JP4883849B2 - Color filter, manufacturing method thereof, and liquid crystal display device - Google Patents

Description

【００５８】
同表から明らかなとおり、ＴｉＯ₂膜の表面粗度はＳｉＯ₂膜に比べて２倍以上であり、これにより、アンカー効果の働きにより、密着性が大きくなっていると考える。
【００５９】
さらに望ましくは、このようなＴiＯ₂膜に対し紫外線照射するとよく、このような工程を経ることでも、樹脂遮光膜との界面での密着性が向上する。
【００６０】
その理由は下記のとおりである。
ＴiＯ₂のような半導体物質は、ＵＶ光等の照射により光励起され、その際に生じる活性の電子と正孔の働きにより、その表面に吸着されている有機性の不純物を分解除去する光触媒作用がある。したがって、有機性の不純物がガラス基板の表面に付着した状態で樹脂遮光膜を形成した場合、そのガラス基板に対する密着性が著しく阻害されるが、本発明のように、ガラス基板上にＴiＯ₂膜を形成し、光硬化性樹脂遮光膜を塗布する直前に、あらかじめガラス基板をＵＶ処理することで、これらの有機性不純物は除去され、ガラス基板と樹脂遮光膜の界面の密着性の低下を防止することができる。たとえば、１８６ｎｍと２５４ｎｍにピークを持つＵＶ光を約２分照射する。
【００６１】
上記のようなＴiＯ₂膜は多結晶であり、それが主成分であり、その他、アモルファス成分を含んでもよい。
【００６２】
次に本発明を図示して詳述する。
【００６３】
（例１）
図１はカラーフィルタの概略断面構造を示し、ソーダライムガラス基板１の上にアルカリイオンの拡散障壁としてのＳiＯ₂膜２をディップコートしている。このような基板を、以下、ディップ基板と称する。
【００６４】
このディップ基板上にＴiＯ₂膜３をスパッタリング法でもって成膜形成した。このＴiＯ₂膜３の膜厚は１０Å、２０Å、５０Å、７０Å、８０Å、９０Åの６とおりである。
【００６５】
次に、これらＴiＯ₂が最表層となった基板上に、それぞれ光硬化性樹脂遮光膜を形成し、露光、次いで現像を行った。そして、現像液に浸漬する時間を５０秒〜１２０秒に変えることで、さまざまなテスト用の試料を作製し、これらに対し光硬化性樹脂遮光膜の密着性（剥離状態）を調べたところ、表２に示すような結果が得られた。
【００６６】
なお、比較例としてディップ基板上（表２にてＳｉＯ₂と表記している）に同じ樹脂遮光膜を形成し同様に測定した。
【００６７】
この実験においては、下記のような条件でもって作製し、そして、評価した。
【００６８】
光硬化性樹脂遮光膜；ポリエステル系の樹脂であり、東京応化工業製ＣＦＰＲブラックレジストを用いた。遮光剤としてはカーボンを使用している。
【００６９】
露光条件
露光機；日立電子エンジニアリング製投影式露光機
フォトマスク；設計幅１０μｍ
露光量；５００mj/cm²（照度３５mW/cm²)
露光ギャップ；１００μｍ
現像条件
現像方式；ディップ式現像
現像液；東京応化工業製無機アルカリ現像液
リンス；超純水水洗（水洗圧１.０kgf/cm²)
評価方法
測長器付き金属顕微鏡を用いた目視観察にて樹脂遮光膜の剥れ状況を確認する。
【００７０】
【表２】

【００７１】
同表中、現像残とは現像のされ方が不足している状態で、現像によって除去されるべき箇所が除去しきれずに残ってしまう現象であり、剥離とは現像のされ方が過剰になった状態であり、パターンとして残るべきところが剥離して無くなってしまうことである。また、現像残と剥離という表記以外の数値は樹脂遮光膜パターン幅の測定値である。
【００７２】
この表から明らかなように、ディップ基板上にＴiＯ₂膜を形成し最表層とすることにより、樹脂遮光膜現像時のパターン剥離が生じにくくなる。また、フォトマスクの設計幅(１０μｍ)に近い膜形成ができ、より解像性の優れた樹脂遮光膜パターンの形成ができる。
【００７３】
たとえば、樹脂遮光膜パターン幅の適合規格を１０.０±１.０μｍとすると、ディップ基板では、現像液の浸漬時間７０秒でしか規格をクリアできていないのに対し、本発明の如く、ＴiＯ₂被覆基板では概ね３０秒間（浸漬時間８０〜１１０秒）の規格に対する現像ラチチュードを有している。
【００７４】
ただし、本例では、ＴiＯ₂膜厚が１０Åというように非常に薄くなると、これら現像性の改善効果は認められなかった。
【００７５】
（例２）
次に（例１）にて作製した各試料において、ディップ基板上（表２にてＳｉＯ₂と表記している）およびＴiＯ₂膜厚１０Å基板の試料については、現像液浸漬時間を７０秒に設定した。また、ＴiＯ₂膜厚２０Å〜９０Å基板の各試料については、現像液浸漬時間を９０秒に設定し、これら各試料を２４０℃のホットプレート上で加熱し、樹脂遮光膜パターンを熱硬化させた。
【００７６】
次に、これら熱硬化させた樹脂遮光膜パターンの密着強度を測定したところ、表３に示す結果が得られた。
【００７７】
【表３】

【００７８】
この表から明らかなように、ディップ基板上にＴiＯ₂膜を形成し、最表層とすることにより、熱硬化された樹脂遮光膜パターンの密着強度が向上したことがわかる。
【００７９】
しかしながら、ＴiＯ₂の膜厚が小さくなるほどに、密着強度が小さくなり、ＴiＯ₂膜厚１０Åの試料については、ディップ基板上に直接樹脂遮光膜パターンを形成した場合と同程度の密着強度となった。
【００８０】
この密着強度は、下記のように測定する。
樹脂遮光膜を上述した如く塗布〜焼成した基板と治具にピンを取り付け、測定器にセットして測定する。測定器は島津製作所製の小型卓上試験機(型式;TZ-TEST SERIES MODEL TEST/CE)である。
【００８１】
（例３）
本例では、上記の各試料でもってカラーフィルタを作製し、その評価を行った。
【００８２】
本例にて、その製造方法を述べるが、順次下記Ａ〜Ｅの各工程を経て、ガラス基板上にＴiＯ₂膜と樹脂遮光膜パターンとを順次形成する。
【００８３】
Ａ工程：
（例１）にて図１に示す如く、ガラス基板（ディップ基板）上にスパッタリングもしくは真空蒸着にてＴiＯ₂膜３で被覆する。
【００８４】
Ｂ工程：
（例１）にて記述したとおり、ＴiＯ₂膜３上に遮光性の着色剤を添加した光硬化性樹脂膜を塗布する。この工程は図４Ａに相当する。
【００８５】
Ｃ工程：
さらに（例１）にて記述したとおり、フォトマスクを用いて光硬化性樹脂膜の所定領域を露光する。この工程は図４Ｂに相当する。
【００８６】
Ｄ工程：
続いて、光硬化性樹脂膜に対し現像し、一部を除去する。
【００８７】
Ｅ工程：
残存する光硬化性樹脂膜を熱硬化する。
【００８８】
これらＤ，Ｅの各工程は、図４Ｃに相当する。
【００８９】
次いで、樹脂遮光膜パターンの隙間に着色膜を形成することで、図１に示すような本発明のカラーフィルタが得られる。
【００９０】
着色膜は、従来周知の技術でもって形成でき、たとえば顔料分散法や染色法がある。
【００９１】
本例では、前述した７種類の各試料に対し、あらかじめ顔料により調合された感光性レジストを基板上に塗布し、フォトリソグラフィにより、それぞれRed着色画素５、次いでGreen着色画素６、その後のBlue着色画素７を形成し、カラーフィルタとした。
【００９２】
なお、これら着色膜の上に、その表面を平坦にするためにアクリル系樹脂からなる平滑化膜８を形成するが、それを形成しなくてもよい。
【００９３】
そして、各カラーフィルタに対し、分光測定機を使用して、可視光領域(４００ｎｍ〜７００ｎｍ)の平均透過率を測定したところ、表４に示すような結果が得られた。
【００９４】
分光測定機にはＴＯＰＣＯＮ ＳＲ−１を用いて、Ｃ光源にて視野角を２.０度にした。
【００９５】
【表４】

