JP3545076B2 - Liquid crystal display device and method of manufacturing the same - Google Patents

Description

【００３５】
なお、上記の表１において用いた液晶はＺＬＩ−４７９２（メルク製）であって、配向膜はＪＡＬＳ−２１４（ＪＳＲ製）である。
表１に示す結果によれば、プリキュアを行わなかったパネルについては電圧保持率が９６．０％であるのに対して、プリキュアを行ったパネルは電圧保持率が９８．０％と高い。また８０℃で１０００時間経過後の電圧保持率についてはプリキュアなしのパネルが９４．０％まで低下しているのに比して、プリキュアを施したパネルは９７％と高い。以上のように、プリキュアを行うことにより、初期での電圧保持率の低下が抑制されるとともに、長期間使用した後でも電圧保持率の低下を抑制することができる。
【００３６】
以上示したように、本発明の実施例に係る液晶表示装置の製造方法によれば、電圧保持率の低下を抑制することができるので、電圧保持率の低下が原因となる当該液晶表示パネルのコントラストの低下を抑制することが可能となる。
（２）第２の実施例
以下で、本発明の第２の実施例に係る液晶表示装置の製造方法について図４を参照しながら説明する。なお、図１のステップＰ１〜Ｐ３については第１の実施例と同様な工程なので、重複を避けるため説明を省略する。
【００３７】
まず、図１のステップＰ４で、ＣＦ基板１のほか、ＴＦＴ基板４の表面にもシール材を形成する。すなわち、図４に示すようにＣＦ基板１の表面に紫外線硬化型の接着材（Ｔ−４７０、長瀬チバ製）からなる第１のシール材２Ｂを液晶を封入する矩形領域を囲むように環状に形成し、かつ第１のシール材２Ｂの形成パターンと同じパターンの第２のシール材５をＴＦＴ基板４の表面に形成する。
【００３８】
次いで、ステップＰ５のプリキュア工程では第１のシール材２と、第２のシール材５の両方にプリキュアを施す。このとき、第１の実施例では液晶と接する部分となる、環状のシール材の内周表面のみを選択的に半硬化状態にしていたが、本実施例ではシール材の全体をプリキュアして、図４に示すように第１のシール材２の表層２Ｃを半硬化状態にし、第２のシール材５の表層５Ａも同様にして半硬化状態にする。
【００３９】
次に、ステップＰ７までは第１の実施例と同様の工程を経て、ステップＰ８ＴＦＴ基板４とＣＦ基板１を重ね合わせて粗合せした後、両者を軽く加圧し、ＴＦＴ基板４とＣＦ基板１の間の隙間を密封する。このとき、粗合わせにより、図４に示すように、第１のシール材２の形成領域に第２のシール材５の形成領域とを一致させる。
【００４０】
その後、第１の実施例と同様の工程を経て、液晶表示パネルが作成される。
以上説明したように、本発明の第２の実施例に係る液晶表示装置の製造方法によれば、ＣＦ基板１の表面に第１のシール材２を形成するのみならず、ＴＦＴ基板４の表面にも第２のシール材５を形成して両者をプリキュアし、のちに第１及び第２のシール材２Ｂ及び５を位置合せしてＴＦＴ基板４とＣＦ基板１とを圧着している。
【００４１】
このため、第１の実施例と同様にして、第１のシール材２Ｂ，第２のシール材５には予めステップＰ５でプリキュアが施されて半硬化状態になっているので、未硬化のシール材と液晶が直接接触せず、液晶の汚染を抑止することができる。これにより、液晶汚染による液晶表示装置の電圧保持率の低下を抑制し、表示の際のコントラストの低下を抑制することが可能になる。
【００４２】
また、本実施例においては第１の実施例と異なり、重ね合わせの際、第１のシール材２と第２のシール材５とが接着されるので、ＣＦ基板１にのみシール材が形成されている液晶表示パネルに比して、両者の密着性がさらに向上する。第１及び第２のシール材２及び５の全部の領域に紫外線を照射して半硬化状態にしても、これらの間の密着性は損なわれることはない。
【００４３】
なお、第１の実施例と同様に、第１，第２のシール材２，５の内周面に選択的に紫外線を照射して照射領域を半硬化状態にしてもよい。
さらにＵＶプリキュアを行うことは、粘度の低い材料（塗布性は良好）を用いて粘度の高いシールを形成することが可能であることを意味し、パネルを大気に戻した際の大気圧によるシールダメージを低減する効果もある。
【００４４】
（３）第３の実施例
以下で、本発明の第３の実施例に係る液晶表示装置の製造方法について図５（ａ），（ｂ）を参照しながら説明する。図５（ａ）は断面図、図５（ｂ）は平面図で、図５（ａ）は同図（ｂ）のＢ−Ｂ線断面図である。なお、第１，第２の実施例と共通する事項については、重複を避けるため説明を省略する。
【００４５】
まず、図１のステップＰ１で透明基板上に液晶表示パネルを形成する上で必要な部材を形成する工程で、ＴＦＴ基板４は第１の実施例と同様の工程で形成するが、ＣＦ基板１の表示領域にカラーフィルタをパターニングして形成する際に、表示領域の外側領域であって、シール材を形成する領域の内側の領域に、環状のカラーフィルタと同じ材料の凸部６Ａ，６Ｂをパターニングして形成する。
【００４６】
このとき、凸部６Ａ，６Ｂが形成された領域は、その周辺の領域よりも高く盛り上がり、この上にＩＴＯ膜からなる透明電極７や配向膜８が形成されると、図５（ａ）に示すような凸部９Ａ，９Ｂが生じて隙間が狭くなる。
その後は第１の実施例と同様の工程を経る。ただし、ステップＰ５のプリキュアについては省略してもよい。
【００４７】
ところで、液晶汚染が生じる原因は液晶と未硬化の接着材が直接接し、且つその領域に紫外線照射処理がなされる為である。滴下注入法を用いても、１０インチクラスのＴＦＴ液晶パネルに完全に液晶が行き渡るには数分（５分程度）の時間かかるため、張り合わせ室より、パネルを取出し、液晶がシール材に達する前に出来るだけ早くシール材に紫外線照射して硬化すれば、液晶汚染による電圧保持率の低下を抑制することが可能になる。しかし、本実施例のように、透明基板の中央部からシール材に至る間に凸部９Ａ，９Ｂを設けて隙間を狭くして液晶の広がりを遅くすることにより、一層確実に未硬化のシール材と液晶との接触を避けることが可能となる。
【００４８】
以下の表２に、１４インチの評価基板を用いて、液晶とシール材とが接触する前に紫外線照射処理を行ったものと、液晶と接触した後に紫外線照射処理を行ったものとの比較を行った結果を示す。
【００４９】
【表２】

【００５０】
なお、上記の表２において用いた液晶はＺＬＩ−４７９２（メルク製）であって、配向膜はＪＡＬＳ−２１４（ＪＳＲ製）である。
表２に示す結果によれば、液晶とシール材とが接触する前に紫外線照射を行ったパネルについては電圧保持率が９８％であるのに対して、液晶とシール材とが接触した後に紫外線照射を行ったパネルは電圧保持率が９６％と低く、また８０℃で１０００時間経過後の電圧保持率については接触前に紫外線照射したパネルが９８％という高い値を維持しているのに比して、接触後に紫外線照射したパネルでは９４％まで低下している。従って、シール材に液晶が接する前に紫外線照射をすることにより、電圧保持率の低下を抑制できるという事実が確認できた。
【００５１】
本発明の第３の実施例に係る液晶表示装置の製造方法はこの事実を利用している。すなわち、ＣＦ基板１上表示領域とシール材の形成領域の間にカラーフィルタと同じ材料からなる凸部６Ａ，６Ｂをパターニングにより形成する。なお、凸部６Ａ，６ＢはＲ，Ｇ，Ｂのうち少なくとも１層を形成すればよい。続いて、凸部６Ａ，６Ｂ上に透明電極７及び配向膜８を順次形成して更に高い凸部９Ａ，９Ｂを形成している。
【００５２】
こうして凸部９Ａ，９Ｂが形成された領域でのＣＦ基板１とＴＦＴ基板４の間のギャップは図５（ａ）に示すように狭くなり、圧着によって拡散された液晶３がシール材２に達するまでの時間を伸ばすことができるので、液晶３がシール材２に達する前に、余裕をもってシール材に紫外線を照射し、硬化させることが可能になる。
【００５３】
これにより、当該液晶表示装置の電圧保持率の低下を抑制し、表示の際のコントラストの低下を抑止することが可能になる。
なお、カラーフィルタによって形成される凸部のパターンは、図５（ａ），（ｂ）に示すように環状のパターンでもよいが、本発明はこれに限らず、例えば図６に示すような、島状のパターンが点在しているような凸部９Ｃを形成してもよい。この場合も図５（ａ），（ｂ）に示すようなパターンの凸部９Ａ，９Ｂを形成した場合と同様の効果を奏する。
【００５４】
（４）第４の実施例
以下で、本発明の第４の実施例に係る液晶表示装置の製造方法について図７（ａ），（ｂ），図８（ａ），（ｂ）を参照しながら説明する。図７（ａ），（ｂ），図８（ａ）は断面図であり、図８（ｂ）は平面図である。図８（ａ）は同図（ｂ）のＣ−Ｃ線断面図である。なお、第１，第２又は第３の実施例と共通する事項については、重複を避けるため説明を省略する。
【００５５】
まず、図１のステップＰ１〜Ｐ７までは第１の実施例と同様の工程を経る。ステップＰ８の粗合わせの工程で、図７（ａ）に示すように、減圧雰囲気中で、載置台ＳＴ上に載置されたＣＦ基板１の一辺にＴＦＴ基板４の一辺が接するように両者の間に厚さ２ｍｍのスペーサ板１１を挟みこんで載置しておく。例えば、図８（ａ），（ｂ）に示すように、重ね合わせたＣＦ基板１とＴＦＴ基板４の間の一箇所にスペーサ板１１を挟みこむ。
【００５６】
また、各基板１，４の四隅には位置ずれが起きないようにガイド棒１０を設けておく。
次いで、スペーサ板１１を横方向に引き抜くと、図７（ｂ）に示すようにＴＦＴ基板４が自重でＣＦ基板１上に落ちて重なる。このとき、ＴＦＴ基板４の四隅にはガイド棒１０が配置されているので、ＴＦＴ基板４がスペーサ板１１に引きずられてずれることはほとんどない。その後の工程は、第１の実施例と同様であるため、説明を省略する。
【００５７】
以上説明したように、本発明の第４の実施例に係る液晶表示装置の製造方法によれば、ＴＦＴ基板４の一辺とＣＦ基板１の一辺とが接するようにこれらの間にスペーサ板１１を挟んでおき、これを引き抜いてＣＦ基板１とＴＦＴ基板１を重ね合わせている。
ＴＦＴ基板をＣＦ基板に対向させたのちに自由落下させることによって液晶が急激に圧着されていた従来に比して、本実施例では少なくともＴＦＴ基板４の一辺とＣＦ基板１の一辺とが接しているので、比較的ゆっくりと落下する。このため、ＣＦ基板１上に形成されたシール材２は従来ほど大きな圧力を受けず、シール材２の潰れも偏らない。従って、ＣＦ基板１とＴＦＴ基板４の間のギャップの間隔の不均一も生じない。
【００５８】
なお、本実施例ではスペーサ板１１をＣＦ基板１とＴＦＴ基板４との間の一箇所にのみ挟んでこれを引き抜くことでＴＦＴ基板４をＣＦ基板１に重ね合わせているが、本発明はこれに限らず、図８（ｃ），（ｄ）に示すように、２つのスペーサ板１１Ａ，１１Ｂを対向してＣＦ基板１とＴＦＴ基板４の間に挟みこんで二点で支持したような場合でも同様の効果を奏し、さらに図９（ａ），（ｂ）に示すように３つのスペーサ板１１Ａ，１１Ｂ，１１Ｃを挟みこんで三点で支持しても同様の効果を奏する。少なくともＣＦ基板１の一辺とＴＦＴ基板の一辺とが接していればよい。なお、図８（ｃ），図９（ａ）は断面図、８（ｄ），図９（ｂ）は平面図であり、図８（ｃ）は同図（ｄ）のＤ−Ｄ線断面図であり、図９（ｂ）は同図（ａ）のＥ−Ｅ線断面図である。
【００５９】
また、本実施例に係る方法を用いると複数の液晶表示パネルについて、ＴＦＴ基板をＣＦ基板上に載置することが短時間でできるようになる。以下でこのことについて図１０，１１を参照しながら説明する。
すなわち、図１０に示すように、ＣＦ基板とＴＦＴ基板を交互に積み重ね、その周囲にガイド棒１０を配置する。この状態を横からみた図が図１１である。下から順にＴＦＴ基板４Ｃ，ＣＦ基板１Ｃ，ＴＦＴ基板４Ｂ，ＣＦ基板１Ｂ，ＴＦＴ基板４Ａ，ＣＦ基板１Ａが順次積層されており、それらの間にはそれぞれスペーサ板１１Ｃ，１１Ｂ，１１Ａが挟みこまれている。
【００６０】
各ＴＦＴ基板をＣＦ基板に載置するには、各スペーサ板１１Ａ，１１Ｂ，１１Ｃを横方向に引き抜くだけで、複数の液晶表示パネルに対応する複数のＴＦＴ基板を、それぞれに対応するＣＦ基板上に、短時間で容易に載置することが可能になる。
（５）第５の実施例
以下で本発明の第５の実施例に係る液晶表示装置の製造方法について図１２（ａ）〜（ｃ）を参照しながら説明する。なお、第１〜第４の実施例と共通する事項については、重複を避けるため説明を省略する。
【００６１】
まず、図１のステップＰ１で透明基板上に液晶表示パネルを形成する上で必要な部材を形成する工程で、ＴＦＴ基板４は第１の実施例と同様の工程で形成するが、ＣＦ基板１についてはその四隅に超鋼ドリルや、炭酸ガスレーザを用いて、直径１ｍｍの複数のガイド孔１Ｈを空けておく。
