JP2004245869A - Liquid crystal alignment layer and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal alignment layer with which high transparency with excellent light resistance is attained and which is excellent in printability and in an adhesion property and a liquid crystal display element which prevents the deterioration caused by light so as to reduce display unevenness and to improve a contrast ratio. <P>SOLUTION: In the liquid crystal alignment layer composed of a soluble polyimide, the soluble polyimide is an imide ring containing oligomer having a recurring unit expressed by a general formula (1) (wherein X is a tetravalent aliphatic residual group with a cyclic, linear or cyclic and linear structure and Y is a divalent aliphatic residual group with a cyclic, linear or cyclic and linear structure). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

（Ｘは、環状、線状または環状と線状構造を有する４価の脂肪族残基であり、Ｙは、環状、績状または環状と線状構造を有する２価の脂肪族残基を示す。）の繰り返し単位を有することを特徴とする液晶配向膜を提供する。
【０００８】
この構成によれば、配向膜は、分子内に芳香族を含まないため、耐光性に優れた高透明化が達成でき、液晶表示素子に適用して高強度の光線を発生する液晶プロジェクタに使用する場合には、不均一な表示むらの低減やコントラスト比の向上など、光による劣化を防止できる。
【０００９】
また、本発明は、上記目的を達成するため、可溶性ポリイミドからなる配向膜と電極とを備えた一対の基板間に液晶層を有する液晶表示素子において、前記可溶性ポリイミドは、イミド環含有オリゴマであって、下記一般式（１）、
【化１０】

（Ｘは、環状、線状または環状と線状構造を有する４価の脂肪族残基でありＹは、環状、線状または環状と線状構造を有する２価の脂肪族残基を示す。）の繰り返し単位を有することを特徴とする液晶表示素子を提供する。
【００１０】
この構成によれば、配向膜は、分子内に芳香族を含まないため、耐光性に優れた高透明化が達成でき、液晶表示素子に適用して高強度の光線を発生する液晶プロジェクタに使用する場合には、不均一な表示むらの低減やコントラスト比の向上など、光による劣化を防止できる。
【００１１】
また、本発明は、上記目的を達成するため、反射ミラーを備えた画素電極、または反射ミラーを兼ねた画素電極とスイッチング素子を有する画素を行および列状に複数個配列し、前記反射ミラー上に可溶性ポリイミドからなる第１の配向膜を設けたアクティブマトリックス基板と、可溶性ポリイミドからなる第２の配向膜と透明電極を備え前記アクティブマトリックス基板と所定の間隔で対向配置された透明基板と、前記アクティブマトリックス基板および前記透明基板間に充填された液晶層とを備えた反射型液晶素子において、前記可溶性ポリイミドは、イミド環含有オリゴマであって、下記一般式（１）、
【化１１】

（Ｘは、環状、線状または環状と線状構造を有する４価の脂肪族残基であり、Ｙは、環状、線状または環状と線状構造を有する２価の脂肪族残基である。）の繰り返し単位を有することを特徴とする液晶表示素子を提供する。
【００１２】
この構成によれば、耐光性に優れ、高透明化が達成できた配向膜を得ることができるので、液晶表示素子を高強度の光線を発生する液晶プロジェクタに適用する場合、不均一な表示むらの低減やコントラスト比の向上など、光による劣化を防止できる。また、イミド環含有オリゴマとして、例えば重量平均分子量を２０，０００以下に押えることにより、印刷性や密着性を満足することができる。
【００１３】
さらに、本発明は、上記目的を達成するため、透明な画素電極とスイッチング素子を有する画素を行および列状に複数個配列し、前記透明な画素電極上に可溶性ポリイミドからなる第１の配向膜を設けたアクティブマトリックス基板と、可溶性ポリイミドからなる第２の配向膜を設けた透明電極を備え前記アクティブマトリックス基板と所定の間隔で対向配置された透明基板と、前記アクティブマトリックス基板および前記透明基板間に充填された液晶層とを備えた透過型液晶素子において、可溶性ポリイミドは、イミド環含有オリゴマであって、下記一般式（１）
【化１２】

（Ｘは、環状、線状または環状と線状構造を有する４価の脂肪族残基であり、Ｙは、環状、線状または環状と線状構造を有する２価の脂肪族残基である。）の繰り返し単位を有することを特徴とする液晶表示素子を提供する。
【００１４】
この構成によれば、耐光性に優れ、高透明化が達成できた配向膜を用いるので、液晶表示素子を高強度の光線を発生する液晶プロジェクタに適用する場合、不均一な表示むらの低減やコントラスト比の向上など、光による劣化を防止できる。また、イミド環含有オリゴマとして、例えば重量平均分子量を２０，０００以下に押えることにより、印刷性や密着性を満足することができる。
【００１５】
【発明の実施の形態】
本発明の第１の実施の形態に係る液晶配向膜について説明する。この液晶配向膜は、可溶性ポリイミドからなる液晶配向膜において、可溶性ポリイミドは、イミド環含有オリゴマであって、下記一般式（１）、
【化１３】

（Ｘは、環状、線状または環状と線状構造を有する４価の脂肪族残基であり、Ｙは、環状、績状または環状と線状構造を有する２価の脂肪族残基を示す。）の繰り返し単位を有し、イミド環含有オリゴマは、ラクトン系の重合触媒を用いて加熱した極性溶媒中でジアミンとテトラカルボン酸二無水物を反応させることにより、直接イミド化したものである。上記のテトラカルボン酸二無水物由来の環状、線状または管状と線状構造を有する４価の脂肪族残基Ｘとしては、下記一般式（３）〜（６）で表わされる化合物またはその異性体を挙げることができる。
【化１４】

【化１５】

【化１６】

【化１７】

【００１６】
なお、一般式（３）は、ビシクロ（２，２，２）オクト−７−エン−２，３，５，６−テトラカルボン酸二無水物（ＢＣＤ）由来の残基の化学式、一般式（４）は、１，２，３，４−シクロペンタンテトラカルボン酸二無水物（ＣＰＤＡ）由来の残基の化学式である。
【００１７】
上記ジアミン由来の環状、線状または環状と線状構造を有する２価の脂肪族残基Ｙとしては、下記一般式（７）〜（１４）で表わされる化合物またはその異性体を挙げることができる。
【化１８】

