JP3690634B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display without any disturbance of orientation, with high contrast and a high numerical aperture and a method for its manufacture. SOLUTION: A liquid crystal layer held between a first and a second substrates is provided. The liquid crystal layer has plural liquid crystal regions divided by columnar spacers reaching the first and the second substrates. In this case, the columnar spacers have planes inclined toward the surfaces of each of the first and the second substrates at the sections brought in contact with the first and the second substrates.

Description

【００４７】
柱状スペーサ２５の傾斜角はＳＥＭによる断面観察の結果、基板８と接する部分で２０度、中間シート３と接する部分で１５度であった。
【００４８】
プラズマ基板２に電圧を加えてプラズマを発生させて液晶層６に電圧を印加して、液晶分子が軸対称状に配向した状態で、ＵＶ光を３６５ｎｍの波長で４ｍＷ／ｃｍ²の強度で１０分間照射して軸対称状の液晶配向を得た。これを偏光顕微鏡（クロスニコル）下で観察すると、実施形態１の時と同様で、図６（ａ）に示すように絵素領域の中央から４辺に向かって消光模様が観察され、絵素領域の周辺部においての透過率の低下は見られなかった。
【００４９】
（実施形態３）
コーニング社製７０５９ガラス基板８の上にＩＴＯからなる厚さ１００ｎｍの透明電極１０を形成し、さらにこの上にに膜厚が５μｍになるようにＶ２５９−ＰＡ（新日鐵化学社製）をスピンコート法で塗布した。ホットプレート上で１００℃／３分間加熱した後に循環オーブンで８０℃／１５分間さらに加熱した。図５のように１００μｍ×１００μｍ角の遮光部２９を有して透光部３０の幅が２５μｍのマスクを用い、マスク越しにコンタクト露光を１２０秒行った。その時の照度は３６５ｎｍで１０ｍＷ／ｃｍ²であった。これを０．４％−Ｋ₂ＣＯ₃・ａｑで３００秒現像し、純水シャワーで１２０秒間リンスを行った後、２４０℃の循環オーブンで１時間ポストベークを行い柱状スペーサ２５を形成した。水平配向膜ＡＬ−３０４６（ＪＳＲ社製）を８０ｎｍの膜厚になるように塗布して、１８０℃の循環オーブンで１時間焼成して配向膜層２６を形成した。
【００５０】
厚さ１００ｎｍのＩＴＯからなる透明電極の付いたガラス基板４の上にも同じ水平配向膜ＡＬ−３０４６を８０ｎｍの膜厚になるように塗布して配向膜層２６を形成し、先のガラス基板８と貼り合わせると図１に示すようなセルを作製することができた。傾斜角はＳＥＭによる断面観察の結果、基板８と接する部分で３６度、基板４と接する部分で４３度であった。
【００５１】
ここに誘電異方性が正の液晶材料Ｅ７（メルク社製）を注入したが、配向不良に起因する透過率変化は観察されず、柱状スペーサ２５周辺部においても配向が乱れていなかった。
【００５２】
（実施形態４）
コーニング社製ガラス基板４、８の上に、１００ｎｍの厚さの透明電極９、１０を形成し、さらにこの上にＪＣＲ ＢＬＡＣＫ５３５（ＪＳＲ社製）をスピンコート法で２．５μｍの膜厚になるように塗布し、ホットプレート上で８０℃／５分間加熱した。図１１のように５０μｍ×５０μｍ角の絵素２８の４角に１０μｍ角の柱状スペーサ２５が形成されるように設計されたマスクを用い、マスク越しにコンタクト露光を２５秒行った。その時の照度は３６５ｎｍで１０ｍＷ／ｃｍ²であった。これを専用現像液ＣＤ−２００ＣＲ（５０倍希釈、２５℃）で８０秒現像し、純水シャワーで６０秒間リンスを行った後、２２０℃の循環オーブンで３０分間ポストベークを行い図１２（ａ）に示すように柱状スペーサ２５（ａ）、２５（ｂ）を形成した。柱状スペーサ２５（ａ）、２５（ｂ）が、ガラス基板４、８と接している点での傾斜角（θ）は共に２５度であることがＳＥＭによる断面観察の結果分かった。両ガラス基板の柱状スペーサが形成された側にさらに垂直配向膜ＪＡＬＳ−２０４（ＪＳＲ社製）を８０ｎｍの膜厚で塗布し、１８０℃で１時間ポストベークを行い配向膜層２６を形成した。図１２（ｂ）に示すように両ガラス基板４、８を柱状スペーサ２５（ａ）と柱状スペーサ２５（ｂ）がちょうど重なり合うように位置合わせを行いシール剤を介して貼り合わせた。
【００５３】
誘電異方性が負の液晶（△ε：−４．０、△ｎ＝０．０８、セルギャップ５μｍで９０度ツイストとなるようにカイラル剤を添加）を先のセルに注入してクロスニコル下で偏光顕微鏡観察を行った。電庄を基板間に印加すると図１３（ａ）に示すように絵素領域の中央から４辺に向かって消光模様が観察されるようになり、軸対称状に液晶分子が配向していた。柱状スペーサ２５近傍での光漏れは観察されなかった。
【００５４】
（比較例３）
コーニング社製ガラス基板４、８の上に、１００ｎｍの厚さの透明電極９、１０を形成し、この上にＪＣＲ ＢＬＡＣＫ５３５（ＪＳＲ社製）をスピンコート法で２．５μｍの膜厚になるように塗布して、ホットプレート上で８０℃／４分間加熱した。実施形態４と同じマスクを用い同じ条件で露光を行った。
これを専用現像液ＣＤ−２００ＣＲ（５０倍希釈、２５℃）で５０秒現像し、純水シャワーで６０秒間リンスを行った。その後、２２０℃の循環オーブンで３０分間ポストベークを行うと、図１４（ａ）に示すように台形の柱状スペーサ２５（ａ）、２５（ｂ）が得られ、それぞれがガラス基板４、８と接している点での傾斜角（θ）は共に８０度であることがＳＥＭによる断面観察の結果分かった。両ガラス基板の柱状スペーサが形成された側にさらに垂直配向膜ＪＡＬＳ−２０４（ＪＳＲ社製）を８０ｎｍ膜厚で塗布し、１８０℃で１時間ポストベークを行い配向膜層２６を作製して、両ガラス基板４、８を、図１４（ｂ）のように柱状スペーサどうしがちょうど重なり合うように位置合わせを行いシール剤を介して貼り合わせた。
【００５５】
実施形態４と同じ誘電異方性が負の液晶（△ε＝−４．０、△ｎ＝０．０８、セルギャップ５μｍで９０度ツイストとなるようにカイラル添加済み）をこのセルに注入してクロスニコル下で偏光顕微鏡観察を行った。電圧を基板間に印加すると図１３（ｂ）に示すように液晶分子が軸対称状に配向することによる消光模様が観察されるが、先の実施形態４とは異なり柱状スペーサ２５近傍で光漏れ３１が観察された。
【００５６】
（実施形態５）
図１５に示すプラズマアドレス型液晶表示装置を形成する。基板４の上にアノード電極Ａおよびカソード電極Ｋをライン状に形成し、アノード電極Ａ上に隔壁７をライン状に形成し、この基板を中間シート３である薄板ガラスと貼り合わせた。この基板４と薄板ガラス３と隔壁７で囲まれた空間に電離用ガスを封入してライン状の放電チャンネル５を形成し、プラズマセル２を作製した。
【００５７】
赤（Ｒ）、緑（Ｇ）、青（Ｂ）およびブラックマトリクス（ＢＭ）からなるカラーフィルター（ＣＦ）１３を形成したガラス基板８にＩＴＯ１０を２５０ｎｍ厚さで形成した。この基板８および先ほどのプラズマ基板２の中間シート３上にＪＣＲ ＢＬＡＣＫ５３５（ＪＳＲ社製）をスピンコート法で３μｍの膜厚になるように塗布し、ホットプレート上で８０℃／５分間加熱した。実施形態４と同じマスクを用い、同じ露光条件、現像条件、焼成（ポストベーク）条件で柱状スペーサを形成した。それぞれの基板と柱状スペーサが接している点での傾斜角（θ）は共に２０度であることがＳＥＭによる断面観察の結果分かった。
【００５８】
両ガラス基板の柱状スペーサが形成された側にさらに垂直配向膜ＪＡＬＳ−２０４（ＪＳＲ社製）を１００ｎｍの膜厚で塗布し、１８０℃で１時間ポストベークを行い配向膜層２６を作製して、プラズマ基板２とガラス基板８を柱状スペーサどうしがちょうど重なり合うように位置合わせを行いシール剤を介して貼り合わせ、図１５に示すプラズマアドレス型の液晶表示用のセルを作製した。
【００５９】
誘電異方性が負の液晶（△ε＝−４．０、△ｎ：０．０８、セルギャップ６μｍで９０度ツイストとなるようにカイラル剤添加）を先のセルに注入してクロスニコル下で偏光顕微鏡観察を行った。プラズマ基板に電圧を印加して基板間にかかる電圧を増していくと先の実施形態４と同様に、図１３（ａ）に示すように絵素領域の中央から４辺に向かって消光模様が観察されるようになり、軸対称状に液晶分子が配向していた。柱状スペーサ２５近傍での光漏れは観察されなかった。
【００６０】
（実施形態６）
１００ｎｍ厚の透明電極１０が形成されたガラス基板８の上に感光性ポリイミドを膜厚６μｍになるようにスピンコーターを使って塗布した。ホットプレートで９０℃／１０ｍｉｎプリベークし、３６５ｎｍで１０ｍＷ／ｃｍ²２０秒コンタクト露光を行い、循環オーブンで１７５℃／１５ｍｉｎポストエクポージャーベークを行い、専用現像液（５０％に希釈）を用いて２５℃で１分間現像行った。その後、ＩＰＡで３０秒間リンスし、循環オーブンで２００℃／３０ｍｉｎポストベークを行った。これらの一連の操作を標準の条件とし、一つだけ条件を変えて図１６に示すように基板上に柱状スペーサ２５（ｂ）を形成し、その柱状スペーサ２５（ｂ）が基板８と接する部分で傾斜になっている面の傾斜角（θ）を測定した。これを図１７（ａ）〜（ｈ）に示す。
図１７（ａ）〜（ｈ）から明らかなように、プリベーク温度（ａ）、プリベーク時間（ｂ）、マスクギャップ（ｃ）、露光強度（ｄ）、露光時間（ｅ）、現像温度（ｆ）、現像時間（ｇ）、現像液濃度（ｈ）のいずれかを変化させると、傾斜角を制御できることが明らかになった。
【００６１】
（実施形態７）
