JP4744657B2 - Transparent ion getter film forming coating solution, coated substrate and liquid crystal display cell - Google Patents

Description

【００２３】
〔ただし、式中、ａ＋ｂは２〜４であり、ａは０〜３であり、ｂは１〜４であり、Ｒは−Ｃ_nＨ_2n+1（ｎ＝３または４）であり、Ｘは−ＣＨ₃、−ＯＣＨ₃、−Ｃ₂Ｈ₅ または−ＯＣ₂Ｈ₅ である。Ｍ₁は周期率表第ＩＢ族、第IIＡ、Ｂ族、第III Ａ、Ｂ族、第IVＡ、Ｂ族、第ＶＡ、Ｂ族、第VIＡ族、第VII Ａ族、第VIII族から選ばれる元素またはバナジル（ＶＯ）である。この内、これらの元素などとａ、ｂの好ましい組み合わせは、次表の通りである。〕
【００２４】
【表１】

【００２５】
このような化合物の具体例としては、たとえばジブトキシ−ビスアセチルアセトナトジルコニウム、トリブトキシ−モノアセチルアセトナトジルコニウム、ビスアセチルアセトナト鉛、トリスアセチルアセトナト鉄、ジブトキシ−ビスアセチルアセトナトハフニウム、モノアセチルアセトナト−トリブトキシハフニウムなどが挙げられる。
【００２６】
(b) ケイ素化合物
本発明に用いられる有機ケイ素化合物としては、
一般式 Ｒ_a −Ｓｉ（ＯＲ’）_4-a （２）
（ただし、式中、Ｒは−Ｃ_n Ｈ_2n+1またはＣ₆Ｈ₅であり、Ｒ’は−Ｃ_n Ｈ_2n+1または−Ｃ₂ Ｈ₄ ＯＣ_n Ｈ_2n+1であり、ａは０ないし３の整数であり、ｎは１ないし４の整数である。）で示される有機ケイ素化合物が用いられる。
【００２７】
このような有機ケイ素化合物としては、具体的には、たとえばテトラメトキシシラン、テトラエトキシシラン、モノメチルトリメトキシシラン、モノエチルトリエトキシシラン、モノエチルトリメトキシシラン、モノメチルトリエトキシシランなどが好ましく用いられる。
【００２８】
これらの有機ケイ素化合物は、そのままの状態でも、あるいは部分加水分解して用いてもよい。このような部分加水分解は、従来から行われている通常の方法、たとえばメタノールまたはエタノールなどのアルコールに有機ケイ素化合物を混合し、水と酸とを加えて部分加水分解する方法に従って得ることができる。
【００２９】
上記有機ケイ素化合物が添加された本発明に係る透明被膜形成用塗布液を基材上に塗布し、得られた被膜を乾燥・焼成すると、耐擦傷性、耐酸性、耐アルカリ性、耐水性および絶縁性に優れた被膜が形成される。
【００３０】
(c) 金属アルコキシド
またマトリックス形成成分として使用される金属アルコキシドとしては、Ｍ₂ (ＯＲ)_n （式中、Ｍ₂は金属原子であり、Ｒはアルキル基または−Ｃ_m Ｈ_2mＯ₂（ｍ＝３〜１０）であり、ｎはＭ₂の原子価と同じ整数である。）で表される化合物またはそれらの縮合体が好ましく、これらの化合物またはその縮合体から選ばれる１種または２種以上を組み合わせて用いることができる。上記式中のＭ₂は、金属であれば特に限定されることはないが、好ましいＭ₂は、Ｂｅ、Ａｌ、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｆｅ、Ｎｉ，Ｚｎ、Ｇａ、Ｇｅ、Ａｓ、Ｓｅ、Ｙ、Ｚｒ、Ｎｂ、Ｉｎ、Ｓｎ、Ｓｂ、Ｔｅ、Ｈｆ、Ｔａ、Ｗ、Ｐｂ、Ｂｉ、ＣｅまたはＣｕである。
【００３１】
このような金属アルコキシドとしては、具体的には、テトラブトキシジルコニウム、ジイソプロポキシ−ジオクチルオキシチタニウム、ジエトキシ鉛などが好ましく用いられる。
【００３２】
上記金属アルコキシドを添加した本発明に係る透明被膜形成用塗布液を塗布・乾燥・焼成すると、この金属アルコキシドの重合硬化により、耐擦傷性、耐酸性、耐アルカリ性、耐水性および絶縁性に優れた被膜が形成される。
【００３３】
(d) ポリシラザン
またマトリックス形成成分として用いられるポリシラザンは、下記式（３）で表される繰り返し単位を有するものである。
【００３４】
【化２】

【００３５】
〔ただし、式中、Ｒ₁、Ｒ₂およびＲ₃は、それぞれ水素原子または炭素原子数１〜８のアルキル基である。〕
マトリクス形成成分として、前記式（３）で表されるポリシラザンを用いる場合、アルキル基がメチル基、エチル基、またはプロピル基であるポリシラザンが好ましい。この場合には、加熱時に分解するアルキル基がなく、加熱時に膜の収縮が少なく、このため収縮ストレス時にクラックが生じることが少なくなり、クラックのほとんどない透明イオンゲッター膜が得られる。
【００３６】
また、上記式（３）で表される繰り返し単位を有するポリシラザンは、直鎖状であっても、環状であってもよく、直鎖状のポリシラザンと環状のポリシラザンとが混合して含まれていてもよい。
【００３７】
さらに、このようなポリシラザンの数平均分子量は、５００〜１０，０００、好ましくは１，０００〜４，０００の範囲にあることが望ましい。数平均分子量が５００未満では、加熱硬化時に低分子量のポリシラザンが揮発し、得られた透明イオンゲッター膜が多孔質になりやすく、また、分子量が１０，０００を越えると、塗布液の流動性が低下する傾向がある。
【００３８】
本発明では、このような（Ａ）マトリックス形成成分を、単独で使用しても、あるいは２種以上混合して使用してもよい。
（Ａ）マトリックス形成成分として２種以上併用する場合、(a)アセチルアセトナトキレート化合物、(b)有機ケイ素化合物、(c)ポリシラザン、(d)金属アルコキシドをそれぞれ、酸化物、窒化物に換算したとき、すなわち(a)アセチルアセトナトキレート化合物を（Ｍ₁Ｏ_x）で表し、(b)有機ケイ素化合物を（ＳiＯ₂）で表し、(c)ポリシラザンを（ＳiＮ）で表し、(d)金属アルコキシドを（Ｍ₂Ｏ_x）で表したとき、各成分の重量比が、以下のような関係を満たしていることが望ましい。
【００３９】
０≦Ｍ₁Ｏ_x／（ＳｉＯ₂＋ＳiＮ＋Ｍ₂Ｏ_x）≦１０
アセチルアセトナトキレート化合物を使用する場合、この値が０．００１以上であると、耐アルカリ性、耐酸性、耐塩水性、耐水性、耐溶剤性に優れた被膜を得ることができる。
【００４０】
また、有機ケイ素化合物およびポリシラザンと金属アルコキシドとの配合割合は、０≦Ｍ₂Ｏ_x／（ＳｉＯ₂＋ＳiＮ＋Ｍ₂Ｏ_x）≦１．０であることが好ましい。
（Ｂ）イオン吸着性無機微粒子
本発明の透明イオンゲッター膜形成用塗布液に用いられる（Ｂ）イオン吸着性無機微粒子は、無機イオン、特に液晶中に存在する無機イオンを吸着しうる微粒子であって、平均粒子径が１ｎｍ〜１０μｍの範囲にあることが好ましく、さらに好ましい範囲は１０ｎｍ〜５μｍである。また、イオン吸着容量は０.１〜３.０ｍｍｏｌ／ｇ、好ましくは０．２〜３．０ｍｍｏｌ／ｇの範囲にあることが好ましい。なお、（Ｂ）イオン吸着性無機微粒子が吸着しうるイオンとしては、たとえば、Ｎａ⁺、Ｋ⁺、Ｒｂ⁺、Ｃｓ⁺、Ｌｉ⁺、Ａｇ⁺、Ｍｇ⁺、Ｃａ⁺、Ｓｒ⁺、Ｂａ⁺、ＮＨ₄ ⁺などが挙げられる。
【００４１】
イオン吸着性無機微粒子は、平均粒子径が小さくなるとイオン吸着容量は高くなり、イオン吸着速度は早くなる傾向があるものの、平均粒径が１ｎｍ未満になると、さらにイオン吸着容量が高くなることもイオン吸着速度が早くなることもなく、さらにまた透明イオンゲッター膜の表面にポリイミド樹脂などの疎水性の強い樹脂からなる別の膜を密着性よく形成することができないことがある。また、平均粒子径が１０μｍを超えるとイオン吸着容量およびイオン吸着速度が低下するとともにイオンゲッター膜の透明性が低下することがある。
【００４２】
特に、平均粒子径が５０ｎｍ以下、好ましくは１０〜４０ｎｍのイオン吸着性無機微粒子を含む塗布液を用いて、３０ｎｍ〜１００μｍの厚さで電極膜と配向膜の間に形成されたイオンゲッター膜は、表面に１〜１０ｎｍの均一な表面荒さを有するので、疎水性の配向膜との密着性に優れている。
【００４３】
また、イオン吸着容量が０.１ｍｍｏｌ／ｇより少ないと、イオンを充分に吸着することができないので、可動イオンによる表示不良を起こしたり、長期信頼性に欠けることがあり、３．０ｍｍｏｌ／ｇより大きいイオン吸着量を有するイオン吸着性無機微粒子は得ることが困難である。
【００４４】
このようなイオン吸着性無機微粒子の平均粒子径はレーザードップラー法またはＴＥＭ観察によって求めることができる。
また、イオン吸着性無機微粒子のイオン吸着容量は以下のような方法で測定される。
【００４５】
濃度１重量％のＮａＣｌ水溶液１００ｇに、１２０℃で乾燥して恒量化した無機イオン吸着体１.５ｇを加え、室温（２５℃）で１５時間攪拌した後、濾過して濾液を採取し、濾液中のＮａイオン濃度を原子吸光法により分析し、元のＮａＣｌ水溶液のＮａイオン濃度との濃度差から、無機イオン吸着体のイオン吸着量（ｍｍｏｌ／ｇ）を求める。
【００４６】
本発明の透明イオンゲッター膜形成用塗布液に用いるイオン吸着性無機微粒子としては、イオン吸着容量および平均粒子径が前記範囲にあれば特に制限はないが、ＭＯ_X・ｎＨ₂Ｏで表され、付着水以外の結晶水、構造水酸基、表面水酸基のいずれかを金属酸化物（ＭＯ_X）１モル当たり水（Ｈ₂Ｏ）をモル数ｎが０.０２〜５の範囲で有している金属酸化物が好ましい。さらに好ましい範囲は０.１〜３である。
【００４７】
このようなイオン吸着性無機微粒子を構成する金属酸化物としては、ＳiＯ₂、Ａl₂Ｏ₃、ＺrＯ₂、ＴiＯ₂、ＳnＯ₂、Ｉn₂Ｏ₃、Ｓb₂Ｏ₅などの金属酸化物、ＳiＯ₂・Ａl₂Ｏ₃、ＳiＯ₂・ＴiＯ₂、Ｉn₂Ｏ₃・ＳnＯ₂、Ｓb₂Ｏ₅・ＳnＯ₂、ＳnＯ₂・Ｉn₂Ｏ₃・Ｓb₂Ｏ₅などの複合金属酸化物あるいは固溶体、ゼオライト（結晶性アルミノシリケート）などが挙げられる。さらに、これらの２種以上の混合物も好ましく用いられる。
【００４８】
上記したイオン吸着性無機微粒子中の水のモル数ｎの値が０.０２モル未満ではイオン吸着容量が小さすぎて液晶中のイオンを効果的に吸着することができず、５モルを越えて高い場合はイオンゲッター膜上に、スパッタリング法でＩＴＯ膜を形成する際などに、水分子として脱離するためにスパッタリング装置内の真空到達時間が長くなる傾向があるので好ましくない。
【００４９】
このようなイオン吸着性無機微粒子に含まれる水のモル数ｎの値は、１２０℃で乾燥して恒量化したイオン吸着性無機微粒子の示差熱分析により、５００℃までに減少した水の量を、金属酸化物１モルあたりの水のモル数として計算することによって求めることができる。
【００５０】
さらに、必要に応じて上記イオン吸着性無機微粒子以外の絶縁性または導電性の無機化合物微粒子を用いてもよい。
このようなイオン吸着性無機微粒子は、水または有機溶媒に分散したゾルの状態で用いることが好ましいが、イオン吸着性無機微粒子を透明イオンゲッター膜形成用塗布液中に単分散または単分散に近い状態で分散できればゾル以外の状態にあるイオン吸着性無機微粒子を用いてもよい。
【００５１】
透明被膜形成用塗布液組成
本発明に係る透明被膜形成用塗布液は、（Ａ）マトリックス形成成分と（Ｂ）イオン吸着性無機微粒子とが水と有機溶媒とからなる混合溶媒に均一に溶解または分散されている。
【００５２】
このような透明被膜形成用塗布液に使用される有機溶媒としては、アルコール類、エーテル類、グリコール類、ケトン類などから選ばれる公知の有機溶媒が使用される。このような有機溶媒は、単独で、または２種以上を混合して使用してもよい。
【００５３】
本発明に係る塗布液中の固形分濃度は、（Ａ）マトリックス形成成分および（Ｂ）イオン吸着性無機微粒子を酸化物、窒化物に換算した合計値で、１５重量％以下であることが好ましい。この値が１５重量％を越えると、塗布液の保存安定性が低下する傾向が生じ、一方、この固形分濃度が極端に低いと、目的の膜厚を得るのに多数回の塗布操作を繰り返すことが必要となるので、固形分濃度は０．１重量％以上が実用的である。
【００５４】
マトリックス形成成分（Ａ）は、酸化物、窒化物換算で、形成したイオンゲッター膜中に、３０〜９５重量％となるような量で塗布液中に、含まれていることが望ましい。
【００５５】