次いで、図１のステップＰ２〜Ｐ７までは第１の実施例と同様の工程を経た後に、図１のステップＰ８の粗合せの工程で、図１２（ａ）に示すように、載置台ＳＴ上のＣＦ基板１の四隅に形成されたガイド孔１Ｈに支持棒１２Ａ，１２Ｂを通し、この上にＴＦＴ基板４を載置する。この段階ではＴＦＴ基板４とＣＦ基板１とを２ｍｍ程度の間隔に離しておく。なお、図１２（ａ）には支持棒１２Ａ，１２Ｂを２本示し、２本を省略している。
【００６２】
その後、図１２（ｂ），（ｃ）に示すように、支持棒１２Ａ，１２Ｂを徐々に降下させてＴＦＴ基板４をＣＦ基板１と重ね合わせる。その後の図１のステップＰ９以降の工程は第１の実施例と同様であるため、説明を省略する。
以上説明したように、本発明の第５の実施例に係る液晶表示装置の製造方法によれば、ＣＦ基板１の四隅にガイド孔１Ｈを形成し、これに支持棒１２Ａ，１２Ｂを通して、支持棒１２Ａ，１２Ｂの上にＴＦＴ基板４を載置し、支持棒１２Ａ，１２Ｂを徐々に降下させることでＴＦＴ基板４をＣＦ基板１と重ね合わせ、粗合わせを行っている。
【００６３】
このため、予め位置合わせをしておいて支持具を降下させる速度を遅くすれば、位置ずれせずにそのまま重ね合わせることが出来るので、粗合わせの精度が向上する。しかも、基板がシール材２に接触する際の偏りも少なく、かつ衝撃が小さいためシール材２の潰れが偏らず、基板間の隙間の間隔の均一性が向上する。
また、本実施例と同様に、ＣＦ基板１にガイド孔１Ｈの代わりに、図１３（ａ），（ｂ）に示すようにＣＦ基板１の四隅に切除部１Ｋを形成して、その切除部１Ｋに支持棒１２Ａ，１２Ｂ，１２Ｃ，１２Ｄを通してこれら四本の支持棒１２Ａ，１２Ｂ，１２Ｃ，１２Ｄ上にＴＦＴ基板４を載置して、支持棒１２Ａ，１２Ｂ，１２Ｃ，１２Ｄを降下させてＴＦＴ基板４をＣＦ基板１と重ね合わせるという方法を用いても、本実施例のガイド孔１Ｈを用いた方法と同様に、ＴＦＴ基板４をＣＦ基板１上にゆっくりと降下させることができるので、本実施例と同様の効果を奏する。
【００６４】
さらに、ＴＦＴ基板とＣＦ基板との間に、エンジニアリングプラスチック用充填材として用いられているガラスカプセルを挟んで、これをスペーサ板として用いる方法もある。このガラスカプセルは基板を圧着する際の加圧により破壊されて細かくなるため、ギャップ制御上何の問題も生じない。また、基板上に残存するガラスカプセルの破片は透明なので、表示上の問題も生じない。
【００６５】
（６）第６の実施例
以下で、本発明の第６の実施例に係る液晶表示装置の製造方法について図面を参照しながら説明する。なお、第１〜第５の実施例と共通する事項については、重複を避けるため説明を省略する。
まず、図１のステップＰ１〜Ｐ３までは第１の実施例と同じ工程を経る。ステップＰ４のシールを形成する工程では第１〜第５の実施例と異なり、まずＣＦ基板１の表面のシール材を形成すべき領域に、可動イオンを捕獲する膜の一例であるシランカップリング材からなる膜１３Ａ（東レ：ＡＰ−４００）を環状に形成する。
【００６６】
同様にして、ＴＦＴ基板４の表面にも、のちにシール材が圧着されるべき領域に同じシランカップリング材からなる膜１３Ｂを形成する。なお、これらの膜１３Ａ，１３Ｂは印刷により形成し、硬化のため温度３００℃にて３０分間熱処理を施す。
次いで、ＣＦ基板１上に形成されたシランカップリング材からなる膜１３Ａ上に、紫外線硬化型の接着材（Ｔ−４７０、長瀬チバ製）からなるシール材２を環状に形成する。
【００６７】
その後、図１のステップＰ５〜Ｐ１０までは第１の実施例と同様の工程を経て、図１４に示すような断面形状を有する液晶表示パネルが完成する。ステップＰ８の粗合わせの工程では、少なくともＴＦＴ基板４のシランカップリング材からなる膜１３Ｂがシール材２の内側の領域に存在する。
以上説明したように、本発明の第６の実施例に係る液晶表示装置の製造方法によれば、図１４に示すように、環状のシール材２の内側の領域であってシール材２の形成領域に、可動イオンを捕獲する膜であるシランカップリング材からなる膜１３Ａ，１３Ｂを形成している。
【００６８】
このため、シール材２の付近に存在する可動イオンがシランカップリング材からなる膜１３Ａ，１３Ｂによって捕獲されるため、可動イオンを介した蓄積電荷のリークを抑制することができる。これにより、電圧保持率の低下を抑制することができ、表示の際の当該液晶表示装置のコントラストの低下を抑制することが可能になる。
【００６９】
シランカップリング材からなる膜をシール材の形成領域近傍に形成すると、電圧保持率の低下を抑制することができるという事実は、本願発明者による実験によって確認されている。以下でこの実験結果について説明する。
下記の表３は、シランカップリング材（東レ製：ＡＰ−４００）からなる膜をシール材の形成領域の隣接領域に形成した液晶表示パネルの電圧保持率と、これを用いていない従来の液晶表示パネルの電圧保持率とを比較した実験結果を示している。
【００７０】
【表３】

【００７１】
なお、上記の表３において用いた液晶はＺＬＩ−４７９２（メルク製）であって、配向膜はＪＡＬＳ−２１４（ＪＳＲ製）である。
表３に示す結果によれば、シランカップリング材からなる膜をシール材の形成領域の隣接領域に形成した液晶表示パネルの電圧保持率が９７％であるのに対して、シランカップリング材からなる膜を有しない従来の液晶表示パネルの電圧保持率は９６％と低く、また８０℃で１０００時間経過後の電圧保持率についてはシランカップリング材からなる膜を有する液晶表示パネルが９７％という高い値を維持しているのに対して、これを有しない従来の液晶表示パネルは９４％まで低下している。従って、シール材の形成領域の隣接領域にシランカップリング材からなる膜を形成した液晶表示パネルについては、電圧保持率の低下が抑制されることが確認された。
【００７２】
なお、本実施例では可動イオンを捕獲する膜の一例としてシランカップリング材からなる膜を用いているが、これに限らず、可動イオンを捕獲する性質を有する膜であって、液晶を汚染しないような膜であれば、本発明を適用することができる。
（７）第７の実施例
以下で、本発明の第７の実施例に係る液晶表示装置の製造装置について図面を参照しながら説明する。この装置は、図１のステップＰ７の真空排気工程と、ステップＰ８の粗合せ工程で用いる貼り合わせ装置である。ＣＦ基板とＴＦＴ基板を収納して、内部を減圧し、これらの基板を重ね合わせて粗合せし、更に基板間の隙間に液晶を封入する工程に用いられる。
【００７３】
本実施例に係る液晶表示装置の製造装置は、図１５に示すように、処理室２０、排気弁２１、排気口２２、リーク弁２３、リーク口２４及び載置台ＳＴを有する。
処理室２０はその内部でＣＦ基板１とＴＦＴ基板４との貼り合わせを行う室である。排気弁２１は減圧手段の一部を構成し、不図示の真空ポンプと排気口２１との間に設けられている。排気弁２１を開き、排気口２２を通じて処理室２０内のガスを排気することにより、処理室２０内を減圧状態にする。
【００７４】
また、リーク弁２３はリーク口２４と、不活性ガス等を収納した不図示のガスボンベとの間に設けられ、リーク弁２３を開くことにより、不図示のガスボンベから噴出するガスをリーク口２４を介して処理室２０内に導入する。リーク弁２３とリーク口２４はリーク手段を構成する。なお、リーク弁２３には不活性ガス等を収納したガスボンベを接続しなくてもよく、大気によるリークを行ってもよい。
【００７５】
上記の液晶表示装置の製造装置を用いる液晶表示装置の製造方法について以下で説明する。
第１の実施例と同様にして図１のステップＰ１〜Ｐ６の工程を経た後に、図１のステップＰ７で、環状のシール材２の内側領域に液晶３が滴下されているＣＦ基板１と、ＴＦＴ基板４とが図１５に示す貼り合わせ装置の処理室２０の内部に搬入される。ＣＦ基板１は載置台ＳＴの上に載置される。
【００７６】
次いで、排気弁２１が開き、その先に設けられた不図示の真空ポンプによって処理室２０が排気される。ここでは５分間排気を行い、処理室２０内の到達真空度を５ｍＴｏｒｒ とした。
その後、図１のステップＰ８の粗合せ工程で、減圧状態下でシール材２を介してＴＦＴ基板４とＣＦ基板１とを重ね合わせ、粗合わせを行う。続いて、加圧を行う。
【００７７】
この加圧工程では、瞬間的にリーク弁２３を開いて、窒素ガス等をリーク口２４からその下のＴＦＴ基板４の上に噴出する。窒素ガスが吹き付けられることでＴＦＴ基板４がＣＦ基板１に加圧される。
ガスは一般に対象物に対して等方的に圧力を及ぼし、ＴＦＴ基板４の表面に遍く行き渡る。従って、これがＴＦＴ基板４の上面に吹き付けられると、ＴＦＴ基板４の受ける圧力はほぼ均一になり、ＴＦＴ基板４は均一な力で加圧されるため、基板１，４間の隙間の間隔は均一になる。これにより、液晶表示パネルの電極に駆動電圧が印加された場合、基板間の液晶に印加される電界も均一になるので、表示特性が向上する。
【００７８】
また、同様にガスを用いた加圧をする貼り合わせ装置として、図１６に示すような張合わせ装置も考えられる。この装置は、液晶表示パネルのシール材２の形成領域に沿ってリーク孔２４が形成されていることが図１５に示す装置と異なっている。
図１６に示す貼り合わせ装置を用いてＣＦ基板１に重ね合わされたＴＦＴ基板４を加圧するには、図１５に示す装置と同様にリーク弁２３を開き、不図示のガスボンベから噴出されるガスをリーク孔２４から吹き付けることで加圧する。この装置では、図１６に示すように、リーク孔２４がシール材２の形成領域に沿って形成されているので、噴出するガスはシール材２の形成領域にのみ吹き付けられることになる。
【００７９】
ＴＦＴ基板４とＣＦ基板１の加圧の際には、結局シール材２を均一に加圧することが重要である。この装置によれば、シール材２に沿ってガスを吹きつけ、シール材２を均一に加圧することができるので、図１５に示す装置と同様に、基板１，４間のギャップの間隔を均一にすることができる。
（８）第８の実施例
以下で本発明の第８の実施例に係る液晶表示装置の製造装置について図１７を参照しながら説明する。この装置は、第７の実施例で説明した液晶表示装置の製造装置と同様に、図１のステップＰ７の真空排気工程と、ステップＰ８の粗合せ工程で用いる貼り合わせ装置であり、ＣＦ基板とＴＦＴ基板を装置内に搬入した後に、装置内を排気し、これらの基板を粗合せする。
【００８０】
本実施例に係る液晶表示装置の製造装置は、図１７に示すように、処理室２０、排気弁２１、排気口２２、第１のリーク弁２３Ａ、第２のリーク弁２３Ｂ、第１のリーク口２４Ａ、第２のリーク口２４Ｂ、圧着板２５及び載置台ＳＴを有する。
処理室２０はその内部で貼り合わせを行う室であって、排気弁２１は、不図示の真空ポンプと排気口２１との間に設けられ、排気弁２１を開き、排気口２２を通じて処理室２０内のガスを排気して、減圧状態にする。
【００８１】
第１のリーク弁２３Ａはリーク口２４Ａの外部に設けられており、第１のリーク弁２３Ａを開くことにより、不図示のガスボンベからのガスを、圧着板２５の上面に吹き付ける。圧着板２５は、伸縮自在のベローズＶＳによって載置台ＳＴの上に支持され、かつ処理室２０内と隔絶されており、ガスが吹き付けられると、ベローズＶＳが伸びて載置台ＳＴの上に搭載されたＴＦＴ基板の上面を圧着する。
【００８２】
第１のリーク弁２３Ｂはリーク口２４Ｂの外部に設けられており、第１のリーク弁２３Ｂを開くことにより、装置外部の空気が、処理室２０内に導入される。
上記の液晶表示装置の製造装置を用いる液晶表示装置の製造方法について以下で説明する。
第１の実施例と同様にして図１のステップＰ１〜Ｐ６の工程を経た後に、図１のステップＰ７で、シール材２が表面に形成されて液晶３が滴下されたＣＦ基板１と、ＴＦＴ基板４とが図１５に示す貼り合わせ装置の処理室２０の内部に搬入され、ＣＦ基板１は載置台ＳＴの上に載置される。
【００８３】
ＴＦＴ基板４をＣＦ基板１上に対向配置したのちに、排気弁２１を開き、その先に設けられた不図示の真空ポンプによって処理室２０が真空排気される。５分間排気を行って、到達真空度を５ｍＴｏｒｒ とした。
その後、図１のステップＰ８の粗合せ工程で、真空状態下でＴＦＴ基板４をＣＦ基板１上に載置して、対向密着状態とし、加圧を行う。
【００８４】
この加圧工程では、瞬間的に第１のリーク弁２３Ａを開くとき、不図示のガスポンプから噴出される窒素ガスが第１のリーク口２４Ａからその下の圧着板２５に均一な圧力で吹き付けられ、ＴＦＴ基板４がこの圧着板２５によって加圧されてＴＦＴ基板４がＣＦ基板１に圧着される。
