JP2004198643A - Liquid crystal display element and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress peeling of a first gap holding member from a substrate by disposing the first gap holding member of which the shape of the plane to be stuck to the substrate does not have an angle of 90° or less and a second gap holding member between the substrates. <P>SOLUTION: The second gap holding members 6 with rectangular cross sectional shapes of which the four angles are made to be fan-shaped are formed in a matrix on an alignment layer of gate lines 12, and similarly, the first gap holding members 5 with rectangular cross sectional shapes of which the four angles are made to be fan-shaped are formed in a matrix on an alignment layer of source lines 13. In this case, because the cross sectional shapes of the first gap holding members 5 do not have an angle of 90° or less, the peeling of the first gap holding members 5 from the substrate is suppressed even when pressurized with external force. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００７】
本発明は斯かる事情に鑑みてなされたものであり、基板に対する接着面の形状が９０°以下の角を有さない第１ギャップ保持材と、第２ギャップ保持材とを、基板間に配置することにより、第１ギャップ保持材の基板からの剥がれを抑制し、外力が加圧された場合においてもギャップが変化しにくい液晶表示素子の提供を目的とする。
【０００８】
また本発明は、第１ギャップ保持材及び／又は第２ギャップ保持材を、光が出射される領域である画素領域を除いて配置することにより、第１ギャップ保持材及び／又は第２ギャップ保持材による透過光の光吸収をなくし、光透過率が低下することのない液晶表示素子の提供を目的とする。
【０００９】
また本発明は、第１ギャップ保持材及び／又は第２ギャップ保持材を、等間隔に、又は第１ギャップ保持材と第２ギャップ保持材とを交互に配置することにより、液晶物質をギャップ間に充填する工程に要する時間を短縮することができる液晶表示素子の提供を目的とする。
【００１０】
更に本発明は、基板に形成された配向膜の配向方向を規制するラビング処理を施した後に、第１ギャップ保持材及び第２ギャップ保持材を形成することにより、均一な配向規制力を有する液晶表示素子の製造方法の提供を目的とする。
【００１１】
【課題を解決するための手段】
請求項１に係る液晶表示素子は、第１基板と第２基板との間に、所定温度にて溶融又は軟化して変形した後、硬化して第１基板及び第２基板に対し接着力を発現する第１ギャップ保持材と、前記所定温度以下の温度における変形量が略零である第２ギャップ保持材とが配置された液晶表示素子において、前記第１ギャップ保持材の前記第１基板及び前記第２基板に対する接着面の形状が、９０°以下の角を有していないことを特徴とする。
【００１２】
請求項２に係る液晶表示素子は、前記接着面の形状が、ｎ角形（ｎ≧５）、円、又は楕円状であることを特徴とする。
【００１３】
請求項３に係る液晶表示素子は、前記第１ギャップ保持材及び／又は前記第２ギャップ保持材が、画素領域を除いて配置されていることを特徴とする。
【００１４】
請求項４に係る液晶表示素子は、前記第１ギャップ保持材及び／又は前記第２ギャップ保持材が、等間隔で配置されていることを特徴とする。
【００１５】
請求項５に係る液晶表示素子は、前記第１ギャップ保持材と前記第２ギャップ保持材とが、交互に配置されていることを特徴とする。
【００１６】
請求項６に係る液晶表示素子の製造方法は、第１電極上に配向膜を設けた第１基板と、第２電極上に配向膜を設けた第２基板との間に、所定温度にて溶融又は軟化して変形した後、硬化して第１基板及び第２基板に対し接着力を発現する第１ギャップ保持材と、前記所定温度以下の温度における変形量が略零である第２ギャップ保持材とが形成される液晶表示素子の製造方法において、前記第１基板及び前記第２基板の配向膜の配向方向を規制するラビング処理を施した後に、前記第１基板及び前記第２基板に対する接着面の形状が９０°以下の角を有していない第１ギャップ保持材と、前記第２ギャップ保持材とを形成することを特徴とする。
【００１７】
請求項１の液晶表示素子にあっては、所定温度にて溶融又は軟化して変形した後、硬化して第１基板及び第２基板に対し接着力を発現し、その接着面の形状が９０°以下の角を有さない第１ギャップ保持材と、所定温度以下の温度における変形量が略零である第２ギャップ保持材とを、基板間に配置することにより、第１ギャップ保持材の基板からの剥がれを抑制する。
【００１８】
請求項２の液晶表示素子にあっては、所定温度にて溶融又は軟化して変形した後、硬化して第１基板及び第２基板に対し接着力を発現し、その接着面の形状がｎ角形（ｎ≧５）、円、又は楕円状である第１ギャップ保持材と、所定温度以下の温度における変形量が略零である第２ギャップ保持材とを、基板間に配置することにより、第１ギャップ保持材の基板からの剥がれを抑制する。
【００１９】
請求項３の液晶表示素子にあっては、第１ギャップ保持材及び／又は第２ギャップ保持材が、画素領域を除いて配置されていることにより、第１ギャップ保持材及び／又は第２ギャップ保持材による透過光の光吸収をなくす。
【００２０】
請求項４の液晶表示素子にあっては、第１ギャップ保持材及び／又は第２ギャップ保持材が、等間隔で配置されていることにより、液晶物質をギャップ間に充填する工程に要する時間を短縮する。
【００２１】
請求項５の液晶表示素子にあっては、第１ギャップ保持材と第２ギャップ保持材とが、交互に配置されていることにより、液晶物質をギャップ間に充填する工程に要する時間を短縮する。