【００９６】
この表から明らかなように、樹脂遮光膜パターンの解像性に優れた２０Å以上のＴiＯ₂最表層基板を使用することにより、カラーフィルタの透過率が向上する。
【００９７】
叙上の（例１）〜（例３）に示す評価結果から、本発明においては、ガラス基板上に被着するＴiＯ₂膜の厚みを１０Åを越えるようにするとよい。
【００９８】
しかしながら、ＴiＯ₂膜の膜厚が大きくなると、多重反射の影響を受け、その効果は低減する。ＴiＯ₂膜厚９０Åにおいては、樹脂遮光膜パターンの解像性向上の効果と多重反射による点灯光の損失が相殺され、ディップ基板とほぼ同等の透過率となった。
【００９９】
上記の多重反射について、さらに述べると、ＴiＯ₂の薄膜をソーダライムガラス基板上に形成させた場合、光の屈折率の異なることで、スネルの法則に従い、入射光の一部がその界面で反射され、これにより、透過率が低下する。
【０１００】
多重反射における反射率は、構成する各層の屈折率と膜厚に依存することが知られている。ここでは、ＴiＯ₂の屈折率(２.５０)およびソーダライムガラスの主成分であるＳiＯ₂の屈折率(１.５２)は定数であり、また、ソーダライムガラス基板の板厚はＴiＯ₂膜に比べて充分に厚いので、ＴiＯ₂の膜厚が反射率を決定する唯一の因子となる。
【０１０１】
図９にソーダライムガラス基板上に形成されたＴiＯ₂の膜厚と、その表面に於ける可視光線（４００nｍ〜７００nｍ）の平均反射率の関係を示す。なお、同図は理論値であり、ガラス基板裏面からの反射光は含まれていない。
【０１０２】
図９から明らかなように、ソーダライムガラス基板上にＴiＯ₂膜を形成する場合、ＴiＯ₂の膜厚を小さく形成するに伴い、多重反射の影響がより低減されることがわかる。
【０１０３】
次に、この多重反射と液晶表示装置との関係を説明する。
【０１０４】
（透過型カラー液晶表示装置について）
この多重反射の現象は、光源からの照射光を液晶パネルに透過させて、その表示面を点灯する構造を有する透過型カラー液晶パネルにおいては、表示面の点灯光の損失になる。したがって、多重反射による点灯光の損失を表示特性上、無視できるレベルまで、少なくすることが重要となる。
【０１０５】
しかしながら、ＴiＯ₂膜の薄膜化にも限界がある上、樹脂遮光膜との密着性向上という当初の目的も考慮する必要があるので、多重反射による点灯光の損失を嫌う透過型カラー液晶パネルにおいては、ＴiＯ₂の膜厚を充分考慮すべきである。
【０１０６】
本発明者が繰り返し行った実験によれば、多重反射の影響も考慮し、最適膜厚としては４０〜６０Åにするとよい。
【０１０７】
（反射型カラー液晶表示装置について）
一方、反射型カラー液晶パネルにおいては、その使用構造上、かかる多重反射に対し留意する必要はなく、ＴiＯ₂の形成膜厚の自由度は比較的高いが、ＴiＯ₂膜自体の吸光による点灯光の損失を考慮すると、自ずからその形成できる膜厚も制約される。
【０１０８】
本発明者が繰り返し行った実験によれば、１００〜１０００Åにするとよい。
【０１０９】
次に本発明の液晶表示装置の構成を述べる。
【０１１０】
（例４）
図５に示す透過型のカラー液晶表示装置の断面概略図でもって説明する。
１６は走査側基板であり、１９は信号側基板であり、走査側基板１６によれば、（例３）に示すカラーフィルタを用いて、さらに平滑膜の上に前記一方電極である透明電極とポリイミド樹脂からなる配向膜とを順次積層し、他方の信号側基板１９ではガラス基板上にも前記他方電極である透明電極とポリイミド樹脂からなる配向膜とを順次積層している。
【０１１１】
そして、走査側基板１６と信号側基板１９とをシール剤１８（三井東圧化学製熱硬化性エポキシ樹脂）を介して貼り合わせるとともに、内部に液晶層１７（ツイスト角２５０±２０°のネマチック型液晶分子）を封入する。セルギャップは６.３μｍである。
【０１１２】
また、走査側基板１６と信号側基板１９の双方の外側にはヨウ素系偏光板１５を設ける。そして、蛍光管バックライト(導光板付き)である光源１４を液晶パネルの裏面側に配し、その照射光を液晶パネルに透過させてパネル表示面２０を点灯するＳＴＮ型単純マトリクス方式（電圧平均化法）の透過型カラー液晶パネルとなる。２１は光源１４の照射光および液晶パネルからの出射光である。
【０１１３】
上記構成の透過型カラー液晶表示装置において、カラーフィルタの内、最表層ＴiＯ₂の膜厚が２０Å、５０Å、７０Å、８０Åのガラス基板にて作製したもの、およびリファレンスとしてのディップ基板にて作製したものを使用して、５種類の透過型カラー液晶パネルを作製した。
【０１１４】
そして、各透過型カラー液晶パネルの対向基板間の付着強度の測定、次いでパネル点灯時のパネル表示面の輝度の測定を行ったところ、表５に示すような結果が得られた。
【０１１５】
付着強度は、パネルの一方を固定し、もう一方をプッシュプルゲージで押さえて（信号側基板のみ押さえる。走査側に比べて信号側基板は少し大きいので、はみ出た部分を押さえる）、対向基板間が剥離したときの圧力を測定する。
【０１１６】
パネル輝度はミノルタ社製のＣＳ１００で表示面の垂直方向の輝度を測定する。
【０１１７】
【表５】

【０１１８】
この表から明らかなように、ガラス基板と樹脂遮光膜パターン界面の密着性に優れ、また、樹脂遮光膜パターンの解像性に優れたＴiＯ₂最表層基板を使用することにより、対向基板間の付着強度およびパネル表示面の輝度が向上する。
【０１１９】
（例５）
図２で示すような、ソーダライムガラス基板１とアルカリイオンの拡散障壁としてのＳiＯ₂膜２の間に、反射性膜９としてＡｌ膜(膜厚１０００Å)を形成した構造を有するガラス基板（以下、反射膜付きディップ基板）の表面に、最表層膜としてＴiＯ₂膜３をスパッタ法を用いて形成した。なお、ＴiＯ₂の膜厚は５００Å、１０００Å、１５００Å、２０００Åの４とおりである。
【０１２０】
次に、リファレンスとしての反射膜付きディップ基板およびこれらのＴiＯ₂最表層基板を使用して、（例１）と同様の方法で樹脂遮光膜パターンの形成を行い、現像時のパターン幅の測定および熱硬化時の密着強度の測定を行った。
【０１２１】
そして、（例２）と同様の方法でカラーフィルタの作製を行い、その可視光領域(４００nｍ〜７００nｍ)の平均反射率比（対ＭＧＯ標準白色板 点光源−２５°受光０°)の測定を行った。測定機にはＹＯＫＯＧＡＷＡ色彩計を、光源にはリング型ハロゲンランプ（Ｃ光源）を用いた。
これらの測定結果を表６および表７に示す。
【０１２２】
【表６】