コーニング社製ガラス基板４，８の上に、１００ｎｍの厚さの透明電極９，１０を形成し、この上に膜厚が３μｍになるようにＪＮＰＣ−４３（ＪＳＲ社製）をスピンコートした。プリベークはホットプレートで温度を６０℃から８０℃、焼成時間を１分から５分間とし、図１８に示す様に１００μｍ×１００μｍの絵素２８の四辺に柱状スペーサ２５が線幅２５μｍで作製されるようなマスクを用い、マスクギャップを５０μｍにして露光を６０秒（ＵＶ照度１０ｍＷ／ｃｍ²３６５ｎｍ）行った。これを専用現像液ＣＤ（１５％希釈、２５℃）で１００秒から３６０秒現像し、純水シャワーで１２０秒間リンスを行った後、２００℃の循環オーブンで１時間ポストベークを行い柱状スペーサ２５（ａ）、２５（ｂ）を形成した。
【００６２】
傾斜角の測定を行うと表１に示すように５度から１００度の範囲のθを持つ柱状スペーサができていることが確認された。
【００６３】
両ガラス基板の柱状スペーサが形成された側に垂直配向膜ＪＡＬＳ−２０４（ＪＳＲ社製）を８０ｎｍの膜厚で塗布し、１８０℃で１時間ポストベークを行い配向膜層２６を作製して、両ガラス基板４，８を柱状スペーサ２５（ａ）と柱状スペーサ２５（ｂ）がちょうど重なり合うように位置合わせを行いシール剤を介して貼り合わせた。誘電異方性が負の液晶（△ε＝−４．０、△ｎ＝０．０８、セルギャップ６μｍで９０度ツイストとなるようにカイラル剤を添加）をセルに注入してガラス基板４，８の外側（液晶層６と反対の側）に偏光板をクロスニコル状態になるように貼り付けた。
【００６４】
両ガラス基板間に電圧を印加していき、閾値電圧（Ｖｔｈ）を越えてもさらに電圧を印加し続けると液晶領域では絵素の中央から４方へのびていく消光模様が観察されるようになるが、本実施形態においては柱状スペーサ２５周辺において電圧無印加時に光漏れが観察されるものがあった。この光漏れの程度を比較するために透過率測定を行った結果を以下の表１に示す。
【００６５】
【表１】

傾斜角度（度） ５ １４ ３８ ４５ ５７ ６３ ７３ ８８ １０８
透過率（％） ２０ ２１ ２４ ２３ ２５ ４８ ４９ ６４ ７１
【００６６】
上記の表１に示したように、傾斜角が６３度になった段階から透過率の低下が発生していることがわかる。これは、傾斜角が６０度を越えると、液晶分子の配向方向が急激に変化するために、柱状スペーサ付近で液晶分子の配向が乱れていることを示している。この結果から、柱状スペーサの傾斜角は６０度以下が好ましいことが分かる。
【００６７】
（実施形態８）
基板４の上にアノード電極Ａおよびカソード電極Ｋをライン状に形成し、アノード電極上に隔壁７をライン状に形成し、この基板を中間シート３である薄板ガラスと貼り合わせた。この基板４と薄板ガラス３と隔壁７で囲まれた空間に電離用ガスを封入してライン状の放電チャンネル５を形成し、プラズマセル２を作製した。
【００６８】
赤（Ｒ）、緑（Ｇ）、青（Ｂ）およびブラックマトリクス（ＢＭ）からなるカラーフィルター（ＣＦ）１３を形成したガラス基板８にＩＴＯからなる電極１０を厚さ２５０ｎｍで形成した。この基板８のＩＴＯ上にＪＣＲ ＢＬＡＣＫ５３５（ＪＳＲ社製）をスピンコート法で６μｍの膜厚になるように塗布し、ホットプレート上で８０℃／８分間加熱した。図１９（ａ）に示すような１００μｍ角の絵素（図中の四角）を囲むように半径２５μｍの断面が円形の柱状スペーサ２５が形成できるような設計になったマスクを用い、マスク越しにコンタクト露光を６０秒行った。その時の照度は３６５ｎｍで１０ｍＷ／ｃｍ²であった。これを専用現像液ＣＤ−２００ＣＲ（５０倍希釈、２５℃）で８０秒現像し、純水シャワーで６０秒間リンスを行った後、さらに同じ現像液で２０秒現像をし、純水シャワーで再び６０秒間リンスを行った。２２０℃の循環オーブンで３０分間ポストベークを行い柱状スペーサ２５を形成した。
【００６９】
柱状スペーサの配置は図１９（ａ）に示した例に限られず、例えば、図１９（ｂ）のように配置してもよい。柱状スペーサの配置及び密度は、液晶表示装置の構成や用途に応じて適宜設定される。
【００７０】
プラズマセル２の中間シート３、およびガラス基板８の柱状スペーサが形成された側に、垂直配向膜ＪＡＬＳ−２０４（ＪＳＲ社製）を６０ｎｍの膜厚で塗布し、１８０℃で１時間ポストペークを行い配向膜層（図示しない）を作製してシール剤を介して貼り合わせ、図２０に示すプラズマアドレス型の液晶表示用のセルを作製した。
【００７１】
ＩＴＯ電極１０および中間シート３とそれぞれ接している点での傾斜角（θ）は２５度および３３度であることがＳＥＭによる断面観察の結果分かった。
【００７２】
誘電異方性が負の液晶（△ε：−４．０、△ｎ＝０．０８、セルギャップ６μｍで９０度ツイストとなるようにカイラル剤添加）を先のセルに注入してクロスニコル下で偏光顕微鏡観察を行った。プラズマに電圧を印加して基板間にかかる電圧を増していくと先の実施形態４と同様で図１３（ａ）に示すように絵素領域の中央から４辺に向かって消光模様が観察されるようになり、軸対称状に液晶分子が配向していた。柱状スペーサ２５近傍での光漏れは観察されなかった。
また同時に作製していたこのセルに、先と同じ液晶材料に対して０．３ｗｔ％の下記の（化２）で表される光重合性材料Ｂと、重合開始剤Irgacure６５１ ０．１ｗｔ％の均一混合物を注入した。プラズマセルに駆動用の電圧を印加して液晶層に５Ｖの電圧を印加して液晶分子を軸対称状に配向させながら、２５℃で紫外線（４ｍＷ／ｃｍ² ３６５ｎｍ）を１０分間、プラズマセル２の側から照射して重合性樹脂を硬化させた。
【００７３】
【化２】

【００７４】
得られたセルも液晶材料のみを注入した場合と同様な消光模様を呈し、軸対称状に液晶分子が配向していることが確認できた。応答時間（立ち上がり時間τｒ＋立ち下がり時間τｄ）は、液晶材料のみの場合（５５ｍＳ）に比べて、３４ｍＳと短くなることが確認された。
【００７５】
上記実施形態においては、軸対称配向した液晶領域を有する液晶表示装置について説明したが、本願発明は、ＴＮモードの液晶表示装置にも適用できる。
【００７６】
【発明の効果】
上述したように、本発明によれば、配向乱れの無い、高コントラストで高開口率の液晶表示装置及びその製造方法が提供される。本発明の液晶表示装置は、柱状スペーサが液晶層を挟持する一対の基板の両表面に対して傾斜した面を有しているので、液晶分子の急激な配向方向の変化は生じず、その結果配向乱れを抑制することが可能となる。本発明をノーマリーホワイトモードの液晶表示装置に適用した場合には、電圧無印加時の透過率の低下が抑制され、ノーマリーブラックモードに適用した場合には、電圧無印加時の白ぬけが抑制され、その結果コントラスト比を向上することができる。
【００７７】
高分子壁を省略して柱状スペーサのみの構造にすることに、区画壁による光の損失を無くすことができるので、開口率を上げることができる。さらに、液晶材料の注入抵抗を減少させることができるので、注入速度を速くしてタクト時間を短縮するとともに、大型パネルにおけるクロマト現象による液晶材料の組成の偏りを減らすことが可能となる。
【図面の簡単な説明】
【図１】本発明による液晶表示装置の構成を示す断面図である。
【図２】図１の円ＩＩ中の部分拡大図である。
【図３】本発明による柱状スペーサの作製プロセスを示す模式図である。
【図４】実施形態１で作製した液晶表示装置の模式図である。
【図５】実施形態１で使用するホトマスクの模式図である。
【図６】液晶セルの絵素を偏光顕微鏡（クロスニコル）で観察した結果の模式図で（ａ）は実施形態１、（ｂ）は比較例１の結果をそれぞれ示す。
【図７】比較例１で作製した液晶表示装置の模式図である。
【図８】比較例２で使用するホトマスクの模式図である。
【図９】比較例２で作製した液晶表示装置の模式図である。
【図１０】実施形態２で作製した液晶表示装置の模式図である。
【図１１】実施形態４で作製する液晶表示装置の柱状スペーサと絵素と非絵素領域の位置関係を示したモデル図である。
【図１２】実施形態４の柱状スペーサを作製するプロセスを示す模式図である。
【図１３】実施形態４で作製した液晶セルの絵素を偏光頭微鏡（クロスニコル）で観察した模式図（ａ）と、比較例３で作製した液晶セルの絵素を偏光頭微鏡（クロスニコル）で観察した模式図（ｂ）である。
【図１４】比較例３の柱状スペーサを作製するプロセスを示した概略図である。
【図１５】実施形態５で作製したプラズマアドレス型の液晶表示装置の概略図である。
【図１６】実施形態６で作製した柱状スペーサのモデル図である。
【図１７】（ａ）〜（ｈ）は、プロセスパラメターと傾斜角度との関係を示すグラフである。
【図１８】実施形態７の液晶表示装置における柱状スペーサと絵素の位置関係を示したモデル図である。
【図１９】実施形態８で作製した液晶表示装置における柱状スペーサと絵素の位置関係を示したモデル図である。
【図２０】実施形態８で作製したプラズマアドレス型液晶表示装置の概略図である。
【符号の説明】
４、８ 基板
９，１０ 透明電極
１１ 液晶分子
１５ 液晶領域
２５ 柱状スペーサ
２６ 配向膜層
２７ 非絵素領域
２８ 絵素
２９ ホトマスクの遮光部
３０ ホトマスクの透光部
３１ 光漏れ[0001]
[Prior art]
As a method for improving viewing angle characteristics, the present inventors have disclosed a display mode (Axially Symmetric Aligned Microcell Mode: ASM mode) in which liquid crystal molecules are aligned symmetrically for each picture element in Japanese Patent Laid-Open No. 7-120728. Disclosure. This method is a technique for orienting liquid crystal molecules in an axially symmetrical manner by utilizing phase separation from a mixture of a liquid crystal material (liquid crystal material having positive dielectric anisotropy: Np type liquid crystal material) and a photopolymerizable resin. This is a P-type ASM display mode in which liquid crystal molecules are aligned axially symmetrically (for example, concentric circles) when no voltage is applied, and liquid crystal molecules are aligned perpendicular to the substrate when a saturation voltage is applied.
