６０に置換したのでは、基板に対して垂直方向に置換基が伸びている状態にはなり難いので、配向秩序は高くならないと考えられる。そこで、環構造などの排除体積効果が期待できる嵩高い構造を有することが好ましい。
【００６３】
さらに、本発明の炭素クラスター誘導体が基板表面で多分子の積層を形成している場合にも、末端基（即ち、一般式におけるＲ）が基板に対して規則性や方向性をもった状態となるためには、該炭素クラスター誘導体がスタッキングするための「ＣＨ／π相互作用」が期待できる、環構造が存在することが好ましいと考えられる。
【００６４】
【実施例】
以下に本発明を実施例により具体的に説明するが、本発明の要旨を超えない限り以下の実施例に制約されるものではない。
［実施例１］
例示化合物［Ｉ−１］ １０ｍｇをトルエンに溶解させ、１重量％のトルエン溶液を調製した。このトルエン溶液をスピンコーターを用いてＩＴＯ付きガラス基板に塗布して、配向制御層付き基板を作製した。さらに、この基板を基板間が１０μｍとなるように配向制御層を内向きに対向させて液晶セルを作製した。この液晶セルに、商品名ＬＳＢ−３３５（三菱化学製）として市販されている二色性色素１％を含有する商品名ＭＬＣ−２０３９（メルク社製）として市販されているフッ素系液晶性物質を主成分とする誘電異方性が負の液晶混合物を注入して液晶素子を作製した。
【００６５】
この液晶素子の電界無印加時にコノスコープ観察したところアイソジャイヤーの黒い十字帯が観察され、垂直配向していることを確認した。さらに、この液晶素子に６０Ｈｚ、１０Ｖの矩形波を印加したところ、二色性色素ＬＳＢ−３３５の青色着色（吸収）変化が確認された。
【００６６】
［実施例２］
例示化合物［Ｉ−２］を実施例１と同様な方法によりトルエンに溶解した後、基板に塗布し、液晶セルを作製した。この液晶セルに商品名ＬＳＢ−３３５（三菱化学製）として市販されている二色性色素１％を含有する商品名ＭＬＣ−２０３９（メルク社製）として市販されている液晶混合物を注入した。
この液晶素子の電界無印加時にコノスコープ観察したところアイソジャイヤーの黒い十字帯が観察され、垂直配向していることを確認した。さらに、この液晶素子に６０Ｈｚ、１０Ｖの矩形波を印加したところ、二色性色素ＬＳＢ−３３５の青色着色（吸収）変化が確認された。
【００６７】
［実施例３］
例示化合物［Ｉ−１］を実施例１と同様な方法によりトルエンに溶解した後、基板に塗布した。この基板に高圧水銀灯（３００ｍＷ／ｃｍ^２）を用いて紫外線照射（１０Ｊ／ｃｍ^２）を行なった。紫外線照射後の基板上の例示化合物［Ｉ−１］膜は鉛筆引っ掻き強度（膜密着強度）およびトルエンに対する対溶出性が紫外線照射前に比べ向上していることが確認された。さらに、紫外線照射した基板を用いて実施例１と同様な方法により液晶セルを作製し、商品名ＭＬＣ−２０３９（メルク社製）として市販されている液晶混合物を注入した。
この液晶素子の電界無印加時にコノスコープ観察したところアイソジャイヤーの黒い十字帯が観察され、垂直配向していることを確認した。更に、この液晶注入済みセルを１４０℃下で１５分加熱した。加熱後、室温まで液晶セルを冷却し、偏光顕微鏡下で観察した結果、加熱による液晶の配向乱れは観察されなかった。
【００６８】
［実施例４］
例示化合物［Ｉ−２］を実施例３と同様な方法によりトルエンに溶解した後、基板塗布、紫外線照射を行ない、液晶セルを作製した。この液晶セルに商品名ＭＬＣ−２０３９（メルク社製）として市販されている液晶混合物を注入した。
この液晶素子の電界無印加時にコノスコープ観察したところアイソジャイヤーの黒い十字帯が観察され、垂直配向していることを確認した。更に、この液晶注入済みセルを１４０℃下で１５分加熱した。加熱後、室温まで液晶セルを冷却し、偏光顕微鏡下で観察した結果、加熱による液晶の配向乱れは観察されなかった。
【００６９】
［実施例５］
例示化合物 ［Ｉ−１］１０ｍｇを商品名ＭＬＣ−２０３９（メルク社製）として市販されている液晶混合物 １ｇに混合、振とう溶解させて液晶組成物を調製した。この液晶組成物を孔径が０．２μｍのＰＴＦＥ製フィルターで濾過したのち、透明電極付きガラス板からなり、電極面を対向させるように構成されたギャップ６μｍのセルに封入し液晶表示素子を作成した。
このセルをコノスコープ観察したところ、電界無印加時に垂直配向していることが確認された。更に、このセルを２５℃下で電圧５Ｖ、ＯＮ時間６０μｓｅｃ、フレーム周波数３０Ｈｚのパルス信号を印加し電圧保持率を測定した。この液晶素子の電圧保持率は８６．５％と良好な値を示した。以上の結果から、配向特性と駆動特性の両立した液晶素子を得ることができることを確認した。
【００７０】
［実施例６］
例示化合物 ［Ｉ−２］１０ｍｇを商品名ＭＬＣ−２０３９（メルク社製）として市販されている液晶混合物 １ｇに混合、振とう溶解させて液晶組成物を調製した。この液晶組成物を実施例５と同様な方法により濾過処理したのち透明電極付きガラス板で挟持して液晶素子を作製した。
このセルをコノスコープ観察したところ、電界無印加時に垂直配向していることが確認された。更に、この液晶素子の電圧保持率を実施例５と同様な方法により測定した結果、９４．８％と良好な値を示した。以上の結果から、配向特性と駆動特性の両立した液晶素子を得ることができることを確認した。
【００７１】
［実施例７］
例示化合物 ［Ｉ−３］１０ｍｇを商品名ＭＬＣ−２０３９（メルク社製）として市販されている液晶混合物 １ｇに混合、振とう溶解させて液晶組成物を調製した。この液晶組成物を実施例５と同様な方法により濾過処理したのち透明電極付きガラス板で挟持して液晶素子を作製した。
このセルをコノスコープ観察したところ、電界無印加時に垂直配向していることが確認された。この液晶素子の電圧保持率を実施例５と同様な方法により測定した結果、８９．２％と良好な値を示した。以上の結果から、配向特性と駆動特性の両立した液晶素子を得ることができることを確認した。
【００７２】
【発明の効果】
本発明の炭素クラスター誘導体からなる液晶配向制御剤、および該誘導体を含む組成物は、電気的、化学的安定性を有し、ＶＡ方式などの垂直配向型液晶表示素子や各種液晶表示素子、液晶光学素子等に応用できる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal alignment controlling agent, a method for controlling alignment of liquid crystal molecules, a liquid crystal composition, and a liquid crystal device. More specifically, the present invention relates to a vertical liquid crystal alignment controlling agent, a method for controlling vertical alignment of liquid crystal molecules, a liquid crystal composition, and a liquid crystal element.