【化１９】

【化２０】

【化２１】

【化２２】

【化２３】

【化２４】

【化２５】

【００１８】
なお、―般式（７）は、３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）の残基の化学式、一般式（１２）は、３，９−ビス（３−アミノプロピル）−２，４，８，１０−テトラオキサスピロ−（５，５）−ウンデカン（ＡＴＵ）由来の残基の化学式、一般式（１４）は、４，４′−ジアミノジシクロヘキシルメタン（ＣＨＤ）由来の残基の化学式である。
【００１９】
上記可溶性ポリイミドは、ラクトン系の重合触媒を用いて加熱した有機極性溶媒中でテトラカルボン酸二無水物とジアミンを反応させることにより、直接イミド化したイミド環含有オリゴマの液晶配向膜および当該液晶配向膜を用いて形成した液晶表示素子である。
【００２０】
有機溶媒としては、Ｎ−メチル−２−ピロリドン（ＮＭＰ）、ジメチルホルムアミド、ジメチルアセトアミド、スルホラン、ジメチルスルホキシド、アニソール、ジオキソラン、ブチルセルソルブアセテート、テトラメチル尿素、ラクトン系などが挙げられ、これら単独で使用することができるが、２種以上を混合して使用してもよい。
【００２１】
重合触媒としてのラクトン系としては、γ−カプロラクトン、γ−バレロラクトン、β−ブチロラクトン、γ−テトロン酸、γ−フタリド、γ−フタリド酸、γ−クマリンなどが挙げられ、ラクトン系とピリジン、キノリン、Ｎ−メチルモルフォリンなどの塩基化合物との混合物も使用することができる。
【００２２】
テトラカルボン酸二無水物とジアミンを有機溶媒中で反応させて得られたポリイミドを有機溶媒で希釈することにより、液晶配向膜材を得ることができる。配向膜材には基板との密着性を向上させるため、γ−アミノプロピルトリエトキシシラン、δ−アミノプロピルメチルジエトキシシラン、Ｎ−β（アミノエチル）γ−アミノプロピルトリメトキシシランなどのアミノ系シランカップリング剤、エポキシ系シランカップリング剤、チタネートカップリング剤、アルミニウムアルコレート、アルミニウムキレート、ジルコニウムキレートなどの表面処理剤、アクリル系樹脂、エポキシ系樹脂を少量混合もしくは反応することもできる。配向膜の形成は一般的なスピン塗布法、印刷法、浸漬法、刷毛塗り、ロールコータ法、スプレー法などによって行うことができる。
【００２３】
液晶としては、例えば４−置換フェニル−４′−置換シクロヘキサン、４−置換シクロヘキシル−４′−置換シクロヘキサン、４−置換フェニル−４′−置換ジシクロヘキサン、４−置換ジシクロヘキシル−４′−置換ジフェニル、４−置換−４′−置換ターフェニル、４−置換ビフェニル−４′−置換シクロヘキサン、２−（４−置換フェニル）−５−ピリミジン、２−（４−置換ジオキサン）−５−フェニル、４−置換安息香酸−４′−フェニルエステル、４−置換シクロヘキサンカルボン酸−４′−置換フェニルエステル、４−置換シクロヘキサンカルボン酸−４′−置換ビフェニルエステル、４−（４−置換シクロヘキサンカルボニルオキシ）安息香酸−４′−置換フェニルエステル、４−（４−置換シクロヘキシル）安息香酸−４′−置換フェニルエステル、４−（４−置換シクロヘキシル）安息香酸−４′−置換シクロヘキシルエステル、４−置換−４′−置換ビフェニル、４−置換シクロヘキシルー４′−置換フェニルジオキサン、４−置換シクロヘキシル−４′−置換フェニルピリミジンなどを挙げることができ、これらの化合物の中でも少なくとも分子の一方の末端にアルキル基、アルコキシ基、アルコキシメチレン基、シアノ基、フッ素基、ジフッ素基、トリフッ素基を有する多成分系の混合液晶組成物が用いられる。
【００２４】
ジアミンとしては、例えば３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）などを挙げることができる。
【００２５】
この第１の実施の形態によれば、一般式（３）〜（６）で表わされる化合物で代表される環状、線状または環状と線状構造を有する４価の脂肪族残基を有するテトラカルボン酸二無水物と、一般式（７）〜（１４）で表わされる化合物で代表される環状、線状または環状と線状構造を有する２価の脂肪族残基を有するジアミンを反応成分として使用しているので、耐光性に優れた液晶表示素子を実現できる。また、このようなテトラカルボン酸二無水物とジアミンの組み合わせは、高い透明性を実現する上でも有用である。さらに、一般式（７）で表わされる化合物を使用することにより、高いプレチルト角の液晶表示素子を実現することができる。
【００２６】
図１は、本発明の第２の実施の形態に係る反射型液晶表示素子を適用した液晶プロジェクタを示す。この液晶プロジェクタは、アクティブマトリックス基板１２と、対向ガラス基板１３との間に液晶層８を配置してセルを構成してなる液晶表示素子と、位相板１４と、偏光子および検光子を兼ねた偏光ビームスプリッタ１５とを有する。アクティブマトリックス基板１２は、単結晶シリコン基板１上に各々が独立して配置されたＭＯＳ（Ｍｅｔａｌ ０ｘｉｄｅ Ｓｅｍｉｃｏｎｄｕｃｔｏｒ）トランジスタ２、反射板を兼ねた反射画素電極４、ＭＯＳトランジスタ２を駆動する信号配線および反射画素電極４とＭＯＳトランジスタ２を電気的に接続する配線等からなる配線層３、保護膜である誘電体謨５、および配向膜６で構成される。対向ガラス基板１３は、配向膜９、透明電極１０を有するガラス基板１１で構成される。
【００２７】
反射型アクティブマトリック基板１２は、単結晶シリコン基板１上に液晶駆動用能動素子としてＭＯＳトランジスタ２を形成したものである。なお、液晶層８は、アクティブマトリックス基板１２と対向ガラス基板１３との間に配置された柱状のスペーサ７によってその層厚を均一に保持されている。
【００２８】
ＭＯＳトランジスタ２は、シリコン基板、ｐ型ウエハの上にソース拡散層、ソース電極、ドレイン拡散層、ドレイン電極、ポリシリコンゲートなどから形成され、層間絶縁のためにスピンオングラス絶縁層を設けている。
【００２９】
反射画素電極４の材料としては、可視光領域での反射率の良好な金属、例えば、アルミニウムあるいは銀などが挙げられる。この反射画素電極４は、平坦な面上に形成した方が安定した膜形成が可能であり、かつ、良好な反射特性を得ることができるため、反射画素電極４の下地として設ける絶縁層は、表面研磨し平坦化しておくことが望ましい。
【００３０】
この第２の実施の形態によれば、アクティブマトリックス基板１２および対向ガラス基板１３の配向膜６，９は、分子内に芳香族を含まないため、不均一な表示むらの低減、コントラストの向上等、光による劣化を防止できる。
【００３１】
図２は、本発明の第３の実施の形態に係る透過型液晶表示素子を適用した２灯３板式の液晶プロジェクタの光学系を示す。この液晶プロジェクタは、平行光を出射する照明装置２１と、照明２１から出射された平行光をインテグレータレンズ２４、偏光変換装置２５および集光レンズ２６を介して導入し、赤色光を透過させ、シアン色光を反射する第１ダイクロイックミラー２７と、第１ダイクロイックミラー２７で反射したシアン色光を凹レンズ３４を介して導入し、青色光を透過させ、緑色光を反射する第２ダイクロイックミラー３５と、第１ダイクロイクミラー２７を透過した赤色光を凹レンズ２８、反射ミラー２９、レンズ３０および透過型の赤色光用液晶ライトバルブ３１を介し、第２ダイクロイックミラー３５で反射した緑色光をレンズ３６および透過型の緑色用液晶ライトバルブ３２を介し、第２ダイクロイックミラー３５を透過した青色光をリレーレンズ３７、全反射ミラー３８、リレーレンズ３９、反射ミラー４０、リレーレンズ４１および透過型の青色光用液晶ライトバルブ３３を介してそれぞれ導入して合成するダイクロイックプリズム４２と、ダイクロイックプリズム４２によって合成されたカラー映像光をスクリーン４４上に拡大投写する投写レンズ４３とを有する。照明装置２１は、横並びに配置された二つの光源２１Ａ、２１Ｂから成る。各光源における発光部２２は、超高圧水銀ランプ、メタルハライドランプ、キセノンランプ等から成り、その照射光はパラボラリフレクタ２３によって平行光となって出射され、インテグレータレンズ２４へと導かれる。
【００３２】
インテグレータレンズ２４は、一対のレンズ群から構成されており、図において左側半分は光源２１Ａから出射された光を液晶ライトバルブ３１，３２，３３の前面に導き、右側半分は光源２１Ｂから出射された光を液晶ライトバルブ３１，３２，３３の前面に導くことになる。インテグレータレンズ２４を経た光は、偏光変換装置２５、集光レンズ２６を経た後、第一ダイクロイックミラー２７（２７Ａ、２７Ｂ）へと導かれることになる。
【００３３】
偏光変換装置２５は、複数の偏光ビームスプリッタアレイ（以下、「ＰＢＳアレイ」という）によって構成されている。ＰＢＳアレイは、偏光分離膜と位相差板（１／２λ板）とを備える（いずれも図示せず）。偏光分離膜は、インテグレータレンズ２４からの光のうち例えばＰ偏光を通過させ、Ｓ偏光を９０°光路変更して反射、出射する。ＰＢＳアレイを通過したＰ偏光はその前側（光出射側）に設けている位相差板によってＳ偏光に変換されて出射される。すなわち、ほぼ全ての光はＳ偏光に変換されるようになっている。
【００３４】
第一ダイクロイックミラー２７は、赤色波長帯域の光を通過し、シアン（緑＋青）の波長帯域の光を反射する。第一ダイクロイックミラー２７は第一分割部２７Ａと第二分割部２７Ｂとから成る。第一ダイクロイックミラー２７を透過した赤色波長帯域の光は、凹レンズ２８を経て反射ミラー２９にて反射されて光路を変更される。反射ミラー２９にて反射された赤色光はレンズ３０を経て赤色光用の透過型の液晶ライトバルブ３１を通過することによって光変調される。一方、第一ダイクロイックミラー２７にて反射したシアンの波長帯域の光は、凹レンズ３４を経て第二ダイクロイックミラー３５に導かれる。
【００３５】
第二ダイクロイックミラー３５は、青色波長帯域の光を透過し、緑色波長帯域の光を反射する。第二ダイクロイックミラー３５にて反射した緑色波長帯域の光は、レンズ３６を経て緑色光用の透過型の液晶ライトバルブ３２に導かれ、これを透過することで光変調される。また、第二ダイクロイックミラー３５を透過した青色波長帯域の光は、リレーレンズ３７、全反射ミラー３８、リレーレンズ３９、反射ミラー４０およびリレ―レンズ４１を経て青色光用の透過型の液晶ライトバルブ３３に導かれ、これを透過することで光変調される。
【００３６】
各液晶ライトバルブ３１、３２、３３は、入射側偏光板３１ａ、３２ａ、３３ａと一対のガラス基板（画素電極や配向膜を形成してある）間に液晶を封入して成るパネル部３１ｂ、３２ｂ、３３ｂと、出射側偏光板３１ｃ、３２ｃ、３３ｃを備えて成る。液晶ライトバルブ３１、３２、３３を経ることで変調された変調光（各色映像光）は、ダイクロイックプリズム４２により合成されてカラー映像光となる。このカラー映像光は投写レンズ４３によって拡大投写され、スクリーン４４上に投影表示される。
【００３７】
この第３の実施の形態によれば、液晶ライトバルブ３１，３２，３３に設けられた配向板は、分子内に芳香族を含まないため、カラー投影像の不均一な表示むらの低減、コントラストの向上等、光による劣化を防止できる。
【００３８】
なお、本発明の配向膜は、上記の配向膜に使用するだけでなく、カラーフィルター部、電極部の両方または一方に適用することもできる。
【００３９】
【実施例】
以下、本発明の実施例を比較例と共に説明する。
【００４０】
（実施例１）
この実施例１では、１，２，３，４−シクロペンタンテトラカルボン酸二無水物（ＣＰＤＡ）８．４１ｇと３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）９．５４ｇをＮ−メチル−２−ピロリドン（ＮＭＰ）６６ｇに溶解させ、生成水を除去するための共沸溶媒としてトルエンを２５ｇ、イミド化触媒としてγ−カプロラクトンを０．４６ｇ、ピリジンを０．６３ｇ加え、常温で窒素雰囲気下で１０分間撹拌した後、１８０℃に昇温して３時間撹拌反応を行うことにより直接イミド化したイミド環含有オリゴマを有し、重量平均分子量が１５，０００の可溶性ポリイミド溶液を得た。次に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加えて固形分濃度５重量％の溶液とし、この溶液を孔径１μｍのフィルタで濾過して液晶配向膜材の溶液を調整した。