【０１２３】
【表７】

【０１２４】
表６および表７から明らかなように、ＴiＯ₂最表層基板を使用することにより、実施例１と同様、樹脂遮光膜パターンの現像性および密着性、およびカラーフィルタの反射率に優れた効果が得られる。ただし、ＴiＯ₂膜厚２０００Åについては、反射膜付きディップ基板と同程度の反射率となった。これは、樹脂遮光膜パターンの解像性向上の効果とＴiＯ₂膜の吸光による照射光の損失が相殺されたものと考えられる。
【０１２５】
（例６）
図６に示す反射型のカラー液晶表示装置の断面概略図である。
【０１２６】
１６は走査側基板であり、１９は信号側基板であり、走査側基板１６によれば、（例５）に示すカラーフィルタを用いて、さらに平滑膜の上に前記一方電極である透明電極とポリイミド樹脂からなる配向膜とを順次積層し、他方の信号側基板１９ではガラス基板上にも前記他方電極である透明電極とポリイミド樹脂からなる配向膜とを順次積層している。
【０１２７】
そして、走査側基板１６と信号側基板１９とをシール剤１８（三井東圧化学製熱硬化性エポキシ樹脂）を介して貼り合わせるとともに、内部に液晶層１７（ツイスト角２５０±２０°のネマチック型液晶分子）を封入する。セルギャップは６.２μｍである。また、信号側基板１９の外側にはヨウ素系偏光板１５を設ける。 このようにしてパネル表示面２０を点灯するＳＴＮ型単純マトリクス方式（電圧平均化法）の反射型カラー液晶パネルとなる。２１は光源１４の入射光および液晶パネルからの出射光である。
【０１２８】
（例５）で作製したカラーフィルタの内、最表層ＴiＯ₂の膜厚が５００Å、１０００Å、１５００Åのガラス基板にて作製したもの、およびリファレンスとしての反射膜付きディップ基板にて作製したものを使用して、反射型カラー液晶パネルの作製を行った。
【０１２９】
次に、完成した反射型カラー液晶パネルの対向基板間の付着強度の測定、次いでパネル点灯時の可視光領域(４００nｍ〜７００nｍ)の平均反射率比（対ＭＧＯ標準白色板 点光源−２５°受光０°）の測定を行った。その測定結果を表８に示す。
【０１３０】
【表８】

【０１３１】
この表から明らかなように、ガラス基板と樹脂遮光膜パターン界面の密着性に優れ、また樹脂遮光膜パターンの解像性に優れたＴiＯ₂最表層基板を使用することにより、対向基板間の付着強度および、パネル表示面の輝度が向上する。
【０１３２】
（例７）
ソーダライムガラス基板上に、ＴiＯ₂膜とＳiＯ₂膜を交互に多重積層させて誘電体多層膜を形成した（以後、誘電体多層膜基板）。
【０１３３】
そして、その誘電体多層膜の最表層がＴiＯ₂のものとＳiＯ₂のものの２種類作製し、それぞれの基板の透過率と反射率の比が共に５０：５０となるように各層の膜厚の設定を行った。ただし、最表層膜の膜厚はＴiＯ₂、ＳiＯ₂共に１００Åとし、双方とも、各層の総数は６層にした。
【０１３４】
次に、これら２種類の誘電体多層膜基板を使用して、（例１）と同様の方法で樹脂遮光膜パターンの形成を行い、現像時のパターン幅の測定および熱硬化時の密着強度の測定を行った。
【０１３５】
次いで、（例１）と同様の方法でカラーフィルタの作製を行い、その可視光領域(４００nｍ〜７００nｍ) の平均透過率および平均反射率比(対ＭＧＯ標準白色板 点光源−２５°受光０°)の測定を行った。これらの測定結果を表９および表１０に示す。
【０１３６】
【表９】

【０１３７】
【表１０】

【０１３８】
表９および表１０から明らかなように、ＴiＯ₂最表層基板を使用することにより、（例１）と同様に、樹脂遮光膜パターンの現像性および密着強度、およびカラーフィルタの透過率および反射率に優れた効果が得られる。
【０１３９】
（例８）
（例７）で作製した２種類のカラーフィルタを使用して、半透過型カラー液晶パネルの作製を行った。その構成は図５に示すとおりである。
【０１４０】
そして、半透過型カラー液晶パネルの対向基板間の付着強度の測定、次いでパネル点灯時の可視光領域(４００nｍ〜７００nｍ)の平均透過率および平均反射率比(対ＭＧＯ標準白色板 点光源−２５°受光０°)の測定を行った。その測定結果を表１１に示す。
【０１４１】
【表１１】