また（Ｂ）イオン吸着性無機微粒子は、塗布液中に、酸化物換算で、形成したイオンゲッター膜中に５〜７０重量％の範囲となるような量で存在していることが好ましい。このような範囲で、イオン吸着性無機微粒子がイオンゲッター膜中に存在していると、この塗布液から得られたイオンゲッター膜の表面に、さらにポリイミド樹脂などの疎水性の強い樹脂からなる別の被膜が密着性よく形成できるとともに、液晶パネル中のイオンを効果的に低減できる透明イオンゲッター膜が形成できる。なお、濃度が７０重量％を越えると、この塗布液から形成されるイオンゲッター膜と下部基板、ＴＦＴアレイ、カラーフィルターなどとの密着性が低下することがある。
【００５６】
さらに、必要に応じてこれらのイオン吸着性無機微粒子以外の絶縁性または導電性の無機化合物微粒子が含まれている場合も、塗布液には、イオン吸着性無機微粒子とイオン吸着性無機微粒子以外の微粒子は、形成したイオンゲッター膜中に酸化物、窒化物の合計として５〜７０重量％の範囲の量で存在していることが好ましい。
【００５７】
本発明に係る透明被膜形成用塗布液塗布液中の水分濃度は、０．１〜５０重量％の範囲であることが好ましい。水分濃度が０．１重量％未満であると、アセチルアセトナトキレート化合物、有機ケイ素化合物、ポリシラザンおよび金属アルコキシドの加水分解、縮重合および複合化などが充分になされず、得られる被膜の耐擦傷性、耐久性が低下する傾向にあり、また、５０重量％を越えると、塗布の際、塗布液が基材からはじかれやすくなり、被膜を形成しにくくなることがある。
【００５８】
本発明に係る透明被膜形成用塗布液では、塗布液中に含まれる（Ａ）マトリックス形成成分と（Ｂ）イオン吸着性無機微粒子との混合割合、（Ａ）マトリックス形成成分に含まれる金属種、（Ｂ）イオン吸着性無機微粒子の種類などによって、得られる被膜の屈折率および誘電率が自由にコントロールすることができる。
【００５９】
このようにして透明電極付基板の透明電極上に屈折率がコントロールされたイオンゲッター膜を形成することにより、たとえばこの上に形成される配向膜の屈折率より高くして電極などが透けて見えるのを防止することができる。
【００６０】
本発明の透明イオンゲッター膜形成用塗布液を用いて形成された透明イオンゲッター膜は、細孔容積が０.０１〜０.３ｍｌ／ｇの範囲にあり、平均細孔径が１〜２０ｎｍの範囲にある細孔を有していることが好ましい。
【００６１】
細孔容積が０.０１ｍｌ／ｇ未満では、細孔が少ないためにイオン吸着性無機微粒子のイオン吸着能を充分発現することができず、０.３ｍｌ／ｇを超えると膜の強度が不十分となることがある。
【００６２】
また、平均細孔径が１ｎｍ未満では、電圧を印加した際のイオンの拡散速度が遅く、イオン吸着性無機微粒子のイオン吸着能を充分発現することができないことがある。また、平均細孔径が２０ｎｍを超えると膜の強度が不十分となることがある。
【００６３】
このような透明イオンゲッター膜の細孔容積および平均細孔径は、基板上に形成した透明イオンゲッター膜を剥離し、剥離した透明イオンゲッター膜についてＮ₂吸着法によって測定される。
【００６４】
［被膜付基材］
次に、本発明に係る被膜付基材について具体的に説明する。
本発明に係る被膜付基材は、基材表面に上記透明イオンゲッター膜形成用塗布液を塗布してなる透明イオンゲッター膜が形成されていることを特徴としている。
【００６５】
透明イオンゲッター膜の細孔容積は、０．０１〜０．３ml/g、好ましくは０．０５〜０．２ml/gの範囲にあることが好ましい。また、透明イオンゲッター膜の平均細孔径は、１〜２０nm、好ましくは２〜８nmの範囲にあることが好ましい。
【００６６】
本発明に係る透明イオンゲッター膜付基材は、ガラス、プラスチックなどの基材表面に上記のような透明膜形成用塗布液をディッピング法、スピナー法、スプレー法、ロールコーター法、フレキソ印刷などの方法で塗布し、次いでこのようにして基材表面に形成された被膜を常温〜９０℃で乾燥し、さらに２００℃以上、場合によっては３００℃以上に加熱して硬化するなどの方法により形成される。
【００６７】
さらにこの基材に形成されている被膜は、次のような方法で硬化促進処理が施されていてもよい。
硬化促進処理として具体的には、記塗布工程または乾燥工程の後に、あるいは乾燥工程中に、未硬化段階の被膜に可視光線よりも波長の短い電磁波を照射したり、未硬化段階の被膜を硬化反応を促進するガス雰囲気中に晒したりする処理が挙げられる。
【００６８】
このような加熱前の未硬化段階の被膜に照射する電磁波としては、具体的には紫外線、電子線、Ｘ線、γ線などが例示され、特に紫外線が好ましい。
紫外線を照射処理を行う際には、たとえば、発光強度が約２５０ｎｍと３６０ｎｍとにおいて極大となり、光強度が１０ｍＷ／ｃｍ² 以上である高圧水銀ランプを紫外線源として使用し、１００ｍＪ／ｃｍ² 以上、好ましくは１０００ｍＪ／ｃｍ² 以上のエネルギー量の紫外線を照射することが望ましい。
【００６９】
また、加熱前の未硬化段階の被膜の硬化反応を促進するガスとしては、たとえばアンモニア、オゾンなどが例示される。またこのようなガス処理を行う場合、未硬化段階の被膜を、ガス濃度が１００〜１００，０００ｐｐｍ、好ましくは１０００〜１０，０００ｐｐｍである上記活性ガス雰囲気下に、１〜６０分曝すことが望ましい。
【００７０】
なお、このガス処理は、加熱硬化後に行っても同様の効果が得られる。
上述したような硬化促進処理を行うと、透明イオンゲッター膜中に含まれるアセチルアセトナトキレート化合物、有機ケイ素化合物、ポリシラザン、金属アルコキシドなどの（Ａ）マトリックス形成成分の縮重合、複合化が促進されると同時に、膜中に残存する水および溶媒の蒸発も促進される。このため、次の加熱工程において必要とされる加熱温度、加熱時間などの加熱硬化条件が緩和され、本発明に係るイオンゲッター膜付基材の製造を効率よく進めることができる。
【００７１】
以上のような工程によって本発明に係る透明イオンゲッター膜付基材が得られる。この基材上に形成され透明イオンゲッター膜は、表面硬度が高く、密着性、透明性に優れるとともに、耐擦傷性、耐水性、耐アルカリ性などの耐久性にも優れている上、液晶パネル中の可動イオンを効果的に低減でき、絶縁抵抗が高く、絶縁性の膜としても好適である。
【００７２】
［液晶表示セル］
次に、本発明に係る液晶表示セルについて、具体的に説明する。
本発明に係る液晶表示セルは、いずれも上記透明イオンゲッター膜形成用塗布液を使用して形成された透明イオンゲッター膜を有する透明電極付基板を用いたものである。
【００７３】
本発明に係る第１の液晶表示セルは、少なくとも一方の基板の表面に透明電極膜、透明イオンゲッター膜および配向膜が順次積層されてなる一対の透明電極付基板が、それぞれの透明電極同士が対向するように所定の間隔をあけて配置され、この一対の透明電極付基板の間に設けられた間隙に液晶が封入されている液晶表示セルである。
【００７４】
図１は、本発明に係る第１の液晶表示セルの一態様例を模式的に表す断面図である。
この液晶表示セル１は、ガラス基板１１の表面に透明電極膜１２、透明イオンゲッター膜１３および配向膜１４が順次積層されてなる一対の透明電極付基板２が、それぞれの透明電極膜１２、１２同士が対向するように複数のスペーサ粒子５により所定の間隔ｄを開けて配置され、この所定間隔ｄに開けられた透明電極膜１２、１２間の隙間に液晶４が封入されて形成されている。
【００７５】
透明イオンゲッター膜１３は、上記透明イオンゲッター膜形成用塗布液を透明電極膜１２上に塗布することにより形成した膜であり、この膜は、表面硬度が高く、透明性および耐擦傷性に優れ、絶縁抵抗が高く、透明イオンゲッター膜１３と配向膜１４との密着性が良好である上に、液晶パネル中の（可動）イオンを効果的に低減することができる。
【００７６】
なお、本発明に係る第１の液晶表示セルでは、ガラス基板１１と透明電極膜１２との間にさらにＳｉＯ₂ 膜などのアルカリパッシベーション膜を形成した透明電極付基板を用いてもよいなど、さまざまな変形が可能である。
【００７７】
本発明に係る第２の液晶表示セルは、少なくとも一方の基板の表面にカラーフィルター、透明イオンゲッター膜、透明電極膜および配向膜が順次積層されてなる一対の透明電極付基板が、それぞれの透明電極同士が対向するように所定の間隔をあけて配置され、この一対の透明電極付基板の間にあけられた間隙に液晶が封入されている液晶表示セルである。
【００７８】
図２は、本発明に係る第２の液晶表示セルの一態様例を模式的に表す概略図である。
この図２にその特徴的部分が示されているカラー液晶表示装置１'は、ガラス基板２１ａ上にアルカリパッシベーション膜２１ｂ、複数の画素電極２１ｃ、透明イオンゲッター膜２１ｄおよび配向膜２１ｅが順次積層された電極板２１と、ガラス基板２２ａ上にアルカリパッシベーション膜２２ｂ、カラーフィルター２２ｃ、透明イオンゲッター膜２２ｄ、透明電極２２ｅおよび配向膜２２ｆが順次積層された対向電極板２２を有する液晶表示セル２'と、この液晶表示セルの両側に一対の偏光板３'、４'とを備えている。このうち、透明イオンゲッター膜２１ｄおよび２２ｄは、前記透明イオンゲッター膜形成用塗布液を塗布して形成された膜である。
【００７９】
前記液晶表示セル２の電極板２１と対向電極板２２とは、それぞれのガラス基板２１ａおよび２２ａを外側にして、複数の画素電極２１ｃのそれぞれと複数のカラーフィルターＲ、Ｇ、Ｂのそれぞれが対向するように配置されている。また、この電極板２１と対向電極板２２との間の隙間には液晶２３が封入されている。
【００８０】
さらに複数の画素電極２１ｃのそれぞれと透明電極２２ｅとの間には不図示の回路が形成され、この回路はカラー液晶表示装置１本体に接続されている。また、対向電極板２２のパッシベーション膜２２ｂ上に形成されたカラーフィルター２２ｃは、Ｒ（レッドフィルター）、Ｇ（グリーンフィルター）、Ｂ（ブルーフィルター）の複数のカラー要素からなり、各カラー要素が互いに隣接するように規則正しく配列され、これにより液晶表示装置１'本体から送られてくる表示信号により特定の画素電極２１ｃと透明電極２２ｅとの間に形成された回路が作動し、表示信号に対応したカラー画像が対向電極板２２の外側に配置された偏光板４を通して観察できるようになっている。
【００８１】
本発明に係る第３の液晶表示セルは、少なくとも一方の基板の表面にはＴＦＴアレイ、透明イオンゲッター膜、透明電極膜および配向膜が順次積層されてなる一対の透明電極付基板が、それぞれの透明電極同士が対向するように所定の間隔をあけて配置され、この一対の透明電極付基板の間にあけられた間隙に液晶が封入されている液晶表示セルである。
【００８２】
図３は、本発明に係る第３の液晶表示セルの一態様例を模式的に表す概略断面図である。
この液晶表示セル１"は、表面にＴＦＴアレイ３２が形成され、このＴＦＴアレイ３２表面に、透明イオンゲッター膜３３、画素電極３４および配向膜３５が順次積層された透明絶縁性基板３１と、
表面にブラックマトリクス（遮蔽膜）４２、カラーフィルター４３、透明イオンゲッター膜４４、対向電極４５および配向膜４６が順次積層された対向基板４１とが、
液晶層５１とを挟んで配向膜３５および４６が対峙するように構成される。
【００８３】
なお、図１のように配向膜３５および４６の間にはスペーサ粒子が介在していてもよい。
ＴＦＴアレイ３２は、ＴＦＴ素子、データ電極などからなるものである。
【００８４】
上記第１〜第３の液晶表示セルでは、透明イオンゲッター膜の細孔容積が０．０１〜０．３ml/gの範囲にあり、平均細孔径が１〜２０nmの範囲にあることが好ましい。
【００８５】
以上のような本発明に係る液晶表示セルは、透明イオンゲッター膜によって液晶中の可動イオン（イオン性不純分）を低減されている。このため本発明に係る液晶表示セルは、高電圧保持率特性に優れ、表示不良が生じることがなく、長期信頼性に優れ、しかも消費電力が少なく済むため電力効率を高めることができる。
【００８６】
【発明の効果】
以上に説明したように、本発明に係る透明イオンゲッター膜形成用塗布液は、（Ａ）マトリックス形成成分として、アセチルアセトナトキレート化合物、有機ケイ素化合物、ポリシラザンおよび金属アルコキシドから選ばれる１種または２種以上の混合物または複合物と、（Ｂ）特定のイオン吸着容量と粒子径を有するイオン吸着性無機微粒子とを含んでいる。