この加圧方法によると、ガスを用いて圧着板２５を加圧し、その圧着板２５でＴＦＴ基板４を圧着している。ガスは一般に等方性を有し、これが圧着板２５の上面に吹き付けられると、そのガスは圧着板２５の全面に遍く行き渡り、かつその圧力はほぼ均一になる。この均一な圧力でＴＦＴ基板４を加圧するので、従来と異なり、ＴＦＴ基板４とＣＦ基板１とを均一な力で加圧することが可能になる。
【００８５】
これにより、これらの基板の間で液晶が均一に行き渡るようにすることができるので、基板１，４間のギャップの間隔を均一にすることができ、表示特性を向上させることが可能になる。
（９）第９の実施例
以下で、本発明の第９の実施例に係る液晶表示装置の製造方法について図１８（ａ），（ｂ）を参照しながら説明する。なお、第１〜第８の実施例と共通する事項については、重複を避けるため説明を省略する。
【００８６】
まず、図１のステップＰ１で、ガラスなどからなる透明基板上に、液晶表示パネルを形成する上で必要な部材を形成する工程で、ＴＦＴ基板４側の加工は第１の実施例と同様であるが、ＣＦ基板１にカラーフィルタを形成する工程で、図１８（ｂ）に示すように当該液晶表示装置の表示領域ＣＲにカラーフィルタを形成するのと同時に表示領域ＣＲに隣接する周辺領域にも、表示領域ＣＲのカラーフィルタの配列順序に従って予備のカラーフィルタＣＭを形成しておく。その後の工程は第１の実施例と同様であるため説明を省略する。
【００８７】
本発明の第９の実施例に係る液晶表示装置の製造方法によれば、図１８（ａ），（ｂ）に示すように、表示領域ＣＲに隣接する周辺領域にも表示領域ＣＲのカラーフィルタの配列順序に従って予備のカラーフィルタＣＭを形成しているので、ＴＦＴ基板４とＣＦ基板１とを重ね合わせたときに位置合わせのずれが生じても、表示領域ＣＲからはみ出した端の部分をこの予備のカラーフィルタＣＭの位置に合わせればよい。このため、位置合わせのための調整幅が少なく、調整が容易であるとともに、調整のための基板の大幅な移動による接着材へのダメージ付与を避けることが出来る。
【００８８】
【発明の効果】
以上述べたように、本発明によれば、未硬化の接着材を介して１対の透明基板を重ね合わせた後、接着材と液晶とが接する前に、接着材に紫外線を照射して硬化させている。
このため、１対の透明基板の固着を確実にするとともに、従来、未硬化の接着材と液晶が接し、その領域に紫外線が照射されることによって生じていた液晶の汚染を抑制することができ、液晶汚染によって当該液晶表示装置の電圧保持率が低下して、その表示の際のコントラストが低下することを極力抑止することが可能になる。
【００８９】
また、第１の透明基板と第２の透明基板にともに環状の接着材を形成し、接着材の表層のみを硬化した後、接着材同士を接触させて第１の透明基板と第２の透明基板を重ね合わせている。
接着材同士が接触するため、表層のみが硬化していても、第１の透明基板と第２の透明基板同士の固着がより強固になる。
【００９１】
特に、１対の透明基板のうち何れか一方の表示領域の外側の領域であって、接着材の形成領域の内側の領域に、液晶の広がり速度を遅らせる凸部を形成することにより、接着材と液晶とが接する前に、一層時間の余裕をもって接着材に紫外線を照射して硬化させることが可能になる。
【図面の簡単な説明】
【図１】本発明の第１の実施例に係る液晶表示装置の製造方法を説明するフローチャートである。
【図２】本発明の第１の実施例に係る液晶表示装置の製造方法を説明する図（その１）である。
【図３】本発明の第１の実施例に係る液晶表示装置の製造方法を説明する図（その２）である。
【図４】本発明の第２の実施例に係る液晶表示装置の製造方法を説明する図である。
【図５】本発明の第３の実施例に係る液晶表示装置の製造方法を説明する図（その１）である。
【図６】本発明の第３の実施例に係る液晶表示装置の製造方法を説明する図（その２）である。
【図７】本発明の第４の実施例に係る液晶表示装置の製造方法を説明する断面図（その１）である。
【図８】本発明の第４の実施例に係る液晶表示装置の製造方法を説明する上面図（その１）である。
【図９】本発明の第４の実施例に係る液晶表示装置の製造方法を説明する上面図（その２）である。
【図１０】本発明の第４の実施例に係る液晶表示装置の製造方法を説明する斜視図である。
【図１１】本発明の第４の実施例に係る液晶表示装置の製造方法を説明する断面図（その２）である。
【図１２】本発明の第５の実施例に係る液晶表示装置の製造方法を説明する断面図である。
【図１３】本発明の第５の実施例に係る液晶表示装置の製造方法を説明する図である。
【図１４】本発明の第６の実施例に係る液晶表示装置の製造方法を説明する断面図である。
【図１５】本発明の第７の実施例に係る液晶表示装置の製造装置を説明する図（その１）である。
【図１６】本発明の第７の実施例に係る液晶表示装置の製造装置を説明する図（その２）である。
【図１７】本発明の第８の実施例に係る液晶表示装置の製造方法を説明する断面図である。
【図１８】本発明の第９の実施例に係る液晶表示装置の製造方法を説明する図である。
【図１９】従来例に係る液晶表示装置の製造方法を説明するフローチャートである。
【図２０】従来例に係る液晶表示装置の製造装置を説明する断面図である。
【図２１】従来例に係る液晶表示装置の製造方法を説明する図（その１）である。
【図２２】従来例に係る液晶表示装置の製造方法を説明する図（その２）である。
【図２３】従来例の問題点を説明するグラフ（その１）である。
【図２４】従来例の問題点を説明するグラフ（その２）である。
【図２５】液晶表示パネルの電圧保持率を説明する図である。
【符号の説明】
１ ＣＦ基板（第１の透明基板）、
１Ａ，１Ｂ，１Ｃ ＣＦ基板、
１Ｈ ガイド孔、
１Ｋ 切除部、
２ シール材（接着材）、
２Ａ シール材の内周面、
２Ｂ 第１のシール材（第１の接着材）、
２Ｃ 半硬化状態のシール材、
３ 液晶、
４ ＴＦＴ基板（第２の透明基板）、
４Ａ，４Ｂ，４Ｃ ＴＦＴ基板、
５ 第２のシール材（第２の接着材）、
５Ａ 半硬化状態のシール材、
６Ａ，６Ｂ，９Ａ，９Ｂ，９Ｃ 凸部、
７ 透明電極、
８ 配向膜、
１０ ガイド棒、
１１ １１Ａ，１１Ｂ，１１Ｃ スペーサ板、
１２Ａ，１２Ｂ，１２Ｃ，１２Ｄ 支持棒、
１３Ａ，１３Ｂ シランカップリング材からなる膜（可動イオンを捕獲する膜）、
２０ 処理室、
２１ 排気弁、
２２ 排気口、
２３ リーク弁、
２３Ａ 第１のリーク弁、
２３Ｂ 第２のリーク弁、
２４，２４Ａ リーク口、
２４Ｂ 第２のリーク口、
２５ 圧着板、
ＣＲ 表示領域、
ＣＭ 予備のカラーフィルタ、
ＳＴ 載置台、
ＳＰ スペーサ、
ＶＳ ベローズ。[0001]
[Industrial applications]
The present invention is a liquid crystal display device And its manufacturing method More specifically, the present invention relates to an improvement in a method called a drop-injection method in which liquid crystal is dropped on one transparent substrate in a reduced-pressure atmosphere, and then the other transparent substrate is overlapped and the liquid crystal is sealed.
[0002]
[Prior art]
According to the vacuum encapsulation method, it took a considerable amount of time to enclose the liquid crystal in the liquid crystal display panel, but the development of the drop-injection method has significantly reduced the time required for enclosing the liquid crystal. It has become.
Hereinafter, a dropping method according to a conventional example will be described with reference to the drawings. FIG. 22A is a sectional view taken along line GG of FIG.
[0003]
First, in step P1 of the flowchart in FIG. 19, members necessary for forming a liquid crystal display panel are formed on a transparent substrate made of glass or the like.
That is, two transparent substrates are prepared for one liquid crystal display panel, and a TFT (Thin Film Transistor), a drain bus line, a gate bus line, a pixel electrode, and the like are formed on the surface of one of the transparent substrates. An alignment film is formed on the substrate to form a TFT substrate. On the other transparent substrate, R (red), G (green), and B (blue) color filters are formed on the surface, and a counter electrode made of a transparent ITO (Indium Tin Oxide) film is formed thereon. Furthermore, a color filter substrate (hereinafter, referred to as a CF substrate) is formed by forming an alignment film thereon.
[0004]
Next, in step P2, a rubbing process is performed on the alignment film formed on the surface of the TFT substrate and the CF substrate.
Next, in Step P3, spacers are sprayed on the TFT substrate. This is to ensure a gap for filling the liquid crystal between the TFT substrate and the CF substrate. On the other hand, in Step P4, an ultraviolet-curable sealing material is formed on the surface of the CF substrate so as to surround the rectangular region in which the liquid crystal is sealed.
[0005]
Next, in step P5, liquid crystal is dropped into a region of the CF substrate surface surrounded by the sealing material.
Next, in step P6, both the TFT substrate and the CF substrate are introduced into a bonding apparatus as shown in FIG. 20, and the inside of the apparatus is evacuated.
