JP3626624B2 - Transparent conductive laminate and transparent tablet - Google Patents

Description

【００５８】
ここでＲ^１〜Ｒ^６は、同一または異なる水素または炭素数１〜３のアルキル基、Ｒ^７は炭素数２〜５のアルキレン基、Ｘはエーテル基、エステル基、ｍは０〜３の整数、ｎは２０〜３００の整数をそれぞれ意味する。そうした中でも特にＲ^１、Ｒ^２はメチル基、Ｒ^３〜Ｒ^６は水素、Ｒ^７はペンチレン基のものが、合成が容易で生産性の面から好ましい。
【００５９】
また、多官能イソシアネート化合物としては、一分子中にイソシアネート基を二つ以上含有する化合物であれば良く、以下のものが例示される。２，６−トリレンジイソシアネート、２，４−トリレンジイソシアネート、トリレンジイソシアネート−トリメチロールプロパンアダクト体、ｔ−シクロヘキサン−１，４−ジイソシアネート、ｍ−フェニレンジイソシアネート、ｐ−フェニレンジイソシアネート、ヘキサメチレンジイソシアネート、１，３，６−ヘキサメチレントリイソシアネート、イソホロンジイソシアネート、１，５−ナフタレンジイソシアネート、トリジンジイソシアネート、キシリレンジイソシアネート、水添キシリレンジイソシアネート、ジフェニルメタン−４，４′−ジイソシアネ−ト、水添ジフェニルメタン−４，４′−ジイソシアネート、リジンジイソシアネート、リジンエステルトリイソシアネート、トリフェニルメタントリイソシアネート、トリス（イソシアネートフェニル）チオホスフェート、ｍ−テトラメチルキシリレンジイソシアネート、ｐ−テトラメチルキシリレンジイソシアネート、１，６，１１−ウンデカントリイソシアネート、１，８−ジイソシアネート−４−イソシアネートメチルオクタン、ビシクロヘプタントリイソシアネート、２，２，４−トリメチルヘキサメチレンジイソシアネート、２，４，４−トリメチルヘキサメチレンジイソシアネート等のポリイソシアネートおよびそれらの混合物あるいは多価アルコール付加体等。この中でも特に汎用性、反応性の観点から２，６−トリレンジイソシアネート、２，４−トリレンジイソシアネート、トリレンジイソシアネート−トリメチロールプロパンアダクト体、ヘキサメチレンジイソシアネートが好ましい。
【００６０】
この他、反応促進剤として、公知のトリエチレンジアミン等の第三アミン、ジブチル錫ジラウレート等の有機錫化合物を適量添加する事で架橋速度を向上することが可能である。
【００６１】
また、エポキシ系樹脂の熱架橋層としては、各種のものが使用できるが、その中でも、下記式（２）で示されるノボラック型のエポキシ樹脂を熱的に架橋させた層が好ましい。
【００６２】
【化２】

【００６３】
ここで、Ｒ^８は水素またはメチル基、Ｒ^９は水素またはグリシジルフェニルエーテル基を示す。また、ｑは１〜５０までの整数を示すが、実際の所、ｑの値は一般的に分布を持っていて特定しにくいが、平均の数として大きい方が好ましく、３以上さらには５以上が好ましい。
【００６４】
このようなエポキシ樹脂を架橋させる硬化剤としては、公知のものが適用される。例えば、アミン系ポリアミノアミド系、酸および酸無水物、イミダゾール、メルカプタン、フェノール樹脂等の硬化剤が用いられる。これらの中でも、酸無水物および脂環族アミン類が好ましく用いられ、さらに好ましくは酸無水物である。酸無水物としては、メチルヘキサヒドロ無水フタル酸、メチルテトラヒドロ無水フタル酸などの脂環族酸無水物、無水フタル酸等の芳香族酸無水物、ドデセニル無水フタル酸等の脂肪族酸無水物が挙げられるが、特にメチルヘキサヒドロ無水フタル酸が好ましい。尚、脂環族アミンとしては、ビス（４−アミノ−３−メチルジシクロヘキシル）メタン、ジアミノシクロヘキシルメタン、イソホロンジアミン等が挙げられ、特にビス（４−アミノ−３−メチルジシクロヘキシル）メタンが好ましい。