【００８７】
このため、平均粒子径が５０ｎｍ以下のイオン吸着性無機微粒子を含む塗布液を用いて基材表面にたとえば平均１〜１０ｎｍの表面粗さを有し、その凹凸の高さがほぼ一定でその分布も均一な被膜を形成することができ、得られた被膜は、耐擦傷性、耐酸性、耐アルカリ性、耐水性および絶縁性に優れ、さらには、この上に形成される膜、たとえばポリイミド樹脂などの疎水性の強い樹脂からなる膜などとの密着性にも優れている。
また、本発明に係る塗布液を用いて凹凸を有する基板、例えばＴＦＴアレイ付基板あるいはカラーフィルター付基板上に形成されたイオンゲッター膜の表面は平坦化されており、このため液晶層と接触する配向膜表面も平坦化されているので、表面形状に起因する液晶の表示乱れの抑制、表示ドメインの発生防止、パネル表示時の光抜けの低減およびコントラストの向上などに有効である。
【００８８】
特に、本発明に係るイオンゲッター膜は、イオン吸着能を有する無機イオン吸着性微粒子を含んでいるために液晶パネル中の（可動）イオンを効果的に低減できる。
【００８９】
このため、本発明に係る透明イオンゲッター膜形成用塗布液から形成される被膜は、液晶表示セルに用いられる透明電極の透明電極膜と配向膜との間に形成される絶縁膜、あるいはＴＦＴアレイ付基板、カラーフィルター付基板上に形成される低誘電率平坦化膜として好適であり、得られる液晶表示装置は表示品位、長期信頼性に優れる。
【００９０】
【実施例】
以下、本発明を実施例により説明するが、本発明はこれら実施例に限定されるものではない。
【００９１】
【実施例１】
塗布液の調製
マトリックス形成成分としてエチルシリケート２８（多摩化学工業社製：ＳiＯ₂濃度２８.８重量％）１４.６ｇを、純水 ５ｇおよびエチルアルコール６２.３ｇとの混合溶媒に添加し、これに濃度６１％の硝酸０.１ｇを加えてエチルシリケートの部分加水分解物（オリゴマー）溶液（分散液）を調製した。
【００９２】
この溶液に、イオン吸着性無機微粒子として平均粒径２０ｎｍ、イオン吸着容量２．４mmmol/gの五酸化アンチモン微粒子（Ｓb₂Ｏ₅・２.７Ｈ₂Ｏ）をヘキシレングリコールに均一分散させた固形分濃度１０重量％のイオン吸着性無機微粒子ゾル１８ｇを加えて２４時間撹拌し、ついで、ヘキシレングリコール７０ｇ加えた後、減圧蒸留を行い固形分濃度６.０重量％の塗布液（Ａ）を調製した。
【００９３】
透明イオンゲッター膜の形成
パターニングされたＩＴＯ表示電極つきガラス基板（旭硝子（株）製：３０Ω／□以下品）上にフレキソ印刷にて塗布液（Ａ）を塗布し、得られた塗膜を９０℃で５分間乾燥させた後、高圧水銀ランプで積算光量６,０００ｍJ/cm²（３６５nm用センサにて測定）の条件で紫外線を照射し、次いで３００℃で３０分間焼成を行いイオンゲッター膜（Ａ）を形成した。得られたイオンゲッター膜（Ａ）の特性を表２に示す。また得られたイオンゲッター膜（Ａ）の膜厚を触針式表面粗さ計で測定したところ８０nmであった。
【００９４】
液晶表示セルの作成
次に、イオンゲッター膜（Ａ）上にポリイミド膜形成用塗料（日産化学（株）製：サンエバー）をフレキソ印刷で塗布し、１００℃で５分間乾燥した後、２４０℃で３０分間加熱処理してポリイミド膜を形成し、ついでラビング処理を行った。
【００９５】
このようにして、硝子基板上に透明電極、イオンゲッター膜（Ａ）およびラビング処理した配向膜が順次積層した透明電極付き基板を作製した。
得られた透明電極付き基板を２枚使用して、一方の基板には（２枚の基板間距離に相当する粒子径）のスペーサを散布し、もう一方の基板にはエポキシ樹脂とシリカ微粒子からなるシーリング用のシール材を印刷し、これらの基板を透明電極同士が互いに対向するように貼り合わせ、ＳＴＮ液晶を封入し、ついで封入口を封止材で封止して、液晶表示セル（Ａ）を作成した。
【００９６】
可動イオン量の測定
得られた液晶表示セル（Ａ）中の可動イオン量をイオン密度測定機（東陽テクニカ社製：ＭＴＲ-１）を用いて、印加電圧１０Ｖ、三角波周波数０.１Ｈzの条件で測定した。液晶中の可動イオンによるピークは検出されなかった。
【００９７】
液晶表示セルの表示ムラの観察
また、上記方法にて１０枚の液晶表示セル（Ａ）を作製し、点灯表示テストを実施し、表示ムラの有無について黙視観察を行った。このとき、表示ムラの発生しなかったパネルの枚数を調べた。
【００９８】
結果を表２に示す。
長期信頼性の評価
上記方法にて作製した１０枚の液晶表示セル（Ａ）を、高温高湿の環境（相対湿度９５％、温度８０℃）に５００時間曝したのち、液晶表示セルの点灯表示テストを実施し、表示ムラの有無について目視観察を行った。このとき、表示ムラの発生しなかったパネルの枚数を調べた。
【００９９】
結果を表２に示す。
【０１００】
【実施例２】
塗布液の調製
イオン吸着性無機微粒子としてシリカゾルを乾燥して得られた平均粒径２５ｎｍ、イオン吸着容量０．２mmol/gのシリカ微粒子（ＳiＯ₂・０.１Ｈ₂Ｏ）を用いた以外は実施例１と同様にして固形分濃度６.０重量％の塗布液（Ｂ）を調製した。
【０１０１】
透明イオンゲッター膜の形成および液晶表示セルの作成
実施例１と同様にして、イオンゲッター膜（Ｂ）を形成し、液晶セル（Ｂ）の作成をした。得られたイオンゲッター膜（Ｂ）の特性を表２に示す。
【０１０２】
可動イオン量の測定
得られた液晶表示セル（Ｂ）中の可動イオン量を測定したところ、印加電圧が１Ｖの付近に可動イオンによるピークが検出され、可動イオン量は６.０nC/cm²であった。
【０１０３】
液晶表示セルの表示ムラの観察
また、液晶表示セル（Ｂ）について実施例１と同様に表示ムラの有無について目視観察を行った。結果を表２に示す。
【０１０４】
長期信頼性の評価
また、液晶表示セル（Ｂ）について実施例１と同様に長期信頼性の評価を行った。結果を表２に示す。
【０１０５】
【実施例３】
塗布液の調製
イオン吸着性無機微粒子としてシリカアルミナゾル（触媒化成工業（株）製：ＵＳＢゾル）を乾燥して得た平均粒径２５ｎｍ、吸着容量のシリカ・アルミナ微粒子０.２５ＳiＯ₂・０.７５Ａｌ₂Ｏ₃・０.３Ｈ₂Ｏ）を用いた以外は実施例１と同様にして固形分濃度６.０重量％の塗布液（Ｃ）を調製した。
【０１０６】
透明イオンゲッター膜の形成および液晶表示セルの作成
実施例１と同様にしてイオンゲッター膜（Ｃ）の形成および液晶セル（Ｃ）の作成をした。得られたイオンゲッター膜（Ｃ）の特性を表２に示す。
【０１０７】
可動イオン量の測定
得られた液晶表示セル（Ｃ）中の可動イオン量を測定したところ、印加電圧が１Ｖの付近に可動イオンによるピークが検出され、可動イオン量は２.５nC/cm²であった。
【０１０８】
液晶表示セルの表示ムラの観察
また、液晶表示セル（Ｃ）について実施例１と同様に表示ムラの有無について目視観察を行った。結果を表２に示す。
【０１０９】
長期信頼性の評価
また、液晶表示セル（Ｃ）について実施例１と同様に長期信頼性の評価を行った。結果を表２に示す。
【０１１０】
【実施例４】
塗布液の調製
マトリックス形成成分としてメチルトリメトキシシラン（信越化学工業（株）製：ＳiＯ₂濃度４４．１重量％）１００ｇとトリブトキシジルコニウムアセチルアセトナート（松本製薬工業（株）製：ＺrＯ₂濃度１３．５重量％）１７ｇをイソプロピルアルコール２００ｇとブタノール６０ｇの混合溶媒に添加し、これを撹拌しながら、純水１１４ｇと濃度６１％の硝酸を１.０ｇ添加し、６０℃で１５時間かけてメチルトリメトキシシランとトリブトキシジルコニウムアセチルアセトナートの加水分解および重縮合物の分散液を調製した。この分散液を３０℃以下に冷却し、陰イオン交換樹脂を添加して陰イオンを除去し、ついで陰イオン交換樹脂を分離してｐＨ５.５の分散液を得た。
【０１１１】
次いで、この分散液に、実施例１で用いた同じ五酸化アンチモン微粒子分散ゾル２１１ｇ、エチルセロソルブ１００ｇ、ジエチレングリコール９０ｇを加えた後、減圧蒸留を行い固形分濃度２０重量％の塗布液（Ｄ）を調製した。
【０１１２】
イオンゲッター膜の形成
カラーフィルターが形成されたガラス基板上に、塗布液（Ｄ）をスピンコーティング法により回転数８００rpmで塗布し、次いで５０℃で１２０分間乾燥した後２２０℃で６０分間熱処理を行い、膜厚１.６μｍのイオンゲッター膜（Ｄ）を形成することによってカラーフィルター画素のオーバーコートを行った。得られたイオンゲッター膜（Ｄ）の特性を表２に示す。
【０１１３】
さらに、上記イオンゲッター膜（Ｄ）上にスパッタリング法によりＩＴＯ膜を形成した。
液晶表示セルの作成
このＩＴＯ膜を常法によりパターニングして表示電極を形成し、その上に実施例１と同様にしてポリイミド配向膜を形成し、ついでラビング処理を行った。このようにして、硝子基板上にカラーフィルター、イオンゲッター膜（Ｄ）、透明電極およびラビング処理した配向膜が順次積層した一対の透明電極付き基板を得た。
【０１１４】
つぎに、対向する共通電極付き基板とスペーサを介してシール材で貼りあわせ、基板間のギャップにＳＴＮ液晶を注入して注入口を封止材で封入し、液晶セル（Ｄ）を作成した。
【０１１５】
可動イオン量の測定
得られた液晶表示セル（Ｄ）中の可動イオン量を測定したが、可動イオンによるピークは検出されなかった。
【０１１６】
液晶表示セルの表示ムラの観察
また、液晶表示セル（Ｄ）について実施例１と同様に表示ムラの有無について目視観察を行った。結果を表２に示す。
【０１１７】
長期信頼性の評価
また、液晶表示セル（Ｄ）について実施例１と同様に長期信頼性の評価を行った。結果を表２に示す。
【０１１８】
【比較例１】
塗布液の調製
五酸化アンチモン微粒子分散ゾルを使用しなかった以外は実施例１と同様にして固形分濃度６.０重量％の塗布液（Ｅ）を調製した。
【０１１９】
イオンゲッター膜の形成および液晶表示セルの作成
実施例１と同様にしてイオンゲッター膜（Ｅ）の形成および液晶セル（Ｅ）の作成をした。なお、得られたイオンゲッター膜（Ｅ）の特性を表２に示す。
【０１２０】
可動イオン量の測定
得られた液晶表示セル（Ｅ）中の可動イオン量を測定したところ、印加電圧が１Ｖの付近に可動イオンによるピークが検出され、可動イオン量は１９.６nC/cm²であった。
【０１２１】
液晶表示セルの表示ムラの観察
また、液晶表示セル（Ｅ）について実施例１と同様に表示ムラの有無について目視観察を行った。結果を表２に示す。
【０１２２】
長期信頼性の評価
また、液晶表示セル（Ｅ）について実施例１と同様に長期信頼性の評価を行った。結果を表２に示す。
【０１２３】
【比較例２】
塗布液の調製
五酸化アンチモン微粒子分散ゾルを使用しなかった以外は実施例４と同様にして固形分濃度２０重量％の塗布液（Ｆ）を調製した。
【０１２４】
イオンゲッター膜の形成および液晶表示セルの作成
実施例２と同様にしてイオンゲッター膜（Ｆ）の形成および液晶セル（Ｆ）の作成をした。なお、得られたイオンゲッター膜（Ｆ）の特性を表２に示す。
【０１２５】
可動イオン量の測定
得られた液晶表示セル（Ｆ）中の可動イオン量を測定したところ、印加電圧が１Ｖの付近に可動イオンによるピークが検出され、可動イオン量は２５nC/cm²であった。
【０１２６】
液晶表示セルの表示ムラの観察
また、液晶セル（Ｆ）について実施例１と同様に表示ムラの有無について目視観察を行った。結果を表２に示す。
【０１２７】
【表２】

【図面の簡単な説明】
【図１】本発明に係る第１の液晶表示セルの一態様例の概略断面図を示す。
【図２】本発明に係る第２の液晶表示セルの一態様例の概略断面図を示す。
【図３】本発明に係る第３の液晶表示セルの一態様例の概略断面図を示す。
【符号の説明】
１、１'、１"・・・液晶表示セル
２、２’・・・・・液晶表示セル
３、４・・・・・・偏光板
５・・・・・・・・スペーサ粒子
６・・・・・・・・液晶
１１・・・・・・・ガラス基板
１２・・・・・・・透明電極膜
１３・・・・・・・透明イオンゲッター膜
１４・・・・・・・配向膜
２１・・・・・・・電極板
２１ａ・・・・・・ガラス基板
２１ｂ・・・・・・アルカリパッシベーション膜
２１ｃ・・・・・・複数の画素電極
２１ｄ・・・・・・透明イオンゲッター膜