Next, in step P7, the TFT substrate and the CF substrate are roughly aligned. In this step, the TFT substrate and the CF substrate are overlapped with each other with a certain degree of alignment in a reduced-pressure atmosphere, and the pressure is weakly applied. The liquid crystal is sealed in a gap between the TFT substrate and the CF substrate by a sealing material 32.
[0006]
In this step, first, the sealing material 32 is formed on the surface, and the CF substrate 31 on which the liquid crystal 33 has been dropped is placed on the stage ST in the apparatus as shown in FIG. On the other hand, the TFT substrate 34 is carried into the apparatus shown in FIG. 20, and is supported by the support SU as shown in FIG.
Next, the exhaust valve 42 shown in FIG. 20 is opened, and the vacuum is exhausted from the exhaust port 41, so that the processing chamber 40 in the apparatus is reduced in pressure. Next, after the TFT substrate 34 is arranged so as to face the CF substrate 33 as shown in FIG. 21A, the TFT substrate 34 is dropped on the CF substrate 31 as shown in FIG. Thereafter, the TFT substrate 34 is pressed from above by a pressing tool 43 as shown in FIG.
[0007]
Next, the transparent substrate roughly aligned in step P8 is taken out to the atmosphere, and the TFT substrate 34 and the CF substrate 33 are precisely aligned so that the display areas correspond to each other.
By this step, the dropped liquid crystal 33 spreads over almost the entire area surrounded by the sealing material 32 as shown in FIGS. 22 (a) and 22 (b).
After that, in step P9, the sealing material 32 is irradiated with ultraviolet rays to be completely cured, and the TFT substrate 34 and the CF substrate 31 are fixed to form a liquid crystal display panel in which liquid crystal is sealed.
[0008]
[Problems to be solved by the invention]
However, according to the above conventional manufacturing method, the following problems occur.
First, as shown in FIGS. 21A and 21B, the TFT substrate 34 is dropped on the CF substrate 31 in the rough matching step shown in Step P7 of FIG. For this reason, there is a problem that the alignment between the TFT substrate 34 and the CF substrate 31 is easily shifted.
[0009]
Secondly, in the rough alignment step, the TFT substrate 34 is thereafter pressed from above by a pressing member 43 as shown in FIG. Since it is difficult to apply pressure uniformly over the entire surface of the substrate, the liquid crystal 33 is not evenly distributed, the gap between the TFT substrate 34 and the CF substrate 31 is not uniform, or a part of the seal is insufficiently pressurized. Problems such as leaks have occurred.
[0010]
Third, when the liquid crystal and the uncured sealing material come into contact with each other and the region is irradiated with ultraviolet rays, the liquid crystal and the sealing material react with each other to cause contamination, thereby lowering the voltage holding ratio of the liquid crystal display panel. I do. Note that the voltage holding ratio is the initial value of the applied voltage between the two electrodes sandwiching the liquid crystal between the voltage application and the next voltage application when the voltage is intermittently applied to the liquid crystal panel. Is a value indicating whether or not the voltage of FIG.
B / A × 100 (%)
Is the value indicated by. In the above equation, A is the area of the shaded area in FIG. 25A (time integral of the voltage held between the electrodes when there is no leak), and B is the area of the shaded area in FIG. (Time integration of the voltage actually held between the electrodes).
[0011]
FIGS. 23 and 24 are graphs showing the relationship between the voltage holding ratio and the irradiation time of ultraviolet rays when the sealing material is irradiated with ultraviolet rays and cured after the liquid crystal and the uncured sealing material come into contact with each other. It is. As shown in FIG. 23, the voltage holding ratio of the central region (25 mm from the seal end) and the vicinity of the seal (10 mm from the seal end) show a decrease in the voltage holding ratio as the irradiation time of the ultraviolet ray increases. In particular, the decrease near the seal is remarkable, and a decrease of about 2 to 4% can be confirmed.
[0012]
FIG. 24 shows how the voltage holding ratio fluctuates when the liquid crystal display panel is formed by enclosing the liquid crystal by the same manufacturing method and then left at a temperature of 80 ° C. for 1000 hours. It is a graph. The measurement point is at the center (25 mm from the end of the seal). As shown in FIG. 24, it can be seen that the decrease in the voltage holding ratio in this case is even more remarkable.
[0013]
As shown in FIGS. 23 and 24, according to the conventional drop injection method in which the sealing material is cured by irradiating ultraviolet rays after the liquid crystal contacts the sealing material, the voltage holding ratio of the liquid crystal display panel is reduced. When the holding ratio is lowered, a sufficient driving voltage is not applied to the liquid crystal display panel, and when used as a display panel, there is a problem that the contrast of the panel is lowered.
[0014]
The present invention has been made in view of such a problem, and a liquid crystal display capable of maintaining a certain degree of positioning accuracy and a uniform gap between substrates by rough alignment and suppressing a decrease in a voltage holding ratio. apparatus And its manufacturing method The purpose is to provide.