【００４１】
この溶液を、液晶配向膜塗布用印刷機を用いて配向膜未形成の対向ガラス基板、反射基板および透明基板に塗布し、１００℃で３０分加熱した後２２０°Ｃで３０分間加熱し、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を揮発させると共にポリイミドで厚さ８００Å（オングストローム）の配向膜を形成した。対向ガラス基板と反射基板（いずれも配向膜を形成したもの）の間、および対向ガラス基板と透明基板（いずれも配向膜を形成したもの）の間にネマチック液晶およびスペーサ材を封入し、反射型液晶表示素子および透過型液晶表示素子をそれぞれ作製した。
【００４２】
この実施例１によれば、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して殆んど低下が認められず、耐光性が非常に優れていることを確認した。本実施例は、ポリイミド溶液タイプの可溶性ポリイミドを液晶配向膜に使用しても、印刷性や密着性が良好であることを確認した。また、直接イミド化したイミド環含有オリゴマからなるポリイミド溶液タイプは常温保存しても粘度変化が発生せず、ポリアミック酸溶液タイプなどのポリイミドに比して非常に優れている。さらに、ラクトン系のイミド化重合触媒を用いており、重合反応時にヒドロキシカルボン酸となって重合触媒作用をなし、反応終了後は元のラクトン系溶媒に戻るのでワニス状態でもポリマの変質が少なく、かつ、乾燥後に揮発して酸が残留しないので、重合物の沈殿、洗浄、乾燥工程が不要になるなど工業的利点を有している。
【００４３】
（実施例２）
この実施例２では、ビシクロ（２，２，２）オクト−７−エン−２，３，５，６−テトラカルボン酸二無水物（ＢＣＤ）９．９６ｇと３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）９．５４ｇをＮ−メチル−２−ピロリドン（ＮＭＰ）７０ｇに溶解させ、生成水を除去するための共沸溶媒としてトルエンを２５ｇ、イミド化触媒としてγ−カプロラクトンを０．４６ｇ、ピリジンを０．６３ｇ加え、常温で窒素雰囲気下で１０分間撹拌した後、１８０℃に昇温して３時間撹拌反応を行うことにより直接イミド化したイミド環含有オリゴマを有し、重量平均分子量が１２，０００の可溶性ポリイミド溶液を得た。次に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加えて固形分濃度５重量％の溶液とし、この溶液を孔径１μｍのフィルタで濾過して液晶配向膜材の溶液を調整した。
【００４４】
この溶液を、液晶配向膜塗布用印刷機を用いて配向膜未形成の対向ガラス基板、反射基板および透明基板に塗布し、１００℃で３０分加熱した後２００℃で３０分間加熱し、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を揮発させると共にポリイミドで厚さ６００Å（オングストローム）の配向膜を形成した。対向ガラス基板と反射基板（いずれも配向膜を形成したもの）の間、および対向ガラス基板と透明基板（いずれも配向膜を形成したもの）の間にネマチック液晶およびスペーサ材を封入し、反射型液晶表示素子および透過型液晶表示素子をそれぞれ作製した。
【００４５】
この実施例２によれば、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して殆んど低下が認められず、耐光性が非常に優れていることを確認した。
【００４６】
（実施例３）
この実施例３では、１，２，３，４−シクロブタンテトラカルボン酸二無水物（ＣＢＴＡ）７．８４ｇと３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）９．５４ｇをＮ−メチル−２−ピロリドン（ＮＭＰ）６８ｇに溶解させ、生成水を除去するための共沸溶媒としてトルエンを２５ｇ、イミド化触媒としてγ−カプロラクトンを０．４６ｇ、ピリジンを０．６３ｇ加え、常温で窒素雰囲気下で１０分間撹拌した後、１８０℃に昇温して３時間撹拌反応を行うことにより直接イミド化したイミド環含有オリゴマを有し、重量平均分子量が１８，０００の可溶性ポリイミド溶液を得た。次に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加えて固形分濃度５重量％の溶液とし、この溶液を孔径１μｍのフィルタで濾過して液晶配向膜材の溶液を調整した。
【００４７】
この溶液を、液晶配向膜塗布用印刷機を用いて配向膜未形成の対向ガラス基板、反射基板および透明基板に塗布し、１００℃で３０分加熱した後２５０℃で３０分間加熱し、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を揮発させると共にポリイミドで厚さ９００Å（オングストロ一ム）の配向膜を形成した。対向ガラス基板と反射基板（いずれも配向膜を形成したもの）の間、および対向ガラス基板と透明基板（いずれも配向膜を形成したもの）の間にネマチック液晶およびスペーサ材を封入し、反射型液晶表示素子および透過型液晶表示素子をそれぞれ作製した。
【００４８】
この実施例３によれば、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して殆んど低下が認められず、耐光性が非常に優れていることを確認した。
【００４９】
（実施例４）
この実施例４では、１，２，３，４−シクロペンタンテトラカルボン酸二無水物（ＣＰＤＡ）４．２１ｇとビシクロ（２，２，２）オクト−７−エン−２，３，５，６−テトラカルボン酸二無水物４．９８ｇと３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）４．７７ｇと３，９−ビス（３−アミノプロピル）−２，４，８，１０−テトラオキサスピロ−（５，５）ウンデカン（ＡＴＵ）５．４９ｇをＮ−メチル−２−ピロリドン（ＮＭＰ）６８ｇに溶解させ、生成水を除去するための共沸溶媒としてトルエンを２５ｇ、イミド化触媒としてγ−カプロラクトンを０．４６ｇ、ピリジンを０．６３ｇ加え、常温で窒素雰囲気下で１０分間撹拌した後、１８０℃に昇温して３時間撹拌反応を行うことにより直接イミド化したイミド環含有オリゴマを有し、重量平均分子量が１９，５００の可溶性ポリイミド溶液を得た。次に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加えて固形分濃度５重量％の溶液とし、この溶液を孔径１μｍのフィルタで濾過して液晶配向膜材の溶液を調整した。
【００５０】
この溶液を、液晶配向膜塗布用印刷機を用いて配向膜未形成の対向ガラス基板、反射基板および透明基板に塗布し、１００℃で３０分加熱した後２２０℃で３０分間加熱し、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を揮発させると共にポリイミドで厚さ７００Å（オングストローム）の配向膜を形成した。対向ガラス基板と反射基板（いずれも配向膜を形成したもの）の間、および対向ガラス基板と透明基板（いずれも配向膜を形成したもの）の間にネマチック液晶およびスペーサ材を封入し、反射型液晶表示素子および透過型液晶表示素子をそれぞれ作製した。
【００５１】
この実施例４によれば、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して殆んど低下が認められず、耐光性が非常に優れていることを確認した。
【００５２】
（実施例５）
この実施例５では、１，２，３，４−シクロペンタンテトラカルボン酸二無水物（ＣＰＤＡ）８．４１ｇと３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）４．７７ｇと４，４′−ジアミノジシクロヘキシルメタン（ＣＨＤ）２．２８ｇをＮ−メチル−２−ピロリドン（ＮＭＰ）６８ｇに溶解させ、生成水を除去するための共沸溶媒としてトルエンを２５ｇ、イミド化触媒としてγ−カプロラクトンを０．４６ｇ、ピリジンを０．６３ｇ加え、常温で窒素雰囲気下で１０分間撹拌した後、１８０℃に昇温して２時間撹拌反応を行うことにより直接イミド化したイミド環含有オリゴマを有し、重量平均分子量が１４，０００の可溶性ポリイミド溶液を得た。次に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加えて固形分濃度５重量％の溶液とし、この溶液を孔径１μｍのフィルタで濾過して液晶配向膜材の溶液を調整した。
【００５３】
この溶液を、液晶配向膜塗布用印刷機を用いて配向膜未形成の対向ガラス基板、反射基板および透過基板に塗布し、１００℃で３０分加熱した後１９０℃で３０分間加熱してＮ−メチル−２−ピロリドン（ＮＭＰ）を揮発させると共にポリイミドで厚さ４００Å（オングストローム）の配向膜を形成した。対向ガラス基板と反射基板（いずれも配向膜を形成したもの）の間、および対向ガラス基板と透明基板（いずれも配向膜を形成したもの）の間にネマチック液晶およびスペーサ材を封入し、反射型液晶表示素子および透過型液晶表示素子をそれぞれ作製した。
【００５４】
この実施例５によれば、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して殆んど低下が認められず、耐光性が非常に優れていることが確認された。
【００５５】
（実施例６）
この実施例６では、１，２，３，４−シクロブタンテトラカルボン酸二無水物（ＣＢＴＡ）７．８４ｇと３，３′−ジメチル−４，４′−ジアミノ−ジシクロヘキシルメタン（ＤＭＨＭ）４．７７ｇと４，４′−ジアミノジシクロヘキシルメタン（ＣＨＤ）２．２８ｇをＮ−メチル−２−ピロリドン（ＮＭＰ）６８ｇに溶解させ、生成水を除去するための共沸溶媒としてトルエンを２５ｇ、イミド化触媒としてγ−カプロラクトンを０．４６ｇ、ピリジンを０．６３ｇ加え、常温で窒素雰囲気下で１０分間撹拌した後、１８０℃に昇温して３時間撹梓反応を行うことにより直接イミド化したイミド環含有オリゴマを有し、重量平均分子量が１１，０００の可溶性ポリイミド溶液を得た。次に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加えて固形分濃度５重量％の溶液とし、この溶液を孔径１μｍのフィルタで濾過して液晶配向膜材の溶液を調整した。
【００５６】
この溶液を、液晶配向膜塗布用印刷機を用いて配向膜未形成の対向ガラス基板、反射基板および透過基板に塗布し、１００℃で３０分加熱した後１９０℃で３０分間加熱してＮ−メチル−２−ピロリドン（ＮＭＰ）を揮発させると共にポリイミドで厚さ４００Å（オングストロ一ム）の配向膜を形成した。対向ガラス基板と反射基板（いずれも配向膜を形成したもの）の間、および対向ガラス基板と透明基板（いずれも配向膜を形成したもの）の間にネマチック液晶およびスペーサ材を封入し、反射型液晶表示素子および透過型液晶表示素子をそれぞれ作製した。
【００５７】
この実施例６によれば、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ液晶表示素子のコントラスト比は、初期の値である５００：１に対して殆んど低下が認められず、耐光性が非常に優れていることが確認された。
【００５８】
実施例１〜６の液晶配向膜についてプレチルト角を測定した。プレチルト角の評価は、ＩＴＯ付きガラス基板上に上記で得た液晶配向材をスピンコート法により塗布、焼付けした後、ラビング処理を施すことで基板とした。この基板をセルギャップ５０μｍで逆平行のホモジニアス配向になるように対向配置して接着剤で固定し、その後真空注入法によりネマチック液晶を注入し、液晶注入口をＵＶ硬化接着剤により封止することで、プレチルト角の評価セルを得た。このようにして得たプレチルト角の評価セルを波長６３３ｎｍのＨｅ−Ｎｅレーザ光を光源として、クリスタルローテーション法により測定した。その結果プレチルト角は実施例１〜６のいずれも約３〜４度であり、比較的高い値であった。
【００５９】
（比較例１）