２１ｅ・・・・・・配向膜
２２・・・・・・・対向電極板
２２ａ・・・・・・ガラス基板
２２ｂ・・・・・・アルカリパッシベーション膜
２２ｃ・・・・・・カラーフィルター
２２ｄ・・・・・・透明イオンゲッター膜
２２ｅ・・・・・・透明電極
２２ｆ・・・・・・配向膜
２３・・・・・・・液晶
３１・・・・・・・透明絶縁性基板
３２・・・・・・・ＴＦＴアレイ
３３・・・・・・・透明イオンゲッター膜
３４・・・・・・・画素電極
３５・・・・・・・配向膜
３６・・・・・・・絶縁膜
４１・・・・・・・対向基板
４２・・・・・・・ブラックマトリクス（遮蔽膜）
４３・・・・・・・カラーフィルター
４４・・・・・・・透明イオンゲッター膜
４５・・・・・・・対向電極
４６・・・・・・・配向膜
５１・・・・・・・液晶層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coating liquid for forming a transparent ion getter film, a substrate with a transparent ion getter film, and a liquid crystal display cell. More specifically, the present invention is excellent in scratch resistance, acid resistance, alkali resistance, water resistance, adhesion with an alignment film, etc., and can flatten a substrate having fine irregularities of about several μm, A coating liquid for forming a transparent film capable of forming a film capable of reducing the amount of ions in a liquid crystal display panel, a substrate with a film having a film formed from the coating liquid for film formation, and the substrate with a film The present invention relates to a liquid crystal display cell.
[0002]
TECHNICAL BACKGROUND OF THE INVENTION
Conventionally, a pair of substrates with a transparent electrode in which a transparent electrode film such as ITO and an alignment film made of a polymer such as polyimide are sequentially laminated on the surface of a glass substrate are arranged so that the transparent electrode films face each other. There is known a liquid crystal display cell in which liquid crystal is sealed in a gap formed at a predetermined interval by the spacer.
[0003]
In this type of liquid crystal display cell, the alignment film is damaged by foreign substances or spacers mixed in the liquid crystal cell during the manufacturing process, resulting in conduction between the upper and lower electrodes, resulting in display defects due to this conduction. was there.
[0004]
For this reason, in the liquid crystal display cell as described above, an insulating film is formed between the transparent electrode film of the substrate with a transparent electrode and the alignment film (JP-A-60-260021, JP-A-1-150116). Gazette, JP-A-2-221923, etc.).
[0005]
By the way, as the alignment film, a highly hydrophobic resin such as a polyimide resin is often used. When such an alignment film made of a highly hydrophobic resin is formed on an insulating film, the adhesion between the insulating film and the alignment film becomes insufficient, and display unevenness due to rubbing scratches or the like may occur in the liquid crystal display cell. . For this reason, the applicant of the present application has proposed in JP-A-4-247427 a coating liquid containing an inorganic compound having a specific particle diameter as a coating liquid capable of forming an insulating film having excellent adhesion to the alignment film. .
[0006]
In addition, when such an insulating film is formed between the transparent electrode and the alignment film, the alignment film may be damaged or defective due to static electricity generated when the alignment film is rubbed. For this reason, the applicant of the present invention disclosed in Japanese Patent Laid-Open No. 5-232459 is composed of conductive fine particles and a matrix and has a surface resistance of 10⁹-10¹³It has been proposed to form a protective film of Ω / □ on the transparent electrode surface.
[0007]
As a liquid crystal display device using such a liquid crystal display cell, a TFT type liquid crystal display device and an STN type liquid crystal display device are known.
In the TFT type liquid crystal display device, a TFT array such as a TFT (thin film transistor) element and a data electrode is provided on a transparent substrate. After flattening the unevenness due to the TFT array with a flattening film, the display electrode such as ITO is attached thereon, thereby improving the aperture ratio and eliminating the liquid crystal orientation disorder due to the unevenness of the TFT array. Yes. Further, in a liquid crystal display device having a color filter, an insulating protective film is provided for flattening the color filter pixels or improving the reliability.
[0008]
As a material for forming a flattening film and an insulating protective film in the field of electronic materials, organic resins such as acrylic resins and polyester resins, SiO₂, Si_ThreeN_FourInorganic materials such as organic and inorganic composite polymers of alkyltrihydroxysilane are used. However, these film forming materials have problems such as heat resistance, generation of cracks, film strength, and formability of a resist film on the film. For this reason, the present applicant has proposed a coating solution for forming a transparent film containing inorganic compound particles and a hydrolyzate of a specific organosilicon compound in WO 97/49775.
[0009]
By the way, among the above-mentioned various liquid crystal display devices, in the TFT type liquid crystal display device, in order to have a high voltage holding ratio characteristic, ions caused by materials constituting the cell and ions mixed in the cell manufacturing process are reduced. However, in order to increase the reliability, it is required to further reduce the impurities in the liquid crystal.