[0002]
[Prior art]
Conventionally, the alignment control method of the liquid crystal element includes a rubbing method of mechanically rubbing a resin film such as polyimide or polyvinyl alcohol, a vacuum deposition method of SiO, and adding an alignment control agent to the liquid crystal material or applying a liquid crystal material to the substrate surface. Practical and studied chemical treatment methods have been used (for example, see Non-Patent Document 1). Of these, the rubbing method is widely used for liquid crystal elements, but since the alignment film is rubbed with a cloth, dust and static electricity are generated to lower the yield, or a cleaning step is required after rubbing, or the productivity is high. Did not. In addition, since the vacuum deposition method of SiO is a non-contact method, there is little possibility of static electricity, chemical contamination and destruction of a fine structure, but there is a problem in productivity by the deposition process.
[0003]
In particular, in recent years, along with an increase in the screen size, high quality such as a high viewing angle has been demanded. A new liquid crystal display system such as a VA (Vertical alignment) system has attracted attention as a system of a liquid crystal display element satisfying these requirements (for example, see Non-Patent Document 2). With respect to the liquid crystal alignment treatment agent and liquid crystal alignment treatment method used in these liquid crystal display devices and the like, new vertical alignment control agents and methods based on chemical treatment methods such as polysiloxane and pyridium quaternary salts have been proposed in addition to the rubbing method. (For example, see Patent Documents 2 to 5).
[0004]
These vertical alignment methods replace the classical methods such as the application of lecithin, amphiphilic surfactants, and organic silane agents.They are transparent, uniform in film thickness, heat resistance, liquid crystal alignment, and physical properties. It aims to obtain the performance required for many real devices such as electrical properties such as mechanical strength, chemical stability and voltage holding ratio, but the stability and lifetime of the orientation are unknown.
[0005]
On the other hand, fullerene C ₆₀ As a technique for adding carbon clusters typified by the above to a liquid crystal alignment film material or a liquid crystal material, a liquid crystal display device in which nanoparticles such as fullerene are added to a guest-host type liquid crystal material for the purpose of improving the contrast ratio (for example, see Patent Document 5), and a liquid crystal composition, an alignment film, and a liquid crystal element (for example, see Patent Documents 6 to 8) for the purpose of preventing flicker and burn-in of the element. In these technologies, fullerene particles in the liquid crystal material disturb the alignment of the liquid crystal material, thereby improving the contrast ratio of the device, and adding fullerenes to the alignment film or the liquid crystal material to reduce the ionic components in the liquid crystal material. The purpose is to trap, and the fullerenes do not function as an alignment controlling agent for the liquid crystal material.
[0006]
Furthermore, it has been found that the carbon cluster derivative used in the present invention spontaneously forms a liquid crystal structure, but it is mentioned that the carbon cluster derivative has a function of controlling the alignment of a liquid crystalline material. Not. (Japanese Patent Application 2001-344616)
[0007]
[Non-Patent Document 1] "Liquid crystal handbook" edited by Liquid Crystal Handbook Editing Committee Maruzen Co., Ltd., published on October 30, 2000, pages 226 to 232
[Non-Patent Document 2] "Liquid crystal handbook" edited by the liquid crystal handbook editing committee Maruzen Co., Ltd., issued on October 30, 2000, pages 501 to 511
[Patent Document 1] JP-A-9-281502
[Patent Document 2] JP-A-2002-327058
[Patent Document 3] JP-A-2002-303870
[Patent Document 4] JP-A-2002-38158
[Patent Document 5] JP-A-2001-337351
[Patent Document 6] JP-A-10-195444
[Patent Document 7] JP-A-11-223815
[Patent Document 8] JP-A-11-222593
[0008]
[Problems to be solved by the invention]
The present invention is directed to a liquid crystal element such as a liquid crystal display element, which has excellent heat resistance and electric characteristics and easily controls the liquid crystal material in a vertical direction, a liquid crystal molecule alignment method, a liquid crystal composition, and a liquid crystal composition. And a liquid crystal device using the same.