【０１４２】
この表から明らかなように、ガラス基板と樹脂遮光膜パターンの界面の密着性に優れ、また樹脂遮光膜パターンの解像性に優れたＴiＯ₂最表層基板を使用することにより、対向基板間の付着強度および、パネル表示面の輝度が向上する。
【０１４３】
以上のとおり、多重反射による表示面の点灯光の損失を嫌う透過型カラー液晶パネルにおいては、ガラス基板表面のＴiＯ₂の膜厚を２０〜８０Å、好適には４０〜６０Å程度にするとよく、反射型カラー液晶パネルでは、ＴiＯ₂の膜厚を２０〜１５００Å、好適には１００〜１０００Åの範囲に設定するとよい。
【０１４４】
なお、本発明は上記の実施形態例に限定されるものではなく、本発明の要旨を逸脱しない範囲内で種々の変更や改良等はなんら差し支えない。
【０１４５】
たとえば、透明ガラス基板としてＳiＯ₂ディップコート付きソーダライムガラス基板を使用したが、これに代えて、ホウケイ酸ガラス等の無アルカリガラスの基板であっても、その表面にＴiＯ₂膜を被覆し、最表層とすることにより、同様の効果が得られる。このホウケイ酸ガラスの屈折率は１.５４であり、ＳiＯ₂とほぼ同等であるので、上記多重反射防止の好適範囲である２０〜８０Åはそのまま適用できる。
【０１４６】
また、最表層がＴiＯ₂膜であればよく、その下層の構成材は合成樹脂など他の材料でもよい。
【０１４７】
【発明の効果】
以上のとおり、本発明によれば、基板と、基板上に設けられたＴｉＯ_２膜と、ＴｉＯ_２膜上に設けられた樹脂遮光膜と、樹脂遮光膜の非被着面におけるＴｉＯ_２膜上に設けられた着色膜と、を備え、ＴｉＯ_２膜は、その厚みが、２０〜８０Åであり、樹脂遮光膜のＴｉＯ _２ 膜に対する密着強度が３０．２〜４１．３ｋｇｆ／ｃｍ ^２ であるので、樹脂遮光膜の界面の密着性が向上し、これにより、光硬化性樹脂遮光膜を露光、現像してパターンを形成する場合、樹脂遮光膜の剥離が生じにくくなるので、非露光部と通常露光部との現像液の溶解性に対するコントラストがつき易くなり、現像ラチチュードが拡大され、その結果、たとえば現像液の濃度や温度等、現像状態を左右する因子によるバラツキの影響が緩和されるので、量産時の現像性が安定し、その製造歩留まりが向上する。
【０１４８】
また、露光して現像する際、樹脂遮光膜パターンが剥離されにくく、より長時間現像液に浸漬させることができるので、非露光部への露光照射光の回折現象により感光された過剰露光部と通常露光部との現像液の溶解性に対するコントラストもつき易くなり、選択的に過剰露光部の樹脂遮光膜を除去し易くなるので、フォトマスクの設計幅に近い、より解像性の優れた樹脂遮光膜パターンの形成ができる。この場合、カラーフィルタの開口率が向上し、表示面の点灯光の損失が低減されるので、より高輝度の、あるいは同じ輝度であってもより低消費電力のカラー液晶パネルの作製ができる。
【０１４９】
さらに、これらガラス基板と樹脂遮光膜の界面の密着性に優れたカラーフィルタを使用して、カラー液晶パネルを作製した場合、対向基板間の付着強度が向上するので、カラー液晶パネルの組立あるいは使用等で生じる負荷に対する耐久性が向上され、より高信頼性のカラー液晶パネルの作製ができ、また、その製造歩留まりも向上する。
【図面の簡単な説明】
【図１】本発明のカラーフィルタの概略断面図である。
【図２】本発明の他のカラーフィルタの概略断面図である。
【図３】顔料分散法により形成したカラーフィルタの断面図である。
【図４】Ａ、Ｂ、Ｃは遮光膜のパターニング方法を示す工程図である。
【図５】透過型のカラー液晶表示装置の断面概略図である。
【図６】反射型のカラー液晶表示装置の断面概略図である。
【図７】Ａ、Ｂは光硬化性樹脂遮光膜のパターンを作成する工程図である。
【図８】カラー液晶表示装置の断面概略図である。
【図９】ＴiＯ₂の膜厚と平均反射率との関係を示す線図である。
【符号の説明】
１・・・ソーダライムガラス基板
２・・・ＳiＯ₂膜
３・・・ＴiＯ₂膜
４・・・樹脂遮光膜パターン
８・・・平滑化膜
１０・・・透明ガラス基板
１１・・・光硬化性樹脂遮光膜
１３・・・フォトマスク
１２・・・露光照射光
２２・・・露光照射光の回折[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color filter used in various display devices, and further relates to a manufacturing method thereof. The present invention also relates to a liquid crystal display device for color liquid crystal display using such a color filter.
[0002]
[Prior art]
A color filter used for a color liquid crystal panel or the like is a fine filter in which a plurality of minute colored films are regularly arranged at a predetermined pitch on a transparent glass substrate. As the material of the transparent glass substrate, alkali glass such as soda lime glass or alkali-free glass such as borosilicate glass is usually used.
[0003]
When a transparent substrate made of alkali glass is used, in order to prevent diffusion of alkali ions contained in the glass substrate, SiO 2 is usually formed on the surface of the glass substrate.₂The membrane is covered.
[0004]
This SiO₂TiO instead of membrane₂Metal oxide film such as SiO₂A technique for forming an extremely thin film as compared with a film has been proposed (see Japanese Patent Laid-Open No. Hei 8-190088).₂A conductive metal oxide film such as ITO is formed directly on the film.
[0005]
In recent years, color filters have been used in various display devices.
According to this color filter, a colored film is formed on a glass substrate. Today, three primary colors of red (Red), green (Green), and blue (Blue), or yellow (Yellow), magenta (Magenta), and cyan are used. A complementary color such as (Cyan) is used. Furthermore, a light-shielding film is formed between the colored films to prevent a decrease in color purity and contrast.
[0006]
A pigment dispersion method is well known as a method for patterning the colored film and the light shielding film into a predetermined shape.
[0007]
That is, a technique for forming a pattern by applying a thin film of a photocurable resin in which a colorant such as pigment or carbon or a light-shielding agent is dispersed, followed by exposure, development, and thermal curing. This is the most common method.
[0008]
This pigment dispersion method will be described with reference to FIGS.
FIG. 3 shows a cross-sectional structure of a color filter formed by a pigment dispersion method. FIG. 4 shows a patterning method of the light shielding film.
[0009]
According to FIG. 3, reference numeral 10 denotes a transparent glass substrate. On the transparent glass substrate 10, a light shielding film pattern 4 and a pattern of a red coloring film 5, a green coloring film 6, and a blue coloring film 7 are formed.
[0010]
According to the patterning method shown in FIG. 4, the light shielding film pattern 4 is formed of a resin, and steps A, B, and C are sequentially shown.
[0011]
According to the first step A, the photocurable resin light-shielding film 11 is applied and formed on the transparent glass substrate 10.
[0012]
In the next step B, the photo-curing resin light-shielding film 11 is partially exposed by using the photomask 13 to pass the exposure irradiation light 12 in a predetermined pattern shape.
[0013]
Then, in the step C, the resin light-shielding film pattern 4 is formed by developing and thermosetting.
[0014]
Through these steps, a colored film is subsequently formed by a pigment dispersion method to obtain a color filter.
[0015]
[Problems to be solved by the invention]
According to the light-shielding film pattern as described above, both the color purity of the color filter and the decrease in contrast are prevented and the aperture ratio is determined, which has a great influence on the display characteristics of the color liquid crystal panel. .
[0016]
In other words, by using a light-shielding film pattern close to the design width of the photomask, a color filter with excellent resolution can be obtained. However, such a light-shielding film pattern has a high aperture ratio and a loss of lighting light on the display surface. As a result, a higher-brightness color liquid crystal panel can be obtained. Further, a color liquid crystal panel with lower power consumption can be obtained even with the same luminance.
[0017]
However, when the light shielding film pattern is formed of resin, it is difficult to obtain a light shielding film pattern close to the design width of the photomask.
[0018]
This problem will be described with reference to FIG.
FIG. 3A shows an exposure process, and FIG. 3B shows a cross-sectional structure after subsequent development and thermal curing.
[0019]
When the photocurable resin light-shielding film 11 as described above is used, due to the characteristics as the light-shielding film, it is less sensitive to light than the photocurable resin colored film forming the colored film pattern, and therefore, as shown in FIG. More exposure light 12 is required, and therefore, the exposure light is easily affected by the diffraction 22 of the exposure light on the non-exposed portion of the photomask 13.
[0020]
As a result, as shown in FIG. 7B, the pattern width 26 of the resin light-shielding film was larger than the design width 25 of the photomask 13.
[0021]
In order to prevent the diffraction of the exposure light, it is easiest to perform exposure by narrowing the gap between the photomask 13 and the glass substrate 10.
[0022]
However, considering prevention of damage to the photomask 13 due to contact with the glass substrate 10, there is a limit to the narrow gap.
[0023]
On the other hand, as the most general method, a method is adopted in which the width of the resin light-shielding film pattern is considered in advance and the photomask design width is narrower than the set width.
[0024]
In other words, the actual finished resin light-shielding film pattern is thicker by about μm than the photomask design width. Therefore, if the light-shielding film material, exposure and development conditions are the same, the width of the thickening is almost the same each time. Therefore, a method of correcting the design width of the photomask in consideration of the thickness is adopted in advance.
[0025]
However, since the overexposed portion exposed by the diffraction of the exposure light is not sufficiently exposed and developability is not stable, there is a problem that the pattern width of the resin light-shielding film tends to vary.
[0026]
In addition, the width of the resin light-shielding film pattern varies depending on the type of exposure machine used and the type of photo-curable resin light-shielding film. If these conditions change, the design width of the photomask and the width of the resin light-shielding film pattern And a photomask needs to be manufactured again.
[0027]
The pattern thickening of the resin light-shielding film due to the diffraction of the exposure light can be brought closer to the design width of the photomask to some extent by increasing the development time.
[0028]
That is, as shown in FIG. 7, in the photocurable resin light-shielding film 11, the overexposed portion 24 exposed by the diffraction 22 of the exposure irradiation light to the non-exposed portion is not sufficiently exposed, and the normal exposure portion Therefore, the resin light-shielding film pattern width 26 is made closer to the photomask design width 25 by selectively removing the excess resin light-shielding film in the overexposed portion 24 due to the difference in solubility. be able to.
[0029]
However, as described above, the photocurable resin light-shielding film is not easily exposed to light, and the tendency is particularly prominent in the vicinity of the interface between the resin light-shielding film and the glass substrate where the exposure light is difficult to reach.
[0030]
In addition, an inorganic material such as a glass substrate and an organic material such as a resin light-shielding film inherently have low adhesion to each other. It was easy.
[0031]
Therefore, the contrast of the solubility in the developing solution between the normal exposure portion and the overexposed portion is difficult to achieve, and it is extremely difficult to make the resin light-shielding film pattern width completely the same as the photomask design width.
[0032]
Even if the resin light-shielding film pattern width can be made the same as the photomask design width, the development latitude is very small, so that pattern peeling is likely to occur when developing the resin light-shielding film pattern, and the manufacturing yield is reduced. Become.
[0033]
To further describe this point, there is an appropriate time for the immersion in the developer, and if the immersion time in the developer is too short, a development residue is generated and there is a place to be removed, whereas if it is too long, the pattern is reversed. Peeling occurs and the area to be left is removed, but the development latitude is an index that indicates how much time is available, in other words, the dissolution of the exposed and unexposed areas in the developer. It can be said that the development latitude is wide when the contrast of the property increases.
[0034]
Therefore, when the width of the appropriate time is widened, it is easier to develop, and as a result, the manufacturing yield is improved.However, in the above example, not only the non-exposed part but also the pattern to the overexposed part is to be removed. The development latitude is extremely narrow.
[0035]
In particular, this tendency is remarkable in recent years when the design width of the photomask for forming the resin light-shielding film pattern tends to be thinned in order to increase the luminance of the display device.
[0036]
Furthermore, when a color filter in which a resin light-shielding film pattern is formed is used in a color liquid crystal display device, there are the following problems.
[0037]
This problem will be described with reference to a schematic cross-sectional view of the color liquid crystal display device shown in FIG.
[0038]
Reference numeral 16 denotes a scanning side substrate, and 19 denotes a signal side substrate. According to the scanning side substrate 16, the resin light-shielding film pattern 4 is formed on the glass substrate constituting the substrate, and a colored film is formed therebetween. The smooth film 8 is coated on these, and the transparent electrode 28 and the alignment film 29 made of polyimide resin are sequentially laminated on the smooth film 8.
[0039]
A transparent electrode 28 and an alignment film 29 made of polyimide resin are sequentially laminated on the glass substrate of the signal side substrate 19.
[0040]
Then, the scanning side substrate 16 and the signal side substrate 19 are bonded together with a sealant 18, and the liquid crystal layer 17 is sealed inside.
[0041]
According to the color liquid crystal display device configured as described above, for the purpose of preventing light leakage from the frame area on the display surface, the resin light shielding film pattern 4 is usually formed and simultaneously extended to form the outer peripheral dummy portion 27. .
[0042]
However, there is a problem in that the adhesion strength between the opposing substrates is lowered due to the fact that the outer peripheral dummy portion 27 is provided just below the sealing agent 18 and the adhesion at the interface between the glass substrate and the resin light-shielding film is low. .
[0043]
That is, when a load is generated by assembling or using the color liquid crystal panel, peeling from the interface occurs, thereby reducing the manufacturing yield and the durability of the color liquid crystal panel.
[0044]
In order to solve such a problem, a technique has been proposed in which the resin light-shielding film pattern of the color filter is coated with an inorganic binder or an organic binder to prevent the pattern separation of the resin light-shielding film (Japanese Patent Laid-Open No. 8-262219). Issue).
[0045]
However, according to this proposal, problems relating to the formation of the resin light-shielding film pattern, such as the manufacturing yield and resolution improvement of the resin light-shielding film pattern, cannot be solved.
[0046]
Therefore, the object of the present invention has been completed in view of the above description, and the object is to provide a highly reliable color filter in which a resin light-shielding film pattern is formed on a substrate and having improved adhesion between the substrate and the resin light-shielding film. Another object of the present invention is to provide a high-luminance color filter and a method for manufacturing the same.
[0047]
Another object of the present invention is to provide a liquid crystal display device that achieves high quality and long-term reliability using such a color filter.
[0048]
[Means for Solving the Problems]
  The color filter of the present invention includes a substrate and TiO provided on the substrate.₂A film and the TiO₂A resin light-shielding film provided on the film, and the TiO on the non-adhering surface of the resin light-shielding film₂A colored film provided on the film, the TiO₂The membrane has a thickness of 20-80 mmThe TiO of the resin light shielding film ₂ Adhesion strength to membrane is 30.2 to 41.3 kgf / cm ² IsIt is characterized by that.
[0051]
  The liquid crystal display device of the present invention has one electrode and an alignment film on the color filter of the present invention.ShapeThe other electrode and the alignment filmShapeOpposite the other substrate, and both,It is arranged via a liquid crystal layer.
[0052]
DETAILED DESCRIPTION OF THE INVENTION
As a result of intensive research conducted by the present inventor, TiO 2 was formed on a glass substrate.₂When the film is coated, if a resin light-shielding film is formed on this film, TiO₂It has been confirmed by experiments conducted by the present inventors that the adhesion at the interface between the film and the resin light-shielding film is improved.
[0053]
Such an effect has not yet been fully elucidated and cannot be deducted from the reasoning, but it is thought to be due to the following reasons.
[0054]
That is, a metal oxide such as titanium has a higher surface roughness at the molecular level than non-metal oxides such as silicon and boron, and adhesion is enhanced by the action of the anchor effect.
[0055]
The inventor conducted an experiment to prove this reason.
TiO on soda lime substrate₂Film or SiO₂Films were formed by sputtering with film thicknesses of 400 mm and 1000 mm, and the surface roughness (arithmetic average roughness Ra) of these films was measured. The results shown in Table 1 were obtained.
[0056]
The surface roughness was measured by a tapping mode, which is a method of periodically bringing a surface sample into contact with a probe using an AFM analyzer (AFM-DI-D3000 manufactured by Digital Instruments). For this measurement, measurement was performed with a probe Si probe and a visual field of 2 × 2 μm.
[0057]
[Table 1]