【００６５】
ここで、硬化剤として酸無水物を用いた場合、エポキシと酸無水物との硬化反応を促進する反応促進剤を添加しても良い。反応促進剤としては、ベンジメチルアミン、２，４，６−トリス（ジメチルアミノメチル）フェノール、ピリジン、１，８−ジアザビシクロ（５，４，０）ウンデセン−１等の公知の第二、第三アミン類やイミダゾール類等の硬化触媒が挙げられる。
【００６６】
また、ケイ素アルコキシドの熱架橋層としては、２〜４官能性、さらに好ましくは３〜４官能性ののケイ素アルコキシドを二種以上混合して用いることが好ましく、これらをあらかじめ溶液中で適度に加水分解ならびに脱水縮合を行なって適度にオリゴマー化させたものも好ましく用いられる。
【００６７】
使用可能なケイ素アルコキシドの例としては、例えばテトラメトキシシラン、テトラエトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、ジメチルジメトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、β−（３、４エポキシシクロヘキシル）エチルトリメトキシシラン、ビニルトリメトキシシラン、Ｎ−β（アミノエチル）γ−アミノプロピルトリメトキシシラン、Ｎ−β（アミノエチル）γ−アミノプロピルメチルジメトキシシラン、γ−アミノプロピルトリエトキシシラン等が例示される。
【００６８】
これらのケイ素アルコキシドによる層は、熱的に架橋が進行するが、必要に応じて紫外線等の活性光線を塗膜に照射する事によって、架橋度をより高めることができる。
【００６９】
尚、これらの保護層は有機高分子からなる基板上に直接、もしくは適当な中間層を介して積層が為される。こうした中間層としては例えば、保護層と基板との密着性を向上させる機能を有する層や、後述するＫ値が負の三次元屈折率特性を有する層等の各種の位相補償層、基板に加わる応力（垂直応力、水平応力）を緩和する粘弾性特性を有する層、例えば室温付近での貯蔵弾性率がおよそ１ｋｇ／ｍｍ^２以下であるような層や、水分や空気の透過を防止する機能もしくは水分や空気を吸収する機能を有する層、紫外線や赤外線を吸収する機能を有する層、基板の帯電性を低下させる機能を有する層等が好ましく挙げられる。
【００７０】
これら保護層の基板への実際のコーティング方法としては、前記の樹脂架橋物の前駆体組成物ならびにフィラー等を各種有機溶剤に溶解して、濃度や粘度を調節した塗液を用いて、被体上に塗工後、放射線の照射や加熱処理等により層を架橋させる。塗工方式としては例えば、マイクログラビヤコート法、マイヤーバーコート法、ダイレクトグラビヤコート法、リバースロールコート法、カーテンコート法、スプレーコート法、コンマコート法、ダイコート法、ナイフコート法、スピンコート法等の各種塗工方法が用いられる。
【００７１】
さて本発明においては必要に応じて、有機高分子からなる基板の表面もしくは基板上にコーティングされる各種のコーティング層の表面が適度に凹凸化させる事も好ましく行われる。
【００７２】
この一つの目的として、基板もしくは前記各種のコーティング層および透明導電層が積層された積層基板の滑り性を向上させ、基板面と基板面もしくは平板等に密着して動かなくなる現象、いわゆるブロッキング現象を防止する事が挙げられ、電極の焼き付き現象の防止、ロールｔｏロールのプロセスにおける基板の巻き出し性、巻き取り性の向上、もしくは枚葉プロセスにおける加工台（平板）上の取り扱い性等を高める事ができる。
【００７３】