【００２２】
請求項６の液晶表示素子の製造方法にあっては、第１基板及び第２基板の配向膜の配向方向を規制するラビング処理を施した後に、所定温度にて溶融又は軟化して変形した後、硬化して第１基板及び第２基板に対し接着力を発現し、その接着面の形状が９０°以下の角を有さない第１ギャップ保持材と、所定温度以下の温度における変形量が略零である第２ギャップ保持材とを形成することにより、第１ギャップ保持材の基板からの剥がれを抑制するとともに、第１ギャップ保持材及び第２ギャップ保持材による配向膜表面での配向性の乱れを防止し、均一な配向規制力を有する液晶表示素子を製造する。
【００２３】
【発明の実施の形態】
以下、本発明をその実施の形態を示す図面に基づいて詳述する。
【００２４】
図１は本発明に係る液晶パネルの一例を示す模式的平面図、図２は図１のII−II線における構造断面図、図３は図１のIII−III線における構造断面図である。図中１、５１は、可視光領域（３８０ｎｍ〜７７０ｎｍ）における透過率が優れたガラス又は石英等からなる平面視が正方形の基板（縦５０ｍｍ×横５０ｍｍ，厚０．７ｍｍ）である。
【００２５】
基板１上には、ＴＦＴ（Thin Film Transistor）の能動層となるアモルファスシリコン等からなる半導体層１１がピッチ８８μｍのマトリックス状に形成されている。そして、ＴＦＴのゲート端子であり、同一行のＴＦＴのゲート端子を直線状に接続したポリシリコン等からなるゲート線１２が酸化膜又は窒化膜等のゲート絶縁膜３１を介して形成されている。更に、図示しないコンタクトホールにより同一列のＴＦＴのソース端子と接続したアルミニウム等からなるソース線１３がＮＳＧ又はＢＰＳＧ等の層間絶縁膜３２を介して形成されている。半導体層１１とゲート線１２とのオーバラップ領域がＴＦＴとして機能し、半導体層１１の幅がゲート幅、ゲート線１２の幅がゲート長となり、この２つのパラメータ及び拡散条件等によりスイッチング特性が決定される。
【００２６】
半導体層１１、ゲート線１２、及びソース線１３が形成された基板１上には、ＩＴＯ（Indium Tin Oxide）製の透過率に優れた画素電極（長さ８０μｍ×幅８０μｍ）３が、透過率に優れたアクリル樹脂等の平坦化膜２を介して、ピッチ８８μｍのマトリックス状に形成されており、図示しないコンタクトホールによりＴＦＴのドレイン端子と接続されている。なお、平坦化膜２により、半導体層１１、ゲート線１２、及びソース線１３等のパターンに起因する段差が平滑化されている。
【００２７】
画素電極３上には、液晶の基板１側の配向方向を規制するために、ポリイミド（例えば、日産化学製：ＳＥ７７９２）等の配向膜４が、２００℃にて１時間ベークすることにより、膜厚１００ｎｍにて形成されている。配向膜４は、レーヨン製の布により図１の上から下方向にラビングされ、配向膜４の側鎖方向が規制されている。
【００２８】
ゲート線１２上の配向膜４上に、ネガ型アクリルフォトレジスト（例えば、ＪＳＲ製：ＭＮ７００）等の第２ギャップ保持材（長さ８０μｍ×幅６μｍ，厚４μｍ）６が、１８０℃にて１時間ポストベークすることにより、ピッチ８８μｍのマトリックス状に形成されている。また、ソース線１３上の配向膜４上に、ポリシラン系材料（日本ペイント製：グラシアＰＳ−ＳＲ１０３）等の第１ギャップ保持材（長さ８０μｍ×幅６μｍ，厚４μｍ）５が、８０℃にて３０分間プリベークすることにより、ピッチ８８μｍのマトリックス状に形成されている。ここで、第１ギャップ保持材５，第２ギャップ保持材６の断面は、長方形の４つの角を半径１μｍの扇形状（所謂、１μｍのＲ）にさせた形状となっており、角（９０°以下の角）を有していない。なお、このような断面形状にするには、フォトマスクを用いてパターニングすればよい。また、第１ギャップ保持材５，第２ギャップ保持材６の形成プロセスの温度制御、時間制御により形成することもできる。
【００２９】
一方、基板５１の基板１対向面には、Ｃｒ（Chromium）又はＷＳｉ（Wolfram(Tungsten) Silicide）等の遮光特性に優れた遮光膜５２が、基板１に形成した画素電極３を除いた領域に形成されている。なお、本実施形態では、画素電極３のエッジ部に発生する光漏れを防止するため、遮光膜５２は画素電極３と僅かながらオーバラップ（２μｍ）されている。そして、遮光膜５２、及び遮光膜５２欠損領域の基板５１面に、ＩＴＯ製の透過率に優れた対向電極（共通電極ともいう）５３が形成され、対向電極５３面に、液晶の基板５１側の配向方向を規制するための配向膜５４が、膜厚１００ｎｍにて形成されている。配向膜５４は、図１の左から右方向にラビングされ、配向膜５４の側鎖方向が規制されている。換言すれば、配向膜４，５４の側鎖方向が９０°となるようにラビングされている。なお、遮光膜５２が形成されていない矩形部が、光が出射される領域である画素領域となる画素開口部（縦８０μｍ×横８０μｍ）７１であり、画素電極３，対向電極５３間に印加された電圧に基づいて液晶の光透過率が制御され、画素開口部７１より光が出射される。
【００３０】
そして、図示しない液晶注入口を設けたシール剤（例えば、三井化学製：ＸＮ−２１Ｆ）が基板５１の外周部に塗布され、基板１，５１は配向膜４，５４を形成した面を対向して配置され、１５０℃にて１時間ポストベークすることにより、シール剤，第１ギャップ保持材５を硬化させて基板１，基板５１に接着させ、基板１、基板５１、及びシール剤により形成された空隙内に、液晶注入口より液晶を充填して液晶層９が形成されている。例えば、液晶層９は、液晶の長軸方向が９０°ツイストするように光学活性剤（カイラル剤）を適量添加したＴＮ液晶（例えば、メルク製：ＺＬＩ−４７９２）を、液晶注入口から真空注入法により充填すればよい。カイラル剤は、リバースツイスト発生によるコントラスト特性の低下を抑制する効果を有する。ここで、第１ギャップ保持材５，第２ギャップ保持材６がマトリックス状（等間隔）に形成されていることにより、液晶の注入経路が規則的になるため、液晶は液晶注入口から均一的に液晶層９へ注入される。従って、液晶をギャップ間に充填する工程に要する時間が短縮される。なお、第１ギャップ保持材５を形成するプロセス、及び基板１，５１を接着させるプロセスは熱反応を利用しているが、これらプロセス（加熱）による第２ギャップ保持材６の変形量は略零であり、第２ギャップ保持材６は変形しないものとして扱える。
【００３１】
基板１の表面には、光吸収軸が配向膜４のラビング方向と平行になるように偏光板７が貼付けられ、基板５１の表面には、光吸収軸が配向膜５４のラビング方向と垂直となるように偏光板５７が貼付けられている。即ち、その光吸収軸が平行になるように偏光板７，５７が貼付けられており、画素電極３，対向電極５３間に電圧を印加することにより、黒表示から白表示へ制御されるノーマリーブラックモードの液晶パネル９９（図４）とする。
【００３２】