[0002]
Japanese Patent Application No. 8-341590 has a pair of electrode substrates and a liquid crystal layer sandwiched between the two substrates, and the liquid crystal molecules of the liquid crystal layer have negative dielectric anisotropy (Nn type liquid crystal material). In addition, a liquid crystal display device is proposed in which liquid crystal molecules are aligned perpendicularly to the substrate when no voltage is applied, and liquid crystal molecules are axially symmetrically aligned for each pixel region when a saturation voltage is applied. Since this liquid crystal display device operates in a normally black mode, a high contrast can be obtained as compared with a conventional ASM mode liquid crystal display device.
[0003]
In Japanese Patent Application Laid-Open No. 6-51319, the alignment of the spacer is made invisible by making the shape of the spacer for maintaining the thickness (cell gap) of the liquid crystal layer constant and making the central portion narrower than the end width. The technology to make is disclosed.
[0004]
[Problems to be solved by the invention]
In the technique disclosed in Japanese Patent Application Laid-Open No. 7-120728, although the viewing angle characteristics are improved, (1) a mixture of an Np-type liquid crystal material and a photopolymerizable resin for orienting liquid crystal molecules in an axisymmetric manner (2) The process of orienting liquid crystal molecules in an axially symmetric manner is complicated. (3) The orientation of Np-type liquid crystal molecules is near the polymer wall (partition wall). There was a problem that the contrast ratio was lowered.
[0005]
Since the technology described in Japanese Patent Application No. 8-341590 operates in a normally black mode using an Nn-type liquid crystal material, a high contrast can be obtained compared to a conventional ASM mode liquid crystal display device. Moreover, there exists an advantage that it can manufacture easily. However, because of the normally black mode, if the alignment of the liquid crystal molecules is disturbed, light leakage may occur and the contrast ratio may be significantly reduced. In particular, alignment disorder of liquid crystal molecules tends to occur in the vicinity of the polymer wall around the picture element, and it is a problem to eliminate / suppress light leakage in this portion. Further, in order to improve the aperture ratio of the panel and to reduce the time for injecting the liquid crystal material at the time of manufacturing, it is a problem to reduce the volume of the polymer wall formed between the substrates as much as possible.
[0006]
Japanese Patent Laid-Open No. 6-51319 discloses that a spacer for maintaining the thickness of the liquid crystal layer is formed in a columnar shape, and the width of the central portion in the thickness direction is made narrower than the width of the end in contact with the substrate. Discloses a technique for making the alignment disorder of liquid crystal molecules invisible. This technique is based on the idea that the disorder of alignment of liquid crystal molecules is maximized at the center of the cell where the alignment regulating force from the alignment films on the upper and lower substrates to the liquid crystal molecules is the weakest. This disordered region is intended to be hidden by a portion where the width of the central portion in the thickness direction of the spacer is narrow. That is, the technique disclosed in this publication has the problem that the orientation disorder cannot be eliminated, and the size and position of the orientation disorder area must be controlled. The spacer column disclosed in the above publication is in contact with the substrate substantially perpendicularly, and the liquid crystal molecules are forced to change significantly in the orientation direction (90 degrees) in this portion, and the orientation is disturbed, resulting in partial transmission. The phenomenon of change will occur.
[0007]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a liquid crystal display device having high contrast and a high aperture ratio, and a method for manufacturing the same, which eliminates alignment disorder.