又、もう一つの目的として、透明導電層の表面で反射する光を適度に散乱させる事が挙げられる。すなわち透明導電層の表面の平坦性が高い場合には、透明タブレットとして相対配置される一対の透明電極基板の透明導電層表面の反射光が相互干渉することに起因する光干渉縞（ニュートンリング）が肉眼で観察され、タブレットの視認性が低下してしまう場合があるが、透明導電層の表面が適度に凹凸を有している場合には光干渉縞が不明瞭となり、視認性の低下が抑制できる。
【００７４】
尚、本発明のように光学干渉層が積層される事によって透明導電層表面の反射率の低下が為された場合には、比較的弱い凹凸の程度であっても光干渉縞が効果的に抑制される特長がある。
【００７５】
ここで本発明の透明導電性積層体の場合においては、前記要件に好適な透明導電層表面の表面粗さは、中心線表面粗さＳＲａ値でおよそ０．０２〜０．０５μｍの範囲が好適である。ＳＲａ値が０．０２μｍに満たない場合には、前記の光干渉縞を不明瞭化する効果が不十分になりやすく、逆に０．０５μｍを超える場合には、透明導電層表面での光散乱性が著しく増加し、表示画像のぼやけや積層体透過率の低下等の不利を生じ易い。
【００７６】
更にもう一つの目的として、ペン等による入力が行われる側の基板表面で反射する外来光（太陽光、室内照明光など）を適度に散乱させる事により防眩性を付与する事が挙げられる。すなわちこの入力が為される側の基板表面が平坦である高い場合には、該表面で外来光が正反射するのでいわゆる映り込み現象が発生しやすく、タブレットの視認性が低下してしまう場合が多い。これに対し、該表面が適度に凹凸を有している場合には外来光が該表面で適度に散乱反射され、前記映り込み現象の抑制すなわち防眩性の発現が為される。
【００７７】
尚、この入力が為される側の基板表面に、主に波長４５０〜６５０ｎｍの領域の反射率を減じる機能を有する光学干渉層を積層する事によっても前記の映り込み現象の低減が実現できるので、場合によってはこうした光学干渉層を該表面に積層することも好ましく行われる。この場合には該表面がある程度平坦であっても構わないが、より好ましくは該表面が比較的弱い凹凸を有している事が好ましい。こうした光学干渉層を形成する材料、形成法としては、前述の透明導電層の下地として積層する光学干渉層と同様の材料、形成法が好ましく用いられる。
【００７８】
このように有機高分子からなる基板の表面もしくは基板上にコーティングする保護層や光学干渉層の表面が適度に凹凸化する方法としては各種のものがあるが、例えば凹凸が刻まれた鋳型を用いて前記基板や各種コーティング層を成形および賦形する方法や、エンボス加工やサンドブラスト加工等の機械的加工を加える方法、前記基板や各種コーティング層内に適量の微粒子（フィラー）を分散状態で混合させる方法等が挙げられる。
【００７９】
特に基板上にコーティングされる保護層もしくは光学干渉層内に適量の微粒子を分散状態で混合させる方法が、工程の簡便性、安定性等の観点から最も好適である。
【００８０】
この場合、微粒子の分散による塗膜強度の低下や光散乱性の上昇、塗膜外観の悪化等を最小限に抑える必要があるが、この目的において、微粒子の平均粒径が塗膜の膜厚の約１．０〜２．０倍、より好ましくは約１．０〜１．５倍、最も好ましくは１．１〜１．３倍の範囲にある微粒子を用いる方法や、微粒子として平均粒径が０．３μｍ以下のものを用い、塗膜内で微粒子がおよそ５μｍ以下、より好ましくは３μｍ以下の凝集径で凝集するような樹脂成分と微粒子の組み合わせを用いる方法等が挙げられる。
【００８１】
微粒子の混合量については、前者の方法では重量比率でおよそ０．０５〜５．０％、より好ましくは０．１〜３．０％の範囲にあることが好ましい。混合量が０．０５％に満たない場合には充分な滑り性が得られない場合が多く、５．０％を越えると光散乱性が著しく増加して、タブレットの視認性を低下させる場合が多いので好ましくない。
【００８２】