この比較例１では、ビシクロ（２，２，２）オクト−７−エン−２，３，５，６−テトラカルボン酸二無水物（ＢＣＤ）９．９６ｇと４，４′−ジアミノジフェニルエーテル（ｐ−ＤＡＤＥ）８ｇをＮ−メチル−２−ピロリドン（ＮＭＰ）７０ｇに溶解させ、生成水を除去するための共沸溶媒としてトルエン２５ｇ、イミド化触媒としてγ−カプロラクトンを０．４６ｇ、ピリジンを０．６３ｇ加え、常温で窒素雰囲気下で１０分間撹拌した後、１８０℃に昇温して２時間撹拌反応を行うことにより、重量平均分子量が４５，０００の可溶性ポリイミド溶液を得た。次に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加えて固形分濃度５重量％の溶液とし、この溶液を孔径１μｍのフィルタで濾過して液晶配向膜材の溶液を調整した。
【００６０】
この溶液を、液晶配向膜塗布用印刷機を用いて配向膜未形成の対向ガラス基板、反射基板および透明基板に塗布した結果、印刷ムラが発生した。その後、１００℃で３０分加熱した後２５０℃で３０分間加熱し、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を揮発させると共にポリイミドで厚さ８００Å（オングストローム）の配向膜を形成した。対向ガラス基板と反射基板（いずれも配向膜を形成したもの）の間、および対向ガラス基板と透明基板（いずれも配向膜を形成したもの）の間にネマチック液晶およびスペーサ材を封入し、反射型液晶表示素子および透過型液晶表示素子をそれぞれ作製した。
【００６１】
この比較例１によると、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して１００：１に低下した。
【００６２】
（比較例２）
この比較例２では、ビシクロ（２，２，２）オクト−７−エン−２，３，５，６−テトラカルボン酸二無水物（ＢＣＤ）９．９６ｇと２，２−ビス｛４−（４−アミノフェノキシ）フェニル｝プロパン（ＢＡＰＰ）１６．４ｇをもとに比較例１と同様に重量平均分子量が３５，０００の可溶性ポリイミド溶液を得て、反射型液晶表示素子および透過型液晶表示素子を作製した。
【００６３】
この比較例２によると、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギ一光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して２０：１と大幅に低下した。また、目視観察で表示むらの発生が認められた。
【００６４】
（比較例３）
この比較例３では、１，２，３，４−シクロペンタンテトラカルボン酸二無水物（ＣＰＤＡ）８．４１ｇと４，４′−ジアミノジフェニルエーテル（ｐ−ＤＡＤＥ）８．０ｇをもとに、Ｎ−メチル−２−ピロリドン（ＮＭＰ）９０ｇに溶解させ、ポリアミック酸タイプのポリイミド溶液を得て、反射型液晶表示素子および透過型液晶表示素子を作製した。
【００６５】
この比較例３によると、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して５０：１と大幅に低下した。
【００６６】
（比較例４）
この比較例４では、１，２，３，４−シクロペンタンテトラカルボン酸二無水物（ＣＰＤＡ）８．４１ｇと２，２−ビス｛４−（４−アミノフェノキシ）フェニル｝プロパン（ＢＡＰＰ）１６．４２ｇをもとに、Ｎ−メチル−２−ピロリドン（ＮＭＰ）１３０ｇに溶解させ、ポリアミック酸タイプのポリイミド溶液を得て、反射型液晶表示素子および透過型液晶表示素子を作製した。
【００６７】
この比較例４によると、各液晶表示素子に５Ｗ／ｃｍ^２のエネルギー光を５００時間照射したところ、液晶表示素子のコントラスト比は、初期の値である５００：１に対して２０：１と大幅に低下した。
【００６８】
【発明の効果】
以上説明してきた通り、本発明によれば、分子内に芳香族を含まない構造とするとともにイミド環含有オリゴマとして、例えば重量平均分子量を２０，０００以下に抑えることとしたため、耐光性に優れた高透明化が達成でき、印刷性や密着性に優れた液晶配向膜を得ることができ、また、表示むらの低減やコントラスト比の向上など、光による劣化を防止する液晶表示素子を得ることができる。
【図面の簡単な説明】
【図１】本発明の第２の実施の形態に係る反射型液晶表示素子を適用した液晶プロジェクタを示す断面図である。
【図２】本発明の第２の実施の形態に係る透過型液晶表示素子を適用した液晶ブロジェクタを示す図である。
【符号の説明】
１ 単結晶シリコン基板
２ ＭＯＳトランジスタ
３ 配線層
４ 反射画素電極
５ 誘電体膜
６、９ 配向膜
７ 柱状スペーサ
８ 液晶層
１０ 透明電極
１１ ガラス基板
１２ アクティブマトリックス基板
１３ 対向ガラス基板
１４ 位相板
１５ 偏光ビームスプリッタ
２１ 照明装置
２１Ａ，２１Ｂ 光源
２２ 発光部
２３ パラボラリフレクタ
２４ インテグレータレンズ
２５ 偏光変換装置
２７ 第一ダイクロイックミラー
２７Ａ 第一分割部
２７Ｂ 第二分割部
２８，３４ 凹レンズ
２９，４０ 反射ミラー
３０，３６ レンズ
３１，３２，３３ 液晶ライトバルブ
３１ａ，３２ａ，３３ａ 入射側偏光板
３１ｂ，３２ｂ，３３ｂ パネル部
３１ｃ，３２ｃ，３３ｃ 出射側偏光板
３５ 第二ダイクロイックミラー
３７，３９，４１ リレーレンズ
３８ 全反射ミラー
４０ 反射ミラー
４２ ダイクロイックプリズム
４３ 投写レンズ
４３ スクリーン[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal alignment film and a liquid crystal display element made of a soluble polyimide, and in particular, a liquid crystal alignment film having excellent light resistance capable of suppressing deterioration due to light, and a liquid crystal alignment film formed using the liquid crystal alignment film, such as a liquid crystal projector. The present invention relates to a reflection-type or transmission-type liquid crystal display element suitable for an apparatus using a light source that generates a high-intensity light beam.
[0002]
[Prior art]
Conventionally, as a method for controlling the alignment of nematic liquid crystal, a method of rubbing a liquid crystal alignment film made of polyimide to impart an alignment property to liquid crystal molecules has been widely used. Have been. Further, conventionally, as a liquid crystal aligning agent, a composition containing a polyamic acid solution type or a polyimide solution type obtained by reacting an aromatic diamine as a main component has been used (for example, see Patent Documents 1 to 9). .).
[0003]
[Patent Document 1]
JP-A-5-27244 ((0009) to (0013))
[Patent Document 2]
JP-A-5-43688 ((0012) to (0015))
[Patent Document 3]
JP-A-6-82794 ((0012))
[Patent Document 4]
JP-A-7-49501 ((0009) to (0018))
[Patent Document 5]
JP-A-8-100061 ((0006))
[Patent Document 6]
JP-A-9-176315 ((0010) to (0014))
[Patent Document 7]
JP-A-11-84391 ((0010) to (0014))
[Patent Document 8]
JP 2001-228483 A ((0013) to (0016))
[Patent Document 9]
JP-A-2002-20487 ((0011) to (0013))
[0004]
[Problems to be solved by the invention]
However, conventional liquid crystal aligning agents cannot achieve high transparency due to the aromatic ring present in the molecule, and therefore, when applied to a liquid crystal projector using a light source that generates high intensity light, non-uniformity occurs when displayed for a long time. There is a problem that deterioration due to light, such as generation of display unevenness and a decrease in contrast ratio, that is, light resistance is insufficient.
[0005]
Further, since the polyimide solution type liquid crystal aligning agent is a imide-ring-closed material, there is a problem that if the molecular weight is excessively increased, printability and adhesion are deteriorated.
[0006]
Therefore, an object of the present invention is to achieve high transparency with excellent light resistance, to achieve a liquid crystal alignment film having excellent printability and adhesion, and to prevent deterioration due to light, such as reduction in display unevenness and improvement in contrast ratio. It is to provide a liquid crystal display element.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a liquid crystal alignment film comprising a soluble polyimide, wherein the soluble polyimide is an imide ring-containing oligomer, and has the following general formula (1):
Embedded image