このように構成された液晶パネル９９の製造方法として、基板１，基板５１の配向膜４，５４の配向方向を規制するラビング処理を施した後に、第１ギャップ保持材５と第２ギャップ保持材６とを形成するようにすれば、第１ギャップ保持材５及び第２ギャップ保持材６による配向膜表面での配向性の乱れを防止できる。
【００３３】
次に、このように構成された液晶パネル９９の耐荷重依存性を評価するため、第１ギャップ保持材５の種々の断面形状に対して、平面静圧耐荷重試験（以下、荷重試験という）を実施した。図４は平面静圧耐荷重試験の実施状態を示す図である。荷重試験は、バックライト９１上に液晶パネル９９を配置し、シリコンシート（縦１０ｍｍ×横１０ｍｍ）９３を介して、５０，１００，２００，３００，４００，５００ｋＰａの平面静圧荷重（以下、荷重という）をプッシュプルゲージ９２により液晶パネル９９へ順に加える。そして、その都度、液晶パネル９９の表示に変化がないか否かを確認し、変化が生じた場合には、そのときの荷重の一つ前に加圧された荷重を平面静圧耐荷重（以下、耐荷重という）とする。例えば、２００ｋＰａの荷重時には変化がなく、３００ｋＰａの荷重時に変化が生じた場合には、耐荷重を２００ｋＰａとする。
【００３４】
荷重試験を行った第１ギャップ保持材５の断面形状は、本発明例として、図５に示すように、五角形（同図（ａ））、六角形（同図（ｂ））、円（同図（ｃ））、楕円（同図（ｄ））、四角形の角の部分を扇形状にさせた形（同図（ｅ））とし、比較例として、図９に示すように、三角形（同図（ａ））、四角形（同図（ｂ））、９０°以下の角と楕円（円を含む）との複合形（以下、涙形という，同図（ｃ））とした。
【００３５】
【表１】

【００３６】
評価結果をまとめると表１のようになり、本発明例のように、第１ギャップ保持材５の断面が９０°以下の角を有さない場合には、３００ｋＰａ程度の応力が加わったときでも、表示に変化がみられなかった。なお、表１中、角の部分を扇形状にさせた四角形を”楕円状”として記載した。一方、比較例のように、９０°以下の角を有する場合には、３００ｋＰａ程度の応力が加わると、加圧領域と非加圧領域とが異なる透過率特性を示す表示ムラが観察された。表示ムラの原因を調べると、第１ギャップ保持材５が基板から剥がれたために、ギャップに変化が生じて表示ムラが発生したことがわかった。つまり、第１ギャップ保持材５の断面が９０°以下の角を有さない場合には、３００ｋＰａ程度の応力が加わったときでも、第１ギャップ保持材５が基板から剥がれないことがわかった。
【００３７】
以下、第１ギャップ保持材５の剥がれの原因について考察する。図６は第１ギャップ保持材５が剥がれる原因を考察するための図である。第１ギャップ保持材５が剥がれる起点が基板との接着面の外周点であり、その外周点を中心とする微小円に含まれる接触面の面積が小さい箇所から剥がれると仮定する。同図（ａ）の正三角形の場合、剥がれる起点は頂点８１Ａであり、頂点８１Ａを中心とする半径ｒの円に含まれる接触面８１の面積はπ×ｒ² ×（１／６）である。同様に、同図（ｂ）の正四角形の場合は頂点８２Ａが、同図（ｃ）の正五角形の場合は頂点８３Ａが、同図（ｄ）の正六角形の場合は頂点８４Ａが、剥がれる起点であり、夫々の頂点８２Ａ，８３Ａ，８４Ａを中心とする半径ｒの円に含まれる接触面８２，接触面８３，接触面８４の面積は、夫々π×ｒ² ×（１／４），π×ｒ² ×（３／１０），π×ｒ² ×（１／３）である。なお、円、楕円等の角を有さないものは、半径ｒの微小円であると考えると、π×ｒ² ×（１／２）となる。
【００３８】
これら外周点を中心とする微小円に含まれる接触面の面積（以下、単に面積という）を横軸に、表１に示した耐荷重を縦軸にプロットしたグラフを図７に示す。図７が示すように、面積と耐荷重とは正の相関関係を持っており、面積が大きいほど、すなわち、第１ギャップ保持材５の基板に接着する断面の形状が有する角の角度が大きいほど、耐荷重が大きいことがわかる。
【００３９】
なお、実施形態にて詳述した液晶パネル９９では、第２ギャップ保持材６をゲート線１２上の配向膜４上に、第１ギャップ保持材５をソース線１３上の配向膜４上に、夫々マトリックス状に形成された形態としたが、これに限定されるものではない。例えば、図８に示すように、ゲート線１２上の配向膜４上に、第１ギャップ保持材５と第２ギャップ保持材６とが交互に８８μｍピッチで形成され、一のソース線１３上の配向膜４上に、第１ギャップ保持材５が８８μｍピッチで形成され、その隣のソース線１３上の配向膜４上に、第２ギャップ保持材６が８８μｍピッチで形成されているような構成であってもよい。なお、その他の構成は図１と同様であるので、対応する部分には同一の符号を付してその詳細な説明を省略する。
【００４０】
また、実施形態にて詳述した液晶パネル９９では、基板１上に、能動層となる半導体層１１を形成した後に、ゲート絶縁膜３１を介してゲート線１２を形成する構造としたが、もちろん、ゲート線１２を形成した後に、ゲート絶縁膜３１を介して半導体層１１を形成する構造としてもよい。
【００４１】
また、ポリシラン系材料の第１ギャップ保持材が形成された形態について詳述したが、これに限定されるものではなく、第１ギャップ保持材を、フェノール樹脂、尿素樹脂、メラミン樹脂、アルキドポリエステル樹脂、不飽和ポリエステル樹脂、珪素樹脂、ポリウレタン樹脂、エポキシ樹脂、フラン樹脂、キシレン樹脂、ホルムアルデヒド及びケトン樹脂、アニリン樹脂、スルホンアミド樹脂、ジアリルフタレート樹脂、シリコン樹脂、レゾルシノール樹脂等の熱硬化性樹脂の一種類、またはそれぞれの二種類以上の組み合わせとすることができる。
【００４２】
また、ネガ型アクリルフォトレジストの第２ギャップ保持材が形成された形態について詳述したが、これに限定されるものではなく、第２ギャップ保持材を、ポリスチレン系架橋重合体樹脂、ジビニルベンゼン系架橋重合体、アミノ樹脂等の有機系合成樹脂の硬化球状粒子の一種類またはそれぞれの二種類以上の組み合わせとすることができ、グラスファイバーを細粉化したもの、ボール状の珪酸ガラス、アルミナ等の無機系材料の粉末の一種類またはそれぞれの二種類以上の組み合わせとすることができる。
【００４３】
また、ＴＦＴの能動層としてポリシリコンが形成されていてもよく、ポリシリコンとすれば、キャリアの電界効果移動度を向上させ、スイッチング特性を向上させることができる。もちろん、スイッチング素子としてＴＦＴに限定されるものではなく、ＭＩＭ（Metal Insulator Metal）等のスイッチング素子であってもよい。もちろん、スイッチング素子を用いない、所謂パッシブ型の液晶表示素子であってもよい。
【００４４】
また、画素電極３の構成を正方配列としたが、もちろん、デルタ配列としてもよい。
【００４５】