[0015]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first invention relates to a method of manufacturing a liquid crystal display device, wherein an ultraviolet-curable adhesive is annularly formed on one of a pair of transparent substrates outside a display region. Forming a liquid crystal on one of the central regions of the pair of transparent substrates, and, after superposing the pair of transparent substrates under reduced pressure, returning the pair to the atmospheric pressure, A step of sealing a gap surrounded by the adhesive between the pair of transparent substrates with the adhesive, and a step of irradiating the adhesive with ultraviolet rays and curing the liquid crystal before reaching the adhesive. Characterized by having
A second invention relates to the method of manufacturing a liquid crystal display device according to the first invention, wherein, prior to the step of forming the adhesive material in a ring shape, any one of the pair of transparent substrates, It is characterized by further having a step of forming a convex portion at a height not in contact with the transparent substrate to be overlapped in a later step in the outer region,
A third invention relates to the method of manufacturing a liquid crystal display device according to the second invention, wherein the convex portion has any one of a ring shape and a dotted island shape,
A fourth invention relates to the method for manufacturing a liquid crystal display device according to the third invention, wherein a color filter is formed in a display region of the transparent substrate on the side where the convex portion is formed, and the convex portion is formed of the color filter and the color filter. Characterized by patterning the same material,
A fifth invention relates to a liquid crystal display device, comprising: a pair of transparent substrates facing each other; and a convex portion not in contact with the other transparent substrate, outside a display region of one of the pair of transparent substrates. An ultraviolet-curing adhesive formed between the pair of transparent substrates and in a region outside the convex portion in a ring shape to form a sealed gap between the pair of transparent substrates; Having a liquid crystal sealed in the sealed gap,
A sixth invention is directed to the liquid crystal display device according to the fifth invention, wherein a color filter is formed in a display region of the transparent substrate on the side where the projection is formed, and the projection is made of the same material as the color filter. It is characterized by becoming.
[0016]
[Operation]
According to the present invention, first, after laminating a pair of transparent substrates via an uncured adhesive, the adhesive is irradiated with ultraviolet rays to be cured before the adhesive and the liquid crystal come into contact with each other. I have.
For this reason, it is possible to ensure the fixation of the pair of transparent substrates and to suppress the contamination of the liquid crystal, which has conventionally occurred when the uncured adhesive is in contact with the liquid crystal and the region is irradiated with ultraviolet light. In addition, it is possible to suppress as much as possible a reduction in the voltage holding ratio of the liquid crystal display device due to the contamination of the liquid crystal and a decrease in contrast at the time of the display.
[0019]
Second, a convex portion for slowing down the spread speed of the liquid crystal is formed in a region outside one of the display regions of the pair of transparent substrates and inside a region where the adhesive is formed.
Since the gap between the transparent substrates is narrowed by the protrusions, the time required for the liquid crystal to reach the adhesive becomes longer.Before the adhesive and the liquid crystal come into contact with each other, the adhesive is irradiated with ultraviolet light and cured. Can be easily performed. In particular, by using the same material as the color filter to be formed in one of the display regions of the pair of transparent substrates as the projection, the projection can be formed at the same time as the formation of the color filter in the display region. Is simplified.
[0026]
【Example】
Hereinafter, a method and an apparatus for manufacturing a liquid crystal display device according to an embodiment of the present invention will be described with reference to the drawings.
(1) First embodiment
Hereinafter, a method for manufacturing the liquid crystal display device according to the first embodiment of the present invention will be described with reference to the flowchart of FIG. 1 and FIGS. 2 (a), 2 (b), 3 (a), and 3 (b). FIG. 2B is a sectional view taken along line AA of FIG.
[0027]
First, in step P1 of FIG. 1, members necessary for producing a liquid crystal display panel are formed on a transparent substrate made of glass or the like.
That is, for one liquid crystal display panel, two transparent substrates made of glass plates equivalent to 10.4 inches are prepared, and R (red), G (green), and B (blue) are formed on the surface of the first transparent substrate. The film formation / patterning is repeated three times in order to form the color filter of (3). Subsequently, after forming a counter electrode made of a transparent ITO (Indium Tin Oxide) film on the color filter, an alignment film is formed on the counter electrode, and a color filter substrate (hereinafter, referred to as a CF substrate) 1 is formed. .
[0028]
On the other hand, a TFT (Thin Film Transistor), a drain bus line, a gate bus line, a pixel electrode, and the like are formed on the surface of the second transparent substrate, and an alignment film is formed thereon to form a TFT substrate 4.
Next, spacers SP are dispersed on the surface of the TFT substrate 4 in Step P3. The spacer SP secures a gap for sealing liquid crystal between the superposed CF substrate 1 and TFT substrate 4. As the spacer SP, a plastic sphere having a diameter of 5.0 μm and having adhesiveness is used. The adhesion is provided by performing a heat treatment after spraying. This is to prevent the spacer SP from moving while the liquid crystal spreads, and to easily perform the overlapping operation.
[0029]
Next, in step P4, as shown in FIG. 2A, an ultraviolet-curable adhesive (T) is applied to the surface of the CF substrate 1 about 5 mm outside the display area so as to surround the rectangular area for enclosing the liquid crystal. -470, manufactured by Chiba Nagase). The seal material 2 finally becomes about 2 mm in width by pressurization.
Next, in Step P5, as shown in FIGS. 2A and 2B, the inner peripheral surface 2A of the annular sealing material 2 formed on the CF substrate 1 is selectively irradiated with ultraviolet rays to thereby irradiate the irradiated portion. The surface layer of the sealing material 2 is brought into a semi-cured state (hereinafter, this processing is referred to as “precure”). In this case, ultraviolet light having a weak intensity of about 500 mJ is irradiated so that only the surface layer of the sealing material 2 at the irradiated portion is cured.
[0030]
Next, in Step P6, liquid crystal is dropped on the surface of the CF substrate 1 in a region surrounded by the sealant 2. Next, in Step P7, both the TFT substrate 4 and the CF substrate 1 are introduced into the bonding apparatus, and the inside of the apparatus is evacuated.
Next, in Step P8, rough alignment is performed. That is, as shown in FIG. 3A, the TFT substrate 4 and the CF substrate 1 are first made to face each other in a reduced-pressure atmosphere, and then, as shown in FIG. Align and roughly align. The accuracy of the rough alignment is about ± 50 μm. By performing rough alignment, the width of adjustment is reduced during precise alignment, thereby preventing damage to the sealing material 2 and ensuring the tightness of the gap between the CF substrate 1 and the TFT substrate 4 for enclosing the liquid crystal. .
[0031]
Subsequently, the substrate is lightly pressed to crush the sealing material 2 to seal the liquid crystal in the gap between the substrates.
Next, in Step P9, the roughly aligned substrate is taken out into the atmosphere and precisely aligned (hereinafter, this step is referred to as precise alignment).
Through this process, the dropped liquid crystal 3 spreads over almost the entire area surrounded by the sealing material 2. Thereafter, in step P10, the sealing material 2 is irradiated with ultraviolet light having a high intensity of about 5000 mJ to completely cure the sealing material 2, and the TFT substrate 4 and the CF substrate 1 are fixed to each other, whereby a liquid crystal display panel is manufactured. Note that the optimum intensity of the ultraviolet light differs depending on the adhesive.
[0032]
As described above, according to the method of manufacturing the liquid crystal display device according to the first embodiment of the present invention, as shown in FIG. Since the pre-curing is performed, even if the liquid crystal 3 reaches the sealing material 2 before being completely cured in the process of Step P10, the uncured sealing material does not directly contact the liquid crystal.
Liquid crystal contamination, which has been a problem in the past, is caused by direct contact between the liquid crystal and the uncured sealing material, and by irradiating the region with ultraviolet rays, but such contamination is unlikely to occur in the above case.
[0033]
This fact has been confirmed by experiments. Hereinafter, the experimental results will be described with reference to Table 1. When the voltage holding force in the vicinity of the seal of the panel manufactured as in the example was measured, an extremely good result was obtained as compared with the case where the pre-cure was not performed. The measurement results are shown in Table 1 below.
[0034]
[Table 1]

[0035]
The liquid crystal used in Table 1 is ZLI-4792 (manufactured by Merck), and the alignment film is JALS-214 (manufactured by JSR).
According to the results shown in Table 1, the voltage holding ratio is 96.0% for the panel not subjected to the precure, while the voltage holding ratio is as high as 98.0% for the panel subjected to the precure. Further, the voltage holding ratio after 1000 hours at 80 ° C. is as high as 97% for the panel subjected to the pre-curing, as compared to 94.0% for the panel without the pre-curing. As described above, by performing the pre-curing, a decrease in the voltage holding ratio at the initial stage can be suppressed, and a decrease in the voltage holding ratio even after long-term use can be suppressed.
[0036]
As described above, according to the method for manufacturing the liquid crystal display device according to the embodiment of the present invention, since the decrease in the voltage holding ratio can be suppressed, the reduction in the voltage holding ratio of the liquid crystal display panel can be suppressed. It is possible to suppress a decrease in contrast.
(2) Second embodiment
Hereinafter, a method for manufacturing a liquid crystal display device according to a second embodiment of the present invention will be described with reference to FIG. Steps P1 to P3 in FIG. 1 are the same as those in the first embodiment, and a description thereof will be omitted to avoid duplication.
[0037]
First, in step P4 of FIG. 1, a sealing material is formed on the surface of the TFT substrate 4 in addition to the CF substrate 1. That is, as shown in FIG. 4, a first sealing material 2B made of an ultraviolet-curable adhesive (T-470, manufactured by Nagase Chiba) is formed on the surface of the CF substrate 1 in a ring shape so as to surround a rectangular region for enclosing the liquid crystal. The second sealing material 5 having the same pattern as the first sealing material 2B is formed on the surface of the TFT substrate 4.
[0038]
Next, in the pre-curing step of step P5, both the first sealing material 2 and the second sealing material 5 are pre-cured. At this time, in the first embodiment, only the inner peripheral surface of the annular sealing material, which is a portion in contact with the liquid crystal, is selectively semi-cured, but in the present embodiment, the entire sealing material is pre-cured. As shown in FIG. 4, the surface layer 2C of the first sealing material 2 is set to a semi-cured state, and the surface layer 5A of the second sealing material 5 is similarly set to a semi-cured state.
[0039]
Next, up to Step P7, through the same process as in the first embodiment, Step P8 The TFT substrate 4 and the CF substrate 1 are overlapped and roughly aligned, and then both are lightly pressed to form the TFT substrate 4 and the CF substrate 1. Seal the gap between them. At this time, as shown in FIG. 4, the formation region of the first sealing material 2 and the formation region of the second sealing material 5 are made to match by rough alignment.
[0040]
Thereafter, through the same steps as in the first embodiment, a liquid crystal display panel is manufactured.
As described above, according to the liquid crystal display device manufacturing method according to the second embodiment of the present invention, not only the first sealant 2 is formed on the surface of the CF substrate 1 but also the surface of the TFT substrate 4. Also, a second sealing material 5 is formed and both are pre-cured, and then the first and second sealing materials 2B and 5 are aligned, and the TFT substrate 4 and the CF substrate 1 are crimped.
[0041]
For this reason, as in the first embodiment, the first sealing material 2B and the second sealing material 5 are pre-cured in step P5 and are in a semi-cured state. Since the material and the liquid crystal do not directly contact, contamination of the liquid crystal can be suppressed. Accordingly, it is possible to suppress a decrease in the voltage holding ratio of the liquid crystal display device due to the contamination of the liquid crystal, and to suppress a decrease in contrast during display.