(X is a tetravalent aliphatic residue having a cyclic, linear, or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear, or cyclic and linear structure. A) a liquid crystal alignment film characterized by having a repeating unit of
[0008]
According to this configuration, since the alignment film does not contain an aromatic in the molecule, it can achieve high transparency with excellent light resistance, and is used in a liquid crystal projector that generates a high-intensity light beam when applied to a liquid crystal display device. In this case, it is possible to prevent deterioration due to light, such as reducing uneven display unevenness and improving the contrast ratio.
[0009]
In order to achieve the above object, the present invention provides a liquid crystal display device having a liquid crystal layer between a pair of substrates provided with an alignment film and electrodes made of a soluble polyimide, wherein the soluble polyimide is an imide ring-containing oligomer. And the following general formula (1):
Embedded image

(X is a tetravalent aliphatic residue having a cyclic, linear or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear or cyclic and linear structure. The present invention provides a liquid crystal display device having a repeating unit of (1).
[0010]
According to this configuration, since the alignment film does not contain an aromatic in the molecule, it can achieve high transparency with excellent light resistance, and is used in a liquid crystal projector that generates a high-intensity light beam when applied to a liquid crystal display device. In this case, it is possible to prevent deterioration due to light, such as reducing uneven display unevenness and improving the contrast ratio.
[0011]
Further, according to the present invention, in order to achieve the above object, a plurality of pixels each including a pixel electrode having a reflection mirror or a pixel electrode also serving as a reflection mirror and a pixel having a switching element are arranged in rows and columns, and An active matrix substrate provided with a first alignment film made of soluble polyimide, a transparent substrate provided with a second alignment film made of soluble polyimide and a transparent electrode, and disposed opposite to the active matrix substrate at a predetermined interval, In a reflective liquid crystal device comprising an active matrix substrate and a liquid crystal layer filled between the transparent substrates, the soluble polyimide is an imide ring-containing oligomer, and has the following general formula (1):
Embedded image

(X is a tetravalent aliphatic residue having a cyclic, linear or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear or cyclic and linear structure. The present invention provides a liquid crystal display device having a repeating unit of (1).
[0012]
According to this configuration, it is possible to obtain an alignment film that is excellent in light resistance and can achieve high transparency, and therefore, when the liquid crystal display element is applied to a liquid crystal projector that generates a high-intensity light beam, uneven display unevenness occurs. It is possible to prevent deterioration due to light, such as reduction of image quality and improvement of contrast ratio. Further, by controlling the weight average molecular weight of the imide ring-containing oligomer to, for example, 20,000 or less, printability and adhesion can be satisfied.
[0013]
Furthermore, in order to achieve the above object, the present invention arranges a plurality of pixels each having a transparent pixel electrode and a switching element in rows and columns, and forms a first alignment film made of soluble polyimide on the transparent pixel electrode. An active matrix substrate provided with a transparent electrode provided with a second alignment film made of a soluble polyimide, a transparent substrate opposed to the active matrix substrate at a predetermined interval, and between the active matrix substrate and the transparent substrate. Wherein the soluble polyimide is an imide ring-containing oligomer and has the following general formula (1):
Embedded image

(X is a tetravalent aliphatic residue having a cyclic, linear or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear or cyclic and linear structure. The present invention provides a liquid crystal display device having a repeating unit of (1).
[0014]
According to this configuration, since an alignment film that is excellent in light resistance and can achieve high transparency is used, when the liquid crystal display element is applied to a liquid crystal projector that generates high-intensity light rays, it is possible to reduce uneven display unevenness. Deterioration due to light, such as improvement in contrast ratio, can be prevented. Further, by controlling the weight average molecular weight of the imide ring-containing oligomer to, for example, 20,000 or less, printability and adhesion can be satisfied.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The liquid crystal alignment film according to the first embodiment of the present invention will be described. This liquid crystal alignment film is a liquid crystal alignment film made of a soluble polyimide, wherein the soluble polyimide is an imide ring-containing oligomer and has the following general formula (1):
Embedded image

(X is a tetravalent aliphatic residue having a cyclic, linear, or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear, or cyclic and linear structure. ), And the imide ring-containing oligomer is directly imidized by reacting a diamine and tetracarboxylic dianhydride in a polar solvent heated using a lactone-based polymerization catalyst. . As the above-mentioned tetravalent aliphatic residue X having a cyclic, linear or tubular and linear structure derived from tetracarboxylic dianhydride, compounds represented by the following general formulas (3) to (6) or isomers thereof The body can be mentioned.
Embedded image

Embedded image

Embedded image

Embedded image

[0016]
The general formula (3) is a chemical formula of a residue derived from bicyclo (2,2,2) oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCD), a general formula ( 4) is a chemical formula of a residue derived from 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA).
[0017]
Examples of the divalent aliphatic residue Y having a cyclic, linear, or cyclic and linear structure derived from the diamine include compounds represented by the following general formulas (7) to (14) or isomers thereof. .
Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