[0009]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a carbon cluster derivative having a specific molecular shape functions as a vertical alignment controlling agent for a liquid crystalline material. The present invention has been completed based on these findings.
That is, a first gist of the present invention resides in a liquid crystal alignment controlling agent containing a carbon cluster derivative represented by the following general formula (I).
[0010]
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[0011]
(In the formula, each R independently represents a substituent containing a total of two or more hydrocarbon rings and / or heterocycles, or a vinyl group having a substituent.)
A second gist of the present invention resides in a liquid crystal alignment controlling agent containing a carbon cluster derivative represented by the following general formula (II) or (III), wherein R in the general formula (I) is each independently.
[0012]
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[0013]
(Where X ¹ And X ² Each independently represents a divalent linking group consisting of a monocyclic or 2 to 3 condensed ring of a 4- to 7-membered hydrocarbon or heterocyclic ring which may have a substituent;
Y ¹ And Y ² Each independently represents a direct bond or a linear divalent linking group;
X ³ Represents a monovalent group of a hydrocarbon ring or a heterocyclic monocyclic ring or a condensed 2 to 3 condensed ring which is a 4- to 7-membered ring which may have a substituent. a shows the integer of 0-2. )
[0014]
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[0015]
(Where W ¹ Is
-CH = CH-, -CH ₂ -Si (CH ₃ ) ₂ -Or -CH ₂ -C (CH ₃ ) ₂ -
X ⁴ And X ⁵ Each independently represents a divalent linking group consisting of a monocyclic or condensed 2 to 3 condensed ring or a direct bond of a hydrocarbon ring or a heterocyclic ring which may have a substituent and is a 4- to 7-membered ring;
Y ³ And Y ⁴ Each independently represents a direct bond or a linear divalent linking group;
X ⁶ May have a substituent, may be a monovalent group of a hydrocarbon ring or a heterocyclic ring which is a 4- to 7-membered ring or a heterocyclic ring, or a monovalent or 2-3 condensed ring, or may have a substituent. It represents a chain hydrocarbon group (however, one or more methylene groups in the hydrocarbon group may be substituted with -O-, -S-, or -COO-).
b shows the integer of 0-2. )
A third gist of the present invention is a method for aligning liquid crystal molecules in a liquid crystal layer containing liquid crystal molecules formed on or between substrates, the method comprising the steps of: adjoining the liquid crystal layer and / or the liquid crystal layer; A carbon cluster derivative represented by the general formula (I) in a layer to be formed, and controlling the alignment of the liquid crystal molecules by the action of the carbon cluster derivative.
[0016]
A fourth gist of the present invention is that a layer formed using the carbon cluster derivative represented by the general formula (I) or a polymer using the carbon cluster derivative as a monomer is formed adjacent to a liquid crystal layer. The present invention is directed to a method for aligning liquid crystalline molecules, characterized by controlling the alignment of liquid crystalline molecules.
A fifth gist of the present invention is that a composition containing a liquid crystal molecule further contains a carbon cluster derivative represented by the general formula (I), and the action of the carbon cluster derivative causes the alignment of the liquid crystal molecule. Is controlled in the liquid crystal composition.
[0017]
A sixth gist of the present invention is that a liquid crystal layer containing liquid crystal molecules formed on a substrate and / or a layer adjacent to the liquid crystal layer contains a carbon cluster derivative represented by the general formula (I). And the liquid crystal molecules are aligned by the action of the carbon cluster derivative.
In addition, since the alignment method of liquid crystal molecules, that is, the interface molecular alignment mechanism is a compound of various causes (Koji Okano, Shunsuke Kobayashi; edited by “Liquid Crystal = Application”, Baifukan (1985), pp. 52-83). It is difficult to discuss the action of the carbon cluster derivative in detail, but it is speculated that the anisotropy and polarity of the carbon cluster derivative molecule contribute to the orientation. That is, when the carbon cluster derivative of the present invention is added to the liquid crystal layer, the carbon cluster derivative is added to the liquid crystal composition and injected from one side of the liquid crystal cell, so that the polarity of the carbon cluster derivative molecule is on the substrate. As a result, the carbon cluster derivative is quickly adsorbed on the substrate surface, and the vertical orientation is obtained by the "chromatographic effect". When the carbon cluster derivative of the present invention is added to a layer adjacent to the liquid crystal layer, the anisotropy and polarity of the carbon cluster derivative molecules minimize the excluded volume with the liquid crystal molecules of the liquid crystal layer and the vertical due to the surface tension effect. An orientation is obtained.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, a carbon cluster derivative molecule used as a liquid crystal alignment controlling agent (hereinafter, may be simply referred to as an “alignment controlling agent”) has a carbon content of 60 carbon atoms. ₆₀ Buckminsterfullerene (fullerene C ₆₀ ) And a substituent having a length of 10 ° or more, preferably 20 ° or more, substituted for the carbon cluster portion.
[0019]
The substituent having a length of 10 ° or more is, for example, a 4- to 7-membered hydrocarbon ring or a heterocyclic ring having at least two or more monocyclic or 2 to 3 condensed rings, or a vinyl group having a substituent. Be composed. In addition, as a substituent which a vinyl group has, the group containing a hydrocarbon ring and / or a heterocyclic ring which is a 4- to 7-membered ring is preferable.
Specifically, as described above, the carbon cluster derivative of the present invention has a skeleton represented by the following general formula (I), ₆₀ R ₅ And a compound represented by H (where R may be the same or different).