[0042]
Also, in the present embodiment, unlike the first embodiment, the first seal material 2 and the second seal material 5 are bonded at the time of superposition, so that the seal material is formed only on the CF substrate 1. Adhesion between the two is further improved as compared with a liquid crystal display panel having the above configuration. Even if the entire region of the first and second sealing members 2 and 5 is irradiated with ultraviolet rays to be in a semi-cured state, the adhesion between them is not impaired.
[0043]
Note that, similarly to the first embodiment, the inner peripheral surfaces of the first and second sealing members 2 and 5 may be selectively irradiated with ultraviolet rays so that the irradiated area is in a semi-cured state.
Further, performing UV pre-curing means that a high-viscosity seal can be formed using a low-viscosity material (having good applicability), and sealing by atmospheric pressure when the panel is returned to the atmosphere. It also has the effect of reducing damage.
[0044]
(3) Third embodiment
Hereinafter, a method of manufacturing the liquid crystal display device according to the third embodiment of the present invention will be described with reference to FIGS. 5A is a sectional view, FIG. 5B is a plan view, and FIG. 5A is a sectional view taken along line BB of FIG. Note that the description of items common to the first and second embodiments will be omitted to avoid duplication.
[0045]
First, in step P1 of FIG. 1, in a step of forming members necessary for forming a liquid crystal display panel on a transparent substrate, the TFT substrate 4 is formed in the same process as in the first embodiment. When a color filter is formed by patterning in the display region, the convex portions 6A and 6B made of the same material as the annular color filter are formed in the region outside the display region and inside the region where the sealing material is formed. It is formed by patterning.
[0046]
At this time, the region where the protrusions 6A and 6B are formed rises higher than the surrounding region, and when the transparent electrode 7 and the alignment film 8 made of the ITO film are formed thereon, FIG. Protrusions 9A and 9B as shown are generated, and the gap becomes narrow.
Thereafter, the same steps as in the first embodiment are performed. However, the precure in step P5 may be omitted.
[0047]
The cause of the liquid crystal contamination is that the liquid crystal and the uncured adhesive are in direct contact with each other, and that region is subjected to an ultraviolet irradiation treatment. Even when using the drop-injection method, it takes several minutes (about 5 minutes) for the liquid crystal to completely reach the 10-inch class TFT liquid crystal panel. Therefore, the panel is taken out from the laminating chamber and before the liquid crystal reaches the sealing material. If the sealing material is irradiated with ultraviolet rays as soon as possible and cured, it is possible to suppress a decrease in the voltage holding ratio due to liquid crystal contamination. However, as in the present embodiment, the protrusions 9A and 9B are provided between the central portion of the transparent substrate and the sealing material to narrow the gap to slow down the spread of the liquid crystal, so that the uncured sealing is more reliably achieved. It is possible to avoid contact between the material and the liquid crystal.
[0048]
Table 2 below shows a comparison between a 14-inch evaluation substrate subjected to ultraviolet irradiation before contacting the liquid crystal with the sealing material and an ultraviolet irradiation treatment performed after contact with the liquid crystal. The results obtained are shown.
[0049]
[Table 2]

[0050]
The liquid crystal used in Table 2 was ZLI-4792 (manufactured by Merck), and the alignment film was JALS-214 (manufactured by JSR).
According to the results shown in Table 2, the voltage holding ratio of the panel irradiated with ultraviolet rays before the liquid crystal and the sealing material came into contact with each other was 98%, whereas the voltage holding ratio was 98% after the liquid crystal and the sealing material came into contact with each other. The irradiated panel has a low voltage holding ratio of 96%, and the voltage holding ratio after 1000 hours at 80 ° C. is higher than that of the panel irradiated with ultraviolet rays before contacting, which is 98%. In the panel irradiated with ultraviolet rays after the contact, the ratio is reduced to 94%. Therefore, it was confirmed that a decrease in voltage holding ratio can be suppressed by irradiating ultraviolet rays before the liquid crystal comes into contact with the sealing material.
[0051]
The manufacturing method of the liquid crystal display device according to the third embodiment of the present invention utilizes this fact. That is, the projections 6A and 6B made of the same material as the color filter are formed by patterning between the display area on the CF substrate 1 and the formation area of the sealing material. The protrusions 6A and 6B may be formed in at least one layer among R, G and B. Subsequently, a transparent electrode 7 and an alignment film 8 are sequentially formed on the protrusions 6A and 6B to form higher protrusions 9A and 9B.
[0052]
The gap between the CF substrate 1 and the TFT substrate 4 in the region where the protrusions 9A and 9B are thus formed becomes narrow as shown in FIG. 5A, and the liquid crystal 3 diffused by the compression reaches the sealing material 2. Before the liquid crystal 3 reaches the sealing material 2, it is possible to irradiate the sealing material with ultraviolet rays and harden it before the liquid crystal 3 reaches the sealing material 2.
[0053]
Accordingly, it is possible to suppress a decrease in the voltage holding ratio of the liquid crystal display device and a decrease in contrast during display.
The pattern of the convex portions formed by the color filters may be an annular pattern as shown in FIGS. 5A and 5B, but the present invention is not limited to this. For example, as shown in FIG. You may form the convex part 9C which an island-shaped pattern is dotted. In this case as well, the same effects as those in the case where the convex portions 9A and 9B of the pattern shown in FIGS. 5A and 5B are formed can be obtained.
[0054]
(4) Fourth embodiment
Hereinafter, a method for manufacturing the liquid crystal display device according to the fourth embodiment of the present invention will be described with reference to FIGS. 7 (a), 7 (b), 8 (a), and 8 (b). 7A, 7B and 8A are sectional views, and FIG. 8B is a plan view. FIG. 8A is a cross-sectional view taken along line CC of FIG. 8B. The description of items common to the first, second or third embodiment will be omitted to avoid duplication.
[0055]
First, steps P1 to P7 in FIG. 1 go through the same steps as in the first embodiment. As shown in FIG. 7A, in the rough matching process of step P8, the two sides of the TFT substrate 4 are brought into contact with one side of the CF substrate 1 mounted on the mounting table ST in a reduced pressure atmosphere. A spacer plate 11 having a thickness of 2 mm is sandwiched between the plates and placed. For example, as shown in FIGS. 8A and 8B, the spacer plate 11 is sandwiched between the superposed CF substrate 1 and the TFT substrate 4 at one place.
[0056]
Further, guide rods 10 are provided at the four corners of each of the substrates 1 and 4 so as to prevent displacement.
Next, when the spacer plate 11 is pulled out in the lateral direction, the TFT substrate 4 falls on the CF substrate 1 by its own weight and overlaps as shown in FIG. 7B. At this time, since the guide rods 10 are arranged at the four corners of the TFT substrate 4, the TFT substrate 4 is hardly shifted by being dragged by the spacer plate 11. Subsequent steps are the same as in the first embodiment, and a description thereof will be omitted.
[0057]
As described above, according to the liquid crystal display device manufacturing method according to the fourth embodiment of the present invention, the spacer plate 11 is provided between the TFT substrate 4 and the CF substrate 1 such that one side of the CF substrate 1 is in contact with the other side. The CF substrate 1 and the TFT substrate 1 are overlapped with each other and pulled out.
In this embodiment, at least one side of the TFT substrate 4 and one side of the CF substrate 1 are in contact with each other, as compared with the related art in which the liquid crystal is rapidly compressed by allowing the TFT substrate to fall freely after facing the CF substrate. Fall relatively slowly. For this reason, the sealing material 2 formed on the CF substrate 1 is not subjected to a large pressure as compared with the related art, and the sealing material 2 is not crushed. Therefore, the gap between the CF substrate 1 and the TFT substrate 4 does not become uneven.
[0058]
In the present embodiment, the TFT substrate 4 is superposed on the CF substrate 1 by sandwiching the spacer plate 11 only at one place between the CF substrate 1 and the TFT substrate 4 and pulling out the spacer plate 11. 8C and 8D, two spacer plates 11A and 11B are sandwiched between the CF substrate 1 and the TFT substrate 4 and supported at two points. However, the same effect can be obtained, and the same effect can be obtained even if the three spacer plates 11A, 11B and 11C are sandwiched and supported at three points as shown in FIGS. 9 (a) and 9 (b). It is sufficient that at least one side of the CF substrate 1 and one side of the TFT substrate are in contact with each other. 8 (c) and 9 (a) are sectional views, 8 (d) and 9 (b) are plan views, and FIG. 8 (c) is a sectional view taken along line DD in FIG. FIG. 9B is a sectional view taken along line EE of FIG. 9A.
[0059]
Further, by using the method according to the present embodiment, the TFT substrate can be mounted on the CF substrate in a short time for a plurality of liquid crystal display panels. This will be described below with reference to FIGS.
That is, as shown in FIG. 10, a CF substrate and a TFT substrate are alternately stacked, and a guide bar 10 is disposed around the CF substrate and the TFT substrate. FIG. 11 shows this state as viewed from the side. A TFT substrate 4C, a CF substrate 1C, a TFT substrate 4B, a CF substrate 1B, a TFT substrate 4A, and a CF substrate 1A are sequentially laminated from the bottom, and spacer plates 11C, 11B, and 11A are sandwiched therebetween. ing.
[0060]
To mount each TFT substrate on the CF substrate, simply pull out each spacer plate 11A, 11B, 11C in the horizontal direction, and a plurality of TFT substrates corresponding to a plurality of liquid crystal display panels are placed on the corresponding CF substrates. In addition, it can be easily mounted in a short time.
(5) Fifth embodiment
Hereinafter, a method for manufacturing a liquid crystal display device according to a fifth embodiment of the present invention will be described with reference to FIGS. Note that the description of items common to the first to fourth embodiments will be omitted to avoid duplication.
[0061]
First, in step P1 of FIG. 1, in a step of forming members necessary for forming a liquid crystal display panel on a transparent substrate, the TFT substrate 4 is formed in the same process as in the first embodiment. A plurality of guide holes 1H each having a diameter of 1 mm are formed in the four corners using a super steel drill or a carbon dioxide laser.
Next, after steps P2 to P7 in FIG. 1 have been performed in the same manner as in the first embodiment, in a rough alignment step in step P8 in FIG. 1, as shown in FIG. The support rods 12A and 12B are passed through guide holes 1H formed at four corners of the CF substrate 1, and the TFT substrate 4 is mounted thereon. At this stage, the TFT substrate 4 and the CF substrate 1 are separated from each other at an interval of about 2 mm. In FIG. 12A, two support rods 12A and 12B are shown, and two are omitted.
[0062]
Then, as shown in FIGS. 12B and 12C, the support rods 12A and 12B are gradually lowered to overlap the TFT substrate 4 with the CF substrate 1. Subsequent processes after step P9 in FIG. 1 are the same as those in the first embodiment, and thus description thereof will be omitted.