更に、画素電極３，対向電極５３間に電圧を印加することにより黒表示から白表示に制御するノーマリーブラックモードの液晶パネル９９としたが、液晶分子の長軸方向が一方に傾いた場合に明状態になるように、基板１，５１の表面に、クロスニコル状態の２枚の偏光板７，５７を夫々貼付け、画素電極３，対向電極５３間に電圧を印加することにより白表示から黒表示に制御するノーマリーホワイトモードの液晶パネルとしてもよく、一般にノーマリーホワイトモードの液晶パネルの方がコントラスト特性に優れる。
【００４６】
【発明の効果】
以上詳述した如く本発明によれば、基板に対する接着面の形状が９０°以下の角を有していない第１ギャップ保持材と、第２ギャップ保持材とを配置させることにより、第１ギャップ保持材の基板からの剥がれを抑制し、外力が加圧された場合においてもギャップの変化を抑制できる。従って、表示ムラ等の表示品質の低下を抑制できる液晶表示素子を提供できる。
【００４７】
また本発明によれば、第１ギャップ保持材及び／又は第２ギャップ保持材を、画素領域を除いた領域に配置することにより、第１ギャップ保持材及び／又は第２ギャップ保持材による透過光の光吸収をなくすことができ、光透過率を低下することなく表示ムラ等の表示品質の低下を抑制できる。
【００４８】
また本発明によれば、第１ギャップ保持材及び／又は２ギャップ保持材を、等間隔に、又は第１ギャップ保持材と第２ギャップ保持材とを交互に配置することにより、液晶物質をギャップ間に充填する工程に要する時間を短縮することができるため、製造コストを削減することができる。
【００４９】
更に本発明によれば、基板に形成された配向膜の配向方向を規制するラビング処理を施した後に、第１ギャップ保持材及び第２ギャップ保持材を形成することにより、均一な配向規制力を有することができるため、表示ムラ等の表示品質の優れた液晶表示素子を製造することができる等、優れた効果を奏する。
【図面の簡単な説明】
【図１】本発明に係る液晶パネルの一例を示す模式的平面図である。
【図２】図１のII−II線における構造断面図である。
【図３】図１のIII−III線における構造断面図である。
【図４】平面静圧耐荷重試験の実施状態を示す図である。
【図５】本発明における第１ギャップ保持材の断面の形状を示す図である。
【図６】第１ギャップ保持材が剥がれる原因を考察するための図である。
【図７】面積と耐荷重との関係を示すグラフである。
【図８】本発明に係る液晶パネルの他の例を示す模式的平面図である。
【図９】比較例における第１ギャップ保持材の断面の形状を示す図である。
【符号の説明】
１ 基板
３ 画素電極
４ 配向膜
５ 第１ギャップ保持材
６ 第２ギャップ保持材
９ 液晶層
１１ 半導体層
１２ ゲート線
１３ ソース線
５１ 基板
５２ 遮光膜
５３ 対向電極
５４ 配向膜
７１ 画素開口部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more specifically, to a liquid crystal display device in which an opposing distance (hereinafter, referred to as a gap) between substrates hardly changes even when external force is applied, and a method of manufacturing the same.
[0002]
[Prior art]
In a liquid crystal display element, a liquid crystal substance is sealed in a gap formed by arranging two substrates provided with electrodes so that the electrodes are opposed to each other, and a voltage is applied between the electrodes. The light transmittance of the determined liquid crystal material is controlled. Since the gap between the substrates is a parameter that determines the light transmittance of the liquid crystal display element, various techniques have been devised for making the design value and in-plane uniformity. One of them is a first gap holding material that can be melted or softened and deformed at a predetermined temperature and then hardened to develop an adhesive force on both substrates, and a deformation amount at a temperature equal to or lower than a predetermined temperature is substantially zero. There is a technique of disposing a patternable second gap holding material between substrates to make the gap uniform in a plane (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-8-110524
[Problems to be solved by the invention]
However, when the shape of the cross section of the first gap holding material that adheres to the substrate is rectangular, the first gap holding material may be peeled off from the substrate when a stress (approximately 300 kPa) is applied. The situation where the first gap holding material is peeled off from the substrate means that the gap is wider than the designed value and the in-plane unevenness occurs. Tone display is not possible, that is, display unevenness occurs.