[0020]
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[0021]
(In the formula, each R independently represents a substituent containing a total of two or more hydrocarbon rings and / or heterocycles, or a vinyl group having a substituent.)
R is not particularly limited as long as it satisfies the above definition and does not depart from the gist of the present invention. As described above, for example, each independently represents a structure represented by the following general formula (II) or (III). Can be
[0022]
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[0023]
(Where X ¹ And X ² Each independently represents a divalent linking group consisting of a monocyclic or 2 to 3 condensed ring of a 4- to 7-membered hydrocarbon or heterocyclic ring which may have a substituent;
Y ¹ And Y ² Each independently represents a direct bond or a linear divalent linking group;
X ³ Represents a monovalent group of a hydrocarbon ring or a heterocyclic monocyclic ring or a condensed 2 to 3 condensed ring which is a 4- to 7-membered ring which may have a substituent. a shows the integer of 0-2. )
[0024]
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[0025]
(Where W ¹ Is
-CH = CH-, -CH ₂ -Si (CH ₃ ) ₂ -Or -CH ₂ -C (CH ₃ ) ₂ -
X ⁴ And X ⁵ Each independently represents a divalent linking group consisting of a monocyclic or condensed 2 to 3 condensed ring or a direct bond of a hydrocarbon ring or a heterocyclic ring which may have a substituent and is a 4- to 7-membered ring;
Y ³ And Y ⁴ Each independently represents a direct bond or a linear divalent linking group;
X ⁶ May have a substituent, may be a monovalent group of a hydrocarbon ring or a heterocyclic ring which is a 4- to 7-membered ring or a heterocyclic ring, or a monovalent or 2-3 condensed ring, or may have a substituent. It represents a chain hydrocarbon group (however, one or more methylene groups in the hydrocarbon group may be substituted with -O-, -S-, or -COO-). b shows the integer of 0-2. )
X of the general formula (II) and the general formula (III) ¹ ~ X ⁵ As a hydrocarbon ring or a heterocyclic ring in each independently, for example,
[0026]
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[0027]
And the like. Among them, X ¹ And X ⁴ Are preferably each independently
[0028]
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[0029]
And the like, and more preferably,
[0030]
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[0031]
Is mentioned. X for a = 1 ² , And X for b = 1 ⁵ Preferably, each independently,
[0032]
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[0033]
Is mentioned. Y ¹ ~ Y ⁴ As each independently, for example,
-COO-, -OCO-, -OCH ₂ -, -CH = N-, -CH = CH-,
—C≡C—, —O—, —COS—, —CONH—, —N ＝ N—, or a direct bond.
-COO-, -OCO-, -OCH ₂ −,
X ¹ And X ² Or X ¹ And X ³ Are directly bonded (Y ¹ Is a direct bond and a is 1 or 0),
X ⁴ And X ⁵ Or X ⁴ And X ⁶ Are directly bonded (Y ² Is a direct bond, and b is 1 or 0)
And more preferably -OCO-.
[0034]
X ³ And X ⁶ Examples of when is a hydrocarbon ring or a heterocyclic ring, for example,
[0035]
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[0036]
And the like, preferably,
[0037]
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[0038]
And the like, and more preferably,
[0039]
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[0040]
And the like. Here, in each of the above structures, c is Z ¹ It represents the number of groups and is usually about 0-3. When c is 2 or more, one X ³ Or X ⁶ Multiple Z ¹ May be the same or different.
Z ¹ A halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a nitro group; a methyl group, an ethyl group, an n-propyl group, an n-dodecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an alkyl group having 1 to 20 carbon atoms such as an n-octadecyl group; a halogen in which a halogen atom such as a fluorine atom is substituted for an alkyl group having 1 to 12 carbon atoms such as a difluoromethyl group, a trifluoroethyl group and a pentafluoropentyl group. A substituted alkyl group; an alkoxy group having 1 to 20 carbon atoms corresponding to the above alkyl group such as a methoxy group, an ethoxy group, or an n-propoxy group; a fluorine atom to an alkoxy group having 1 to 12 carbon atoms such as a trifluoroethoxy group or a difluoroethoxy group; A halogen-substituted alkoxy group in which a halogen atom such as an atom is substituted; a methoxymethyl group, a methoxyethyl group, Tokishibuchiru group, ethoxymethyl group, an alkoxyalkyl group having 2 to 20 carbon atoms such as an ethoxyethyl group or an ethoxy butyl group; -O (C _k H _2k O) _n (K = 1 to 3, n = 2 to 20) a polyalkylene oxide group; having 1 to 20 carbon atoms such as a vinyl group, an allyl group, a 1-propenyl group, a 1-butenyl group, and a 2-butenyl group. Linear or branched alkenyl group; linear or branched carboxylic ester group having 1 to 20 carbon atoms such as methoxycarbonyl group and ethoxycarbonyl group; methylthio group, ethylthio group, n-propylthio, etc. Examples thereof include an alkylthio group having 1 to 20 carbon atoms. Further, these alkyl group, alkoxy group, alkoxyalkyl group, polyalkylene oxide group, alkenyl group, carboxylic acid ester group is a polymerizable group such as an epoxy group, an acrylic group, a vinyl group, particularly a radical-reactive polymerizable group. It may be replaced. Also Z ¹ Examples also include a polyorganosiloxane group having the above-mentioned groups as substituents.