また後者の方法では微粒子の混合割合は重量比率でおよそ０．５〜３０％、より好ましくは０．５〜２０％の範囲にある事が好ましい。混合量が０．５％に満たない場合には十分な滑り性で得られない場合が多く、３０％を超えると光散乱性が著しく増加する場合が多く、塗膜のクラック等を生じる場合があるので好ましくない。
【００８３】
微粒子の種類としては、塗工液中で微粒子の沈降が起こりにくいものを用いることが好ましく、具体的には市販の有機シリコン微粒子や架橋アクリル微粒子、架橋ポリスチレン微粒子等が好ましく用いられる。
【００８４】
本発明によれば、上記透明導電性積層体を少なくとも一方の電極基板として用いることにより、反射及び着色が少なく、透明性が良好なタブレットを提供するものである。ここで本発明の透明導電性積層体をタブレットの一対の電極基板すなわち可動電極基板と固定電極基板の両方に用いた場合に本発明の意図する効果が特に著しくなるので最も好ましいが、可動電極基板と固定電極基板の一方のみに用いても効果を得ることができる。例えば可動電極基板に本発明の透明導電性積層体を用い、固定電極基板に従来の硝子板に透明電極を形成した硝子電極基板を用いたタブレットの構成等においても良好な視認性を得ることができる。
【００９８】
以下、本発明の実施例を示す。尚、以下の実施例と比較例における各種特性の評価は次の要領にて行った。
【００９９】
全光線透過率およびヘイズ値：日本電色工業社製の測定器（商品名「ＣＯＨ−３００Ａ」）を用いて測定を行った。
【０１００】
透過スペクトル、反射スペクトル、反射率の測定、ならびに色彩（ｂ^＊値）の計算：日立製分光光度計Ｕ３５００の積分球測定モードおよび計算プログラムを用いて各スペクトルの測定ならびに色彩の計算を行った。尚、測定光のサンプルへの入射角度は透過モードでは０度、反射モードでは１０度とし、反射モードでの測定においてはサンプルの裏面側を市販の黒色スプレーを用いて遮光層を形成し、サンプルの裏面反射や裏面側からの光の入射がほとんどない状態で測定を行った。また反射色彩の計算においては光源として日本工業規格Ｚ８７２０に規定される標準の光Ｄ_６５を採用し、２度視野の条件で測定を行った。
【０１０１】
耐溶剤性の評価：明細書内の前記記載の方法にて行った。
【０１０２】
ハードコート性の評価：日本工業規格Ｋ５４００に準拠し、１ｋｇの荷重にて鉛筆硬度を測定した。
【０１０３】
各層の屈折率と膜厚：光学干渉層および透明導電層については、これらの層と屈折率が相違する適当な熱可塑性フィルム基板上に同様のコーティング条件で単層で積層し、該積層面の光反射スペクトル上に光干渉効果に基づいて発現する反射率の極大ピークもしくは極小ピークの波長とそのピーク反射率の値を用いて、光学シミュレーションにより算出した。また保護層の屈折率はアッベ屈折率計を用いて測定し、保護層の厚みは前記の光学干渉層と同様の光干渉法を用いた計算により求めた。
【０１０４】
［実施例１］
厚みが約７５μｍの二軸延伸ポリエチレンテレフタレート（ＰＥＴ）フィルム（帝人製ＨＳＬ−７５、面内屈折率約１．６４、鉛筆硬度Ｆ）の片面に二層からなる光学干渉層を積層した。
【０１０５】
すなわちまずテトラブトキシチタネート（日本曹達社製の商品名「Ｂ−４」）をリグロイン（和光純薬工業社製の等級が一級品）とブタノール（和光純薬工業社製の等級が特級品）の混合溶媒で希釈した塗液を用いてロールコーティングし、１３０℃で２分間熱処理して、膜厚約４１ｎｍ、屈折率約１．８２の層を形成した。
【０１０６】