[0058]
As is clear from the table, TiO₂The surface roughness of the film is SiO₂It is more than twice that of the film, and it is considered that the adhesion is increased by the action of the anchor effect.
[0059]
More preferably, such TiO₂The film may be irradiated with ultraviolet rays, and the adhesiveness at the interface with the resin light-shielding film can be improved also through such a process.
[0060]
The reason is as follows.
TiO₂Such a semiconductor material is photoexcited by irradiation with UV light or the like, and has a photocatalytic action of decomposing and removing organic impurities adsorbed on the surface by the action of active electrons and holes generated at that time. Therefore, when the resin light-shielding film is formed in a state where organic impurities are attached to the surface of the glass substrate, the adhesion to the glass substrate is remarkably hindered. However, as in the present invention, TiO is deposited on the glass substrate.₂Immediately before forming the film and applying the photo-curing resin light-shielding film, the glass substrate is pre-treated with UV to remove these organic impurities and reduce the adhesion at the interface between the glass substrate and the resin light-shielding film. Can be prevented. For example, UV light having peaks at 186 nm and 254 nm is irradiated for about 2 minutes.
[0061]
TiO as above₂The film is polycrystalline, it is the main component, and may contain other amorphous components.
[0062]
Next, the present invention will be illustrated and described in detail.
[0063]
(Example 1)
FIG. 1 shows a schematic cross-sectional structure of a color filter. On a soda lime glass substrate 1, SiO as a diffusion barrier for alkali ions is shown.₂The film 2 is dip coated. Such a substrate is hereinafter referred to as a dip substrate.
[0064]
TiO on this dip substrate₂The film 3 was formed by sputtering. This TiO₂The film 3 has six thicknesses of 10 mm, 20 mm, 50 mm, 70 mm, 80 mm, and 90 mm.
[0065]
Next, these TiO₂A photocurable resin light-shielding film was formed on each of the substrates having the outermost layer, and exposure and then development were performed. Then, by changing the time of immersion in the developer from 50 seconds to 120 seconds, various test samples were prepared, and the adhesiveness (peeled state) of the photocurable resin light-shielding film was examined for these, Results as shown in Table 2 were obtained.
[0066]
As a comparative example, on a dip substrate (in Table 2, SiO 2₂The same resin light-shielding film was formed and measured in the same manner.
[0067]
In this experiment, it was produced and evaluated under the following conditions.
[0068]
Photocurable resin light-shielding film;This is a polyester resin and uses CFPR black resist manufactured by Tokyo Ohka Kogyo. Carbon is used as the light shielding agent.
[0069]
Exposure conditions
Exposure machine: Hitachi Electronics Engineering Projection Exposure Machine
Photomask; Design width 10μm
Exposure amount: 500mj / cm²(Illuminance 35mW / cm²)
Exposure gap: 100 μm
Development conditions
Development method: Dip development
Developer: Tokyo Ohka Kogyo inorganic alkali developer
Rinse; ultrapure water washing (water washing pressure 1.0 kgf / cm²)
Evaluation methods
The peeling state of the resin light-shielding film is confirmed by visual observation using a metal microscope with a length measuring device.
[0070]
[Table 2]