[0008]
[Means for Solving the Problems]
The liquid crystal display device of the present invention includes a first substrate, a second substrate, and a liquid crystal layer sandwiched between the first substrate and the second substrate. A plurality of liquid crystal regions divided by a first substrate and a columnar spacer reaching the second substrate, wherein the columnar spacer is in contact with the first substrate and the second substrate, respectively; Having a surface inclined at an angle of not less than 3 degrees and not more than 60 degrees with respect to the surface of the second substrate and the surface of the second substrate.An alignment film is formed on the surface of the first substrate and the second substrate in contact with the liquid crystal layer and on the surface of the columnar spacer, the alignment film is a vertical alignment film, and the liquid crystal molecules It has negative dielectric anisotropy, and the liquid crystal molecules of the liquid crystal layer are aligned axially symmetrically for each pixel region,This achieves the above object.
[0009]
The first substrate includes a line-shaped discharge channel surrounded by a substrate, a dielectric sheet, and a partition formed between the substrate and the dielectric sheet, and the columnar spacer includes the second spacer.ofIt is good also as a structure currently formed between the board | substrate and this dielectric material sheet.
[0010]
The liquid crystal layer may include a liquid crystal material and at least one of a polymerizable resin, a cured polymer resin, and a polymerization initiator.
[0014]
The columnar spacer is preferably formed of a photosensitive resin.
[0015]
The method for manufacturing a liquid crystal display device according to the present invention includes a first substrate, a second substrate, and a liquid crystal layer sandwiched between the first substrate and the second substrate, and the liquid crystal layer Has a plurality of liquid crystal regions divided by columnar spacers that reach the first substrate and the second substrate, and the columnar spacers are in contact with the first substrate and the second substrate, respectively. A method of manufacturing a liquid crystal display device having a surface inclined at an angle of 3 degrees to 60 degrees with respect to the surfaces of the first substrate and the second substrate, and a photolithography process using a photosensitive resinIn this step, columnar spacers are formed in advance on the first substrate and the second substrate, respectively, and the columnar spacers formed on the first substrate and the second substrate are overlapped with each other. The columnar spacers are formed,The angles of the inclined surface with respect to the surfaces of the first substrate and the second substrate are prebaking temperature, prebaking time, mask gap, exposure intensity, exposure time, development temperature, development time, development in the photolithography process. It is controlled by any of the liquid concentrations, thereby achieving the above objective.
[0016]
The angles of the inclined surface with respect to the surfaces of the first substrate and the second substrate are prebaking temperature, prebaking time, mask gap, exposure intensity, exposure time, development temperature, development time, development in the photolithography process. It may be controlled by any two or more combinations of liquid concentrations.
[0017]
The operation will be described below.
[0018]
According to the present invention, in the above-described conventional liquid crystal display device, the columnar spacer is located with respect to the substrate surface at the location where the alignment disorder of the liquid crystal molecules is likely to occur, that is, in the boundary region between the substrate and the columnar spacer formed on the substrate. Since it has an inclined surface, a sudden change in the alignment direction of the liquid crystal molecules does not occur, and as a result, it is possible to suppress alignment disturbance. Since the columnar spacer of the present invention has an inclined surface at a portion in contact with both of the pair of substrates sandwiching the liquid crystal layer, it can suppress alignment disorder in a region where both the substrate surface and the columnar spacer are in contact. it can. When the present invention is applied to a normally white mode liquid crystal display device, a decrease in transmittance when no voltage is applied is suppressed, and when applied to a normally black mode, whitening when no voltage is applied is suppressed. As a result, the contrast ratio can be improved.
[0019]
By omitting the partition wall (polymer wall) and using only the columnar spacer, the loss of light due to the partition wall can be eliminated, so that the aperture ratio can be increased. Furthermore, since the injection resistance of the liquid crystal material can be reduced, the injection speed can be increased and the tact time can be shortened. Further, by increasing the injection speed, it is possible to reduce the compositional deviation of the liquid crystal material due to the chromatographic phenomenon in the large panel.
[0020]
When the columnar spacer is formed using a photosensitive resin, the conditions for forming the columnar spacer by patterning by photolithography, for example, exposure intensity, exposure time, pre-baking temperature, pre-baking time, mask gap, or developing time, developing temperature The inclination angle of the inclined surface of the columnar spacer can be easily controlled to a desired value by changing the developer concentration.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Members having substantially the same function are denoted by the same reference numerals.
[0022]
FIG. 1 is a cross-sectional view schematically showing a liquid crystal display device 100 of the present invention, and FIG. 2 is a partial cross-sectional view extracted from a circle II in FIG.
[0023]
A signal electrode 10 (for example, made of ITO) is formed on the glass substrate 8, and a columnar spacer 25 is formed thereon. Further, an alignment layer 26 is formed on the side surface of the columnar spacer 25 and on the signal electrode 10. The columnar spacer 25 is in contact with the surface of the substrate 8 at an inclination angle θ. In this state, since the pretilt angle of the liquid crystal molecules 11 from the side surfaces of the columnar spacers 25 to the surface of the substrate 8 continuously changes, no extreme alignment disturbance occurs. A scanning electrode 9 is formed on the glass substrate 4 disposed opposite to the glass substrate 8, and the columnar spacer 25 is in contact with the surface of the substrate 4 at an inclination angle θ. The inclination angle of the columnar spacer 25 with respect to the substrate 4 and the inclination angle with respect to the substrate 8 may be the same or different. Further, the inclination angles on both sides of the columnar spacer 25 may be different or the same. In the liquid crystal region 15 at least partially surrounded by the columnar spacer 25, the liquid crystal molecules 11 can be configured to be axially symmetrically aligned with the voltage on / off. A liquid crystal display device having a liquid crystal region in which liquid crystal molecules are axially symmetrically aligned has small azimuth dependency of viewing angle characteristics and wide viewing angle characteristics.
[0024]
The effect of the inclined surface of the columnar spacer 25 will be described with reference to FIG. The alignment state of the liquid crystal molecules schematically shown in FIG. 2 is a voltage application state when the alignment film 26 formed on the surface of the substrate 8 is a horizontal alignment film and the liquid crystal material has positive dielectric anisotropy, Or it is sectional drawing which represented typically the orientation state of the liquid crystal molecule 11 in the columnar spacer 25 vicinity of the voltage-less application state in case the orientation film 26 is a vertical orientation film and a liquid crystal material has negative dielectric anisotropy. .
[0025]
If the inclination angle (θ) at the portion where the columnar spacer 25 is in contact with the substrate 8 (more precisely, the alignment film 26 on the substrate 8) is about 60 degrees or less, the pretilt angle continuously changes as shown in FIG. In addition, no light leakage due to orientation disturbance is observed. Even when the liquid crystal molecules 11 are aligned in an axially symmetric manner for each pixel region, no light leakage is observed and a stable axially symmetric orientation can be obtained. However, as θ decreases, the area where the columnar spacers 25 are in contact with the substrate 8 increases, causing problems such as a decrease in the aperture ratio. Therefore, θ needs to be about 3 degrees or more. When a vertical alignment film is used, θ is preferably about 3 ° or more in order to define the direction in which the liquid crystal molecules are tilted. If it is less than about 3 degrees, the direction in which the liquid crystal molecules fall may not be constant.
[0026]
As a material for the columnar spacer, a negative or positive photosensitive resin is preferably used. As the photosensitive resin used in the present invention, acrylate-based, epoxy-based, methacrylate-based, styrene-based, novolac-based, polyimide-based resins, and derivatives thereof can be used. Photopolymerization initiators can also be added to these resins. The columnar spacers may be colorless, transparent, or colored with pigments or pigments in black, red, green, and blue. It is possible to form such a columnar spacer with an inorganic material, but it is less preferable because it is less stretchable than an organic material such as a resin material, and may be deformed or broken from that part by pressing or the like. Absent.
[0027]
The columnar spacer can be formed by processing an organic material or an inorganic material using a photolithography technique using a resist. Since the manufacturing process can be simplified, it is preferable to form the columnar spacers using a photosensitive resin. A specific manufacturing method using the photosensitive resin will be described below.
[0028]
(A) A photosensitive resin is applied to the substrate surface. The substrate includes a substrate in which electrodes and switching elements such as TFTs are formed in advance on a glass substrate or the like.
(B) Pre-baking the photosensitive resin.
(C) Using a mask having a predetermined pattern, the photosensitive resin is exposed with a predetermined mask gap.
(D) The exposed photosensitive resin is developed to form a photosensitive resin having a predetermined pattern.
(E) The developer remaining in the photosensitive resin is removed by rinsing.