As described above, according to the liquid crystal display device manufacturing method according to the fifth embodiment of the present invention, the guide holes 1H are formed at the four corners of the CF substrate 1, and the support rods 12A and 12B are passed through the guide holes 1H. The TFT substrate 4 is placed on the substrates 12A and 12B, and the TFTs 4 are overlapped with the CF substrate 1 by gradually lowering the support rods 12A and 12B, thereby performing rough alignment.
[0063]
For this reason, if the position of the support is lowered in advance and the support is lowered, it is possible to superimpose the support without any displacement, thereby improving the accuracy of the rough alignment. In addition, there is little deviation when the substrate comes into contact with the sealing material 2 and the impact is small, so that the sealing material 2 is not crushed evenly and the uniformity of the gap between the substrates is improved.
13A and 13B, cutouts 1K are formed at the four corners of the CF substrate 1 instead of the guide holes 1H in the CF substrate 1, as in the present embodiment. The TFT substrate 4 is placed on the four support rods 12A, 12B, 12C, and 12D through the support rods 12A, 12B, 12C, and 12D in 1K, and the support rods 12A, 12B, 12C, and 12D are lowered to make the TFTs. Even if the method of superposing the substrate 4 on the CF substrate 1 is used, the TFT substrate 4 can be slowly lowered onto the CF substrate 1 as in the method using the guide holes 1H of the present embodiment. An effect similar to that of the embodiment is obtained.
[0064]
Further, there is a method in which a glass capsule used as a filler for engineering plastic is sandwiched between a TFT substrate and a CF substrate, and this is used as a spacer plate. This glass capsule is broken by the pressurization at the time of press-bonding the substrate and becomes fine, so that there is no problem in controlling the gap. Further, since the fragments of the glass capsule remaining on the substrate are transparent, there is no display problem.
[0065]
(6) Sixth embodiment
Hereinafter, a method for manufacturing a liquid crystal display device according to a sixth embodiment of the present invention will be described with reference to the drawings. Note that the description of items common to the first to fifth embodiments will be omitted to avoid duplication.
First, steps P1 to P3 in FIG. 1 go through the same steps as in the first embodiment. In the step of forming a seal in step P4, unlike the first to fifth embodiments, first, a silane coupling material, which is an example of a film that captures mobile ions, is provided on the surface of the CF substrate 1 where a seal material is to be formed. A film 13A (Toray: AP-400) is formed in a ring shape.
[0066]
Similarly, a film 13B made of the same silane coupling material is also formed on the surface of the TFT substrate 4 in a region where the sealing material is to be pressed later. These films 13A and 13B are formed by printing, and are subjected to a heat treatment at a temperature of 300 ° C. for 30 minutes for curing.
Next, on the film 13A made of a silane coupling material formed on the CF substrate 1, a sealing material 2 made of an ultraviolet-curable adhesive (T-470, manufactured by Chise Nagase) is formed in a ring shape.
[0067]
Thereafter, through steps P5 to P10 in FIG. 1 through the same steps as in the first embodiment, a liquid crystal display panel having a sectional shape as shown in FIG. 14 is completed. In the rough alignment step of Step P8, at least the film 13B made of the silane coupling material of the TFT substrate 4 exists in the region inside the sealing material 2.
As described above, according to the method of manufacturing the liquid crystal display device according to the sixth embodiment of the present invention, as shown in FIG. In the region, films 13A and 13B made of a silane coupling material, which are films for capturing mobile ions, are formed.
[0068]
For this reason, the mobile ions existing near the sealing material 2 are captured by the films 13A and 13B made of the silane coupling material, so that the leakage of the accumulated charges via the mobile ions can be suppressed. Accordingly, a decrease in the voltage holding ratio can be suppressed, and a decrease in the contrast of the liquid crystal display device during display can be suppressed.
[0069]
The fact that a reduction in voltage holding ratio can be suppressed by forming a film made of a silane coupling material in the vicinity of the formation region of the sealant has been confirmed by experiments by the present inventors. Hereinafter, the results of this experiment will be described.
Table 3 below shows the voltage holding ratio of a liquid crystal display panel in which a film made of a silane coupling material (manufactured by Toray: AP-400) was formed in a region adjacent to the region where the sealing material was formed, and a conventional liquid crystal not using the same. 9 shows the results of an experiment comparing the voltage holding ratio of the display panel with the voltage holding ratio.
[0070]
[Table 3]

[0071]
The liquid crystal used in Table 3 was ZLI-4792 (manufactured by Merck), and the alignment film was JALS-214 (manufactured by JSR).
According to the results shown in Table 3, the voltage holding ratio of the liquid crystal display panel in which the film made of the silane coupling material was formed in the region adjacent to the formation region of the sealing material was 97%, whereas the voltage holding ratio of the silane coupling material was 97%. The voltage holding ratio of a conventional liquid crystal display panel having no film is as low as 96%, and the voltage holding ratio after 1000 hours at 80 ° C. is 97% for a liquid crystal display panel having a film made of a silane coupling material. While maintaining the high value, the conventional liquid crystal display panel having no value is reduced to 94%. Therefore, it was confirmed that a decrease in the voltage holding ratio was suppressed in a liquid crystal display panel in which a film made of a silane coupling material was formed in a region adjacent to the region where the seal material was formed.
[0072]
In this embodiment, a film made of a silane coupling material is used as an example of a film that captures mobile ions. However, the present invention is not limited to this. The film has a property of capturing mobile ions and does not contaminate the liquid crystal. The present invention can be applied to such a film.
(7) Seventh embodiment
Hereinafter, an apparatus for manufacturing a liquid crystal display device according to a seventh embodiment of the present invention will be described with reference to the drawings. This device is a bonding device used in the vacuum evacuation process in step P7 and the rough bonding process in step P8 in FIG. It is used in a process in which a CF substrate and a TFT substrate are housed, the inside thereof is depressurized, these substrates are overlapped and roughly aligned, and a liquid crystal is sealed in a gap between the substrates.
[0073]
As shown in FIG. 15, the apparatus for manufacturing a liquid crystal display device according to the present embodiment includes a processing chamber 20, an exhaust valve 21, an exhaust port 22, a leak valve 23, a leak port 24, and a mounting table ST.
The processing chamber 20 is a chamber in which the CF substrate 1 and the TFT substrate 4 are bonded. The exhaust valve 21 constitutes a part of the pressure reducing means, and is provided between a vacuum pump (not shown) and the exhaust port 21. By opening the exhaust valve 21 and exhausting the gas in the processing chamber 20 through the exhaust port 22, the inside of the processing chamber 20 is depressurized.
[0074]
The leak valve 23 is provided between a leak port 24 and a gas cylinder (not shown) containing an inert gas or the like. When the leak valve 23 is opened, the gas ejected from the gas cylinder (not shown) flows through the leak port 24. It is introduced into the processing chamber 20 through the processing chamber. The leak valve 23 and the leak port 24 constitute a leak unit. Note that a gas cylinder containing an inert gas or the like may not be connected to the leak valve 23, and a leak may be performed by the atmosphere.
[0075]
A method for manufacturing a liquid crystal display device using the above-described apparatus for manufacturing a liquid crystal display device will be described below.
After passing through steps P1 to P6 in FIG. 1 in the same manner as in the first embodiment, in step P7 in FIG. 1, the CF substrate 1 in which the liquid crystal 3 is dropped on the inner region of the annular sealing material 2, The TFT substrate 4 is carried into the processing chamber 20 of the bonding apparatus shown in FIG. The CF substrate 1 is mounted on the mounting table ST.
[0076]
Next, the exhaust valve 21 is opened, and the processing chamber 20 is exhausted by a vacuum pump (not shown) provided ahead of the exhaust valve 21. Here, evacuation was performed for 5 minutes, and the ultimate vacuum in the processing chamber 20 was set to 5 mTorr.
Thereafter, in the rough matching process in step P8 in FIG. 1, the TFT substrate 4 and the CF substrate 1 are overlapped with each other via the sealing material 2 under reduced pressure, and rough matching is performed. Subsequently, pressure is applied.
[0077]
In this pressurizing step, the leak valve 23 is momentarily opened, and nitrogen gas or the like is spouted from the leak port 24 onto the TFT substrate 4 therebelow. By spraying nitrogen gas, the TFT substrate 4 is pressed against the CF substrate 1.
The gas generally exerts an isotropic pressure on the object, and spreads all over the surface of the TFT substrate 4. Therefore, when this is sprayed on the upper surface of the TFT substrate 4, the pressure received by the TFT substrate 4 becomes almost uniform, and the TFT substrate 4 is pressed with a uniform force. become. Thus, when a drive voltage is applied to the electrodes of the liquid crystal display panel, the electric field applied to the liquid crystal between the substrates is also uniform, so that the display characteristics are improved.
[0078]
Similarly, as a bonding device that pressurizes using gas, a bonding device as shown in FIG. 16 can be considered. This device is different from the device shown in FIG. 15 in that a leak hole 24 is formed along the formation region of the sealing material 2 of the liquid crystal display panel.
To press the TFT substrate 4 superimposed on the CF substrate 1 using the bonding apparatus shown in FIG. 16, the leak valve 23 is opened as in the apparatus shown in FIG. Pressure is applied by spraying from the leak hole 24. In this device, as shown in FIG. 16, since the leak holes 24 are formed along the formation region of the seal material 2, the gas to be jetted is blown only to the formation region of the seal material 2.
[0079]
When the TFT substrate 4 and the CF substrate 1 are pressurized, it is important to pressurize the sealant 2 uniformly after all. According to this apparatus, a gas can be blown along the sealing material 2 to uniformly press the sealing material 2, so that the gaps between the substrates 1 and 4 can be made uniform as in the apparatus shown in FIG. Can be
(8) Eighth embodiment
Hereinafter, an apparatus for manufacturing a liquid crystal display according to an eighth embodiment of the present invention will be described with reference to FIG. This device is a bonding device used in the vacuum evacuation step in step P7 and the rough bonding step in step P8 in FIG. 1, similarly to the liquid crystal display device manufacturing apparatus described in the seventh embodiment. After the TFT substrate is carried into the apparatus, the inside of the apparatus is evacuated and these substrates are roughly aligned.
[0080]
As shown in FIG. 17, the liquid crystal display device manufacturing apparatus according to the present embodiment includes a processing chamber 20, an exhaust valve 21, an exhaust port 22, a first leak valve 23A, a second leak valve 23B, and a first leak valve. There is a port 24A, a second leak port 24B, a pressure plate 25, and a mounting table ST.
The processing chamber 20 is a chamber for performing bonding inside the processing chamber. An exhaust valve 21 is provided between a vacuum pump (not shown) and an exhaust port 21. The exhaust valve 21 is opened, and the processing chamber 20 is opened through the exhaust port 22. The gas inside is evacuated to reduce the pressure.