[0005]
For example, when a TN (Twisted Nematic) liquid crystal is used as the liquid crystal material, the product of the birefringence Δn and the gap d of the TN liquid crystal is called a retardation Δn · d, and the transmitted light intensity I is obtained by using the retardation Δn · d as a parameter. , Is determined by equation (1) known per se (λ: wavelength). Therefore, if the gap d becomes non-uniform in the plane of the liquid crystal display element, the light transmittance changes in the plane, and uneven brightness occurs in the monochrome liquid crystal display element and the single-panel type color liquid crystal display element. Color unevenness occurs in a color projector or the like that uses light of three primary colors, such as red, green, and blue, respectively, incident on a monochrome liquid crystal display element of a plate.
[0006]
(Equation 1)

[0007]
The present invention has been made in view of such circumstances, and a first gap holding material having a shape of an adhesive surface to a substrate having no angle of 90 ° or less and a second gap holding material are arranged between the substrates. By doing so, an object of the present invention is to provide a liquid crystal display element in which the first gap holding material is prevented from peeling from the substrate, and the gap is hardly changed even when an external force is applied.
[0008]
Further, according to the present invention, by disposing the first gap holding material and / or the second gap holding material except for a pixel region which is a region from which light is emitted, the first gap holding material and / or the second gap holding material are arranged. An object of the present invention is to provide a liquid crystal display element in which light absorption of transmitted light by a material is eliminated and light transmittance does not decrease.
[0009]
Further, according to the present invention, the first gap holding material and / or the second gap holding material are arranged at equal intervals, or the first gap holding material and the second gap holding material are alternately arranged, so that the liquid crystal material is formed between the gaps. It is an object of the present invention to provide a liquid crystal display element capable of shortening the time required for the step of filling the liquid crystal.
[0010]
Further, the present invention provides a liquid crystal having a uniform alignment control force by forming a first gap holding material and a second gap holding material after performing a rubbing process for controlling an alignment direction of an alignment film formed on a substrate. An object is to provide a method for manufacturing a display element.
[0011]
[Means for Solving the Problems]
The liquid crystal display element according to claim 1 is configured such that after being melted or softened at a predetermined temperature and deformed between the first substrate and the second substrate, the liquid crystal display element is cured and has an adhesive force to the first and second substrates. In a liquid crystal display element in which a first gap holding material that develops and a second gap holding material whose deformation at a temperature equal to or lower than the predetermined temperature is substantially zero are disposed, the first substrate of the first gap holding material and The shape of the bonding surface to the second substrate does not have an angle of 90 ° or less.
[0012]
The liquid crystal display element according to claim 2 is characterized in that the shape of the bonding surface is an n-sided polygon (n ≧ 5), a circle, or an ellipse.
[0013]
The liquid crystal display element according to claim 3 is characterized in that the first gap holding material and / or the second gap holding material are arranged except for a pixel region.
[0014]
A liquid crystal display element according to a fourth aspect is characterized in that the first gap holding material and / or the second gap holding material are arranged at equal intervals.
[0015]
A liquid crystal display element according to a fifth aspect is characterized in that the first gap holding members and the second gap holding members are alternately arranged.
[0016]
A method for manufacturing a liquid crystal display element according to claim 6, wherein a predetermined temperature is set between a first substrate provided with an alignment film on the first electrode and a second substrate provided with an alignment film on the second electrode. A first gap holding material that is melted or softened and deformed and then hardened to exhibit an adhesive force to the first substrate and the second substrate; and a second gap having a deformation amount of substantially zero at a temperature equal to or lower than the predetermined temperature. In the method for manufacturing a liquid crystal display element in which a holding material is formed, after performing a rubbing process for regulating an orientation direction of an orientation film of the first substrate and the second substrate, the rubbing process is performed on the first substrate and the second substrate. The method is characterized in that a first gap holding member having an angle of 90 ° or less in the shape of an adhesive surface and the second gap holding member are formed.
[0017]
In the liquid crystal display element according to the first aspect, after being melted or softened and deformed at a predetermined temperature, it is cured and expresses an adhesive force to the first and second substrates, and the shape of the adhesive surface is 90%. By disposing a first gap holding material having no angle of not more than ° and a second gap holding material having a deformation amount of substantially zero at a temperature equal to or lower than a predetermined temperature between the substrates, Suppresses peeling from the substrate.
[0018]
In the liquid crystal display element according to the second aspect, after being melted or softened at a predetermined temperature and deformed, it is cured and develops an adhesive force to the first substrate and the second substrate, and the shape of the adhesive surface is n. By disposing a first gap holding material having a square shape (n ≧ 5), a circle, or an ellipse and a second gap holding material having a deformation amount of substantially zero at a temperature equal to or lower than a predetermined temperature between substrates, The first gap holding material is prevented from peeling from the substrate.
[0019]
In the liquid crystal display element according to the third aspect, the first gap holding material and / or the second gap holding material are arranged except for the pixel region, so that the first gap holding material and / or the second gap holding material are arranged. Eliminates light absorption of transmitted light by the holding material.
[0020]
In the liquid crystal display device according to the fourth aspect, the first gap holding material and / or the second gap holding material are arranged at equal intervals, so that the time required for the step of filling the gap with the liquid crystal material is reduced. Shorten.
[0021]
In the liquid crystal display device according to the fifth aspect, the first gap holding material and the second gap holding material are alternately arranged, so that the time required for the step of filling the gap with the liquid crystal material is reduced. .
[0022]
In the method for manufacturing a liquid crystal display element according to claim 6, after performing a rubbing treatment for regulating the alignment direction of the alignment film of the first substrate and the second substrate, after deforming by melting or softening at a predetermined temperature. The first gap holding material, which is cured to exhibit an adhesive force to the first substrate and the second substrate and has an adhesive surface having no angle of 90 ° or less, and a deformation amount at a temperature of a predetermined temperature or less. By forming the second gap holding material that is substantially zero, it is possible to prevent the first gap holding material from being peeled off from the substrate, and to control the orientation of the first gap holding material and the second gap holding material on the alignment film surface. And a liquid crystal display element having a uniform alignment regulating force is manufactured.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments.