[0018]
The general formula (7) is the chemical formula of the residue of 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane (DMHM), and the general formula (12) is 3,9-bis (3- The chemical formula of the residue derived from (aminopropyl) -2,4,8,10-tetraoxaspiro- (5,5) -undecane (ATU), general formula (14), is represented by 4,4′-diaminodicyclohexylmethane (CHD) ) Is the chemical formula of the residue.
[0019]
The soluble polyimide is a liquid crystal alignment film of an imide ring-containing oligomer directly imidized by reacting tetracarboxylic dianhydride and diamine in an organic polar solvent heated using a lactone-based polymerization catalyst and the liquid crystal alignment. This is a liquid crystal display element formed using a film.
[0020]
Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, sulfolane, dimethylsulfoxide, anisole, dioxolan, butylcellosolve acetate, tetramethylurea, and lactone. It can be used, but two or more kinds may be used as a mixture.
[0021]
Examples of the lactone system as a polymerization catalyst include γ-caprolactone, γ-valerolactone, β-butyrolactone, γ-tetronic acid, γ-phthalide, γ-phthalide acid, γ-coumarin, and the like. , N-methylmorpholine and other basic compounds can also be used.
[0022]
A liquid crystal alignment film material can be obtained by diluting a polyimide obtained by reacting tetracarboxylic dianhydride and diamine in an organic solvent with an organic solvent. In order to improve the adhesion to the substrate, an alignment film material such as an amino-based material such as γ-aminopropyltriethoxysilane, δ-aminopropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, etc. A small amount of a silane coupling agent, an epoxy silane coupling agent, a titanate coupling agent, a surface treatment agent such as aluminum alcoholate, aluminum chelate, or zirconium chelate, an acrylic resin, or an epoxy resin can be mixed or reacted. The alignment film can be formed by a general spin coating method, printing method, dipping method, brush coating, roll coater method, spray method, or the like.
[0023]
Examples of the liquid crystal include 4-substituted phenyl-4'-substituted cyclohexane, 4-substituted cyclohexyl-4'-substituted cyclohexane, 4-substituted phenyl-4'-substituted dicyclohexane, 4-substituted dicyclohexyl-4'-substituted diphenyl, 4-substituted-4'-substituted terphenyl, 4-substituted biphenyl-4'-substituted cyclohexane, 2- (4-substituted phenyl) -5-pyrimidine, 2- (4-substituted dioxane) -5-phenyl, 4- Substituted benzoic acid-4'-phenyl ester, 4-substituted cyclohexanecarboxylic acid-4'-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid-4'-substituted biphenyl ester, 4- (4-substituted cyclohexanecarbonyloxy) benzoic acid -4'-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid-4 -Substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid-4'-substituted cyclohexyl ester, 4-substituted-4'-substituted biphenyl, 4-substituted cyclohexyl-4'-substituted phenyldioxane, 4-substituted cyclohexyl- And 4'-substituted phenylpyrimidine. Among these compounds, at least one terminal of the molecule has an alkyl group, an alkoxy group, an alkoxymethylene group, a cyano group, a fluorine group, a difluorine group, and a trifluorine group. A multi-component mixed liquid crystal composition is used.
[0024]
Examples of the diamine include 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane (DMHM).
[0025]
According to the first embodiment, a tetracyclic group having a tetravalent aliphatic residue having a cyclic, linear or cyclic and linear structure represented by the compounds represented by the general formulas (3) to (6) A carboxylic dianhydride and a diamine having a cyclic, linear or divalent aliphatic residue having a cyclic and linear structure represented by the compounds represented by the general formulas (7) to (14) as reaction components. Since it is used, a liquid crystal display device having excellent light resistance can be realized. Such a combination of a tetracarboxylic dianhydride and a diamine is also useful for achieving high transparency. Further, by using the compound represented by the general formula (7), a liquid crystal display device having a high pretilt angle can be realized.
[0026]
FIG. 1 shows a liquid crystal projector to which a reflection type liquid crystal display device according to a second embodiment of the present invention is applied. This liquid crystal projector also served as a liquid crystal display element in which a liquid crystal layer 8 was disposed between an active matrix substrate 12 and a counter glass substrate 13 to constitute a cell, a phase plate 14, a polarizer, and an analyzer. A polarization beam splitter 15. The active matrix substrate 12 includes a MOS (Metal Oxide Semiconductor) transistor 2, each of which is independently arranged on the single-crystal silicon substrate 1, a reflective pixel electrode 4 also serving as a reflector, a signal wiring for driving the MOS transistor 2, and a reflector. It is composed of a wiring layer 3 composed of wiring and the like for electrically connecting the pixel electrode 4 and the MOS transistor 2, a dielectric film 5 as a protective film, and an alignment film 6. The opposing glass substrate 13 includes a glass substrate 11 having an alignment film 9 and a transparent electrode 10.
[0027]
The reflective active matrix substrate 12 is formed by forming a MOS transistor 2 as an active element for driving a liquid crystal on a single crystal silicon substrate 1. The thickness of the liquid crystal layer 8 is uniformly maintained by the columnar spacers 7 disposed between the active matrix substrate 12 and the opposing glass substrate 13.
[0028]
The MOS transistor 2 is formed of a source diffusion layer, a source electrode, a drain diffusion layer, a drain electrode, a polysilicon gate, and the like on a silicon substrate and a p-type wafer, and has a spin-on-glass insulating layer for interlayer insulation.
[0029]
Examples of the material of the reflective pixel electrode 4 include metals having good reflectance in the visible light region, such as aluminum and silver. When the reflective pixel electrode 4 is formed on a flat surface, a stable film can be formed and good reflection characteristics can be obtained. It is desirable that the surface be polished and flattened.
[0030]
According to the second embodiment, since the alignment films 6 and 9 of the active matrix substrate 12 and the counter glass substrate 13 do not contain aromatics in their molecules, uneven display unevenness is reduced, contrast is improved, and the like. And deterioration due to light can be prevented.
[0031]
FIG. 2 shows an optical system of a two-light three-panel liquid crystal projector to which a transmission type liquid crystal display element according to a third embodiment of the present invention is applied. This liquid crystal projector introduces an illuminating device 21 that emits parallel light, and parallel light emitted from the illumination 21 through an integrator lens 24, a polarization conversion device 25, and a condenser lens 26, transmits red light, and transmits cyan light. A first dichroic mirror 27 that reflects colored light, a second dichroic mirror 35 that introduces cyan light reflected by the first dichroic mirror 27 through a concave lens 34, transmits blue light, and reflects green light; The red light transmitted through the dichroic mirror 27 is passed through the concave lens 28, the reflection mirror 29, the lens 30, and the liquid crystal light valve 31 for transmission red light, and the green light reflected by the second dichroic mirror 35 is transmitted to the lens 36 and transmission type. The blue light transmitted through the second dichroic mirror 35 via the green liquid crystal light valve 32 is relayed. The dichroic prism 42, which is introduced and synthesized through the lens 37, the total reflection mirror 38, the relay lens 39, the reflection mirror 40, the relay lens 41, and the transmission type liquid crystal light valve 33 for blue light, and the dichroic prism 42, respectively. And a projection lens 43 for enlarging and projecting the color image light onto a screen 44. The lighting device 21 includes two light sources 21A and 21B arranged side by side. The light emitting section 22 of each light source is composed of an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like. The irradiation light is emitted as parallel light by a parabolic reflector 23 and guided to an integrator lens 24.
[0032]
The integrator lens 24 is composed of a pair of lens groups. In the figure, the left half guides light emitted from the light source 21A to the front surfaces of the liquid crystal light valves 31, 32, 33, and the right half emits light from the light source 21B. The light is guided to the front surfaces of the liquid crystal light valves 31, 32, 33. The light that has passed through the integrator lens 24 passes through the polarization converter 25 and the condenser lens 26, and is then guided to the first dichroic mirror 27 (27A, 27B).
[0033]
The polarization conversion device 25 is configured by a plurality of polarization beam splitter arrays (hereinafter, referred to as “PBS arrays”). The PBS array includes a polarization splitting film and a retardation plate (1 / 2λ plate) (both are not shown). The polarization splitting film allows, for example, P-polarized light of the light from the integrator lens 24 to pass through, and reflects and emits S-polarized light by changing the optical path by 90 °. The P-polarized light that has passed through the PBS array is converted into S-polarized light by a phase difference plate provided on the front side (light emission side) and emitted. That is, almost all light is converted into S-polarized light.
[0034]
The first dichroic mirror 27 passes light in the red wavelength band and reflects light in the cyan (green + blue) wavelength band. The first dichroic mirror 27 includes a first division 27A and a second division 27B. The light in the red wavelength band transmitted through the first dichroic mirror 27 passes through the concave lens 28 and is reflected by the reflection mirror 29 to change the optical path. The red light reflected by the reflection mirror 29 passes through a lens 30 and passes through a transmissive liquid crystal light valve 31 for red light to be light-modulated. On the other hand, the light in the cyan wavelength band reflected by the first dichroic mirror 27 is guided to the second dichroic mirror 35 via the concave lens 34.
[0035]
The second dichroic mirror 35 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 35 is guided to a transmission type liquid crystal light valve 32 for green light through a lens 36, and is transmitted through the liquid crystal light valve 32, where the light is modulated. The light in the blue wavelength band transmitted through the second dichroic mirror 35 passes through a relay lens 37, a total reflection mirror 38, a relay lens 39, a reflection mirror 40, and a relay lens 41, and is a transmission type liquid crystal light valve for blue light. The light is guided to 33 and transmitted therethrough to be optically modulated.
[0036]
Each of the liquid crystal light valves 31, 32, 33 includes a panel unit 31b, 32b formed by sealing liquid crystal between the incident side polarizing plates 31a, 32a, 33a and a pair of glass substrates (on which a pixel electrode and an alignment film are formed). , 33b, and the output side polarizing plates 31c, 32c, 33c. The modulated lights (image light of each color) modulated by passing through the liquid crystal light valves 31, 32, 33 are combined by the dichroic prism 42 to become color image light. This color image light is enlarged and projected by the projection lens 43 and is projected and displayed on the screen 44.
[0037]
According to the third embodiment, since the alignment plates provided in the liquid crystal light valves 31, 32, and 33 do not contain aromatics in the molecules, the unevenness of the color projection image is reduced, and the contrast is reduced. It is possible to prevent deterioration due to light, such as an improvement in lightness.
[0038]
The alignment film of the present invention can be applied not only to the above-mentioned alignment film but also to both or one of the color filter portion and the electrode portion.
[0039]
【Example】
Hereinafter, examples of the present invention will be described together with comparative examples.
[0040]
(Example 1)
In Example 1, 8.41 g of 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and 9,3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane (DMHM) 9. 54 g was dissolved in 66 g of N-methyl-2-pyrrolidone (NMP), 25 g of toluene was used as an azeotropic solvent for removing formed water, 0.46 g of γ-caprolactone was used as an imidization catalyst, and 0.63 g of pyridine were added. A soluble polyimide having an imide ring-containing oligomer directly imidized by stirring at room temperature for 10 minutes under a nitrogen atmosphere, and then raising the temperature to 180 ° C. and performing a stirring reaction for 3 hours, and having a weight average molecular weight of 15,000. A solution was obtained. Next, N-methyl-2-pyrrolidone (NMP) was added to prepare a solution having a solid content of 5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to prepare a solution of a liquid crystal alignment film material.
[0041]
This solution was applied to a counter glass substrate, a reflective substrate, and a transparent substrate on which an alignment film was not formed using a liquid crystal alignment film coating printer, heated at 100 ° C. for 30 minutes, and then heated at 220 ° C. for 30 minutes. Methyl-2-pyrrolidone (NMP) was volatilized, and an alignment film having a thickness of 800 ° (angstrom) was formed of polyimide. A nematic liquid crystal and a spacer material are sealed between the opposing glass substrate and the reflective substrate (both having an alignment film) and between the opposing glass substrate and the transparent substrate (both having an alignment film). A liquid crystal display device and a transmission type liquid crystal display device were manufactured.
[0042]
According to the first embodiment, each liquid crystal display element has 5 W / cm. ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element hardly decreased from the initial value of 500: 1, and it was confirmed that the light resistance was very excellent. . In this example, it was confirmed that printability and adhesion were good even when a polyimide solution type soluble polyimide was used for the liquid crystal alignment film. In addition, the polyimide solution type comprising an imide ring-containing oligomer directly imidized does not cause a change in viscosity even when stored at room temperature, and is extremely superior to polyimides such as a polyamic acid solution type. Furthermore, using a lactone-based imidization polymerization catalyst, it becomes a hydroxycarboxylic acid at the time of polymerization reaction and acts as a polymerization catalyst, and after the reaction is completed, it returns to the original lactone-based solvent. In addition, since there is no acid remaining after volatilization after drying, there is an industrial advantage such that the steps of polymer precipitation, washing and drying are not required.
[0043]
(Example 2)
In Example 2, 9.96 g of bicyclo (2,2,2) oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCD) and 3,3′-dimethyl-4, 9.54 g of 4'-diamino-dicyclohexylmethane (DMHM) is dissolved in 70 g of N-methyl-2-pyrrolidone (NMP), 25 g of toluene is used as an azeotropic solvent for removing generated water, and γ- is used as an imidization catalyst. 0.46 g of caprolactone and 0.63 g of pyridine were added, and the mixture was stirred at room temperature under a nitrogen atmosphere for 10 minutes. Then, the mixture was heated to 180 ° C. and stirred for 3 hours. Thus, a soluble polyimide solution having a weight average molecular weight of 12,000 was obtained. Next, N-methyl-2-pyrrolidone (NMP) was added to prepare a solution having a solid content of 5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to prepare a solution of a liquid crystal alignment film material.