(F) The post-baked and patterned photosensitive resin is dried and stabilized.
[0029]
The inclination angle of the columnar spacers at the portions in contact with the upper and lower substrates described above can be controlled by changing the conditions of the steps (a) to (f). Alternatively, after the steps (a) to (e) are performed once, the steps (d) and (e) are performed again, and then the post-baking (f) may be performed.
[0030]
Depending on the photosensitive material used, there is a material in which it is difficult to control the inclination angle of the portion of the columnar spacer in contact with the upper and lower substrates to a desired value in one step described above. In such a case, as shown in FIG. 3 (a), columnar spacers 25 (a) and 25 on each of the upper substrate 4 and the lower substrate 8 in which the inclination angle (θ) of the portion in contact with the substrate is controlled. It is also possible to form columnar spacers by forming (b) in advance and bonding the upper and lower substrates 4 and 8 together as shown in FIG.
[0031]
Process parameters (processing conditions) such as pre-baking temperature, pre-baking time, exposure intensity, exposure time, mask gap, developer concentration, developer temperature, development time when forming columnar spacers with photosensitive resin using photolithography technology The inclination angle of the columnar spacer can be changed by changing. If one of the above parameters changes, the tilt angle changes. The tilt angle may be controlled by changing two or more of the above parameters in combination.
[0032]
(Embodiment 1)
FIG. 4 is a schematic diagram of the liquid crystal display device 200 according to the first embodiment. A transparent electrode 10 having a thickness of 100 nm made of ITO (mixture of indium oxide and tin oxide) is formed on a 7059 glass substrate 8 manufactured by Corning, and V259-PA (Nippon Steel Co., Ltd.) is formed on the transparent electrode 10 to a thickness of 5 μm. Chemical Co., Ltd.) was applied by spin coating. After heating at 100 ° C./3 minutes on a hot plate, it was further heated (prebaked) in a circulating oven at 80 ° C./15 minutes.
[0033]
As shown in FIG. 5, contact exposure was performed for 120 seconds through the mask using a mask having a light shielding portion 29 of 100 μm × 100 μm square and a width of the light transmitting portion 30 of 25 μm. Illuminance at that time is 365 m and 10 mW / cm²Met. 0.4% -K₂CO_ThreeDevelopment was performed with aq for 300 seconds, rinsed with a pure water shower for 120 seconds, and then post-baked in a circulation oven at 240 ° C. for 1 hour to form columnar spacers 25. When a glass substrate 4 with a transparent electrode made of ITO having a thickness of 100 nm is attached to the glass substrate 8, a cell as shown in FIG. 4 can be produced. As a result of cross-sectional observation by SEM, the inclination angle (θ) was 40 degrees at the portion in contact with the substrate 8 and 45 degrees at the portion in contact with the substrate 4.
[0034]
As a resin material, β- (perfluorooctyl) ethyl acrylate 2%, stearyl acrylate 4%, trimethylpropane triacrylate 1%, 4-fluorostyrene 3%, liquid crystal ZLI-4792 (Merck, dielectric anisotropy) Is a positive liquid crystal material, a chiral agent is added so that the cell thickness is 5 μm and twisted 90 degrees), and the polymerization initiator Irgacure 651 is added to 0.5% of the mixture of the liquid crystal material and the resin material (both by weight%) And mixed uniformly and injected into the previously prepared cell in a compatible state. While applying voltage (3.1V), UV light is 4 mW / cm at a wavelength of 365 nm.²The liquid crystal display device 200 in which the liquid crystal molecules were aligned in an axially symmetric manner in the liquid crystal region 15 was obtained by irradiation for 10 minutes at an intensity of. When a voltage is applied, the liquid crystal molecules are stably axisymmetrically aligned due to the wall effect of the columnar spacer 25. In addition, by curing the photopolymerizable material in a voltage applied state, the axially symmetric orientation is further stabilized.
[0035]
When this is observed under a polarizing microscope (crossed Nicols), a quenching pattern is observed from the center of the picture element area (square in the figure) toward the four sides as shown in FIG. There was no decrease in transmittance at the periphery of the film.
[0036]
Note that the liquid crystal display device described above has been described using a simple matrix liquid crystal display device with transparent electrodes facing each other as a model in order to explain the structure. However, the present invention is not limited to this, and the present invention is not limited to this. Can also be adapted. An active matrix liquid crystal display device has a switching element such as a thin film transistor (TFT) on one substrate, a signal electrode for sending a gate signal or a source signal, and a pixel electrode. Is a structure in which a counter electrode is formed.
[0037]
(Comparative Example 1)
A transparent electrode 10 made of ITO having a thickness of 100 nm is formed on a 7059 glass substrate 8 manufactured by Corning, and V259-PA (manufactured by Nippon Steel Chemical Co., Ltd.) is spin-coated so as to have a film thickness of 5 μm. It was applied with. After heating on a hot plate at 100 ° C./1 minute, it was further heated in a circulating oven at 80 ° C./10 minutes. As shown in FIG. 5, contact exposure was performed for 30 seconds through the mask using a mask capable of obtaining a pixel area of 100 μm × 100 μm square. Illuminance at that time is 365 m and 10 mW / cm²Met. 0.4% -K₂CO_ThreeAfter developing with aq for 120 seconds and rinsing with a pure water shower for 120 seconds, post-baking was performed in a circulation oven at 240 ° C. for 1 hour to form columnar spacers 25. When the glass substrate 4 with a transparent electrode made of ITO having a thickness of 100 nm was bonded to the previous glass substrate 8, a cell as shown in FIG. 7 could be produced. As a result of cross-sectional observation by SEM, the columnar spacer 25 was in contact with both substrates substantially perpendicularly.
[0038]
A material similar to that of the first embodiment is injected into the previously prepared cell in a compatible state, and UV light is applied at a wavelength of 365 nm to 4 mW / cm while applying a voltage, as in the first embodiment.²Axisymmetric liquid crystal alignment was obtained by irradiation for 10 minutes at an intensity of. When this is observed under a polarizing microscope (crossed Nicol), a quenching pattern is observed from the center of the picture element region toward the four sides as shown in FIG. 6 (b). A decreasing part was seen.
[0039]
(Comparative Example 2)
Transparent electrodes 9 and 10 made of ITO are formed on Corning 7059 glass substrates 4 and 8, and V259-PA (manufactured by Nippon Steel Chemical Co., Ltd.) is formed thereon to a thickness of 1 μm. Was applied by spin coating. Heated on a hot plate at 100 ° C./2 minutes. Contact exposure was performed for 10 seconds in the same manner as in the first embodiment, using a mask from which a 100 μm × 100 μm square light shielding region 29 shown in FIG. 5 was obtained. 0.4% -K₂CO_ThreeAfter developing with aq for 30 seconds and rinsing with a pure water shower for 120 seconds, post-baking was performed in a circulation oven at 240 ° C. for 1 hour to form columnar spacers 25. V-259PA was further applied to the substrate 8 on which the columnar spacers 25 were formed so that the film thickness from the substrate surface was 4 μm and heated at 100 ° C./1 minute on a hot plate, and then further heated at 80 ° C./10 minutes in a circulation oven. . As shown in FIG. 8, the light shielding part 29 is 110 μm × 110 μm, the width of the light transmitting part 30 is 15 μm, and the mask shown in FIG. 5 is the same as the center of the light shielding part. For 30 seconds. Illuminance at that time is 365 m and 10 mW / cm²Met. 0.4% -K₂CO_ThreeAfter developing with aq for 150 seconds and rinsing with a pure water shower for 120 seconds, post-baking was performed in a circulating oven at 240 ° C. for 1 hour to form columnar spacers 25.
[0040]
When the glass substrate 4 on which the columnar spacers have been formed is aligned and bonded to the glass substrate 8 that has passed through the two film forming steps, a cell having a cross section as shown in FIG. 9 can be produced. did it. As a result of cross-sectional observation by SEM, the columnar spacers 25 were in contact with the substrate substantially perpendicularly.
[0041]
A material similar to that of the first embodiment is injected into the previously prepared cell in a compatible state, and UV light is applied at a wavelength of 365 nm to 4 mW / cm while applying a voltage, as in the first embodiment.²Axisymmetric liquid crystal alignment was obtained by irradiation for 10 minutes at an intensity of. When this is observed under a polarizing microscope (crossed Nicol), a quenching pattern is observed from the center of the picture element region toward the four sides as shown in FIG. The part where the transmittance | permeability fell in the peripheral part was seen.