[0071]
In the same table, undeveloped residue is a phenomenon in which development is insufficient and parts that should be removed by development remain without being removed, and peeling is an excessive development. In other words, the portion that should remain as a pattern is peeled off and lost. The numerical values other than the notation of development residue and peeling are measured values of the resin light-shielding film pattern width.
[0072]
As is clear from this table, TiO on the dip substrate.₂By forming a film as the outermost layer, pattern peeling during development of the resin light-shielding film is less likely to occur. In addition, a film close to the design width (10 μm) of the photomask can be formed, and a resin light-shielding film pattern with better resolution can be formed.
[0073]
For example, if the conforming standard of the resin light-shielding film pattern width is 10.0 ± 1.0 μm, the dip substrate can clear the standard only in the developing solution immersion time of 70 seconds.₂The coated substrate has a development latitude for the standard of approximately 30 seconds (immersion time of 80 to 110 seconds).
[0074]
However, in this example, TiO₂When the film thickness was very thin, such as 10 mm, no effect of improving the developability was observed.
[0075]
(Example 2)
Next, in each sample prepared in (Example 1), on the dip substrate (in Table 2, SiO 2₂And TiO)₂For a 10 mm thick substrate sample, the developer immersion time was set to 70 seconds. TiO₂About each sample of a 20 to 90-thickness board | substrate, the developing solution immersion time was set to 90 second, these each sample was heated on a 240 degreeC hotplate, and the resin light-shielding film pattern was thermosetted.
[0076]
Next, when the adhesion strength of these heat-cured resin light-shielding film patterns was measured, the results shown in Table 3 were obtained.
[0077]
[Table 3]

[0078]
As is clear from this table, TiO on the dip substrate.₂It can be seen that the adhesion strength of the heat-cured resin light-shielding film pattern was improved by forming a film and forming the outermost layer.
[0079]
However, TiO₂The smaller the film thickness, the lower the adhesion strength and the TiO₂For the sample having a thickness of 10 mm, the adhesion strength was the same as when the resin light-shielding film pattern was directly formed on the dip substrate.
[0080]
This adhesion strength is measured as follows.
Pins are attached to the substrate and jig on which the resin light-shielding film has been coated and baked as described above, and set in a measuring instrument for measurement. The measuring instrument is a small table tester (model: TZ-TEST SERIES MODEL TEST / CE) manufactured by Shimadzu Corporation.
[0081]
(Example 3)
In this example, a color filter was produced from each of the above samples and evaluated.
[0082]
In this example, the manufacturing method will be described. The following steps A to E are sequentially performed, and TiO is formed on the glass substrate.₂A film and a resin light-shielding film pattern are sequentially formed.
[0083]
Process A:
As shown in FIG. 1 in (Example 1), TiO 2 was sputtered or vacuum deposited on a glass substrate (dip substrate).₂Cover with membrane 3.
[0084]
Process B:
As described in Example 1, TiO₂A photocurable resin film to which a light-shielding colorant is added is applied on the film 3. This step corresponds to FIG. 4A.
[0085]
Process C:
Further, as described in (Example 1), a predetermined region of the photocurable resin film is exposed using a photomask. This step corresponds to FIG. 4B.
[0086]
D process:
Then, it develops with respect to a photocurable resin film, and removes a part.
[0087]
E process:
The remaining photocurable resin film is thermally cured.
[0088]
These steps D and E correspond to FIG. 4C.
[0089]
Next, a color film of the present invention as shown in FIG. 1 is obtained by forming a colored film in the gap between the resin light-shielding film patterns.
[0090]
The colored film can be formed by a conventionally known technique, for example, a pigment dispersion method or a dyeing method.
[0091]
In this example, for each of the seven types of samples described above, a photosensitive resist prepared in advance with a pigment is applied on a substrate, and by photolithography, each of a red coloring pixel 5, then a green coloring pixel 6, and then a blue coloring. Pixel 7 was formed and used as a color filter.
[0092]
A smoothing film 8 made of an acrylic resin is formed on these colored films in order to flatten the surface, but it may not be formed.
[0093]
And when the average transmittance | permeability of visible region (400 nm-700 nm) was measured with respect to each color filter using the spectrometer, the result as shown in Table 4 was obtained.
[0094]
The spectrophotometer was TOPCON SR-1, and the viewing angle was set to 2.0 degrees with a C light source.
[0095]
[Table 4]