[0041]
Substituent Z ¹ Among them, a linear alkoxy group having 10 to 20 carbon atoms is preferable, and a linear alkoxy group having 12 to 18 carbon atoms is more preferable. Substituent Z ¹ The number c is not particularly limited, and may be generally about 0 to 3 as described above. When the number of hydrocarbon rings and heterocycles in the entire substituent R is 2, c = 2 is preferable.
[0042]
X ⁶ Is a chain hydrocarbon group (however, one or more methylene groups in the hydrocarbon group may be substituted with -O-, -S-, or -COO-), for example, a methyl group, It has a linear or branched substituent having 1 to 20 carbon atoms such as an ethyl group, an n-propyl group, an n-dodecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, and an n-octadecyl group. An alkyl group which may be substituted; a halogen-substituted alkyl group in which an alkyl group having 1 to 12 carbon atoms such as a difluoromethyl group, a trifluoroethyl group and a pentafluoropentyl group is substituted with a halogen atom such as a fluorine atom; a methoxy group and an ethoxy group , An alkoxy group having 1 to 20 carbon atoms corresponding to the above alkyl group such as an n-propoxy group; and an alkoxy group having 1 to 12 carbon atoms such as a trifluoroethoxy group and a difluoroethoxy group. A halogen-substituted alkoxy group in which a halogen atom such as a fluorine atom is substituted for a oxy group; an alkoxy having 2 to 20 carbon atoms such as a methoxymethyl group, a methoxyethyl group, a methoxybutyl group, an ethoxymethyl group, an ethoxyethyl group or an ethoxybutyl group; Alkyl group; —O (C _k H _2k O) _n (K = 1 to 3, n = 2 to 20) a polyalkylene oxide group; having 1 to 20 carbon atoms such as a vinyl group, an allyl group, a 1-propenyl group, a 1-butenyl group, and a 2-butenyl group. Linear or branched alkenyl group; linear or branched carboxylic ester group having 1 to 20 carbon atoms such as methoxycarbonyl group and ethoxycarbonyl group; methylthio group, ethylthio group, n-propylthio, etc. And represents an alkylthio group having 1 to 20 carbon atoms. These are Z ¹ The group may be substituted with the group described above.
[0043]
X ⁶ As the above-mentioned hydrocarbon ring group, heterocyclic group, and chain hydrocarbon group (provided that one or more methylene groups in the hydrocarbon group are substituted with -O-, -S-, or -COO-). A hydrocarbon ring group or a heterocyclic group which may have a substituent. Among the hydrocarbon ring groups and heterocyclic groups which may have a substituent, preferred are as described above.
[0044]
R in the general formula (I) is preferably the case represented by the general formula (II), more preferably a = 0 in the formula (II), and the hydrocarbon ring group and the heterocyclic group in the formula (II) This is the case where the number of ring groups is two.
The five Rs in one compound may be the same or different, but are preferably all the same from the viewpoint of easy synthesis.
[0045]
In the carbon cluster derivative represented by the general formula (I), specific examples of the substituent R are shown in the following [Table 1], but are not limited thereto.
[0046]
[Table 1]

[0047]
[Table 2]

[0048]
The compounds shown in Table 1 can be prepared by the methods described in Examples of the present invention, the methods described in JP-A-10-167994, JP-A-11-255509, Japanese Patent Application No. 2001-344616, or It can be manufactured by a known method according to these.
The liquid crystal alignment controlling agent containing the carbon cluster derivative of the present invention can be prepared by, for example, dissolving the carbon cluster derivative and, if necessary, an optional component described later in a solvent such as toluene, chloroform, or chlorobenzene, and then subjecting the solution to spin coating or bar coating. An orientation control layer can be formed by coating and drying by a known coating method such as a coat. By providing this alignment control layer adjacent to a liquid crystal layer containing liquid crystal molecules, the liquid crystal molecules contained in the liquid crystal layer can be aligned, so that it can be used for various applications described later. Further, the substrate coated with the orientation controlling agent containing the carbon cluster derivative is irradiated with radioactivity such as ultraviolet rays or heated, thereby polymerizing the carbon cluster derivative, thereby obtaining a polymer (a dimer or more). Multimer).
[0049]
The liquid crystal alignment controlling agent of the present invention, and the alignment controlling layer formed using the same may contain a plurality of the carbon cluster derivatives, and the carbon cluster derivative may be used without departing from the gist of the present invention. An orientation control agent other than the above may be contained. Further, various additives may be included. Examples of the various additives include various binder resins, conductive polymers, and other additives such as a donor substance for the orientation control layer to also function as a photocharge generation layer and a monomer having a functional polymer group.
[0050]
The concentration of the carbon cluster derivative in the alignment control agent of the present invention and the alignment control layer formed using the alignment control agent is appropriately selected within a range that does not hinder the expression of the alignment control function. Specifically, the appropriate range is determined depending on the solubility of the derivative itself in a solvent and the types and concentrations of other various additive components, but is usually about 0.1 to 10% by weight, preferably 0.1 to 10% by weight. It is about 5 to 3% by weight.
[0051]
The liquid crystal layer whose alignment is controlled by the alignment control layer of the present invention is a low-molecular liquid crystal or a main-chain high-molecular liquid crystal exhibiting a known phase such as a nematic phase for liquid crystal display, a cholesteric phase, a smectic phase, and a discotic phase. In addition to polymer liquid crystals such as side-chain polymer liquid crystals and polymerizable monomer liquid crystals, liquid crystal optical elements using liquid crystal substances such as spatial light modulators, organic semiconductor elements with liquid crystal substances aligned, and organic solar cells It can also be used for batteries, organic electroluminescent devices, and the like.