次に該層上に下記組成からなる塗液を用いてロールコーティングし、１３０℃で５分間熱処理して、膜厚約５１ｎｍ、屈折率約１．４７の層を形成した。すなわち水７２０重量部と２−プロパノール１０８０重量部と酢酸４６重量部を混合した後に、γ−グリシドキシプロピルトリメトキシシラン（信越化学社製の商品名「ＫＢＭ４０３」）４８０重量部とメチルトリメトキシシラン（信越化学社製の商品名「ＫＢＭ１３」）２４０重量部とＮ−β（アミノエチル）γ−アミノプロピルトリメトキシシラン（信越化学社製の商品名「ＫＢＭ６０３」）１２０重量部を順次混合し、３時間攪拌して前記アルコキシシラン混合液の加水分解、部分縮合を行い、さらにイソプロピルアルコールと１メトキシ２プロパノールの重量比率１：１の混合溶媒で希釈して該層形成用の塗液とした。
尚、この光学干渉層が積層されたフィルムの表面の耐溶剤性は良好であった。
【０１０７】
次に、前記光学干渉層が積層されたフィルム表面に透明導電層を積層して透明導電性フィルムを作製した。透明導電層としてはインジウム−錫の酸化物（ＩＴＯ）を用い、ＤＣマグネトロンスパッタリング法により膜厚が約２２ｎｍとなるように層を形成した。すなわちターゲットとして酸化インジウムと酸化錫が重量比９５：５の組成で充填密度が９８％のＩＴＯターゲットを用い、スパッタ装置内に前記フィルムをセットした後、１．３ｍＰａの圧力まで排気を行い、ついでＡｒとＯ_２の体積比９８．５：１．５の混合ガスを導入し、雰囲気圧力を０．２７Ｐａにした。そしてフィルム温度を５０℃、投入電力密度が１Ｗ／ｃｍ^２の条件でスパッタリングを行い、前記光学干渉層上にＩＴＯによる透明導電層を積層した。この透明導電層の表面抵抗は約２３０Ω／□であり、屈折率はおよそ２．０であった。
表１にこの透明導電性フィルムの光学特性について記す。
【０１０８】
［実施例２］
厚みが約１８８μｍの二軸延伸ポリエチレンテレフタレートフィルム（帝人製ＯＦＷ−１８８、面内屈折率１．６５前後、鉛筆硬度Ｆ）の両面に以下のように保護層を積層した以外は全く実施例１と同様にして透明導電性フィルムを作成した。
【０１０９】
すなわち光学干渉層および透明導電層を積層する側のフィルム面には、ポリエステルアクリレート（東亜合成化学製Ｍ８５６０）５０重量部、ジペンタエリスリトールヘキサアクリレート（日本化薬製ＤＰＨＡ）５０重量部、光開始剤（チバガイギー製イルガキュア１８４）７重量部、レベリング剤としてシリコンオイル（東レ・ダウケミカル製ＳＨ２８ＰＡ）０．０３重量部、希釈溶剤として１メトキシ２プロパノール２００重量部からなる塗液を用いてロールコーティングを行い、６０℃で１分間溶剤を乾燥させた後にランプ強度が１６０Ｗ／ｃｍの高圧水銀灯を用いて積算光量約６００ｍＪ／ｃｍ^２の条件で紫外線の照射を行ってコーティング層を硬化させ、膜厚が約４．３μｍの表面が平滑な保護層を積層した。
【０１１０】
また前記と反対側のフィルム面には、前記塗液組成に更にフィラーとして平均粒径が約４．５μｍのシリコーン架橋微粒子（東芝シリコーン製トスパール１４５）を２．０重量部添加してなる塗液を用いて、前記と同様にコーティングを行い、膜厚が約４．１μｍで表面に一様に微細な凹凸が形成された保護層を積層した。
【０１１１】
これらの保護層の屈折率はアッベ屈折率計によればおよそ１．５３前後であり、フィルム上での鉛筆硬度はともに２Ｈで、耐溶剤性も良好であった。また前記微細な凹凸が形成された保護層の表面は良好な防眩性を有していた。
【０１１２】
更に前記の表面平滑な保護層上に実施例１と全く同様に光学干渉層および透明導電層を積層して透明導電性フィルムを作成した。表１に本フィルムの光学特性について記す。
【０１１３】
［実施例３］
厚みが約７５μｍの二軸延伸ポリエチレンテレフタレートフィルム（帝人製ＯＦＷ−７５、屈折率１．６４、鉛筆硬度Ｆ）の両面に以下のように保護層を積層した以外は全く実施例１と同様にして透明導電性フィルムを作成した。
【０１１４】