[0096]
As is apparent from this table, TiO of 20 mm or more excellent in the resolution of the resin light-shielding film pattern.₂By using the outermost substrate, the transmittance of the color filter is improved.
[0097]
From the evaluation results shown in the above (Example 1) to (Example 3), in the present invention, TiO deposited on the glass substrate is used.₂The thickness of the film should be over 10 mm.
[0098]
However, TiO₂When the film thickness is increased, the effect is reduced due to the influence of multiple reflection. TiO₂At a film thickness of 90 mm, the effect of improving the resolution of the resin light-shielding film pattern was offset by the loss of lighting light due to multiple reflection, and the transmittance was almost the same as that of the dip substrate.
[0099]
To further describe the above multiple reflection, TiO₂When the thin film is formed on a soda-lime glass substrate, a part of incident light is reflected at the interface in accordance with Snell's law due to the difference in the refractive index of light, thereby reducing the transmittance.
[0100]
It is known that the reflectivity in multiple reflection depends on the refractive index and film thickness of each constituent layer. Here, TiO₂Refractive index (2.50) and SiO, the main component of soda lime glass₂The refractive index of 1.52 is a constant, and the thickness of the soda lime glass substrate is TiO₂TiO is thick enough compared to the membrane₂The film thickness is the only factor that determines the reflectivity.
[0101]
FIG. 9 shows TiO formed on a soda-lime glass substrate.₂And the average reflectance of visible light (400 nm to 700 nm) on the surface thereof. In addition, the figure is a theoretical value and the reflected light from the glass substrate back surface is not included.
[0102]
As is clear from FIG. 9, TiO on the soda lime glass substrate.₂When forming a film, TiO₂It can be seen that the influence of multiple reflection is further reduced as the film thickness is reduced.
[0103]
Next, the relationship between the multiple reflection and the liquid crystal display device will be described.
[0104]
(Transmission type color liquid crystal display)
This multiple reflection phenomenon causes a loss of lighting light on the display surface in a transmissive color liquid crystal panel having a structure in which the light emitted from the light source is transmitted through the liquid crystal panel and the display surface is turned on. Therefore, it is important to reduce the loss of lighting light due to multiple reflections to a level that can be ignored in terms of display characteristics.
[0105]
However, TiO₂Since there is a limit to the reduction in film thickness and it is necessary to consider the original purpose of improving the adhesion to the resin light-shielding film, in a transmissive color liquid crystal panel that dislikes the loss of lighting light due to multiple reflection, TiO₂The thickness of the film should be fully considered.
[0106]
According to experiments repeatedly conducted by the present inventor, the optimum film thickness is preferably 40 to 60 mm in consideration of the influence of multiple reflection.
[0107]
(Reflective color liquid crystal display device)
On the other hand, in a reflective color liquid crystal panel, there is no need to pay attention to such multiple reflection because of its use structure.₂Although the degree of freedom of the film thickness is relatively high, TiO₂Considering the loss of lighting light due to the absorption of the film itself, the film thickness that can be formed by itself is also limited.
[0108]
According to experiments conducted repeatedly by the present inventor, it is preferable that the thickness be 100 to 1000 mm.
[0109]
Next, the configuration of the liquid crystal display device of the present invention will be described.
[0110]
(Example 4)
The transmissive color liquid crystal display device shown in FIG.
Reference numeral 16 denotes a scanning side substrate, 19 denotes a signal side substrate, and according to the scanning side substrate 16, the color filter shown in (Example 3) is used, and the transparent electrode that is the one electrode is further formed on the smooth film. An alignment film made of polyimide resin is sequentially laminated, and on the other signal side substrate 19, a transparent electrode as the other electrode and an alignment film made of polyimide resin are sequentially laminated also on the glass substrate.
[0111]
Then, the scanning side substrate 16 and the signal side substrate 19 are bonded to each other via a sealant 18 (a thermosetting epoxy resin manufactured by Mitsui Toatsu Chemicals), and a liquid crystal layer 17 (a nematic type having a twist angle of 250 ± 20 °) is provided therein. Encapsulate liquid crystal molecules). The cell gap is 6.3 μm.
[0112]
Further, an iodine polarizing plate 15 is provided outside both the scanning side substrate 16 and the signal side substrate 19. A light source 14 that is a fluorescent tube backlight (with a light guide plate) is disposed on the back side of the liquid crystal panel, and the STN type simple matrix system (voltage average) that illuminates the panel display surface 20 by transmitting the irradiation light to the liquid crystal panel. Transmissive color liquid crystal panel. Reference numeral 21 denotes light emitted from the light source 14 and light emitted from the liquid crystal panel.
[0113]
In the transmissive color liquid crystal display device having the above configuration, the outermost layer TiO of the color filters.₂Five types of transmissive color liquid crystal panels were prepared using a glass substrate having a thickness of 20 mm, 50 mm, 70 mm, and 80 mm and a glass substrate having a dip substrate as a reference.
[0114]
Then, when the adhesion strength between the opposing substrates of each transmissive color liquid crystal panel was measured, and then the brightness of the panel display surface when the panel was turned on, the results shown in Table 5 were obtained.
[0115]
Adhesion strength is fixed between one panel and the other with a push-pull gauge (press only the signal side substrate. The signal side substrate is slightly larger than the scanning side, so the protruding part is pressed). Measure the pressure when the peels.
[0116]
The panel brightness is measured in the vertical direction on the display surface with CS100 manufactured by Minolta.
[0117]
[Table 5]

[0118]
As is apparent from this table, TiO excellent in the adhesion between the glass substrate and the resin light-shielding film pattern interface and excellent in the resolution of the resin light-shielding film pattern.₂By using the outermost substrate, the adhesion strength between the opposing substrates and the brightness of the panel display surface are improved.
[0119]
(Example 5)
As shown in FIG. 2, soda lime glass substrate 1 and SiO as a diffusion barrier for alkali ions.₂On the surface of a glass substrate (hereinafter referred to as a dip substrate with a reflective film) having an Al film (thickness: 1000 mm) formed as a reflective film 9 between the films 2, TiO as the outermost layer film is formed.₂The film 3 was formed using a sputtering method. TiO₂There are four types of film thickness of 500 mm, 1000 mm, 1500 mm, and 2000 mm.
[0120]
Next, a dip substrate with a reflective film as a reference and these TiO substrates₂Using the outermost layer substrate, a resin light-shielding film pattern was formed in the same manner as in (Example 1), and the pattern width during development and the adhesion strength during thermosetting were measured.
[0121]
Then, a color filter is prepared in the same manner as in (Example 2), and the average reflectance ratio in the visible light region (400 nm to 700 nm) (vs. MGO standard white plate, point light source—25 ° light reception 0 °) is measured. went. A YOKOGAWA colorimeter was used as the measuring instrument, and a ring-type halogen lamp (C light source) was used as the light source.
These measurement results are shown in Tables 6 and 7.
[0122]
[Table 6]

[0123]
[Table 7]

[0124]
As is clear from Tables 6 and 7, TiO₂By using the outermost layer substrate, as in Example 1, it is possible to obtain an effect excellent in the developability and adhesion of the resin light-shielding film pattern and the reflectance of the color filter. However, TiO₂With a film thickness of 2000 mm, the reflectance was comparable to that of the dip substrate with a reflective film. This is because the effect of improving the resolution of the resin light-shielding film pattern and TiO₂It is thought that the loss of irradiation light due to the absorption of the film was offset.
[0125]
(Example 6)
FIG. 7 is a schematic cross-sectional view of the reflective color liquid crystal display device shown in FIG. 6.
[0126]
16 is a scanning side substrate, 19 is a signal side substrate, and according to the scanning side substrate 16, the transparent electrode that is the one electrode is further formed on the smooth film by using the color filter shown in (Example 5). An alignment film made of polyimide resin is sequentially laminated, and on the other signal side substrate 19, a transparent electrode as the other electrode and an alignment film made of polyimide resin are sequentially laminated also on the glass substrate.
[0127]
Then, the scanning side substrate 16 and the signal side substrate 19 are bonded to each other via a sealant 18 (a thermosetting epoxy resin manufactured by Mitsui Toatsu Chemicals), and a liquid crystal layer 17 (a nematic type having a twist angle of 250 ± 20 °) is provided therein. Encapsulate liquid crystal molecules). The cell gap is 6.2 μm. Further, an iodine polarizing plate 15 is provided outside the signal side substrate 19. In this way, the reflective color liquid crystal panel of the STN type simple matrix system (voltage averaging method) for lighting the panel display surface 20 is obtained. Reference numeral 21 denotes incident light from the light source 14 and outgoing light from the liquid crystal panel.
[0128]
Of the color filters produced in Example 5, the outermost layer TiO₂A reflective color liquid crystal panel was prepared using a glass substrate having a thickness of 500 mm, 1000 mm, and 1500 mm and a dip substrate with a reflective film as a reference.
[0129]
Next, measurement of the adhesion strength between the opposing substrates of the completed reflective color liquid crystal panel, and then the average reflectance ratio in the visible light region (400 nm to 700 nm) when the panel is lit (vs. MGO standard white plate, point light source-25 ° light reception) 0 °) was measured. The measurement results are shown in Table 8.
[0130]
[Table 8]