[0010]
In STN liquid crystal display devices, liquid crystal materials are being improved in order to reduce power consumption. In order to reduce this power consumption, liquid crystal materials having a strong polar functional group exhibiting a low threshold voltage have been used as a liquid crystal material. However, a panel using such a liquid crystal is a conventional liquid crystal. Display defects may occur due to mobile ions in the liquid crystal rather than the display device panel. For this reason, it has been attempted to reduce mobile ions (ionic impurities) in the liquid crystal, but it is difficult to remove the ions highly and effectively, and the problem of display defects has not been solved. Furthermore, since such ionic impurities may elute from the cell constituent material over time and lack long-term reliability, it is required to keep the ionic impurity concentration low for a long period of time.
[0011]
Under such circumstances, the present inventors diligently studied a method for reducing the impurity ion component in the liquid crystal,
By providing a transparent ion getter film containing inorganic ultrafine particles with ion adsorption capacity between the transparent electrode and alignment film of the liquid crystal display cell, the ion content in the liquid crystal is reduced and the display quality of the liquid crystal display device is improved. The present inventors have found that this can be done and have completed the present invention.
[0012]
OBJECT OF THE INVENTION
The present invention has been made to solve the above-described problems in the prior art, that is, excellent in scratch resistance, acid resistance, alkali resistance, water resistance and insulation, and hydrophobic such as an electrode film or a polyimide resin. A coating solution for forming a transparent film, which has excellent adhesion to an alignment film made of a strong resin, etc. and can form a film that reduces impurity ion components in liquid crystals, and a substrate with a film having such a film And it aims at providing a liquid crystal display cell.
[0013]
SUMMARY OF THE INVENTION
The coating solution for forming a transparent ion getter film according to the present invention comprises:
(A) a matrix-forming component and (B) ion-adsorbing inorganic fine particles are dispersed in a mixed solvent composed of water and an organic solvent,
The average particle diameter of the (B) ion-adsorbing inorganic fine particles is in the range of 1 nm to 10 μm, and the ion adsorption capacity of the ion-adsorbing inorganic fine particles is in the range of 0.1 to 3.0 mmol / g. Yes.
[0014]
The (A) matrix-forming component is preferably composed of one or a mixture of two or more selected from acetylacetonato chelate compounds, organosilicon compounds, metal alkoxides, and polysilazanes.
[0015]
The substrate with a transparent ion getter film according to the present invention is characterized in that a transparent ion getter film formed by applying the coating solution for forming a transparent ion getter film on the surface of the substrate is formed.
[0016]
A first liquid crystal display cell according to the present invention comprises:
A pair of substrates with a transparent electrode, in which a transparent electrode film, a transparent ion getter film, and an alignment film are sequentially laminated on the surface of the substrate, are arranged at predetermined intervals so that the transparent electrodes face each other. In a liquid crystal display cell in which liquid crystal is sealed in a gap provided between the substrates with transparent electrodes,
The transparent ion getter film is a film formed by applying the coating liquid for forming the transparent ion getter film.
[0017]
The second liquid crystal display cell according to the present invention comprises:
A pair of substrates with a transparent electrode, in which a color filter, a transparent ion getter film, a transparent electrode film, and an alignment film are sequentially laminated on the surface of the substrate, are arranged at predetermined intervals so that the transparent electrodes face each other. In a liquid crystal display cell in which liquid crystal is sealed in a gap opened between the pair of substrates with transparent electrodes,
The transparent ion getter film is a film formed by applying the coating liquid for forming the transparent ion getter film.
[0018]
A third liquid crystal display cell according to the present invention comprises:
A pair of substrates with transparent electrodes in which a TFT array, a transparent ion getter film, a transparent electrode film, and an alignment film are sequentially laminated on the surface of the substrate are arranged at predetermined intervals so that the transparent electrodes face each other. In a liquid crystal display cell in which liquid crystal is sealed in a gap opened between the pair of substrates with transparent electrodes,
The transparent ion getter film is a film formed by applying the coating liquid for forming the transparent ion getter film.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the coating solution for forming a transparent ion getter film, the substrate with a film, and a liquid crystal display cell according to the present invention will be specifically described.
[0020]
[Coating liquid for forming transparent ion getter film]
First, the coating solution for forming a transparent ion getter film according to the present invention will be described.
In the coating solution for forming a transparent ion getter film according to the present invention, (A) a matrix-forming component and (B) ion-adsorbing inorganic fine particles are dispersed in a mixed solvent composed of water and an organic solvent.
(A) Matrix-forming component
The (A) matrix-forming component used in the coating solution for forming a transparent ion getter film of the present invention is selected from (a) acetylacetonato chelate compound, (b) organosilicon compound, (c) polysilazane, and (d) metal alkoxide. It is preferable that it consists of 1 type, or 2 or more types of mixtures. Such matrix-forming components are matrix precursors.
[0021]
(a) Acetyl acetonato chelate compound
The acetylacetonato chelate compound used in the present invention is a chelate compound having acetylacetone as a ligand, and is a compound represented by the following chemical formula (1) or a condensate thereof.
[0022]
[Chemical 1]

[0023]
[Wherein, a + b is 2 to 4, a is 0 to 3, b is 1 to 4, and R is -C._nH_{2n + 1}(N = 3 or 4) and X is —CH_Three, -OCH_Three, -C₂H_FiveOr -OC₂H_FiveIt is. M₁Is an element selected from Group IB, Group IIA, Group B, Group IIIA, Group B, Group IVA, Group B, Group VA, Group B, Group VIA, Group VIIA, Group VIII or Vanadyl (VO). Among these, preferred combinations of these elements and a and b are as shown in the following table. ]
[0024]
[Table 1]

[0025]
Specific examples of such compounds include, for example, dibutoxy-bisacetylacetonatozirconium, tributoxy-monoacetylacetonatozirconium, bisacetylacetonatolead, trisacetylacetonatoiron, dibutoxy-bisacetylacetonatohafnium, monoacetylacetate. And nato-tributoxy hafnium.
[0026]
(b) Silicon compounds
As the organosilicon compound used in the present invention,
General formula R_a-Si (OR ')_4-a                      (2)
(Where R is -C_nH_{2n + 1}Or C₆H_FiveAnd R 'is -C_nH_{2n + 1}Or -C₂H_FourOC_nH_{2n + 1}A is an integer from 0 to 3, and n is an integer from 1 to 4. ) Is used.
[0027]
Specifically, for example, tetramethoxysilane, tetraethoxysilane, monomethyltrimethoxysilane, monoethyltriethoxysilane, monoethyltrimethoxysilane, monomethyltriethoxysilane and the like are preferably used as such an organosilicon compound.
[0028]
These organosilicon compounds may be used as they are or after partial hydrolysis. Such partial hydrolysis can be obtained in accordance with a conventional method conventionally performed, for example, a method in which an organosilicon compound is mixed with an alcohol such as methanol or ethanol, and water and an acid are added to perform partial hydrolysis. .
[0029]
When the coating liquid for forming a transparent film according to the present invention to which the organosilicon compound is added is applied onto a substrate, and the resulting film is dried and fired, scratch resistance, acid resistance, alkali resistance, water resistance and insulation are obtained. A film having excellent properties is formed.
[0030]
(c) Metal alkoxide
Examples of the metal alkoxide used as a matrix forming component include M₂(OR)_n(Where M₂Is a metal atom, R is an alkyl group or -C_mH_2mO₂(M = 3 to 10), and n is M₂It is the same integer as the valence of. ) Or a condensate thereof is preferable, and one or two or more selected from these compounds or the condensates thereof can be used in combination. M in the above formula₂Is not particularly limited as long as it is a metal, but preferred M₂Are Be, Al, Sc, Ti, V, Cr, Fe, Ni, Zn, Ga, Ge, As, Se, Y, Zr, Nb, In, Sn, Sb, Te, Hf, Ta, W, Pb, Bi, Ce or Cu.
[0031]
As such a metal alkoxide, specifically, tetrabutoxyzirconium, diisopropoxy-dioctyloxytitanium, diethoxylead and the like are preferably used.
[0032]
When the coating solution for forming a transparent film according to the present invention to which the above metal alkoxide is added is applied, dried, and fired, the metal alkoxide is polymerized and cured, so that it has excellent scratch resistance, acid resistance, alkali resistance, water resistance and insulation. A film is formed.
[0033]
(d) Polysilazane
The polysilazane used as a matrix forming component has a repeating unit represented by the following formula (3).
[0034]
[Chemical 2]

[0035]
[However, in the formula, R₁, R₂And R_ThreeAre each a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ]
When the polysilazane represented by the formula (3) is used as the matrix forming component, polysilazane whose alkyl group is a methyl group, an ethyl group, or a propyl group is preferable. In this case, there is no alkyl group that decomposes during heating, and there is little shrinkage of the film during heating. Therefore, cracks are less likely to occur during shrinkage stress, and a transparent ion getter film with almost no cracks can be obtained.
[0036]
The polysilazane having a repeating unit represented by the above formula (3) may be linear or cyclic, and contains a mixture of linear polysilazane and cyclic polysilazane. May be.
[0037]
Furthermore, the number average molecular weight of such polysilazane is desirably in the range of 500 to 10,000, preferably 1,000 to 4,000. When the number average molecular weight is less than 500, the low molecular weight polysilazane volatilizes at the time of heat curing, and the obtained transparent ion getter film tends to be porous. When the molecular weight exceeds 10,000, the fluidity of the coating solution is low. There is a tendency to decrease.
[0038]
In the present invention, such a matrix forming component (A) may be used alone or in combination of two or more.
(A) When two or more types are used together as a matrix forming component, (a) acetylacetonato chelate compound, (b) organosilicon compound, (c) polysilazane, and (d) metal alkoxide are converted to oxide and nitride, respectively. That is, (a) acetylacetonato chelate compound (M₁O_x) And (b) an organosilicon compound (SiO)₂), (C) polysilazane (SiN), (d) metal alkoxide (M)₂O_x), It is desirable that the weight ratio of each component satisfies the following relationship.
[0039]
0 ≦ M₁O_x/ (SiO₂+ SiN + M₂O_x) ≦ 10
When an acetylacetonato chelate compound is used, when this value is 0.001 or more, a film excellent in alkali resistance, acid resistance, salt water resistance, water resistance, and solvent resistance can be obtained.
[0040]
The blending ratio of the organosilicon compound and polysilazane to the metal alkoxide is 0 ≦ M₂O_x/ (SiO₂+ SiN + M₂O_x) ≦ 1.0 is preferable.
(B) Ion-adsorbing inorganic fine particles
The (B) ion-adsorbing inorganic fine particles used in the coating liquid for forming a transparent ion getter film of the present invention are fine particles that can adsorb inorganic ions, particularly inorganic ions present in liquid crystals, and have an average particle diameter of 1 nm to It is preferable that it exists in the range of 10 micrometers, and a more preferable range is 10 nm-5 micrometers. The ion adsorption capacity is preferably in the range of 0.1 to 3.0 mmol / g, preferably 0.2 to 3.0 mmol / g. Examples of ions that can be adsorbed by (B) ion-adsorbing inorganic fine particles include Na⁺, K⁺, Rb⁺, Cs⁺, Li⁺, Ag⁺, Mg⁺, Ca⁺, Sr⁺, Ba⁺, NH_Four ⁺Etc.
[0041]
Ion-adsorbing inorganic fine particles have a higher ion adsorption capacity and a higher ion adsorption rate when the average particle size becomes smaller. However, when the average particle size is less than 1 nm, the ion adsorption capacity can be further increased. In addition, the adsorption rate does not increase, and another film made of a highly hydrophobic resin such as polyimide resin cannot be formed on the surface of the transparent ion getter film with good adhesion. On the other hand, when the average particle diameter exceeds 10 μm, the ion adsorption capacity and the ion adsorption rate may be lowered and the transparency of the ion getter film may be lowered.