[0044]
This solution was applied to a counter glass substrate, a reflective substrate and a transparent substrate on which an alignment film was not formed using a liquid crystal alignment film coating printer, heated at 100 ° C. for 30 minutes, and then heated at 200 ° C. for 30 minutes to obtain N- Methyl-2-pyrrolidone (NMP) was volatilized, and an alignment film having a thickness of 600 ° (angstrom) was formed with polyimide. A nematic liquid crystal and a spacer material are sealed between the opposing glass substrate and the reflective substrate (both having an alignment film) and between the opposing glass substrate and the transparent substrate (both having an alignment film). A liquid crystal display device and a transmission type liquid crystal display device were manufactured.
[0045]
According to the second embodiment, each liquid crystal display element has 5 W / cm. ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element hardly decreased from the initial value of 500: 1, and it was confirmed that the light resistance was very excellent. .
[0046]
(Example 3)
In Example 3, 7.84 g of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBTA) and 9.54 g of 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane (DMHM) Was dissolved in 68 g of N-methyl-2-pyrrolidone (NMP), 25 g of toluene was used as an azeotropic solvent for removing generated water, 0.46 g of γ-caprolactone was used as an imidization catalyst, and 0.63 g of pyridine were added. A soluble polyimide solution having an imide ring-containing oligomer directly imidized by stirring at room temperature for 10 minutes under a nitrogen atmosphere and then raising the temperature to 180 ° C. and performing a stirring reaction for 3 hours, and having a weight average molecular weight of 18,000. Got. Next, N-methyl-2-pyrrolidone (NMP) was added to prepare a solution having a solid content of 5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to prepare a solution of a liquid crystal alignment film material.
[0047]
This solution was applied to a counter glass substrate, a reflective substrate, and a transparent substrate on which an alignment film was not formed using a liquid crystal alignment film coating printer, heated at 100 ° C. for 30 minutes, and then heated at 250 ° C. for 30 minutes to obtain N- Methyl-2-pyrrolidone (NMP) was volatilized, and an alignment film having a thickness of 900 ° (angstrom) was formed with polyimide. A nematic liquid crystal and a spacer material are sealed between the opposing glass substrate and the reflective substrate (both having an alignment film) and between the opposing glass substrate and the transparent substrate (both having an alignment film). A liquid crystal display device and a transmission type liquid crystal display device were manufactured.
[0048]
According to the third embodiment, 5 W / cm ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element hardly decreased from the initial value of 500: 1, and it was confirmed that the light resistance was very excellent. .
[0049]
(Example 4)
In Example 4, 4.21 g of 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and bicyclo (2,2,2) oct-7-ene-2,3,5,6 4.98 g of tetracarboxylic dianhydride, 4.77 g of 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane (DMHM) and 3,9-bis (3-aminopropyl) -2,4 5.49 g of 8,10-tetraoxaspiro- (5,5) undecane (ATU) is dissolved in 68 g of N-methyl-2-pyrrolidone (NMP), and 25 g of toluene is used as an azeotropic solvent for removing generated water. Then, 0.46 g of γ-caprolactone and 0.63 g of pyridine were added as an imidization catalyst, and the mixture was stirred at room temperature under a nitrogen atmosphere for 10 minutes, and then heated to 180 ° C. for 3 hours to perform a stirring reaction. It has imidization imide ring-containing oligomer, the weight average molecular weight to obtain a soluble polyimide solution 19,500. Next, N-methyl-2-pyrrolidone (NMP) was added to prepare a solution having a solid content of 5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to prepare a solution of a liquid crystal alignment film material.
[0050]
This solution was applied to a counter glass substrate, a reflective substrate, and a transparent substrate on which an alignment film was not formed using a liquid crystal alignment film coating printer, heated at 100 ° C. for 30 minutes, and then heated at 220 ° C. for 30 minutes to obtain N- Methyl-2-pyrrolidone (NMP) was volatilized and an alignment film having a thickness of 700 ° (angstrom) was formed with polyimide. A nematic liquid crystal and a spacer material are sealed between the opposing glass substrate and the reflective substrate (both having an alignment film) and between the opposing glass substrate and the transparent substrate (both having an alignment film). A liquid crystal display device and a transmission type liquid crystal display device were manufactured.
[0051]
According to the fourth embodiment, each liquid crystal display element has 5 W / cm. ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element hardly decreased from the initial value of 500: 1, and it was confirmed that the light resistance was very excellent. .
[0052]
(Example 5)
In this Example 5, 8.41 g of 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane (DMHM) 4. 77 g and 2.28 g of 4,4'-diaminodicyclohexylmethane (CHD) are dissolved in 68 g of N-methyl-2-pyrrolidone (NMP), 25 g of toluene is used as an azeotropic solvent for removing generated water, and an imidization catalyst is used. 0.46 g of γ-caprolactone and 0.63 g of pyridine were added, and the mixture was stirred at room temperature under a nitrogen atmosphere for 10 minutes, and then heated to 180 ° C. and stirred for 2 hours to directly perform imidization, thereby containing an imide ring. A soluble polyimide solution having an oligomer and a weight average molecular weight of 14,000 was obtained. Next, N-methyl-2-pyrrolidone (NMP) was added to prepare a solution having a solid content of 5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to prepare a solution of a liquid crystal alignment film material.
[0053]
This solution was applied to a counter glass substrate, a reflection substrate, and a transmission substrate on which an alignment film was not formed using a liquid crystal alignment film coating printer, heated at 100 ° C. for 30 minutes, and then heated at 190 ° C. for 30 minutes to obtain N-. Methyl-2-pyrrolidone (NMP) was volatilized, and a 400 ° (angstrom) thick alignment film was formed of polyimide. A nematic liquid crystal and a spacer material are sealed between the opposing glass substrate and the reflective substrate (both having an alignment film) and between the opposing glass substrate and the transparent substrate (both having an alignment film). A liquid crystal display device and a transmission type liquid crystal display device were manufactured.
[0054]
According to the fifth embodiment, 5 W / cm ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element hardly declined from the initial value of 500: 1, and it was confirmed that the light resistance was very excellent. Was.
[0055]
(Example 6)
In Example 6, 7.84 g of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBTA) and 4.77 g of 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane (DMHM) were used. And 2,4 g of 4,4'-diaminodicyclohexylmethane (CHD) are dissolved in 68 g of N-methyl-2-pyrrolidone (NMP), 25 g of toluene as an azeotropic solvent for removing generated water, and 0.46 g of γ-caprolactone and 0.63 g of pyridine were added, and the mixture was stirred at room temperature under a nitrogen atmosphere for 10 minutes, then heated to 180 ° C. and subjected to a stirring reaction for 3 hours to contain an imide ring directly imidized. A soluble polyimide solution having an oligomer and a weight average molecular weight of 11,000 was obtained. Next, N-methyl-2-pyrrolidone (NMP) was added to prepare a solution having a solid content of 5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to prepare a solution of a liquid crystal alignment film material.
[0056]
This solution was applied to a counter glass substrate, a reflection substrate, and a transmission substrate on which an alignment film was not formed using a liquid crystal alignment film coating printer, heated at 100 ° C. for 30 minutes, and then heated at 190 ° C. for 30 minutes to obtain N-. Methyl-2-pyrrolidone (NMP) was volatilized, and an alignment film having a thickness of 400 ° (angstrom) was formed with polyimide. A nematic liquid crystal and a spacer material are sealed between the opposing glass substrate and the reflective substrate (both having an alignment film) and between the opposing glass substrate and the transparent substrate (both having an alignment film). A liquid crystal display device and a transmission type liquid crystal display device were manufactured.
[0057]
According to the sixth embodiment, each liquid crystal display element has 5 W / cm ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element hardly decreased from the initial value of 500: 1, and it was confirmed that the light resistance was very excellent. .
[0058]
The pretilt angles of the liquid crystal alignment films of Examples 1 to 6 were measured. The evaluation of the pretilt angle was performed by applying and baking the liquid crystal alignment material obtained above on a glass substrate with ITO by a spin coating method, and then performing a rubbing treatment. This substrate is disposed facing the anti-parallel homogeneous alignment with a cell gap of 50 μm and fixed with an adhesive, and then a nematic liquid crystal is injected by a vacuum injection method, and the liquid crystal injection port is sealed with a UV curing adhesive. Thus, an evaluation cell having a pretilt angle was obtained. The pretilt angle evaluation cell obtained in this manner was measured by a crystal rotation method using He-Ne laser light having a wavelength of 633 nm as a light source. As a result, the pretilt angle was about 3 to 4 degrees in all of Examples 1 to 6, which was a relatively high value.
[0059]
(Comparative Example 1)
In Comparative Example 1, 9.96 g of bicyclo (2,2,2) oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCD) and 4,4′-diaminodiphenyl ether (p -DADE) was dissolved in 70 g of N-methyl-2-pyrrolidone (NMP), and 25 g of toluene was used as an azeotropic solvent for removing formed water, 0.46 g of γ-caprolactone was used as an imidization catalyst, and 0.1 g of pyridine was used. After adding 63 g and stirring at room temperature for 10 minutes under a nitrogen atmosphere, the temperature was raised to 180 ° C., and a stirring reaction was performed for 2 hours to obtain a soluble polyimide solution having a weight average molecular weight of 45,000. Next, N-methyl-2-pyrrolidone (NMP) was added to prepare a solution having a solid content of 5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to prepare a solution of a liquid crystal alignment film material.
[0060]
This solution was applied to a counter glass substrate, a reflective substrate, and a transparent substrate on which an alignment film was not formed using a liquid crystal alignment film coating printer, and as a result, printing unevenness occurred. Thereafter, the film was heated at 100 ° C. for 30 minutes and then at 250 ° C. for 30 minutes to volatilize N-methyl-2-pyrrolidone (NMP) and form an alignment film having a thickness of 800 ° (angstrom) with polyimide. A nematic liquid crystal and a spacer material are sealed between the opposing glass substrate and the reflective substrate (both having an alignment film) and between the opposing glass substrate and the transparent substrate (both having an alignment film). A liquid crystal display device and a transmission type liquid crystal display device were manufactured.
[0061]
According to Comparative Example 1, each liquid crystal display element had a 5 W / cm ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element was reduced to 100: 1 from the initial value of 500: 1.
[0062]
(Comparative Example 2)
In Comparative Example 2, 9.96 g of bicyclo (2,2,2) oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCD) and 2,2-bis {4- ( Based on 16.4 g of 4-aminophenoxy) phenyl @ propane (BAPP), a soluble polyimide solution having a weight average molecular weight of 35,000 was obtained in the same manner as in Comparative Example 1, and a reflection type liquid crystal display device and a transmission type liquid crystal display device were obtained. Was prepared.
[0063]
According to Comparative Example 2, 5 W / cm ² Irradiating the liquid with the same energy for 500 hours, the contrast ratio of the liquid crystal display element was greatly reduced to 20: 1 from the initial value of 500: 1. In addition, display unevenness was observed by visual observation.
[0064]
(Comparative Example 3)
In Comparative Example 3, based on 8.21 g of 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and 8.0 g of 4,4′-diaminodiphenyl ether (p-DADE), N The resultant was dissolved in 90 g of -methyl-2-pyrrolidone (NMP) to obtain a polyimide solution of a polyamic acid type, thereby producing a reflection type liquid crystal display device and a transmission type liquid crystal display device.
[0065]
According to Comparative Example 3, 5 W / cm was applied to each liquid crystal display element. ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element was greatly reduced to 50: 1 from the initial value of 500: 1.
[0066]
(Comparative Example 4)
In Comparative Example 4, 8.41 g of 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and 2,2-bis {4- (4-aminophenoxy) phenyl} propane (BAPP) 16 The solution was dissolved in 130 g of N-methyl-2-pyrrolidone (NMP) based on 0.42 g to obtain a polyamic acid-type polyimide solution, thereby producing a reflection type liquid crystal display device and a transmission type liquid crystal display device.
[0067]
According to Comparative Example 4, 5 W / cm ² Was irradiated for 500 hours, the contrast ratio of the liquid crystal display element was greatly reduced to 20: 1 from the initial value of 500: 1.
[0068]
【The invention's effect】
As described above, according to the present invention, the structure is such that no aromatic is contained in the molecule, and the imide ring-containing oligomer has a weight-average molecular weight of, for example, 20,000 or less. It is possible to obtain a liquid crystal alignment film which can achieve high transparency, have excellent printability and adhesiveness, and which can prevent deterioration due to light, such as reducing display unevenness and improving a contrast ratio. it can.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a liquid crystal projector to which a reflection type liquid crystal display device according to a second embodiment of the present invention is applied.
FIG. 2 is a view showing a liquid crystal projector to which a transmission type liquid crystal display element according to a second embodiment of the present invention is applied.
[Explanation of symbols]
1 Single crystal silicon substrate
2 MOS transistor
3 Wiring layer
4 Reflection pixel electrode
5 Dielectric film
6, 9 alignment film
7 Column spacer
8 Liquid crystal layer
10 Transparent electrode
11 Glass substrate
12 Active matrix substrate
13 Opposing glass substrate
14 Phase plate
15 Polarizing beam splitter
21 Lighting equipment
21A, 21B light source
22 Light emitting unit
23 Parabolic reflector
24 Integrator lens
25 Polarization converter
27 First Dichroic Mirror
27A First division
27B Second division
28,34 concave lens
29,40 Reflecting mirror
30, 36 lens
31, 32, 33 Liquid crystal light valve
31a, 32a, 33a Incident side polarizing plate
31b, 32b, 33b Panel section
31c, 32c, 33c Outgoing side polarizing plate
35 Second Dichroic Mirror
37,39,41 relay lens
38 Total reflection mirror
40 reflection mirror
42 dichroic prism
43 Projection lens
43 screen