[0052]
The liquid crystal composition of the present invention can exhibit an alignment control function by incorporating a carbon cluster derivative represented by the general formula (I) into a composition containing liquid crystal molecules. As the type of the liquid crystal phase in the composition, a nematic phase, a cholesteric phase, a smectic phase, a low-molecular liquid crystal or a main-chain high-molecular liquid crystal exhibiting a known phase such as a discotic phase, a side-chain high-molecular liquid crystal, A polymer liquid crystal such as a polymerizable monomer liquid crystal can be used.
[0053]
When using a known liquid crystalline substance (liquid crystalline molecule), specifically, edited by the 142nd Committee of the Japan Society for the Promotion of Science; “Liquid Crystal Device Handbook”, Nihon Kogyo Shimbun (1989), pp. 152-192 and Liquid Crystal Handbook Editing Committee; "Liquid Crystal Handbook" Maruzen Co., Ltd. (2000), various types such as biphenyl, phenylcyclohexane, phenylpyrimidine, and cyclohexylcyclohexane as described on pages 260 to 330. Low molecular weight compounds or mixtures can be used. Also, a high molecular compound or a mixture as described in Liquid Crystal Handbook, edited by Liquid Crystal Handbook Editing Committee, Maruzen Co., Ltd. (2000), pp. 365-415 can be used.
[0054]
The liquid crystal composition of the present invention contains various additives such as a chiral dopant, a dichroic dye, a polymer, a polymerizer, a sensitizer, an ultraviolet absorber, and a stabilizer in a range that does not impair the orientation of the liquid crystal composition. You can go out.
In the liquid crystal composition of the present invention, the content of the carbon cluster derivative is usually 0.1 to 5% by weight with respect to the liquid crystal substance, and the solubility of the carbon cluster derivative in the liquid crystal substance and the visible level of the carbon cluster derivative can be determined. It is preferably 0.5 to 3% by weight from the viewpoint of light absorption intensity and the like.
[0055]
The liquid crystal composition of the present invention can be easily obtained by mixing and dissolving a liquid crystal material, a carbon cluster derivative, and various additives that are added as required by an operation such as shaking.
In the present invention, for example, nematic liquid crystals and smectic liquid crystals having a rod-like (rod-like) molecular shape, and disc-like (disk-like) liquid crystal materials which are preferable as liquid crystal molecules in a liquid crystal composition used for a liquid crystal display device are preferred. Discotic liquid crystals having a molecular shape, polymer liquid crystals having these molecules as mesogenic groups, and more preferably those exemplified below, but the present invention is not limited to any of the following Absent.
[0056]
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[0057]
(In each of the above formulas, R ^a Represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an alkoxyalkyl group, or an alkenyl group; ^b Is a cyano group; a halogen atom such as a fluorine atom or a chlorine atom; a substituted alkyl group, a substituted alkoxy group, a substituted alkoxyalkyl group, or a substituted alkenyl having 1 to 10 carbon atoms having a halogen atom such as a fluorine atom or a chlorine atom as a substituent. Group: represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an alkoxyalkyl group, or an alkenyl group. Further, the benzene ring or cyclohexane ring in each of the above formulas may be substituted by a cyano group, a fluorine atom, or a chlorine atom. )
Further, in a liquid crystal display device such as a VA system, a liquid crystal having negative dielectric anisotropy in which fluorine is substituted in a side direction of a molecule is preferable.
The alignment control agent containing the carbon cluster derivative of the present invention and the liquid crystal composition containing the carbon cluster derivative adhere to the substrate surface of the liquid crystal cell by being injected into the liquid crystal cell, and vertical alignment is obtained. Further, in order to obtain more uniform alignment, the liquid crystal cell into which the alignment controlling agent and / or the liquid crystal composition has been injected may be subjected to heating and aging treatment.
[0058]
Further, the cell after the liquid crystal alignment may be irradiated with radiation such as ultraviolet rays to polymerize the carbon cluster derivative to form a polymer (multimer).
However, when the liquid crystal composition is used by injecting it between the substrates (in the liquid crystal cell), the irradiation treatment of the carbon cluster derivative is usually performed after the liquid crystal composition is injected into the cell. In this case, care must be taken because polymerization may not be performed efficiently due to the absorption of radiation by the liquid crystal cell substrate, and the liquid crystal material may be deteriorated by the radiation. Therefore, when performing the irradiation treatment, it is preferable that the carbon cluster derivative is contained in the alignment control layer adjacent to the liquid crystal layer. When a carbon cluster derivative is contained in the alignment control layer formed adjacent to the liquid crystal layer, it is preferable to perform ultraviolet treatment from the viewpoint of thermal stability of the alignment.
[0059]
In the present invention, the carbon cluster derivative is preferably added to the liquid crystal layer because it is not necessary to form an alignment layer in advance, for example, from the viewpoint of simplifying the manufacturing process of the liquid crystal element. On the other hand, from the viewpoint of display quality such as a wide viewing angle, it is preferable to include it in a layer (alignment control layer) adjacent to the liquid crystal layer because a post-processing step by multi-domain processing such as MVA is added.
[0060]
The present invention relates to a liquid crystal display device such as a VA system, and a spatial light modulation as described in “Liquid Crystal Handbook” Maruzen Co., Ltd. (2000), pp. 511 to 515, edited by Liquid Crystal Handbook Editing Committee. Used for various devices such as a liquid crystal light valve as described in Tableware and Liquid Crystal Device Handbook, Nihon Kogyo Shimbun (1989), pp. 633-634, edited by the 142nd Committee of the Japan Society for the Promotion of Science. be able to. In this case, the carbon cluster derivative can also have a photoconductive function in addition to the orientation control depending on the element configuration and the like.