[0042]
In particular, an ion getter film formed between an electrode film and an alignment film with a thickness of 30 nm to 100 μm using a coating liquid containing ion-adsorbing inorganic fine particles having an average particle diameter of 50 nm or less, preferably 10 to 40 nm Since the surface has a uniform surface roughness of 1 to 10 nm, it has excellent adhesion to a hydrophobic alignment film.
[0043]
If the ion adsorption capacity is less than 0.1 mmol / g, ions cannot be sufficiently adsorbed, which may cause display defects due to mobile ions and lack long-term reliability. It is difficult to obtain ion-adsorbing inorganic fine particles having a large ion adsorption amount.
[0044]
The average particle diameter of such ion-adsorptive inorganic fine particles can be determined by laser Doppler method or TEM observation.
Further, the ion adsorption capacity of the ion-adsorbing inorganic fine particles is measured by the following method.
[0045]
To 100 g of 1% by weight NaCl aqueous solution, 1.5 g of an inorganic ion adsorbent dried and constant at 120 ° C. is added and stirred for 15 hours at room temperature (25 ° C.), followed by filtration to collect a filtrate. The Na ion concentration in the solution is analyzed by atomic absorption, and the ion adsorption amount (mmol / g) of the inorganic ion adsorbent is determined from the concentration difference from the Na ion concentration of the original NaCl aqueous solution.
[0046]
The ion-adsorbing inorganic fine particles used in the coating liquid for forming a transparent ion getter film of the present invention are not particularly limited as long as the ion adsorption capacity and the average particle diameter are within the above ranges._X・ NH₂O, and any one of water of crystallization other than adhering water, structural hydroxyl group, and surface hydroxyl group is converted into a metal oxide (MO_X) Water per mole (H₂A metal oxide having O) in the range of mole number n of 0.02 to 5 is preferred. A more preferable range is 0.1 to 3.
[0047]
Examples of the metal oxide constituting such ion-adsorbing inorganic fine particles include SiO.₂, Al₂O_Three, ZrO₂, TiO₂, SnO₂, In₂O_Three, Sb₂O_FiveMetal oxides such as SiO₂・ Al₂O_Three, SiO₂・ TiO₂, In₂O_Three・ SnO₂, Sb₂O_Five・ SnO₂, SnO₂・ In₂O_Three・ Sb₂O_FiveAnd a mixed metal oxide or solid solution such as zeolite (crystalline aluminosilicate). Furthermore, a mixture of two or more of these is also preferably used.
[0048]
If the value of the number of moles n of water in the above-mentioned ion-adsorptive inorganic fine particles is less than 0.02 mol, the ion adsorption capacity is too small to effectively adsorb ions in the liquid crystal, exceeding 5 mol. If it is high, it is not preferable because when the ITO film is formed on the ion getter film by a sputtering method, the time to reach the vacuum in the sputtering apparatus tends to be long because it is desorbed as water molecules.
[0049]
The number of moles n of water contained in such ion-adsorptive inorganic fine particles is determined by the amount of water reduced to 500 ° C. by differential thermal analysis of the ion-adsorptive inorganic fine particles dried and constant at 120 ° C. , By calculating as the number of moles of water per mole of metal oxide.
[0050]
Further, if necessary, insulating or conductive inorganic compound fine particles other than the ion-adsorbing inorganic fine particles may be used.
Such ion-adsorbing inorganic fine particles are preferably used in the form of a sol dispersed in water or an organic solvent. However, the ion-adsorbing inorganic fine particles are monodispersed or nearly monodispersed in a coating solution for forming a transparent ion getter film. If it can be dispersed in a state, ion-adsorbing inorganic fine particles in a state other than the sol may be used.
[0051]
Coating liquid composition for transparent film formation
In the coating liquid for forming a transparent film according to the present invention, (A) a matrix-forming component and (B) ion-adsorbing inorganic fine particles are uniformly dissolved or dispersed in a mixed solvent composed of water and an organic solvent.
[0052]
As the organic solvent used in such a coating solution for forming a transparent film, a known organic solvent selected from alcohols, ethers, glycols, ketones and the like is used. Such organic solvents may be used alone or in admixture of two or more.
[0053]
The solid content concentration in the coating liquid according to the present invention is preferably 15% by weight or less in terms of a total value obtained by converting (A) the matrix-forming component and (B) ion-adsorbing inorganic fine particles into oxides and nitrides. . If this value exceeds 15% by weight, the storage stability of the coating solution tends to decrease. On the other hand, if this solid content concentration is extremely low, a large number of coating operations are repeated to obtain the desired film thickness. Therefore, the solid content concentration is practically 0.1% by weight or more.
[0054]
The matrix-forming component (A) is desirably contained in the coating solution in an amount of 30 to 95% by weight in the formed ion getter film in terms of oxide and nitride.
[0055]
In addition, (B) the ion-adsorbing inorganic fine particles are preferably present in the coating solution in an amount in the range of 5 to 70% by weight in the formed ion getter film in terms of oxide. Within this range, if ion-adsorbing inorganic fine particles are present in the ion getter film, the surface of the ion getter film obtained from this coating solution is further separated from a strongly hydrophobic resin such as a polyimide resin. Thus, a transparent ion getter film that can effectively reduce ions in the liquid crystal panel can be formed. If the concentration exceeds 70% by weight, the adhesion between the ion getter film formed from this coating solution and the lower substrate, TFT array, color filter, or the like may deteriorate.
[0056]
Furthermore, when insulating or conductive inorganic compound fine particles other than these ion-adsorbing inorganic fine particles are included as required, the coating liquid contains other than ion-adsorbing inorganic fine particles and ion-adsorbing inorganic fine particles. The fine particles are preferably present in the formed ion getter film in an amount in the range of 5 to 70% by weight as the total of oxide and nitride.
[0057]
The water concentration in the coating liquid for forming a transparent film according to the present invention is preferably in the range of 0.1 to 50% by weight. When the water concentration is less than 0.1% by weight, hydrolysis, polycondensation and complexation of acetylacetonato chelate compound, organosilicon compound, polysilazane and metal alkoxide are not sufficiently performed, and the resulting coating has scratch resistance. Durability tends to decrease, and if it exceeds 50% by weight, the coating solution tends to be repelled from the substrate during coating, and it may be difficult to form a coating.
[0058]
In the coating liquid for forming a transparent film according to the present invention, the mixing ratio of (A) matrix-forming component and (B) ion-adsorbing inorganic fine particles contained in the coating liquid, (A) metal species contained in the matrix-forming component, (B) The refractive index and dielectric constant of the resulting coating can be freely controlled depending on the type of ion-adsorbing inorganic fine particles.
[0059]
By forming an ion getter film having a controlled refractive index on the transparent electrode of the substrate with the transparent electrode in this way, the electrode can be seen through, for example, higher than the refractive index of the alignment film formed thereon. Can be prevented.
[0060]
The transparent ion getter film formed using the coating solution for forming a transparent ion getter film of the present invention has a pore volume in the range of 0.01 to 0.3 ml / g and an average pore diameter in the range of 1 to 20 nm. It is preferable to have the pore which exists in.
[0061]
When the pore volume is less than 0.01 ml / g, the ion adsorption ability of the ion-adsorbing inorganic fine particles cannot be sufficiently exhibited due to the small number of pores. When the pore volume exceeds 0.3 ml / g, the strength of the membrane is insufficient. It may become.
[0062]
In addition, when the average pore diameter is less than 1 nm, the ion diffusion rate when a voltage is applied is slow, and the ion-adsorbing ability of the ion-adsorbing inorganic fine particles may not be sufficiently exhibited. On the other hand, when the average pore diameter exceeds 20 nm, the strength of the film may be insufficient.
[0063]
The pore volume and the average pore diameter of such a transparent ion getter film are such that the transparent ion getter film formed on the substrate is peeled off and the peeled transparent ion getter film is N₂Measured by adsorption method.
[0064]
[Substrate with coating]
Next, the coated substrate according to the present invention will be specifically described.
The coated substrate according to the present invention is characterized in that a transparent ion getter film formed by applying the coating liquid for forming a transparent ion getter film is formed on the surface of the substrate.
[0065]
The pore volume of the transparent ion getter membrane is preferably in the range of 0.01 to 0.3 ml / g, preferably 0.05 to 0.2 ml / g. The average pore diameter of the transparent ion getter film is preferably in the range of 1 to 20 nm, preferably 2 to 8 nm.
[0066]
The substrate with a transparent ion getter film according to the present invention is a glass, plastic or the like substrate surface such as dipping method, spinner method, spray method, roll coater method, flexographic printing, etc. The film formed on the surface of the base material in this way is then dried at room temperature to 90 ° C. and further cured by heating to 200 ° C. or higher, and in some cases 300 ° C. or higher. The
[0067]
Furthermore, the coating film formed on the base material may be subjected to curing acceleration treatment by the following method.
Specifically, as the curing acceleration treatment, after the coating process or the drying process or during the drying process, the uncured film is irradiated with an electromagnetic wave having a wavelength shorter than that of visible light, or the uncured film is cured. For example, it may be exposed to a gas atmosphere that promotes the reaction.
[0068]
Specific examples of the electromagnetic wave applied to the uncured coating film before heating include ultraviolet rays, electron beams, X-rays, and γ rays, and ultraviolet rays are particularly preferable.
When performing the irradiation treatment with ultraviolet rays, for example, the emission intensity becomes maximum at about 250 nm and 360 nm, and the light intensity is 10 mW / cm.²Using the above high-pressure mercury lamp as an ultraviolet ray source, 100 mJ / cm²Or more, preferably 1000 mJ / cm²It is desirable to irradiate ultraviolet rays having the above energy amount.
[0069]
Examples of the gas that accelerates the curing reaction of the uncured film before heating include ammonia and ozone. Moreover, when performing such a gas treatment, it is desirable to expose the uncured stage coating to the above active gas atmosphere having a gas concentration of 100 to 100,000 ppm, preferably 1000 to 10,000 ppm for 1 to 60 minutes. .
[0070]
The same effect can be obtained even if this gas treatment is performed after heat curing.
When the curing acceleration treatment as described above is performed, polycondensation and complexation of (A) matrix-forming components such as acetylacetonate chelate compound, organosilicon compound, polysilazane, and metal alkoxide contained in the transparent ion getter film are promoted. At the same time, evaporation of water and solvent remaining in the film is also promoted. For this reason, the heat curing conditions such as the heating temperature and the heating time required in the next heating step are relaxed, and the production of the substrate with an ion getter film according to the present invention can be efficiently advanced.
[0071]
The base material with a transparent ion getter film according to the present invention is obtained by the steps as described above. The transparent ion getter film formed on this substrate has high surface hardness, excellent adhesion and transparency, and excellent durability such as scratch resistance, water resistance and alkali resistance. The mobile ions can be effectively reduced, the insulation resistance is high, and it is also suitable as an insulating film.
[0072]
[Liquid crystal display cell]
Next, the liquid crystal display cell according to the present invention will be specifically described.
The liquid crystal display cells according to the present invention each use a substrate with a transparent electrode having a transparent ion getter film formed using the coating liquid for forming a transparent ion getter film.
[0073]
The first liquid crystal display cell according to the present invention includes a pair of substrates with a transparent electrode in which a transparent electrode film, a transparent ion getter film, and an alignment film are sequentially laminated on the surface of at least one substrate. In this liquid crystal display cell, liquid crystal is sealed in a gap provided between the pair of substrates with a transparent electrode.