[0081]
The first leak valve 23A is provided outside the leak port 24A. By opening the first leak valve 23A, a gas from a gas cylinder (not shown) is blown onto the upper surface of the crimp plate 25. The pressure bonding plate 25 is supported on the mounting table ST by a telescopic bellows VS, and is separated from the inside of the processing chamber 20. When the gas is blown, the bellows VS is extended and mounted on the mounting table ST. The upper surface of the TFT substrate is pressed.
[0082]
The first leak valve 23B is provided outside the leak port 24B. By opening the first leak valve 23B, air outside the apparatus is introduced into the processing chamber 20.
A method for manufacturing a liquid crystal display device using the above-described apparatus for manufacturing a liquid crystal display device will be described below.
After passing through the steps P1 to P6 in FIG. 1 in the same manner as in the first embodiment, in step P7 in FIG. 1, the CF substrate 1 on which the sealing material 2 is formed and the liquid crystal 3 is dropped, and the TFT The substrate 4 is carried into the processing chamber 20 of the bonding apparatus shown in FIG. 15, and the CF substrate 1 is mounted on the mounting table ST.
[0083]
After the TFT substrate 4 is arranged opposite to the CF substrate 1, the exhaust valve 21 is opened, and the processing chamber 20 is evacuated by a vacuum pump (not shown) provided in front thereof. Evacuation was performed for 5 minutes, and the ultimate vacuum was set to 5 mTorr.
Thereafter, in the rough matching process in step P8 in FIG. 1, the TFT substrate 4 is placed on the CF substrate 1 in a vacuum state, brought into a close contact state, and pressurized.
[0084]
In this pressurizing step, when the first leak valve 23A is instantaneously opened, nitrogen gas ejected from a gas pump (not shown) is blown from the first leak port 24A to the pressing plate 25 thereunder at a uniform pressure. The TFT substrate 4 is pressed by the pressure plate 25 to press the TFT substrate 4 against the CF substrate 1.
According to this pressing method, the press plate 25 is pressurized using gas, and the TFT substrate 4 is pressed by the press plate 25. The gas generally has isotropic properties. When the gas is blown onto the upper surface of the crimping plate 25, the gas spreads over the entire surface of the crimping plate 25, and the pressure becomes substantially uniform. Since the TFT substrate 4 is pressurized with the uniform pressure, the TFT substrate 4 and the CF substrate 1 can be pressurized with a uniform force, unlike the related art.
[0085]
As a result, the liquid crystal can be evenly distributed between these substrates, so that the gap between the substrates 1 and 4 can be made uniform, and the display characteristics can be improved.
(9) Ninth embodiment
Hereinafter, a method for manufacturing the liquid crystal display device according to the ninth embodiment of the present invention will be described with reference to FIGS. Descriptions of items common to the first to eighth embodiments are omitted to avoid duplication.
[0086]
First, in step P1 of FIG. 1, in a step of forming members necessary for forming a liquid crystal display panel on a transparent substrate made of glass or the like, the processing on the TFT substrate 4 side is the same as in the first embodiment. However, in the step of forming a color filter on the CF substrate 1, as shown in FIG. 18B, the color filter is formed in the display area CR of the liquid crystal display device and simultaneously in the peripheral area adjacent to the display area CR. Also, a spare color filter CM is formed in accordance with the arrangement order of the color filters in the display area CR. Subsequent steps are the same as in the first embodiment, and a description thereof will be omitted.
[0087]
According to the liquid crystal display device manufacturing method according to the ninth embodiment of the present invention, as shown in FIGS. 18A and 18B, the color filter of the display region CR is also provided in the peripheral region adjacent to the display region CR. The spare color filters CM are formed in accordance with the arrangement order of the above. Therefore, even if the misalignment occurs when the TFT substrate 4 and the CF substrate 1 are overlapped with each other, the end portions protruding from the display region CR are removed. What is necessary is just to match with the position of the spare color filter CM. For this reason, the adjustment width for the alignment is small, the adjustment is easy, and the damage to the adhesive due to the significant movement of the substrate for the adjustment can be avoided.
[0088]
【The invention's effect】
As described above, according to the present invention, after laminating a pair of transparent substrates via an uncured adhesive, the adhesive is irradiated with ultraviolet light and cured before the adhesive and the liquid crystal come into contact with each other. Let me.
For this reason, it is possible to ensure the fixation of the pair of transparent substrates and to suppress the contamination of the liquid crystal, which has conventionally occurred when the uncured adhesive is in contact with the liquid crystal and the region is irradiated with ultraviolet light. In addition, it is possible to suppress as much as possible a reduction in the voltage holding ratio of the liquid crystal display device due to the contamination of the liquid crystal and a decrease in contrast at the time of the display.
[0089]
Further, an annular adhesive is formed on both the first transparent substrate and the second transparent substrate, and only the surface layer of the adhesive is cured, and then the adhesives are brought into contact with each other to form the first transparent substrate and the second transparent substrate. The substrates are overlaid.
Since the adhesives are in contact with each other, even when only the surface layer is cured, the first transparent substrate and the second transparent substrate are more firmly fixed to each other.
[0091]
In particular, by forming a convex portion that slows down the spread rate of the liquid crystal in a region outside one of the display regions of the pair of transparent substrates and inside the formation region of the adhesive, Before the liquid crystal and the liquid crystal come into contact with each other, the adhesive can be irradiated with ultraviolet rays and cured with more time.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating a method for manufacturing a liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is a diagram (part 1) for explaining the method of manufacturing the liquid crystal display device according to the first embodiment of the present invention.
FIG. 3 is a diagram (part 2) for explaining the method for manufacturing the liquid crystal display device according to the first embodiment of the present invention.
FIG. 4 is a diagram illustrating a method for manufacturing a liquid crystal display device according to a second embodiment of the present invention.
FIG. 5 is a view (No. 1) for explaining the method of manufacturing the liquid crystal display device according to the third embodiment of the present invention.
FIG. 6 is a drawing (part 2) for explaining the method of manufacturing the liquid crystal display device according to the third embodiment of the present invention.
FIG. 7 is a sectional view (part 1) for explaining the method for manufacturing the liquid crystal display device according to the fourth embodiment of the present invention.
FIG. 8 is a top view (part 1) for explaining the method for manufacturing the liquid crystal display device according to the fourth embodiment of the present invention.
FIG. 9 is a top view (part 2) for explaining the method for manufacturing the liquid crystal display device according to the fourth embodiment of the present invention.
FIG. 10 is a perspective view illustrating a method for manufacturing a liquid crystal display device according to a fourth embodiment of the present invention.
FIG. 11 is a sectional view (part 2) for explaining the method for manufacturing the liquid crystal display device according to the fourth embodiment of the present invention.
FIG. 12 is a cross-sectional view illustrating a method for manufacturing a liquid crystal display according to a fifth embodiment of the present invention.
FIG. 13 is a diagram illustrating a method for manufacturing the liquid crystal display device according to the fifth embodiment of the present invention.
FIG. 14 is a sectional view illustrating a method for manufacturing a liquid crystal display device according to a sixth embodiment of the present invention.
FIG. 15 is a view (No. 1) for explaining the liquid crystal display device manufacturing apparatus according to the seventh embodiment of the present invention.
FIG. 16 is a diagram (part 2) for explaining the liquid crystal display device manufacturing apparatus according to the seventh embodiment of the present invention.
FIG. 17 is a sectional view illustrating the method for manufacturing the liquid crystal display according to the eighth embodiment of the present invention.
FIG. 18 is a view illustrating a method for manufacturing the liquid crystal display device according to the ninth embodiment of the present invention.
FIG. 19 is a flowchart illustrating a method for manufacturing a liquid crystal display device according to a conventional example.
FIG. 20 is a cross-sectional view illustrating an apparatus for manufacturing a liquid crystal display device according to a conventional example.
FIG. 21 is a view (No. 1) for explaining the method of manufacturing the liquid crystal display device according to the conventional example.
FIG. 22 is a view (No. 2) for explaining the method of manufacturing the liquid crystal display device according to the conventional example.
FIG. 23 is a graph (part 1) for explaining a problem of the conventional example.
FIG. 24 is a graph (part 2) for explaining a problem of the conventional example.
FIG. 25 is a diagram illustrating a voltage holding ratio of a liquid crystal display panel.
[Explanation of symbols]
1 CF substrate (first transparent substrate),
1A, 1B, 1C CF substrate,
1H guide hole,
1K resection,
2 sealant (adhesive),
2A inner peripheral surface of sealing material,
2B first sealing material (first adhesive);
2C semi-cured sealing material,
3 liquid crystal,
4 TFT substrate (second transparent substrate),
4A, 4B, 4C TFT substrate,
5 a second sealing material (a second adhesive);
5A semi-cured sealing material,
6A, 6B, 9A, 9B, 9C convex part,
7 transparent electrode,
8 alignment film,
10 guide rods,
11 11A, 11B, 11C spacer plate,
12A, 12B, 12C, 12D support rod,
13A, 13B A film made of a silane coupling material (a film that captures mobile ions),
20 processing rooms,
21 exhaust valve,
22 exhaust port,
23 leak valve,
23A first leak valve,
23B second leak valve,
24, 24A leak port,
24B second leak,
25 crimping plate,
CR display area,
CM spare color filter,
ST mounting table,
SP spacer,
VS Bellows.

Claims (6)

A step of forming an ultraviolet-curable adhesive in an annular region on one of the pair of transparent substrates and outside the display region;
A step of dropping liquid crystal on one of the central regions of the pair of transparent substrates;
Returning to atmospheric pressure after stacking the pair of transparent substrates under reduced pressure, and sealing the gap between the pair of transparent substrates surrounded by the adhesive with the adhesive;
Irradiating the adhesive with ultraviolet rays to cure the liquid crystal, and then the liquid crystal reaches the adhesive. Before the step of forming the adhesive material in a ring shape, a convex portion having a height that is not in contact with a transparent substrate which is one of the pair of transparent substrates and is superimposed on a region outside a display region in a later step. 2. The method according to claim 1, further comprising the step of: 3. The method according to claim 2, wherein the protrusion has one of a ring shape and a dotted island shape. 4. The liquid crystal according to claim 3, wherein a color filter is formed in a display area of the transparent substrate on a side where the protrusion is formed, and the protrusion is formed by patterning the same material as the color filter. 5. A method for manufacturing a display device. A pair of transparent substrates facing each other,
A projection that is not in contact with the other transparent substrate, outside a display area on one facing surface of the pair of transparent substrates,
An ultraviolet-curing adhesive that is formed between the pair of transparent substrates and is annular in an area outside the convex portion to form a sealed gap between the pair of transparent substrates;
And a liquid crystal sealed in the sealed gap. 6. The liquid crystal display device according to claim 5, wherein a color filter is formed in a display area of the transparent substrate on the side where the protrusion is formed, and the protrusion is made of the same material as the color filter. Method.

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