[0061]
The thus obtained alignment controlling agent comprising the carbon cluster derivative of the present invention and the composition containing the carbon cluster derivative have excellent alignment controlling ability and various properties such as electrical and chemical stability. It can be applied to liquid crystal display elements, liquid crystal optical elements, photoelectric conversion elements, and the like.
[0062]
In addition, since the alignment mechanism of the liquid crystal molecules, that is, the alignment mechanism of the liquid crystal molecules at the substrate interface is a composite of various factors, depending on the configuration of the device using the alignment control agent of the present invention and the type and method of the manufacturing process, Although it is difficult to limit the preferable range of the alignment controlling agent, the interaction with the liquid crystal molecules related to the alignment strength is the case of chemisorption (alignment treatment) using a known surfactant or silanizing agent. This suggests that it is important to have a terminal group having about 10 to 20 carbon atoms. However, the flexible group is simply a carbon cluster C ₆₀ Is difficult to be in a state where the substituent extends in the direction perpendicular to the substrate, it is considered that the orientation order does not become high. Therefore, it is preferable to have a bulky structure, such as a ring structure, which can expect an excluded volume effect.
[0063]
Furthermore, even when the carbon cluster derivative of the present invention forms a multi-molecular stack on the substrate surface, the terminal group (that is, R in the general formula) has a regularity and a direction with respect to the substrate. In order to achieve this, it is considered preferable that there be a ring structure in which “CH / π interaction” for stacking the carbon cluster derivatives can be expected.
[0064]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded.
[Example 1]
10 mg of the exemplified compound [I-1] was dissolved in toluene to prepare a 1% by weight toluene solution. This toluene solution was applied to a glass substrate with ITO using a spin coater to produce a substrate with an orientation control layer. Further, a liquid crystal cell was prepared by setting the orientation control layer of the substrate to face inward such that the distance between the substrates was 10 μm. Into this liquid crystal cell, a fluorine-based liquid crystal substance commercially available as MLC-2039 (manufactured by Merck) containing 1% of a dichroic dye commercially available as LSB-335 (manufactured by Mitsubishi Chemical) is used. A liquid crystal mixture having a negative dielectric anisotropy as a main component was injected to produce a liquid crystal element.
[0065]
When the liquid crystal element was observed with a conoscope when no electric field was applied, a black cross band of the isogyre was observed, and it was confirmed that the liquid crystal element was vertically aligned. Further, when a rectangular wave of 60 Hz and 10 V was applied to the liquid crystal element, a change in blue coloring (absorption) of the dichroic dye LSB-335 was confirmed.
[0066]
[Example 2]
The exemplary compound [I-2] was dissolved in toluene in the same manner as in Example 1, and then applied to a substrate to produce a liquid crystal cell. A liquid crystal mixture commercially available as MLC-2039 (manufactured by Merck) containing 1% of a dichroic dye commercially available as LSB-335 (manufactured by Mitsubishi Chemical) was injected into the liquid crystal cell.
When the liquid crystal element was observed with a conoscope when no electric field was applied, a black cross band of the isogyre was observed, and it was confirmed that the liquid crystal element was vertically aligned. Further, when a rectangular wave of 60 Hz and 10 V was applied to the liquid crystal element, a change in blue coloring (absorption) of the dichroic dye LSB-335 was confirmed.
[0067]
[Example 3]
The exemplary compound [I-1] was dissolved in toluene in the same manner as in Example 1, and then applied to a substrate. A high-pressure mercury lamp (300 mW / cm ² ) With UV irradiation (10 J / cm ² ). It was confirmed that the film of Exemplified Compound [I-1] on the substrate after the ultraviolet irradiation had improved pencil scratching strength (film adhesion strength) and elution with respect to toluene as compared with before the ultraviolet irradiation. Further, a liquid crystal cell was prepared in the same manner as in Example 1 using the substrate irradiated with ultraviolet light, and a liquid crystal mixture commercially available as trade name MLC-2039 (manufactured by Merck) was injected.
When the liquid crystal element was observed with a conoscope when no electric field was applied, a black cross band of the isogyre was observed, and it was confirmed that the liquid crystal element was vertically aligned. Further, the liquid crystal filled cell was heated at 140 ° C. for 15 minutes. After heating, the liquid crystal cell was cooled to room temperature and observed under a polarizing microscope. As a result, no disorder in the alignment of the liquid crystal due to heating was observed.
[0068]
[Example 4]
After dissolving Exemplified Compound [I-2] in toluene in the same manner as in Example 3, the substrate was coated and irradiated with ultraviolet rays to produce a liquid crystal cell. A liquid crystal mixture commercially available as trade name MLC-2039 (manufactured by Merck) was injected into the liquid crystal cell.
When the liquid crystal element was observed with a conoscope when no electric field was applied, a black cross band of the isogyre was observed, and it was confirmed that the liquid crystal element was vertically aligned. Further, the liquid crystal filled cell was heated at 140 ° C. for 15 minutes. After heating, the liquid crystal cell was cooled to room temperature and observed under a polarizing microscope. As a result, no disorder in the alignment of the liquid crystal due to heating was observed.
[0069]
[Example 5]
A liquid crystal composition was prepared by mixing 10 mg of the exemplified compound [I-1] with 1 g of a liquid crystal mixture commercially available under the trade name MLC-2039 (manufactured by Merck) and shaking to dissolve it. This liquid crystal composition was filtered through a PTFE filter having a pore size of 0.2 μm, and then sealed in a cell having a gap of 6 μm, which was made of a glass plate with a transparent electrode and was configured so that the electrode surfaces faced each other, to produce a liquid crystal display device. .