すなわち光学干渉層および透明導電層を積層する側のフィルム面には、ポリエステルアクリレート（東亜合成化学製Ｍ８５６０）５０重量部、ジペンタエリスリトールヘキサアクリレート（日本化薬製ＤＰＨＡ）５０重量部、フィラーとして平均粒径が約３．０μｍのシリコーン架橋微粒子（東芝シリコーン製トスパール１３０）を１．０重量部、光開始剤（チバガイギー製イルガキュア１８４）７重量部、レベリング剤としてシリコンオイル（東レ・ダウケミカル製ＳＨ２８ＰＡ）０．０３重量部、希釈溶剤として１メトキシ２プロパノール２００重量部からなる塗液を用いてロールコーティングを行い、６０℃で１分間溶剤を乾燥させた後にランプ強度が１６０Ｗ／ｃｍの高圧水銀灯を用いて積算光量約６００ｍＪ／ｃｍ^２の条件で紫外線の照射を行ってコーティング層を硬化させ、膜厚が約２．７μｍで表面に一様に微細な凹凸が形成された保護層を積層した。
【０１１５】
また前記と反対側のフィルム面には、前記塗液組成のシリコーン架橋微粒子を混合していない組成の塗液を用いて、前記と同様にコーティングを行い、膜厚が約２．７μｍの表面の平滑な保護層を積層した。
【０１１６】
これらの保護層のフィルム上での鉛筆硬度はともにＨないしは２Ｈであり、耐溶剤性も良好であった。
【０１１７】
更に、前記の表面に一様に凹凸が形成された保護層上に実施例１と全く同様に光学干渉層および透明導電層を積層して透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１１８】
この透明導電性フィルムを可動電極基板として用い、固定電極基板として厚みが１．１ｍｍで片面にＩＴＯによる透明導電層が積層された硝子板を用いて、公知の方法で作成した透明タブレットを市販の三波長蛍光ランプ下で観察したところ、光干渉縞（ニュートンリング）の発生は観られず、非常に視認性に優れていた。
【０１１９】
［実施例４］
実施例３において積層したチタンアルコキシドの硬化層の膜厚を４７ｎｍとし、珪素アルコキシドの硬化層の膜厚を５７ｎｍとした以外は全く実施例１と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１２０】
［実施例５］
実施例３において積層したチタンアルコキシドの硬化層の膜厚を７４ｎｍとし、珪素アルコキシドの硬化層の膜厚を３０ｎｍとした以外は全く実施例１と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１２１】
［実施例６］
実施例３において積層したチタンアルコキシドの硬化層の膜厚を３８ｎｍとし、珪素アルコキシドの硬化層の膜厚を４７ｎｍとした以外は全く実施例１と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１２２】
［実施例７］
実施例３において積層したチタンアルコキシドの硬化層の膜厚を５３ｎｍとし、珪素アルコキシドの硬化層の膜厚を６５ｎｍとし、透明導電層の膜厚を１５ｎｍとした以外は全く実施例１と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１２３】
［実施例８］
実施例３において表面に一様に凹凸が形成された保護層上に、ＲＦマグネトロンスパッタリング法により膜厚が約３４ｎｍ、屈折率が約２．２の酸化ジルコニウム層を形成した。すなわちターゲットとして充填密度９０％の酸化チタンのターゲットを用い、スパッタ装置内に前記フィルムをセットした後、１ｍＰａの圧力まで排気を行い、ついでＡｒとＯ２の体積比９８：２の混合ガスを導入し、雰囲気圧力を０．２７Ｐａにした。そしてフィルム温度を５０℃、投入電力密度が１Ｗ／ｃｍ^２の条件でスパッタリングを行い、酸化ジルコニウム層を積層した。
【０１２４】