[0042]
(Embodiment 2)
FIG. 10 shows an example in which the present invention is applied to a plasma addressed liquid crystal display device.
[0043]
The anode electrode A and the cathode electrode K are formed in a line shape on the substrate 4, and the partition wall 7 is formed in a line shape on the anode electrode, and this substrate is bonded to a thin glass (thickness 50 μm) as the intermediate sheet 3. It was. An ionizing gas was sealed in a space surrounded by the substrate 4, the thin glass plate 3, and the partition walls 7 to form a line-shaped discharge channel 5, thereby producing a plasma cell 2. The present invention can be applied to a known plasma addressed liquid crystal display device. A plasma addressed liquid crystal display device is disclosed in, for example, Japanese Patent Laid-Open No. 4-313788.
[0044]
An electrode 10 made of ITO was formed to a thickness of 150 nm on a glass substrate 8 on which a color filter (CF) 13 made of red (R), green (G), blue (B) and black matrix (BM) was formed. On top of this, JNPC-43 (manufactured by JSR) was applied by spin coating so that the film thickness was 6 μm. After heating on a hot plate at 80 ° C. for 3 minutes, contact exposure was performed through the mask for 60 seconds using a mask having a light-shielding portion 29 of 100 μm × 100 μm square and a width of the light-transmitting portion 30 of 25 μm. Illuminance at that time is 365m and 10mW / cm²Met. This was developed with developer CD (15% dilution, 25 ° C.) for 200 seconds, rinsed with a pure water shower for 120 seconds, and then post-baked in a circulating oven at 200 ° C. for 1 hour to form columnar spacers 25.
[0045]
R-684 (Nippon Kayaku Co., Ltd.) 4%, p-phenylstyrene 4%, Compound A 2% shown in the following (Chemical Formula 1), liquid crystal ZLI-4792 (manufactured by Merck Ltd., liquid crystal material having positive dielectric anisotropy) The liquid crystal layer 6 is a uniform mixture of 90% and Irgacure 651 so that 0.5% by weight of the above material is added. A plasma address type liquid crystal display device shown in FIG. 10 was formed in such a manner that the liquid crystal layer 6 was sandwiched between the substrate 8 and the plasma cell 2 formed thereon.
[0046]
[Chemical 1]

[0047]
As a result of cross-sectional observation by SEM, the inclination angle of the columnar spacer 25 was 20 degrees at the portion in contact with the substrate 8 and 15 degrees at the portion in contact with the intermediate sheet 3.
[0048]
A voltage is applied to the plasma substrate 2 to generate plasma, and a voltage is applied to the liquid crystal layer 6 so that the liquid crystal molecules are aligned in an axially symmetrical manner, and UV light is 4 mW / cm at a wavelength of 365 nm.²Axisymmetric liquid crystal alignment was obtained by irradiation for 10 minutes at an intensity of. When this is observed under a polarizing microscope (crossed Nicol), as in the first embodiment, a quenching pattern is observed from the center of the picture element region toward the four sides as shown in FIG. There was no decrease in transmittance at the periphery of the region.
[0049]
(Embodiment 3)
A transparent electrode 10 made of ITO and having a thickness of 100 nm is formed on a 7059 glass substrate 8 manufactured by Corning, and V259-PA (manufactured by Nippon Steel Chemical Co., Ltd.) is spun so that the film thickness becomes 5 μm. The coating method was applied. After heating on a hot plate at 100 ° C./3 minutes, it was further heated in a circulating oven at 80 ° C./15 minutes. As shown in FIG. 5, a mask having a 100 μm × 100 μm square light shielding portion 29 and a light transmitting portion 30 having a width of 25 μm was used, and contact exposure was performed for 120 seconds through the mask. Illuminance at that time is 365 m and 10 mW / cm²Met. 0.4% -K₂CO_ThreeAfter developing for 300 seconds with aq and rinsing for 120 seconds with a pure water shower, post-baking was performed for 1 hour in a circulation oven at 240 ° C. to form columnar spacers 25. A horizontal alignment film AL-3046 (manufactured by JSR) was applied to a thickness of 80 nm, and baked in a circulating oven at 180 ° C. for 1 hour to form an alignment film layer 26.
[0050]
The same horizontal alignment film AL-3046 is applied on the glass substrate 4 with a transparent electrode made of ITO having a thickness of 100 nm so as to have a film thickness of 80 nm to form the alignment film layer 26. When bonded to 8, a cell as shown in FIG. 1 could be produced. As a result of cross-sectional observation by SEM, the inclination angle was 36 degrees at the portion in contact with the substrate 8 and 43 degrees at the portion in contact with the substrate 4.
[0051]
A liquid crystal material E7 (manufactured by Merck & Co., Inc.) having a positive dielectric anisotropy was injected here, but no change in transmittance due to poor alignment was observed, and the alignment was not disturbed in the periphery of the columnar spacer 25.
[0052]
(Embodiment 4)
Transparent electrodes 9 and 10 having a thickness of 100 nm are formed on glass substrates 4 and 8 made by Corning, and JCR BLACK535 (manufactured by JSR) is further formed thereon to a thickness of 2.5 μm by spin coating. And heated on a hot plate at 80 ° C. for 5 minutes. As shown in FIG. 11, using a mask designed to form 10 μm square columnar spacers 25 at four corners of a 50 μm × 50 μm square picture element 28, contact exposure was performed for 25 seconds through the mask. Illuminance at that time is 365 m and 10 mW / cm²Met. This was developed with a dedicated developer CD-200CR (50-fold dilution, 25 ° C.) for 80 seconds, rinsed with a pure water shower for 60 seconds, and then post-baked in a circulating oven at 220 ° C. for 30 minutes. Columnar spacers 25 (a) and 25 (b) were formed as shown in FIG. As a result of cross-sectional observation by SEM, it was found that the inclination angle (θ) at which the columnar spacers 25 (a) and 25 (b) are in contact with the glass substrates 4 and 8 are both 25 degrees. A vertical alignment film JALS-204 (manufactured by JSR) was further applied at a film thickness of 80 nm on the side of both glass substrates on which the columnar spacers were formed, and post-baked at 180 ° C. for 1 hour to form an alignment film layer 26. As shown in FIG. 12 (b), the glass substrates 4 and 8 were aligned so that the columnar spacers 25 (a) and the columnar spacers 25 (b) were just overlapped, and were bonded together via a sealant.
[0053]
Crossed Nicols by injecting liquid crystal with negative dielectric anisotropy (Δε: -4.0, Δn = 0.08, adding chiral agent so that the cell gap is 5 μm and 90 degree twist) into the previous cell. Observation under a polarizing microscope was performed below. When a voltage is applied between the substrates, as shown in FIG. 13A, a quenching pattern is observed from the center of the picture element region toward the four sides, and the liquid crystal molecules are aligned in an axially symmetrical manner. Light leakage in the vicinity of the columnar spacer 25 was not observed.
[0054]
(Comparative Example 3)
Transparent electrodes 9 and 10 having a thickness of 100 nm are formed on glass substrates 4 and 8 made by Corning, and JCR BLACK535 (manufactured by JSR) is formed thereon with a thickness of 2.5 μm by spin coating. And heated on a hot plate at 80 ° C. for 4 minutes. Exposure was performed under the same conditions using the same mask as in the fourth embodiment.
This was developed with a dedicated developer CD-200CR (50-fold dilution, 25 ° C.) for 50 seconds and rinsed with a pure water shower for 60 seconds. After that, when post-baking is performed for 30 minutes in a circulation oven at 220 ° C., trapezoidal columnar spacers 25 (a) and 25 (b) are obtained as shown in FIG. As a result of cross-sectional observation by SEM, it was found that the inclination angle (θ) at the contact point was 80 degrees. A vertical alignment film JALS-204 (manufactured by JSR) is further applied to the side of both glass substrates on which the columnar spacers are formed to a thickness of 80 nm, and post-baking is performed at 180 ° C. for 1 hour to prepare an alignment film layer 26. Both glass substrates 4 and 8 were aligned with each other so that the columnar spacers overlapped as shown in FIG.