[0024]
1 is a schematic plan view showing an example of the liquid crystal panel according to the present invention, FIG. 2 is a structural sectional view taken along line II-II in FIG. 1, and FIG. 3 is a structural sectional view taken along line III-III in FIG. In the drawing, reference numerals 1 and 51 denote a square substrate (50 mm long × 50 mm wide, 0.7 mm thick) made of glass, quartz, or the like having excellent transmittance in the visible light region (380 nm to 770 nm).
[0025]
On the substrate 1, a semiconductor layer 11 made of amorphous silicon or the like to be an active layer of a TFT (Thin Film Transistor) is formed in a matrix with a pitch of 88 μm. A gate line 12 made of polysilicon or the like, which is a gate terminal of the TFT and linearly connects the gate terminals of the TFTs in the same row, is formed via a gate insulating film 31 such as an oxide film or a nitride film. Further, a source line 13 made of aluminum or the like connected to the source terminal of the TFT in the same column by a contact hole (not shown) is formed via an interlayer insulating film 32 such as NSG or BPSG. The overlap region between the semiconductor layer 11 and the gate line 12 functions as a TFT, and the width of the semiconductor layer 11 is the gate width and the width of the gate line 12 is the gate length. The switching characteristics are determined by these two parameters and diffusion conditions. Is done.
[0026]
On the substrate 1 on which the semiconductor layer 11, the gate lines 12, and the source lines 13 are formed, a pixel electrode (length 80 μm × width 80 μm) 3 made of ITO (Indium Tin Oxide) having excellent transmittance is provided. It is formed in a matrix with a pitch of 88 μm via a flattening film 2 made of acrylic resin or the like excellent in quality, and is connected to a drain terminal of the TFT through a contact hole (not shown). It should be noted that the level difference caused by the pattern of the semiconductor layer 11, the gate line 12, the source line 13, and the like is smoothed by the flattening film 2.
[0027]
An alignment film 4 made of polyimide (for example, SE7792 manufactured by Nissan Chemical Industries, Ltd.) or the like is baked at 200 ° C. for 1 hour on the pixel electrode 3 to regulate the alignment direction of the liquid crystal on the substrate 1 side. It is formed with a thickness of 100 nm. The alignment film 4 is rubbed downward from above in FIG. 1 with a cloth made of rayon, and the side chain direction of the alignment film 4 is regulated.
[0028]
On the alignment film 4 on the gate line 12, a second gap holding material (length 80 μm × width 6 μm, thickness 4 μm) 6 such as a negative type acrylic photoresist (for example, manufactured by JSR: MN700) is placed at 180 ° C. By post-baking for a time, a matrix having a pitch of 88 μm is formed. On the alignment film 4 on the source line 13, a first gap holding material (length 80 μm × width 6 μm, thickness 4 μm) 5 such as a polysilane-based material (Nippon Paint: Gracia PS-SR103) is heated to 80 ° C. By pre-baking for 30 minutes, a matrix having a pitch of 88 μm is formed. Here, the cross section of the first gap holding member 5 and the second gap holding member 6 has a shape in which four corners of a rectangle are formed into a fan shape with a radius of 1 μm (a so-called 1 μm R), and the corner (90 ° or less). Note that in order to obtain such a cross-sectional shape, patterning may be performed using a photomask. Further, the first gap holding member 5 and the second gap holding member 6 can be formed by controlling the temperature and time of the forming process.
[0029]
On the other hand, a light-shielding film 52 having excellent light-shielding properties, such as Cr (Chromium) or WSi (Wolfram (Tungsten) Silicide), is provided on the surface of the substrate 51 facing the substrate 1 in a region excluding the pixel electrodes 3 formed on the substrate 1. Is formed. In the present embodiment, the light-shielding film 52 slightly overlaps (2 μm) with the pixel electrode 3 in order to prevent light leakage occurring at the edge of the pixel electrode 3. An opposing electrode (also referred to as a common electrode) 53 made of ITO having excellent transmittance is formed on the light-shielding film 52 and the surface of the substrate 51 in a region where the light-shielding film 52 is defective. An alignment film 54 for regulating the alignment direction is formed with a thickness of 100 nm. The alignment film 54 is rubbed from left to right in FIG. 1, and the side chain direction of the alignment film 54 is regulated. In other words, the rubbing is performed so that the side chain direction of the alignment films 4 and 54 is 90 degrees. A rectangular portion where the light-shielding film 52 is not formed is a pixel opening (80 μm × 80 μm) 71 serving as a pixel region which is a region from which light is emitted, and is applied between the pixel electrode 3 and the counter electrode 53. The light transmittance of the liquid crystal is controlled based on the applied voltage, and light is emitted from the pixel opening 71.
[0030]
Then, a sealant (for example, XN-21F manufactured by Mitsui Chemicals, Inc.) provided with a liquid crystal injection port (not shown) is applied to the outer peripheral portion of the substrate 51, and the substrates 1, 51 face the surfaces on which the alignment films 4, 54 are formed. The sealing agent and the first gap holding material 5 are hardened by post-baking at 150 ° C. for one hour and adhered to the substrate 1 and the substrate 51, and are formed by the substrate 1, the substrate 51, and the sealing agent. A liquid crystal is filled in the gap from a liquid crystal injection port to form a liquid crystal layer 9. For example, the liquid crystal layer 9 vacuum-injects a TN liquid crystal (for example, ZLI-4792, manufactured by Merck) into which an appropriate amount of an optically active agent (chiral agent) is added so that the major axis direction of the liquid crystal is twisted by 90 °. What is necessary is just to fill by the method. The chiral agent has an effect of suppressing a decrease in contrast characteristics due to occurrence of reverse twist. Here, since the first gap holding material 5 and the second gap holding material 6 are formed in a matrix shape (equal intervals), the liquid crystal injection path becomes regular, so that the liquid crystal is uniformly supplied from the liquid crystal injection port. Is injected into the liquid crystal layer 9. Therefore, the time required for the step of filling the liquid crystal between the gaps is reduced. Although the process of forming the first gap holding material 5 and the process of bonding the substrates 1 and 51 utilize a thermal reaction, the amount of deformation of the second gap holding material 6 due to these processes (heating) is substantially zero. Thus, the second gap holding member 6 can be treated as being not deformed.