次にＤＣマグネトロンスパッタリング法により膜厚が５１ｎｍ、屈折率が約１．４６の酸化珪素層を形成した。すなわちターゲットとして珪素のターゲットを用い、スパッタ装置内に前記フィルムをセットした後、１ｍＰａの圧力まで排気を行い、ついでＡｒとＯ_２の体積比７０：３０の混合ガスを導入し、雰囲気圧力を０．２７Ｐａにした。そしてフィルム温度を５０℃、投入電力密度が１Ｗ／ｃｍ^２の条件でスパッタリングを行い、酸化珪素層を積層した。
【０１２５】
その後実施例１と全く同様に酸化インジウムによる膜厚２２ｎｍ、屈折率２．０の透明導電層を積層して透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１２６】
［実施例９］
基板として厚みが約１００μｍのポリカーボネートフィルム（帝人製ピュアエース、屈折率１．５８６、鉛筆硬度６Ｂ以下、面内リタデーション１０ｎｍ以下）の両面に実施例３と全く同様に保護層を積層し、更に実施例３と全く同様に片面の保護層上に光学干渉層と透明導電層を積層して透明導電性フィルムを作成した。
これらの保護層のフィルム上での鉛筆硬度はともにＢであり、耐溶剤性も良好であった。本フィルムの光学特性を表１に記す。
【０１２７】
［比較例１］
実施例３においてチタンアルコキシドの硬化層および珪素アルコキシドの硬化層を積層せず、ＰＥＴフィルム上に直接透明導電層を積層した以外は全く実施例３と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１２８】
［比較例２］
実施例３において積層したチタンアルコキシドの硬化層の膜厚を５５ｎｍとし、珪素アルコキシドの硬化層の膜厚を６６ｎｍとした以外は全く実施例３と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１２９】
［比較例３］
実施例３において積層したチタンアルコキシドの硬化層の膜厚を３４ｎｍとし、珪素アルコキシドの硬化層の膜厚を４２ｎｍとした以外は全く実施例３と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１３０】
［比較例４］
比較例１と同様に、チタンアルコキシドの硬化層および珪素アルコキシドの硬化層を積層せず、ＰＥＴフィルム上に直接透明導電層を積層し、透明導電層の膜厚を１５ｎｍにした以外は全く比較例１と同様にして透明導電性フィルムを作成した。本フィルムの光学特性を表１に記す。
【０１３３】
【表１】

【０１３４】
注）反射率の測定値は迷光やサンプルの裏面反射等の影響により、実際の値より若干大きい値を示す傾向にある。（測定誤差はおよそ０．３％以内）
【０１３５】
【発明の効果】
本発明の透明導電性積層体は、透明導電層表面の反射率が低く、かつ積層体の透過光の着色が少ないという特長を有し、この透明導電性積層体を用いて作成した透明タブレットでは非常に優れた視認性を得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention provides a transparent conductive laminate having an extremely high light transmittance, in which a layer having optical interference and a transparent conductive layer are laminated in this order on at least one surface of a substrate made of an organic polymer. Further, the present invention relates to a transparent tablet using the transparent conductive laminate as at least one transparent electrode substrate.