[0055]
A liquid crystal having the same dielectric anisotropy as that of the fourth embodiment (Δε = −4.0, Δn = 0.08, chiral added so that the cell gap is 5 μm and a twist of 90 degrees) is injected into this cell. Then, a polarizing microscope was observed under crossed Nicols. When a voltage is applied between the substrates, as shown in FIG. 13B, a quenching pattern is observed due to the alignment of the liquid crystal molecules in an axially symmetrical manner, but unlike the fourth embodiment, light leakage occurs in the vicinity of the columnar spacer 25. 31 was observed.
[0056]
(Embodiment 5)
The plasma addressed liquid crystal display device shown in FIG. 15 is formed. The anode electrode A and the cathode electrode K were formed in a line shape on the substrate 4, and the partition wall 7 was formed in a line shape on the anode electrode A, and this substrate was bonded to a thin glass as the intermediate sheet 3. An ionizing gas was sealed in a space surrounded by the substrate 4, the thin glass plate 3, and the partition walls 7 to form a line-shaped discharge channel 5, thereby producing a plasma cell 2.
[0057]
ITO 10 was formed to a thickness of 250 nm on a glass substrate 8 on which a color filter (CF) 13 composed of red (R), green (G), blue (B) and black matrix (BM) was formed. JCR BLACK535 (manufactured by JSR) was applied to the substrate 8 and the intermediate sheet 3 of the plasma substrate 2 by spin coating so as to have a film thickness of 3 μm, and heated on a hot plate at 80 ° C. for 5 minutes. Columnar spacers were formed using the same mask as in Embodiment 4 under the same exposure conditions, development conditions, and baking (post-bake) conditions. As a result of cross-sectional observation by SEM, it was found that the inclination angle (θ) at the point where each substrate and the columnar spacer were in contact was 20 degrees.
[0058]
A vertical alignment film JALS-204 (manufactured by JSR Co.) is further applied with a film thickness of 100 nm on the side on which the columnar spacers of both glass substrates are formed, and post-baking is performed at 180 ° C. for 1 hour to prepare the alignment film layer 26 Then, the plasma substrate 2 and the glass substrate 8 were aligned with each other so that the columnar spacers were overlapped with each other, and were bonded together with a sealant to produce a plasma address type liquid crystal display cell shown in FIG.
[0059]
Liquid crystal with negative dielectric anisotropy (Δε = -4.0, Δn: 0.08, chiral agent added so that the cell gap is 6 μm and twisted 90 degrees) was injected into the previous cell and crossed Nicols Was observed with a polarizing microscope. When a voltage is applied to the plasma substrate and the voltage applied between the substrates is increased, a quenching pattern is formed from the center of the pixel region toward the four sides as shown in FIG. As a result, the liquid crystal molecules were axially symmetrical. Light leakage in the vicinity of the columnar spacer 25 was not observed.
[0060]
(Embodiment 6)
Photosensitive polyimide was applied on the glass substrate 8 on which the transparent electrode 10 having a thickness of 100 nm was formed using a spin coater so as to have a film thickness of 6 μm. Pre-baked at 90 ° C for 10 min on a hot plate and 10 mW / cm at 365 nm²Contact exposure was performed for 20 seconds, post-exposure baking was performed at 175 ° C./15 min in a circulation oven, and development was performed at 25 ° C. for 1 minute using a dedicated developer (diluted to 50%). Then, it rinsed with IPA for 30 second, and performed 200 degreeC / 30min post-baking with the circulation oven. A series of these operations is a standard condition, and only one condition is changed to form a columnar spacer 25 (b) on the substrate as shown in FIG. 16, and the columnar spacer 25 (b) is in contact with the substrate 8 The inclination angle (θ) of the inclined surface was measured. This is shown in FIGS.
As apparent from FIGS. 17A to 17H, the pre-bake temperature (a), the pre-bake time (b), the mask gap (c), the exposure intensity (d), the exposure time (e), and the development temperature (f). It was revealed that the tilt angle can be controlled by changing either the development time (g) or the developer concentration (h).
[0061]
(Embodiment 7)
Transparent electrodes 9 and 10 having a thickness of 100 nm were formed on glass substrates 4 and 8 made by Corning, and JNPC-43 (manufactured by JSR) was spin-coated so that the film thickness was 3 μm. The pre-baking is performed on a hot plate at a temperature of 60 ° C. to 80 ° C. and a baking time of 1 minute to 5 minutes. As shown in FIG. 18, columnar spacers 25 are produced with a line width of 25 μm on four sides of a picture element 28 of 100 μm × 100 μm. A mask with a mask gap of 50 μm and exposure for 60 seconds (UV illumination 10 mW / cm²365 nm). This is developed with a dedicated developer CD (15% diluted, 25 ° C.) for 100 seconds to 360 seconds, rinsed with a pure water shower for 120 seconds, and then post-baked in a circulating oven at 200 ° C. for 1 hour to form the columnar spacer 25. (A) and 25 (b) were formed.
[0062]
When the inclination angle was measured, it was confirmed that a columnar spacer having θ in the range of 5 degrees to 100 degrees was formed as shown in Table 1.
[0063]
A vertical alignment film JALS-204 (manufactured by JSR) is applied with a film thickness of 80 nm on the side where the columnar spacers of both glass substrates are formed, and post-baking is performed at 180 ° C. for 1 hour to prepare the alignment film layer 26. Both glass substrates 4 and 8 were aligned so that the columnar spacers 25 (a) and the columnar spacers 25 (b) overlapped each other, and were bonded together via a sealant. A liquid crystal having a negative dielectric anisotropy (Δε = −4.0, Δn = 0.08, a chiral agent added so that the cell gap is 6 μm and a twist of 90 degrees) is injected into the cell, and the glass substrate 4, A polarizing plate was attached to the outer side of 8 (the side opposite to the liquid crystal layer 6) so as to be in a crossed Nicol state.
[0064]
When a voltage is applied between both glass substrates and the voltage is further applied even if the threshold voltage (Vth) is exceeded, a quenching pattern extending in the four directions from the center of the picture element is observed in the liquid crystal region. However, in this embodiment, light leakage is observed around the columnar spacer 25 when no voltage is applied. Table 1 below shows the results of measuring transmittance to compare the degree of light leakage.
[0065]
[Table 1]

Tilt angle (degree) 5 14 38 45 57 63 73 88 108
Transmittance (%) 20 21 24 23 25 48 49 49 64 71
[0066]
As shown in Table 1 above, it can be seen that a decrease in transmittance has occurred since the inclination angle reached 63 degrees. This indicates that when the tilt angle exceeds 60 degrees, the alignment direction of the liquid crystal molecules changes abruptly, so that the alignment of the liquid crystal molecules is disturbed in the vicinity of the columnar spacer. From this result, it can be seen that the inclination angle of the columnar spacer is preferably 60 degrees or less.
[0067]
(Embodiment 8)
The anode electrode A and the cathode electrode K were formed in a line shape on the substrate 4, and the partition wall 7 was formed in a line shape on the anode electrode, and this substrate was bonded to the thin glass as the intermediate sheet 3. An ionizing gas was sealed in a space surrounded by the substrate 4, the thin glass plate 3, and the partition walls 7 to form a line-shaped discharge channel 5, thereby producing a plasma cell 2.
[0068]
An electrode 10 made of ITO was formed with a thickness of 250 nm on a glass substrate 8 on which a color filter (CF) 13 made of red (R), green (G), blue (B) and black matrix (BM) was formed. JCR BLACK535 (manufactured by JSR) was applied on the ITO of the substrate 8 to a film thickness of 6 μm by spin coating, and heated on a hot plate at 80 ° C. for 8 minutes. A mask designed to form a columnar spacer 25 having a circular cross section with a radius of 25 μm so as to surround a 100 μm square picture element (square in the figure) as shown in FIG. Contact exposure was performed for 60 seconds. Illuminance at that time is 365 m and 10 mW / cm²Met. This was developed with a dedicated developer CD-200CR (50-fold dilution, 25 ° C.) for 80 seconds, rinsed with a pure water shower for 60 seconds, further developed with the same developer for 20 seconds, and again with a pure water shower. Rinse was performed for 60 seconds. Post-baking was performed for 30 minutes in a circulation oven at 220 ° C. to form columnar spacers 25.
[0069]
The arrangement of the columnar spacers is not limited to the example shown in FIG. 19A, and may be arranged as shown in FIG. 19B, for example. The arrangement and density of the columnar spacers are appropriately set according to the configuration and application of the liquid crystal display device.