When this cell was observed with a conoscope, it was confirmed that the cell was vertically aligned when no electric field was applied. Further, a pulse signal having a voltage of 5 V, an ON time of 60 μsec, and a frame frequency of 30 Hz was applied to the cell at 25 ° C., and the voltage holding ratio was measured. The voltage holding ratio of this liquid crystal element was as good as 86.5%. From the above results, it was confirmed that a liquid crystal element having both alignment characteristics and driving characteristics could be obtained.
[0070]
[Example 6]
A liquid crystal composition was prepared by mixing 10 mg of Exemplified Compound [I-2] with 1 g of a liquid crystal mixture commercially available as trade name MLC-2039 (manufactured by Merck Ltd.), shaking and dissolving. This liquid crystal composition was subjected to a filtration treatment in the same manner as in Example 5, and then sandwiched between glass plates with transparent electrodes to produce a liquid crystal element.
When this cell was observed with a conoscope, it was confirmed that the cell was vertically aligned when no electric field was applied. Further, the voltage holding ratio of this liquid crystal element was measured by the same method as in Example 5, and as a result, a good value of 94.8% was shown. From the above results, it was confirmed that a liquid crystal element having both alignment characteristics and driving characteristics could be obtained.
[0071]
[Example 7]
A liquid crystal composition was prepared by mixing 10 mg of Exemplified Compound [I-3] with 1 g of a liquid crystal mixture commercially available under the trade name MLC-2039 (manufactured by Merck) with shaking and dissolving. This liquid crystal composition was subjected to a filtration treatment in the same manner as in Example 5, and then sandwiched between glass plates with transparent electrodes to produce a liquid crystal element.
When this cell was observed with a conoscope, it was confirmed that the cell was vertically aligned when no electric field was applied. The voltage holding ratio of this liquid crystal element was measured by the same method as in Example 5, and as a result, a good value of 89.2% was shown. From the above results, it was confirmed that a liquid crystal element having both alignment characteristics and driving characteristics could be obtained.
[0072]
【The invention's effect】
The liquid crystal alignment controlling agent comprising the carbon cluster derivative of the present invention and the composition containing the derivative have electrical and chemical stability, and have a vertical alignment type liquid crystal display device such as a VA system, various liquid crystal display devices, and a liquid crystal. It can be applied to optical elements and the like.

Claims (6)

A liquid crystal alignment controlling agent containing a carbon cluster derivative represented by the following general formula (I).

(In the formula, each R independently represents a substituent containing a total of two or more hydrocarbon rings and / or heterocycles, or a vinyl group having a substituent.) The liquid crystal alignment controlling agent according to claim 1, wherein in the general formula (I), Rs are each independently represented by the following general formula (II) or the following general formula (III).

(In the formula, X ¹ and X ² are each independently a divalent monovalent or 2-3 condensed ring of a hydrocarbon ring or a heterocyclic ring which is a 4- to 7-membered ring which may have a substituent. Represents a linking group of
Y ¹ and Y ² each independently represent a direct bond or a linear divalent linking group, and X ³ represents a 4- to 7-membered hydrocarbon ring or heterocyclic ring which may have a substituent. , A monovalent group or a monovalent group comprising 2 to 3 condensed rings.
a shows the integer of 0-2. )

(Wherein, W ¹ represents —CHＣＨCH—, —CH ₂ —Si (CH ₃ ) ₂ —, or —CH ₂ —C (CH ₃ ) ₂ —, and X ⁴ and X ⁵ each independently represent Represents a divalent linking group or a direct bond composed of a monocyclic or 2 to 3 condensed ring of a hydrocarbon ring or a heterocyclic ring which is a 4- to 7-membered ring which may have a substituent,
Y ³ and Y ⁴ each independently represent a direct bond or a linear divalent linking group;
X ⁶ is a monovalent group consisting of a monocyclic or condensed 2 to 3 condensed ring of a hydrocarbon ring or a heterocyclic ring which is a 4 to 7-membered ring which may have a substituent, or has a substituent. A good chain hydrocarbon group (however, one or more methylene groups in the hydrocarbon group may be substituted with -O-, -S-, or -COO-).
b shows the integer of 0-2. ) A method for aligning liquid crystal molecules in a liquid crystal layer containing liquid crystal molecules formed on a substrate or between substrates, wherein the liquid crystal layer and / or a layer adjacent to the liquid crystal layer is provided. 3. A method for aligning liquid crystal molecules, comprising the carbon cluster derivative according to 2, and controlling the alignment of liquid crystal molecules by the action of the carbon cluster derivative. An alignment of liquid crystal molecules is controlled by forming a layer formed using the carbon cluster derivative according to claim 1 or a polymer using the carbon cluster derivative as a monomer adjacent to a liquid crystal layer. A method for aligning liquid crystalline molecules. 3. A liquid crystal composition comprising a composition containing liquid crystal molecules, further comprising the carbon cluster derivative according to claim 1 or 2, and controlling the orientation of the liquid crystal molecules by the action of the carbon cluster derivative. object. A liquid crystal layer containing liquid crystal molecules formed on a substrate and / or a layer adjacent to the liquid crystal layer contains the carbon cluster derivative according to claim 1 or 2, and the liquid crystal is formed by the action of the carbon cluster derivative. A liquid crystal element in which molecules are aligned.