Claims (16)

In a liquid crystal alignment film made of soluble polyimide,
The soluble polyimide is an imide ring-containing oligomer and has the following general formula (1):

(X is a tetravalent aliphatic residue having a cyclic, linear, or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear, or cyclic and linear structure. A) a liquid crystal alignment film comprising: The imide ring-containing oligomer is directly imidized by reacting a diamine and tetracarboxylic dianhydride in a polar solvent heated using a lactone-based polymerization catalyst. The liquid crystal alignment film as described in the above. The liquid crystal alignment film according to claim 1, wherein the soluble polyimide has a weight average molecular weight of 20,000 or less. The soluble polyimide is a unit represented by the following general formula (2) as a divalent aliphatic residue Y having a cyclic, linear or cyclic and linear structure,

3. The liquid crystal alignment film according to claim 2, comprising the isomer. In a liquid crystal display element having a liquid crystal layer between a pair of substrates having an alignment film and electrodes made of soluble polyimide,
The soluble polyimide is an imide ring-containing oligomer and has the following general formula (1):

(X is a tetravalent aliphatic residue having a cyclic, linear or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear or cyclic and linear structure. A liquid crystal display device having a repeating unit of the formula (1). The imide ring-containing oligomer is directly imidized by reacting a diamine and tetracarboxylic dianhydride in a polar solvent heated using a lactone-based polymerization catalyst. The liquid crystal display element as described in the above. 6. The liquid crystal display device according to claim 5, wherein the soluble polyimide has a weight average molecular weight of 20,000 or less. The soluble polyimide is a unit represented by the following general formula (2) as a divalent aliphatic residue Y having a cyclic, linear or cyclic and linear structure,

6. The liquid crystal display device according to claim 5, wherein the liquid crystal display device comprises: A plurality of pixel electrodes each having a reflection mirror or a plurality of pixels each having a pixel electrode also serving as a reflection mirror and a switching element are arranged in rows and columns, and a first alignment film made of soluble polyimide is provided on the reflection mirror. An active matrix substrate, a transparent substrate including a second alignment film made of soluble polyimide and a transparent electrode, and a transparent substrate opposed to the active matrix substrate at a predetermined interval, and a liquid crystal filled between the active matrix substrate and the transparent substrate A reflective liquid crystal device comprising
The soluble polyimide is an imide ring-containing oligomer and has the following general formula (1):

(X is a tetravalent aliphatic residue having a cyclic, linear or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear or cyclic and linear structure. A liquid crystal display device comprising a repeating unit of the formula (1). The imide ring-containing oligomer is directly imidized by reacting a diamine and tetracarboxylic dianhydride in a polar solvent heated using a lactone-based polymerization catalyst. The liquid crystal display element as described in the above. The liquid crystal display device according to claim 7, wherein the soluble polyimide has a weight average molecular weight of 20,000 or less. The soluble polyimide is a unit represented by the following general formula (2) as a divalent aliphatic residue Y having a cyclic, linear or cyclic and linear structure,

The liquid crystal display device according to claim 7, wherein the liquid crystal display device contains the isomer. An active matrix substrate in which a plurality of pixels each having a transparent pixel electrode and a switching element are arranged in rows and columns, and a first alignment film made of a soluble polyimide is provided on the transparent pixel electrode; A transmission type liquid crystal comprising: a transparent substrate provided with a transparent electrode provided with a second alignment film; and a transparent substrate opposed to the active matrix substrate at a predetermined interval; and a liquid crystal layer filled between the active matrix substrate and the transparent substrate. In the element
The soluble polyimide is an imide ring-containing oligomer and has the following general formula (1)

(X is a tetravalent aliphatic residue having a cyclic, linear or cyclic and linear structure, and Y is a divalent aliphatic residue having a cyclic, linear or cyclic and linear structure. A liquid crystal display device comprising a repeating unit of the formula (1). 12. The imide ring-containing oligomer is directly imidized by reacting a diamine and tetracarboxylic dianhydride in a polar solvent heated using a lactone-based polymerization catalyst. The liquid crystal display element as described in the above. The liquid crystal display device according to claim 11, wherein the soluble polyimide has a weight average molecular weight of 20,000 or less. The soluble polyimide is a unit represented by the following general formula (2) as a divalent aliphatic residue Y having a cyclic, linear or cyclic and linear structure,

12. The liquid crystal display device according to claim 11, wherein the liquid crystal display device contains the isomer.

Images