[0070]
A vertical alignment film JALS-204 (manufactured by JSR) is applied to a thickness of 60 nm on the intermediate sheet 3 of the plasma cell 2 and the side of the glass substrate 8 where the columnar spacers are formed, and post-paque is performed at 180 ° C. for 1 hour. An alignment film layer (not shown) was prepared and bonded through a sealant to prepare a plasma address type liquid crystal display cell shown in FIG.
[0071]
As a result of cross-sectional observation by SEM, it was found that the inclination angles (θ) at the points in contact with the ITO electrode 10 and the intermediate sheet 3 were 25 degrees and 33 degrees, respectively.
[0072]
Liquid crystal with negative dielectric anisotropy (Δε: -4.0, Δn = 0.08, chiral agent added so that the cell gap is 6 μm and 90 degrees twisted) was injected into the previous cell and crossed Nicols Was observed with a polarizing microscope. When a voltage is applied to the plasma and the voltage applied between the substrates is increased, a quenching pattern is observed from the center of the picture element region toward the four sides as shown in FIG. As a result, the liquid crystal molecules were aligned in an axially symmetrical manner. Light leakage in the vicinity of the columnar spacer 25 was not observed.
In addition, 0.3 wt% of the photopolymerizable material B represented by the following (Chemical Formula 2) and the polymerization initiator Irgacure 651 0.1 wt% in a uniform amount of 0.3 wt% with respect to the same liquid crystal material as previously described. The mixture was injected. While applying a driving voltage to the plasma cell and applying a voltage of 5 V to the liquid crystal layer to align the liquid crystal molecules in an axially symmetrical manner, ultraviolet rays (4 mW / cm at 25 ° C.)²365 nm) for 10 minutes from the plasma cell 2 side to cure the polymerizable resin.
[0073]
[Chemical 2]

[0074]
The obtained cell also exhibited a quenching pattern similar to that in the case of injecting only the liquid crystal material, and it was confirmed that the liquid crystal molecules were aligned in an axial symmetry. It was confirmed that the response time (rise time τr + fall time τd) was as short as 34 mS compared to the case of the liquid crystal material alone (55 mS).
[0075]
In the above embodiment, a liquid crystal display device having a liquid crystal region aligned in an axial symmetry has been described, but the present invention can also be applied to a TN mode liquid crystal display device.
[0076]
【The invention's effect】
As described above, according to the present invention, there is provided a liquid crystal display device having a high contrast and a high aperture ratio which is free from alignment disturbance and a method for manufacturing the same. In the liquid crystal display device of the present invention, since the columnar spacer has inclined surfaces with respect to both surfaces of the pair of substrates sandwiching the liquid crystal layer, a sudden change in the alignment direction of the liquid crystal molecules does not occur. It becomes possible to suppress alignment disorder. When the present invention is applied to a normally white mode liquid crystal display device, a decrease in transmittance when no voltage is applied is suppressed, and when applied to a normally black mode, whitening when no voltage is applied is suppressed. As a result, the contrast ratio can be improved.
[0077]
By omitting the polymer wall and using only the columnar spacer, the loss of light due to the partition wall can be eliminated, so that the aperture ratio can be increased. Furthermore, since the injection resistance of the liquid crystal material can be reduced, the injection speed can be increased to shorten the tact time, and the deviation of the composition of the liquid crystal material due to the chromatographic phenomenon in the large panel can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a liquid crystal display device according to the present invention.
FIG. 2 is a partially enlarged view of a circle II in FIG.
FIG. 3 is a schematic view showing a manufacturing process of a columnar spacer according to the present invention.
4 is a schematic view of a liquid crystal display device manufactured in Embodiment 1. FIG.
5 is a schematic view of a photomask used in Embodiment 1. FIG.
FIGS. 6A and 6B are schematic diagrams of results obtained by observing picture elements of a liquid crystal cell with a polarizing microscope (crossed Nicols), where FIG. 6A shows the results of Embodiment 1, and FIG. 6B shows the results of Comparative Example 1;
7 is a schematic view of a liquid crystal display device manufactured in Comparative Example 1. FIG.
8 is a schematic diagram of a photomask used in Comparative Example 2. FIG.
9 is a schematic view of a liquid crystal display device manufactured in Comparative Example 2. FIG.
10 is a schematic view of a liquid crystal display device manufactured in Embodiment 2. FIG.
FIG. 11 is a model diagram showing a positional relationship among columnar spacers, picture elements, and non-picture element regions of a liquid crystal display device manufactured in Embodiment 4;
12 is a schematic diagram showing a process for producing a columnar spacer according to Embodiment 4. FIG.
13 is a schematic diagram (a) in which picture elements of a liquid crystal cell manufactured in Embodiment 4 are observed with a polarizing head mirror (crossed Nicols), and a picture element of a liquid crystal cell manufactured in Comparative Example 3 is used as a polarizing head microscope. It is the schematic diagram (b) observed by (Cross Nicol).
14 is a schematic view showing a process for producing a columnar spacer of Comparative Example 3. FIG.
15 is a schematic view of a plasma addressed liquid crystal display device manufactured in Embodiment 5. FIG.
16 is a model diagram of a columnar spacer manufactured in Embodiment 6. FIG.
FIGS. 17A to 17H are graphs showing a relationship between a process parameter and an inclination angle.
FIG. 18 is a model diagram showing the positional relationship between columnar spacers and picture elements in the liquid crystal display device of Embodiment 7.
19 is a model diagram showing a positional relationship between columnar spacers and picture elements in the liquid crystal display device manufactured in Embodiment 8. FIG.
20 is a schematic view of a plasma addressed liquid crystal display device manufactured in Embodiment 8. FIG.
[Explanation of symbols]
4, 8 substrate
9,10 Transparent electrode
11 Liquid crystal molecules
15 Liquid crystal area
25 Columnar spacer
26 Alignment film layer
27 Non-pixel region
28 picture elements
29 Shading part of photomask
30 Translucent part of photomask
31 Light leakage

Claims (6)

A first substrate; a second substrate; a liquid crystal layer sandwiched between the first substrate and the second substrate;
The liquid crystal layer has a plurality of liquid crystal regions divided by columnar spacers reaching the first substrate and the second substrate,
The columnar spacer is a surface inclined at an angle of 3 degrees or more and 60 degrees or less with respect to the surfaces of the first substrate and the second substrate, respectively, at a portion in contact with the first substrate and the second substrate. have a,
An alignment film is formed on the surface of the first substrate and the second substrate in contact with the liquid crystal layer, and on the surface of the columnar spacer,
The liquid crystal display device , wherein the alignment film is a vertical alignment film, the liquid crystal molecules have negative dielectric anisotropy, and the liquid crystal molecules of the liquid crystal layer are aligned in an axially symmetrical manner for each pixel region . The first substrate has a linear discharge channel surrounded by a substrate, a dielectric sheet, and a partition formed between the substrate and the dielectric sheet;
The liquid crystal display device according to claim 1, wherein the columnar spacer is formed between the second substrate and the dielectric sheet. The liquid crystal display device according to claim 1, wherein the liquid crystal layer includes a liquid crystal material and at least one of a polymerizable resin, a polymerizable resin cured product, and a polymerization initiator. The columnar spacer is formed of a photosensitive resin, a liquid crystal display device according to any one of claims 1 to 3. A first substrate; a second substrate; and a liquid crystal layer sandwiched between the first substrate and the second substrate, wherein the liquid crystal layer includes the first substrate and the second substrate. A plurality of liquid crystal regions divided by columnar spacers that reach the first substrate, the columnar spacers being in contact with the first substrate and the second substrate, respectively, the first substrate and the second substrate; A method of manufacturing a liquid crystal display device having a surface inclined at an angle of 3 degrees to 60 degrees with respect to the surface of
Columnar spacers are formed in advance on the first substrate and the second substrate in a photolithography process using a photosensitive resin, respectively, and are formed on the first substrate and the second substrate , respectively. The columnar spacers are formed by overlapping the columnar spacers,
The angles of the inclined surface with respect to the surfaces of the first substrate and the second substrate are prebaking temperature, prebaking time, mask gap, exposure intensity, exposure time, development temperature, development time, development in the photolithography process. A method for manufacturing a liquid crystal display device, which is controlled by any one of liquid concentrations. The angles of the inclined surface with respect to the surfaces of the first substrate and the second substrate are prebaking temperature, prebaking time, mask gap, exposure intensity, exposure time, development temperature, development time, development in the photolithography process. The method for manufacturing a liquid crystal display device according to claim 5 , which is controlled by a combination of any two or more of liquid concentrations.

Images