[0131]
As is apparent from this table, TiO has excellent adhesion between the glass substrate and the resin light-shielding film pattern interface, and has excellent resolution of the resin light-shielding film pattern.₂By using the outermost substrate, the adhesion strength between the opposing substrates and the brightness of the panel display surface are improved.
[0132]
(Example 7)
TiO on a soda lime glass substrate₂Membrane and SiO₂A dielectric multilayer film was formed by alternately laminating films (hereinafter referred to as a dielectric multilayer film substrate).
[0133]
The outermost layer of the dielectric multilayer film is TiO₂And SiO₂The thickness of each layer was set so that the ratio between the transmittance and the reflectance of each substrate was 50:50. However, the film thickness of the outermost layer film is TiO₂, SiO₂Both were 100 mm, and the total number of each layer was 6 layers.
[0134]
Next, using these two types of dielectric multilayer substrates, a resin light-shielding film pattern is formed in the same manner as in Example 1, and the pattern width is measured during development and the adhesion strength during thermosetting is measured. Measurements were made.
[0135]
Next, a color filter was prepared in the same manner as in (Example 1), and the average transmittance and average reflectance ratio of the visible light region (400 nm to 700 nm) (vs. MGO standard white plate, point light source −25 ° light reception 0 °). ) Was measured. The measurement results are shown in Table 9 and Table 10.
[0136]
[Table 9]

[0137]
[Table 10]

[0138]
As is clear from Tables 9 and 10, TiO₂By using the outermost layer substrate, as in (Example 1), an effect excellent in developability and adhesion strength of the resin light-shielding film pattern and transmittance and reflectance of the color filter can be obtained.
[0139]
(Example 8)
A transflective color liquid crystal panel was produced using the two types of color filters produced in (Example 7). The configuration is as shown in FIG.
[0140]
Then, measurement of the adhesion strength between the opposing substrates of the transflective color liquid crystal panel, and then the average transmittance and average reflectance ratio in the visible light region (400 nm to 700 nm) when the panel is turned on (vs. MGO standard white plate, point light source-25) (0 ° light reception) was measured. The measurement results are shown in Table 11.
[0141]
[Table 11]

[0142]
As is apparent from this table, TiO has excellent adhesion at the interface between the glass substrate and the resin light-shielding film pattern, and has excellent resolution of the resin light-shielding film pattern.₂By using the outermost substrate, the adhesion strength between the opposing substrates and the brightness of the panel display surface are improved.
[0143]
As described above, in the transmissive color liquid crystal panel that dislikes the loss of lighting light on the display surface due to multiple reflection, the TiO on the glass substrate surface₂The film thickness is 20 to 80 mm, preferably about 40 to 60 mm. In a reflective color liquid crystal panel, TiO₂The film thickness of 20 to 1500 mm, preferably 100 to 1000 mm.
[0144]
It should be noted that the present invention is not limited to the above-described embodiments, and various changes and improvements can be made without departing from the scope of the present invention.
[0145]
For example, as a transparent glass substrate₂A soda lime glass substrate with a dip coat was used, but instead of a non-alkali glass substrate such as borosilicate glass, TiO on the surface thereof.₂The same effect can be obtained by coating the film to form the outermost layer. The refractive index of this borosilicate glass is 1.54, and SiO₂Therefore, 20 to 80 mm, which is a preferable range for preventing multiple reflections, can be applied as it is.
[0146]
The outermost layer is TiO₂Any material may be used as long as it is a film, and the underlying material may be other materials such as synthetic resin.
[0147]
【The invention's effect】
  As described above, according to the present invention, the substrate and the TiO provided on the substrate are provided.₂Film and TiO₂Resin light-shielding film provided on the film and TiO on the non-adhered surface of the resin light-shielding film₂A colored film provided on the film, and TiO₂The membrane has a thickness of 20-80 mmTiO of resin light shielding film ₂ Adhesion strength to membrane is 30.2 to 41.3 kgf / cm ² IsTherefore, the adhesion at the interface of the resin light-shielding film is improved, so that when the photocurable resin light-shielding film is exposed and developed to form a pattern, the resin light-shielding film is less likely to be peeled off. Usually, the contrast of the developer with the exposed area is easily contrasted, and the development latitude is expanded.As a result, the influence of variations due to factors that influence the development state, such as the concentration and temperature of the developer, is alleviated. Developability at the time of mass production is stabilized, and the production yield is improved.
[0148]
In addition, when exposed and developed, the resin light-shielding film pattern is hard to be peeled off and can be immersed in a developer for a longer time, so that the overexposed portion exposed by the diffraction phenomenon of the exposure light to the non-exposed portion and It is easy to add contrast to the solubility of the developer in the normal exposure area, and it is easy to selectively remove the resin light-shielding film in the overexposed area, making it a resin with better resolution that is close to the design width of the photomask. A light shielding film pattern can be formed. In this case, the aperture ratio of the color filter is improved and the loss of lighting light on the display surface is reduced. Therefore, a color liquid crystal panel with higher luminance or lower power consumption can be manufactured even with the same luminance.
[0149]
In addition, when a color liquid crystal panel is manufactured using a color filter having excellent adhesion at the interface between the glass substrate and the resin light-shielding film, the adhesion strength between the opposing substrates is improved. As a result, durability against a load caused by the above and the like can be improved, a highly reliable color liquid crystal panel can be manufactured, and a manufacturing yield thereof can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a color filter of the present invention.
FIG. 2 is a schematic cross-sectional view of another color filter of the present invention.
FIG. 3 is a cross-sectional view of a color filter formed by a pigment dispersion method.
FIGS. 4A to 4C are process diagrams showing a method for patterning a light-shielding film. FIGS.
FIG. 5 is a schematic cross-sectional view of a transmissive color liquid crystal display device.
FIG. 6 is a schematic cross-sectional view of a reflective color liquid crystal display device.
FIGS. 7A and 7B are process diagrams for creating a pattern of a photocurable resin light-shielding film. FIGS.
FIG. 8 is a schematic cross-sectional view of a color liquid crystal display device.
FIG. 9 TiO₂It is a diagram which shows the relationship between the film thickness and average reflectance.
[Explanation of symbols]
1 ... Soda lime glass substrate
2 ... SiO₂film
3 ... TiO₂film
4 ... Resin light shielding film pattern
8 ... Smoothing film
10 ... Transparent glass substrate
11 ... Light-curing resin light-shielding film
13 ... Photomask
12 ... Exposure light
22 ... Diffraction of exposure light

Claims (3)

A substrate,
A TiO ₂ film provided on the substrate;
A resin light-shielding film provided on the TiO ₂ film;
A colored film provided on the TiO ₂ film on the non-adhering surface of the resin light-shielding film,
The TiO ₂ layer has a thickness, Ri 20~80Å der,
Color filter adhesion strength with respect to the TiO ₂ layer of the resin light shielding film is characterized in that it is a 30.2~41.3kgf / cm ^2. The color filter according to claim 1, further comprising a SiO ₂ film provided between the substrate and the TiO ₂ film.   An electrode and an alignment film are formed on the color filter according to claim 1 or 2, and the other electrode and the alignment film are opposed to another substrate, and both are disposed via a liquid crystal layer. A liquid crystal display device.

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