[0031]
A polarizing plate 7 is attached to the surface of the substrate 1 so that the light absorption axis is parallel to the rubbing direction of the alignment film 4, and the light absorption axis is perpendicular to the rubbing direction of the alignment film 54 on the surface of the substrate 51. The polarizing plate 57 is stuck so that That is, the polarizing plates 7 and 57 are stuck so that their light absorption axes are parallel to each other, and a voltage is applied between the pixel electrode 3 and the counter electrode 53 to control normally from black display to white display. It is assumed that the liquid crystal panel 99 is in the black mode (FIG. 4).
[0032]
As a method of manufacturing the liquid crystal panel 99 configured as described above, the first gap holding material 5 and the second gap holding material are subjected to a rubbing process for regulating the alignment direction of the alignment films 4 and 54 of the substrates 1 and 51. 6 can prevent the first gap holding material 5 and the second gap holding material 6 from disturbing the alignment on the alignment film surface.
[0033]
Next, in order to evaluate the load resistance of the liquid crystal panel 99 configured as described above, a plane static pressure load test (hereinafter, referred to as a load test) is performed on various cross-sectional shapes of the first gap holding member 5. Was carried out. FIG. 4 is a diagram showing an implementation state of a plane static pressure withstand load test. In the load test, a liquid crystal panel 99 is arranged on a backlight 91, and a plane static pressure load (hereinafter, referred to as a load) of 50, 100, 200, 300, 400, 500 kPa is applied through a silicon sheet (length 10 mm × width 10 mm) 93. ) Is sequentially applied to the liquid crystal panel 99 by the push-pull gauge 92. Each time, it is checked whether or not there is a change in the display of the liquid crystal panel 99, and when a change occurs, the load applied immediately before the load at that time is applied to the flat static pressure resistance load ( Hereinafter, it is referred to as withstand load). For example, if there is no change at a load of 200 kPa and a change occurs at a load of 300 kPa, the withstand load is set to 200 kPa.
[0034]
The cross-sectional shape of the first gap holding material 5 subjected to the load test is, as shown in FIG. 5, a pentagon (FIG. 5A), a hexagon (FIG. 5B), and a circle (FIG. 5). FIG. 9 (c)), an ellipse (FIG. 9 (d)), and a shape in which the corners of the square are formed into a fan shape (FIG. 9 (e)). As a comparative example, as shown in FIG. (A), a square (FIG. (B)), and a compound shape of a 90 ° or less angle and an ellipse (including a circle) (hereinafter referred to as a tear shape, (c) in the figure).
[0035]
[Table 1]

[0036]
The evaluation results are summarized in Table 1, and when the cross section of the first gap holding material 5 does not have an angle of 90 ° or less as in the example of the present invention, even when a stress of about 300 kPa is applied. , The display did not change. In Table 1, a quadrangle in which a corner portion is formed into a fan shape is described as “elliptical”. On the other hand, in the case of having an angle of 90 ° or less, as in the comparative example, when a stress of about 300 kPa is applied, display unevenness indicating different transmittance characteristics between the pressurized region and the non-pressurized region was observed. When the cause of the display unevenness was examined, it was found that the gap was changed and the display unevenness occurred because the first gap holding material 5 was peeled off from the substrate. That is, it was found that when the cross section of the first gap holding material 5 did not have an angle of 90 ° or less, the first gap holding material 5 did not peel off from the substrate even when a stress of about 300 kPa was applied.
[0037]
Hereinafter, the cause of the peeling of the first gap holding member 5 will be considered. FIG. 6 is a diagram for considering the cause of the first gap holding material 5 being peeled off. It is assumed that the starting point at which the first gap holding material 5 is peeled is the outer peripheral point of the bonding surface with the substrate, and that the first gap retaining material 5 is peeled from a portion where the area of the contact surface included in the minute circle centered on the outer peripheral point is small. In the case of the equilateral triangle shown in FIG. 7A, the starting point of the separation is the vertex 81A, and the area of the contact surface 81 included in a circle having a radius r centered on the vertex 81A is π × r ² × (1/6). . Similarly, the vertex 82A in the case of the regular square in FIG. 4B, the vertex 83A in the case of the regular pentagon in FIG. 4C, and the vertex 84A in the case of the regular hexagon in FIG. And the areas of the contact surface 82, the contact surface 83, and the contact surface 84 included in a circle having a radius r centered on the respective vertices 82A, 83A, and 84A are π × r ² × (1/4) and π, respectively. × r ² × (3/10) and π × r ² × (1/3). Note that a circle, an ellipse, or the like having no corners is π × r ² × (）) assuming that it is a minute circle having a radius r.
[0038]
FIG. 7 is a graph in which the area of the contact surface (hereinafter, simply referred to as the area) included in the minute circle centered on the outer peripheral point is plotted on the horizontal axis, and the load resistance shown in Table 1 is plotted on the vertical axis. As shown in FIG. 7, the area and the withstand load have a positive correlation, and the larger the area, that is, the larger the angle of the corner of the cross-sectional shape of the first gap holding material 5 adhered to the substrate. It can be seen that the greater the load resistance, the greater the load resistance.
[0039]
In the liquid crystal panel 99 described in detail in the embodiment, the second gap holding material 6 is provided on the alignment film 4 on the gate line 12, and the first gap holding material 5 is provided on the alignment film 4 on the source line 13. Each of them is in the form of a matrix, but is not limited to this. For example, as shown in FIG. 8, on the alignment film 4 on the gate line 12, the first gap holding members 5 and the second gap holding members 6 are alternately formed at a pitch of 88 μm. A configuration in which first gap holding members 5 are formed at a pitch of 88 μm on the alignment film 4, and second gap holding members 6 are formed at a pitch of 88 μm on the alignment film 4 on the adjacent source line 13. It may be. Since other configurations are the same as those in FIG. 1, corresponding portions are denoted by the same reference numerals and detailed description thereof will be omitted.
[0040]
Further, the liquid crystal panel 99 described in detail in the embodiment has a structure in which the semiconductor layer 11 serving as an active layer is formed on the substrate 1 and then the gate line 12 is formed via the gate insulating film 31. After the gate line 12 is formed, the semiconductor layer 11 may be formed with the gate insulating film 31 interposed therebetween.