[0074]
FIG. 1 is a cross-sectional view schematically showing an embodiment of the first liquid crystal display cell according to the present invention.
In the liquid crystal display cell 1, a pair of substrates with a transparent electrode 2 in which a transparent electrode film 12, a transparent ion getter film 13, and an alignment film 14 are sequentially laminated on the surface of a glass substrate 11 are respectively formed into transparent electrode films 12, 12. A plurality of spacer particles 5 are arranged at a predetermined interval d so as to face each other, and the liquid crystal 4 is sealed in a gap between the transparent electrode films 12 and 12 opened at the predetermined interval d. .
[0075]
The transparent ion getter film 13 is a film formed by applying the above-mentioned transparent ion getter film forming coating solution on the transparent electrode film 12, and this film has high surface hardness and excellent transparency and scratch resistance. In addition, the insulation resistance is high, the adhesion between the transparent ion getter film 13 and the alignment film 14 is good, and (movable) ions in the liquid crystal panel can be effectively reduced.
[0076]
In the first liquid crystal display cell according to the present invention, SiO 2 is further interposed between the glass substrate 11 and the transparent electrode film 12.₂Various modifications are possible, such as using a substrate with a transparent electrode on which an alkali passivation film such as a film is formed.
[0077]
In the second liquid crystal display cell according to the present invention, a pair of substrates with a transparent electrode, in which a color filter, a transparent ion getter film, a transparent electrode film, and an alignment film are sequentially laminated on the surface of at least one substrate, In this liquid crystal display cell, liquid crystal is sealed in a gap formed between the pair of substrates with a transparent electrode, which is arranged with a predetermined interval so that the electrodes face each other.
[0078]
FIG. 2 is a schematic view schematically showing an example of an embodiment of the second liquid crystal display cell according to the present invention.
In the color liquid crystal display device 1 ′ whose characteristic portion is shown in FIG. 2, an alkali passivation film 21b, a plurality of pixel electrodes 21c, a transparent ion getter film 21d, and an alignment film 21e are sequentially laminated on a glass substrate 21a. A liquid crystal display cell 2 ′ having a counter electrode plate 22 in which an alkali passivation film 22b, a color filter 22c, a transparent ion getter film 22d, a transparent electrode 22e, and an alignment film 22f are sequentially laminated on a glass substrate 22a. The liquid crystal display cell includes a pair of polarizing plates 3 ′ and 4 ′ on both sides. Among these, the transparent ion getter films 21d and 22d are films formed by applying the coating liquid for forming the transparent ion getter film.
[0079]
The electrode plate 21 and the counter electrode plate 22 of the liquid crystal display cell 2 face each of the plurality of pixel electrodes 21c and the plurality of color filters R, G, B with the glass substrates 21a and 22a facing outside. Are arranged to be. A liquid crystal 23 is sealed in a gap between the electrode plate 21 and the counter electrode plate 22.
[0080]
Further, a circuit (not shown) is formed between each of the plurality of pixel electrodes 21c and the transparent electrode 22e, and this circuit is connected to the main body of the color liquid crystal display device 1. The color filter 22c formed on the passivation film 22b of the counter electrode plate 22 is composed of a plurality of color elements R (red filter), G (green filter), and B (blue filter). A circuit formed between the specific pixel electrode 21c and the transparent electrode 22e is actuated by a display signal sent from the liquid crystal display device 1 ′ main body so as to be regularly arranged so as to correspond to the display signal. A color image can be observed through the polarizing plate 4 disposed outside the counter electrode plate 22.
[0081]
A third liquid crystal display cell according to the present invention includes a pair of substrates with transparent electrodes, each of which has a TFT array, a transparent ion getter film, a transparent electrode film, and an alignment film sequentially stacked on the surface of at least one substrate. This is a liquid crystal display cell in which liquid crystals are sealed in a gap formed between the pair of substrates with a transparent electrode. The liquid crystal display cells are arranged at a predetermined interval so that the transparent electrodes face each other.
[0082]
FIG. 3 is a schematic cross-sectional view schematically showing an example of an aspect of the third liquid crystal display cell according to the present invention.
The liquid crystal display cell 1 ″ has a TFT array 32 formed on the surface thereof, a transparent insulating substrate 31 in which a transparent ion getter film 33, a pixel electrode 34 and an alignment film 35 are sequentially laminated on the surface of the TFT array 32;
A counter substrate 41 having a black matrix (shielding film) 42, a color filter 43, a transparent ion getter film 44, a counter electrode 45, and an alignment film 46 sequentially stacked on the surface;
The alignment films 35 and 46 are configured to face each other with the liquid crystal layer 51 interposed therebetween.
[0083]
As shown in FIG. 1, spacer particles may be interposed between the alignment films 35 and 46.
The TFT array 32 includes TFT elements, data electrodes, and the like.
[0084]
In the first to third liquid crystal display cells, the transparent ion getter film preferably has a pore volume in the range of 0.01 to 0.3 ml / g and an average pore diameter in the range of 1 to 20 nm.
[0085]
In the liquid crystal display cell according to the present invention as described above, mobile ions (ionic impurities) in the liquid crystal are reduced by the transparent ion getter film. For this reason, the liquid crystal display cell according to the present invention is excellent in high voltage holding ratio characteristics, does not cause display defects, has excellent long-term reliability, and consumes less power, thereby improving power efficiency.
[0086]
【The invention's effect】
As described above, the transparent ion getter film-forming coating solution according to the present invention comprises (A) one or two selected from acetylacetonato chelate compounds, organosilicon compounds, polysilazanes, and metal alkoxides as a matrix-forming component. It contains a mixture or composite of at least seeds and (B) ion-adsorbing inorganic fine particles having a specific ion adsorption capacity and particle size.
[0087]
For this reason, the surface of the substrate has an average surface roughness of, for example, 1 to 10 nm on average using a coating liquid containing ion-adsorbing inorganic fine particles having an average particle diameter of 50 nm or less, and the unevenness height is substantially constant and the distribution thereof. A uniform film can be formed, and the obtained film is excellent in scratch resistance, acid resistance, alkali resistance, water resistance and insulation, and further, a film formed thereon, such as a polyimide resin, etc. Excellent adhesion to films made of highly hydrophobic resin.
Further, the surface of an ion getter film formed on a substrate having irregularities using the coating liquid according to the present invention, for example, a substrate with a TFT array or a substrate with a color filter, is flattened, and thus is in contact with the liquid crystal layer. Since the alignment film surface is also flattened, it is effective for suppressing liquid crystal display disturbance due to the surface shape, preventing the occurrence of display domains, reducing light leakage during panel display, and improving contrast.
[0088]
In particular, since the ion getter film according to the present invention includes inorganic ion-adsorbing fine particles having ion adsorption ability, it can effectively reduce (movable) ions in the liquid crystal panel.
[0089]
For this reason, the film formed from the coating solution for forming a transparent ion getter film according to the present invention is an insulating film or a TFT array formed between the transparent electrode film and the alignment film of the transparent electrode used in the liquid crystal display cell. It is suitable as a low dielectric constant planarizing film formed on a substrate with a color filter or a substrate with a color filter, and the obtained liquid crystal display device is excellent in display quality and long-term reliability.
[0090]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
[0091]
[Example 1]
Preparation of coating solution
As a matrix forming component, ethyl silicate 28 (manufactured by Tama Chemical Industry Co., Ltd .: SiO₂14.6 g (concentration 28.8 wt%) was added to a mixed solvent of 5 g of pure water and 62.3 g of ethyl alcohol, 0.1 g of nitric acid having a concentration of 61% was added thereto, and a partial hydrolyzate of ethyl silicate ( An oligomer) solution (dispersion) was prepared.
[0092]
Antimony pentoxide fine particles (Sb) having an average particle diameter of 20 nm and an ion adsorption capacity of 2.4 mmol / g as ion-adsorbing inorganic fine particles were added to this solution.₂O_Five・ 2.7H₂O) was uniformly dispersed in hexylene glycol, 18 g of an ion-adsorbing inorganic fine particle sol having a solid concentration of 10% by weight was added and stirred for 24 hours, and then 70 g of hexylene glycol was added, followed by distillation under reduced pressure. A 6.0 wt% coating solution (A) was prepared.
[0093]
Formation of transparent ion getter film
The coating liquid (A) is applied by flexographic printing on a patterned glass substrate with an ITO display electrode (Asahi Glass Co., Ltd .: 30Ω / □ or less), and the resulting coating film is dried at 90 ° C. for 5 minutes. After that, the integrated light quantity is 6,000mJ / cm with a high-pressure mercury lamp.²An ion getter film (A) was formed by irradiating ultraviolet rays under the conditions of (measured with a 365 nm sensor) and then baking at 300 ° C. for 30 minutes. Table 2 shows the characteristics of the obtained ion getter film (A). The film thickness of the obtained ion getter film (A) was 80 nm when measured with a stylus type surface roughness meter.
[0094]
Creation of liquid crystal display cell
Next, a polyimide film-forming paint (Nissan Chemical Co., Ltd .: Sunever) is applied on the ion getter film (A) by flexographic printing, dried at 100 ° C. for 5 minutes, and then heated at 240 ° C. for 30 minutes. A polyimide film was formed, and then a rubbing treatment was performed.
[0095]
In this way, a substrate with a transparent electrode was prepared in which a transparent electrode, an ion getter film (A), and a rubbing-treated alignment film were sequentially laminated on a glass substrate.
Using two obtained substrates with transparent electrodes, spacers (particle diameter corresponding to the distance between the two substrates) are dispersed on one substrate, and epoxy resin and silica fine particles are dispersed on the other substrate. A sealing material for sealing is printed, these substrates are bonded so that the transparent electrodes face each other, STN liquid crystal is sealed, and the sealing port is sealed with a sealing material. )created.
[0096]
Measurement of mobile ion content
The amount of mobile ions in the obtained liquid crystal display cell (A) was measured using an ion density measuring device (manufactured by Toyo Technica Co., Ltd .: MTR-1) under conditions of an applied voltage of 10 V and a triangular wave frequency of 0.1 Hz. No peak due to mobile ions in the liquid crystal was detected.
[0097]
Observation of display unevenness of liquid crystal display cell
In addition, ten liquid crystal display cells (A) were prepared by the above method, a lighting display test was performed, and the presence or absence of display unevenness was observed with sight. At this time, the number of panels in which display unevenness did not occur was examined.
[0098]
The results are shown in Table 2.
Evaluation of long-term reliability
Ten liquid crystal display cells (A) prepared by the above method were exposed to a high temperature and high humidity environment (relative humidity 95%, temperature 80 ° C.) for 500 hours, and then a lighting display test of the liquid crystal display cell was performed. Visual observation was performed about the presence or absence of the display nonuniformity. At this time, the number of panels in which display unevenness did not occur was examined.
[0099]
The results are shown in Table 2.
[0100]
[Example 2]
Preparation of coating solution
Silica fine particles (SiO 2) having an average particle size of 25 nm and an ion adsorption capacity of 0.2 mmol / g obtained by drying silica sol as ion-adsorbing inorganic fine particles₂・ 0.1H₂A coating solution (B) having a solid content concentration of 6.0% by weight was prepared in the same manner as in Example 1 except that O) was used.
[0101]
Formation of transparent ion getter film and liquid crystal display cell
In the same manner as in Example 1, an ion getter film (B) was formed to prepare a liquid crystal cell (B). Table 2 shows the characteristics of the obtained ion getter film (B).
[0102]
Measurement of mobile ion content
When the amount of mobile ions in the obtained liquid crystal display cell (B) was measured, a peak due to mobile ions was detected in the vicinity of an applied voltage of 1 V, and the amount of mobile ions was 6.0 nC / cm.²Met.
[0103]
Observation of display unevenness of liquid crystal display cell
Further, the liquid crystal display cell (B) was visually observed for the presence or absence of display unevenness in the same manner as in Example 1. The results are shown in Table 2.
[0104]
Evaluation of long-term reliability
Further, the long-term reliability of the liquid crystal display cell (B) was evaluated in the same manner as in Example 1. The results are shown in Table 2.
[0105]
[Example 3]
Preparation of coating solution
Silica alumina sol having an average particle size of 25 nm and an adsorption capacity of 0.25 SiO obtained by drying silica alumina sol (catalyst conversion industry: USB sol) as ion-adsorbing inorganic fine particles₂・ 0.75Al₂O_Three・ 0.3H₂A coating solution (C) having a solid concentration of 6.0% by weight was prepared in the same manner as in Example 1 except that O) was used.
[0106]
Formation of transparent ion getter film and liquid crystal display cell
In the same manner as in Example 1, an ion getter film (C) was formed and a liquid crystal cell (C) was prepared. Table 2 shows the characteristics of the obtained ion getter film (C).
[0107]
Measurement of mobile ion content
When the amount of mobile ions in the obtained liquid crystal display cell (C) was measured, a peak due to mobile ions was detected in the vicinity of an applied voltage of 1 V, and the amount of mobile ions was 2.5 nC / cm.²Met.
[0108]
Observation of display unevenness of liquid crystal display cell
Further, the liquid crystal display cell (C) was visually observed for the presence or absence of display unevenness in the same manner as in Example 1. The results are shown in Table 2.
[0109]
Evaluation of long-term reliability
Further, the long-term reliability of the liquid crystal display cell (C) was evaluated in the same manner as in Example 1. The results are shown in Table 2.
[0110]
[Example 4]
Preparation of coating solution
Methyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: SiO) as a matrix forming component₂100 g of 44.1% by weight) and tributoxyzirconium acetylacetonate (Matsumoto Pharmaceutical Co., Ltd .: ZrO)₂17 g of 13.5 wt%) was added to a mixed solvent of 200 g of isopropyl alcohol and 60 g of butanol. While stirring this, 114 g of pure water and 1.0 g of nitric acid having a concentration of 61% were added, and the mixture was added at 60 ° C. for 15 hours. A dispersion of hydrolysis and polycondensate of methyltrimethoxysilane and tributoxyzirconium acetylacetonate was prepared. The dispersion was cooled to 30 ° C. or less, an anion exchange resin was added to remove anions, and then the anion exchange resin was separated to obtain a dispersion having a pH of 5.5.
[0111]
Next, 211 g of the same antimony pentoxide fine particle dispersion sol used in Example 1, 100 g of ethyl cellosolve, and 90 g of diethylene glycol were added to this dispersion, followed by vacuum distillation to obtain a coating solution (D) having a solid content concentration of 20% by weight. Prepared.
[0112]
Formation of ion getter film
On the glass substrate on which the color filter is formed, the coating solution (D) is applied by a spin coating method at a rotation speed of 800 rpm, then dried at 50 ° C. for 120 minutes, and then heat-treated at 220 ° C. for 60 minutes. The color filter pixel was overcoated by forming a 6 μm ion getter film (D). Table 2 shows the characteristics of the obtained ion getter film (D).
[0113]
Further, an ITO film was formed on the ion getter film (D) by sputtering.
Creation of liquid crystal display cell
This ITO film was patterned by a conventional method to form a display electrode, on which a polyimide alignment film was formed in the same manner as in Example 1, followed by a rubbing treatment. In this way, a pair of substrates with a transparent electrode was obtained in which a color filter, an ion getter film (D), a transparent electrode, and a rubbing-treated alignment film were sequentially laminated on a glass substrate.
[0114]
Next, the substrate with a common electrode and a spacer were attached to each other with a sealing material, and STN liquid crystal was injected into the gap between the substrates, and the injection port was sealed with a sealing material to prepare a liquid crystal cell (D).
[0115]
Measurement of mobile ion content
The amount of mobile ions in the obtained liquid crystal display cell (D) was measured, but no peak due to mobile ions was detected.
[0116]
Observation of display unevenness of liquid crystal display cell
Further, the liquid crystal display cell (D) was visually observed for the presence or absence of display unevenness in the same manner as in Example 1. The results are shown in Table 2.
[0117]
Evaluation of long-term reliability
Further, the long-term reliability of the liquid crystal display cell (D) was evaluated in the same manner as in Example 1. The results are shown in Table 2.
[0118]
[Comparative Example 1]
Preparation of coating solution
A coating solution (E) having a solid content of 6.0% by weight was prepared in the same manner as in Example 1 except that the antimony pentoxide fine particle-dispersed sol was not used.
[0119]
Formation of ion getter film and liquid crystal display cell
In the same manner as in Example 1, an ion getter film (E) was formed and a liquid crystal cell (E) was prepared. The characteristics of the obtained ion getter film (E) are shown in Table 2.
[0120]
Measurement of mobile ion content
When the amount of mobile ions in the obtained liquid crystal display cell (E) was measured, a peak due to mobile ions was detected in the vicinity of an applied voltage of 1 V, and the amount of mobile ions was 19.6 nC / cm.²Met.
[0121]
Observation of display unevenness of liquid crystal display cell
Further, the liquid crystal display cell (E) was visually observed for the presence or absence of display unevenness in the same manner as in Example 1. The results are shown in Table 2.
[0122]
Evaluation of long-term reliability
Further, the long-term reliability of the liquid crystal display cell (E) was evaluated in the same manner as in Example 1. The results are shown in Table 2.
[0123]
[Comparative Example 2]
Preparation of coating solution
A coating liquid (F) having a solid concentration of 20% by weight was prepared in the same manner as in Example 4 except that the antimony pentoxide fine particle dispersed sol was not used.
[0124]
Formation of ion getter film and liquid crystal display cell
In the same manner as in Example 2, an ion getter film (F) and a liquid crystal cell (F) were formed. The properties of the obtained ion getter film (F) are shown in Table 2.
[0125]
Measurement of mobile ion content
When the amount of mobile ions in the obtained liquid crystal display cell (F) was measured, a peak due to mobile ions was detected when the applied voltage was around 1 V, and the amount of mobile ions was 25 nC / cm.²Met.
[0126]
Observation of display unevenness of liquid crystal display cell
Further, the liquid crystal cell (F) was visually observed for the presence or absence of display unevenness in the same manner as in Example 1. The results are shown in Table 2.
[0127]
[Table 2]

[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of one embodiment of a first liquid crystal display cell according to the present invention.
FIG. 2 is a schematic cross-sectional view of one embodiment of a second liquid crystal display cell according to the present invention.
FIG. 3 is a schematic cross-sectional view of one embodiment of a third liquid crystal display cell according to the present invention.
[Explanation of symbols]
1, 1 ', 1 "... Liquid crystal display cell
2, 2 '... Liquid crystal display cell
3, 4 ... Polarizing plate
5 ... Spacer particles
6 ... Liquid crystal
11 ..... Glass substrate
12 .... Transparent electrode film
13 .... Transparent ion getter membrane
14 .... Alignment film
21 ・ ・ ・ ・ ・ ・ ・ Electrode plate
21a ... Glass substrate
21b .... Alkali passivation film
21c .... Multiple pixel electrodes
21d ・ ・ ・ ・ ・ ・ Transparent ion getter membrane
21e ・ ・ ・ ・ ・ ・ Alignment film
22 .... Counter electrode plate
22a ... Glass substrate
22b ... Alkali passivation film
22c ・ ・ ・ ・ ・ ・ Color filter
22d ... Transparent ion getter membrane
22e ··· Transparent electrode
22f ・ ・ ・ ・ ・ ・ Alignment film
23 ..... LCD
31 ... Transparent insulating substrate
32 ... TFT array
33 .... Transparent ion getter film
34 ..... Pixel electrode
35 ..... Alignment film
36 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Insulating film
41... Counter substrate
42 ... Black matrix (shielding film)
43 ... Color filters
44 ・ ・ ・ ・ ・ ・ ・ Transparent ion getter membrane
45 ..... Counter electrode
46 ..... Alignment film
51 .... Liquid crystal layer

Claims (8)

(A) a matrix-forming component and (B) ion-adsorbing inorganic fine particles are dispersed in a mixed solvent composed of water and an organic solvent,
The (B) ion-adsorbing inorganic fine particles are represented by MO _x · nH ₂ O (MO _x is SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , Sb ₂ O ₅ , SiO ₂ · Al ₂ O ₃ , SiO ₂ · TiO ₂ , In ₂ O ₃ · SnO ₂ , Sb ₂ O ₅ · SnO ₂ , SnO ₂ · In ₂ O ₃ · Sb ₂ O ₅ , crystalline aluminosilicate be), and n is in the range of 0.02 to 5,
Transparent ion getter film formation characterized in that the average particle size of the ion-adsorbing inorganic fine particles is in the range of 1 nm to 10 μm and the ion adsorption capacity of the ion-adsorbing inorganic fine particles is in the range of 0.1 to 3.0 mmol / g Coating liquid.   2. The coating for forming a transparent ion getter film according to claim 1, wherein the matrix-forming component comprises one or a mixture of two or more selected from acetylacetonato chelate compounds, organosilicon compounds, metal alkoxides and polysilazanes. liquid.   A substrate with a transparent ion getter film, wherein a transparent ion getter film formed by applying the coating solution for forming a transparent ion getter film according to claim 1 or 2 is formed on a surface of the substrate.   The transparent ion getter membrane according to claim 3, wherein the pore volume of the transparent ion getter membrane is in the range of 0.01 to 0.3 ml / g, and the average pore diameter is in the range of 1 to 20 nm. Base material.   A pair of substrates with a transparent electrode, in which a transparent electrode film, a transparent ion getter film, and an alignment film are sequentially laminated on the surface of at least one substrate, are arranged at predetermined intervals so that the transparent electrodes face each other. In a liquid crystal display cell in which liquid crystal is sealed in a gap provided between the pair of substrates with a transparent electrode, the transparent ion getter film is a coating liquid for forming a transparent ion getter film according to claim 1 or 2. A liquid crystal display cell, which is a film formed by coating.   A pair of substrates with a transparent electrode in which a color filter, a transparent ion getter film, a transparent electrode film, and an alignment film are sequentially laminated on the surface of at least one substrate are spaced apart from each other so that the transparent electrodes face each other. The liquid crystal display cell in which liquid crystal is sealed in a gap formed between the pair of substrates with transparent electrodes, and the transparent ion getter film is for forming a transparent ion getter film according to claim 1 or 2. A liquid crystal display cell, which is a film formed by applying a coating solution.   A pair of substrates with a transparent electrode, in which a TFT array, a transparent ion getter film, a transparent electrode film, and an alignment film are sequentially laminated on the surface of at least one substrate, have a predetermined interval so that the transparent electrodes face each other. 3. A transparent ion getter film according to claim 1 or 2, wherein the transparent ion getter film is disposed in a liquid crystal display cell that is disposed in a gap and liquid crystal is sealed in a gap formed between the pair of substrates with transparent electrodes. A liquid crystal display cell, which is a film formed by applying a coating liquid for use.   The pore volume of the transparent ion getter membrane is in the range of 0.01 to 0.3 ml / g, and the average pore diameter is in the range of 1 to 20 nm. Liquid crystal display cell.

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