[0041]
Further, although the form in which the first gap holding material of the polysilane material is formed has been described in detail, the invention is not limited to this, and the first gap holding material may be a phenol resin, a urea resin, a melamine resin, an alkyd polyester resin. , Unsaturated polyester resin, silicon resin, polyurethane resin, epoxy resin, furan resin, xylene resin, formaldehyde and ketone resin, aniline resin, sulfonamide resin, diallyl phthalate resin, silicone resin, resorcinol resin and other thermosetting resins It can be a type or a combination of two or more types.
[0042]
In addition, although the form in which the second gap holding material of the negative type acrylic photoresist is formed has been described in detail, the present invention is not limited to this, and the second gap holding material may be a polystyrene-based crosslinked polymer resin, a divinylbenzene-based resin. A crosslinked polymer, one type of hardened spherical particles of an organic synthetic resin such as an amino resin or a combination of two or more types thereof can be used, and finely divided glass fibers, ball-shaped silicate glass, alumina, etc. Or a combination of two or more of the inorganic material powders.
[0043]
Further, polysilicon may be formed as an active layer of the TFT. If polysilicon is used, the field-effect mobility of carriers can be improved, and the switching characteristics can be improved. Of course, the switching element is not limited to a TFT, and may be a switching element such as MIM (Metal Insulator Metal). Of course, a so-called passive type liquid crystal display element that does not use a switching element may be used.
[0044]
Further, the configuration of the pixel electrodes 3 is a square array, but may be a delta array.
[0045]
Further, the liquid crystal panel 99 of a normally black mode in which a black display is controlled to a white display by applying a voltage between the pixel electrode 3 and the counter electrode 53 is used. The two polarizing plates 7 and 57 in the crossed Nicols state are respectively adhered to the surfaces of the substrates 1 and 51 so as to be in a bright state, and a voltage is applied between the pixel electrode 3 and the counter electrode 53 to change from white display to black. A normally white mode liquid crystal panel for controlling display may be used, and a normally white mode liquid crystal panel generally has better contrast characteristics.
[0046]
【The invention's effect】
As described in detail above, according to the present invention, the first gap holding member and the second gap holding member having the shape of the bonding surface with respect to the substrate not having an angle of 90 ° or less are arranged, so that the first gap holding member is formed. Peeling of the holding material from the substrate can be suppressed, and a change in the gap can be suppressed even when an external force is applied. Therefore, it is possible to provide a liquid crystal display element that can suppress a decrease in display quality such as display unevenness.
[0047]
Further, according to the present invention, the first gap holding material and / or the second gap holding material are arranged in a region excluding the pixel region, so that light transmitted by the first gap holding material and / or the second gap holding material is provided. , And the deterioration of display quality such as display unevenness can be suppressed without lowering the light transmittance.
[0048]
Further, according to the present invention, the first gap holding material and / or the two gap holding materials are arranged at equal intervals or the first gap holding material and the second gap holding material are alternately arranged, so that the liquid crystal material is formed in a gap. Since the time required for the step of filling in between can be reduced, the manufacturing cost can be reduced.
[0049]
Furthermore, according to the present invention, after performing a rubbing process for regulating the orientation direction of the orientation film formed on the substrate, the first gap retaining material and the second gap retaining material are formed, so that a uniform orientation regulating force can be obtained. Because of this, excellent effects such as the production of a liquid crystal display element having excellent display quality such as display unevenness can be produced.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an example of a liquid crystal panel according to the present invention.
FIG. 2 is a structural sectional view taken along line II-II of FIG.
FIG. 3 is a structural sectional view taken along line III-III in FIG. 1;
FIG. 4 is a diagram showing an implementation state of a plane static pressure withstand load test.
FIG. 5 is a diagram illustrating a cross-sectional shape of a first gap holding member according to the present invention.
FIG. 6 is a diagram for considering the cause of the first gap holding material coming off.
FIG. 7 is a graph showing a relationship between an area and a load resistance.
FIG. 8 is a schematic plan view showing another example of the liquid crystal panel according to the present invention.
FIG. 9 is a diagram illustrating a cross-sectional shape of a first gap holding member in a comparative example.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 substrate 3 pixel electrode 4 alignment film 5 first gap holding material 6 second gap holding material 9 liquid crystal layer 11 semiconductor layer 12 gate line 13 source line 51 substrate 52 light-shielding film 53 counter electrode 54 alignment film 71 pixel opening

Claims (6)

A first gap holding material that melts or softens at a predetermined temperature, deforms, and then cures to develop an adhesive force to the first and second substrates between the first substrate and the second substrate; In a liquid crystal display element in which a second gap holding member whose deformation amount at a temperature equal to or lower than a predetermined temperature is substantially zero is disposed,
A liquid crystal display element, wherein a shape of a bonding surface of the first gap holding member to the first substrate and the second substrate does not have an angle of 90 ° or less. The liquid crystal display element according to claim 1, wherein the shape of the bonding surface is an n-sided polygon (n ≧ 5), a circle, or an ellipse. The liquid crystal display device according to claim 1, wherein the first gap holding material and / or the second gap holding material are arranged except for a pixel region. 4. The liquid crystal display device according to claim 1, wherein the first gap holding material and / or the second gap holding material are arranged at equal intervals. 5. The liquid crystal display device according to claim 1, wherein the first gap holding members and the second gap holding members are alternately arranged. Between a first substrate provided with an alignment film on the first electrode and a second substrate provided with an alignment film on the second electrode, the material is melted or softened and deformed at a predetermined temperature, and then hardened and cured. A method for manufacturing a liquid crystal display element, in which a first gap holding material exhibiting an adhesive force to a first substrate and a second substrate and a second gap holding material having a deformation amount of substantially zero at a temperature equal to or lower than the predetermined temperature are formed. At
After performing a rubbing process for regulating the orientation direction of the orientation film of the first substrate and the second substrate, the shape of the bonding surface to the first substrate and the second substrate does not have an angle of 90 ° or less. A method for manufacturing a liquid crystal display element, comprising forming a first gap holding material and the second gap holding material.

Images