[0002]
[Prior art]
In recent years, portable information devices equipped with a liquid crystal display for displaying information and a transparent tablet for inputting information (also referred to as a touch switch, a touch panel, or a flat switch) have begun to be widely used. A resistive film type transparent tablet, which is often used as a transparent tablet, is composed of two transparent electrode substrates on which a transparent conductive layer is formed facing each other at an interval of about 10 μm. The two electrodes are in contact with each other and operate as a switch. For example, it is possible to select a menu on the display screen or input a figure or a handwritten document.
[0003]
As such a transparent electrode substrate, a transparent conductive layer made of a metal oxide such as indium oxide (ITO) containing tin oxide or zinc oxide is laminated on a substrate such as glass or various thermoplastic polymer films. Are widely used.
[0004]
Now, the transparent tablet is often placed on various displays such as liquid crystal display devices and CRTs. However, if the reflectance or absorption rate of light when passing through the transparent tablet is large, the display screen is displayed. This is not preferable because it causes a decrease in contrast and brightness.
[0005]
When only one transparent conductive layer is laminated on the substrate, the light interference of reflected light at the two interfaces between the substrate and the transparent conductive layer and between the transparent conductive layer and the air, the light absorption of the transparent conductive layer itself, etc. In many cases, the light transmitted through the transparent electrode substrate is colored. For example, a transparent conductive layer having a thickness of about 20 to 30 nm is currently widely used in applications of transparent tablets, and transmitted light often has a slightly brownish coloration. Is not preferable because the hue of the display screen is changed.
[0006]
[Problems to be solved by the invention]
Proposal of a method of laminating a layer having an appropriate optical interference property (hereinafter referred to as an optical interference layer) on the base of the transparent conductive layer as a method for reducing the reflectance of the transparent electrode surface is proposed Patents such as Japanese Patent No. 1815750, Japanese Patent Application Laid-Open No. 8-216327, Japanese Patent Application Laid-Open No. 10-24516, etc., are not sufficient for the coloring phenomenon of transmitted light of the latter transparent conductive substrate. It could not be said that it was suppressed.
[0007]
[Means for Solving the Problems]
The present inventors have found that the above problem can be solved by satisfying a specific relationship between the optical interference layer and the transparent conductive layer.
[0008]
That is, according to the present invention, in a transparent conductive laminate in which a transparent conductive layer is laminated on the outermost surface of at least one surface of a substrate made of an organic polymer, the refractive index is (A1) from 1.7 in order from the substrate side. Layer having a refractive index of +0.3 in the transparent conductive layer and a thickness in the range of 20 to 90 nm (H ₁ Layer), (B1) a layer having a refractive index in the range of 1.35 to 1.5 and a film thickness in the range of 30 to 110 nm (L ₁ Layer), (C) a transparent conductive layer having a film thickness in the range of 12 to 30 nm, (D) the sum of the optical film thicknesses of the three layers is in the range of 180 to 230 nm, and (F) The average reflectance at a wavelength of 450 to 650 nm on the laminated surface of the transparent conductive layer is 5.5% or less, and (G) L defined in Japanese Industrial Standard Z8729 of the transmitted light of the laminate. ^* a ^* b ^* Color system chromaticness index b ^* It is achieved by a transparent conductive laminate characterized in that the value is in the range of 0-2.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
That is, as described above, for the purpose of reducing the reflectance inside the transparent tablet and obtaining the achromatic color or the color of transmitted light close thereto, the wavelength of 450 to 650 nm on the surface where the transparent conductive layer of the transparent conductive laminate is laminated. The average reflectance is 5.5% or less, and the transmitted light of the transparent conductive laminate is L in accordance with Japanese Industrial Standards (JIS standard) Z8729. ^* a ^* b ^* Color system chromaticness index b ^* It is important that the value is in the range 0-2, preferably in the range 0-1.5. B of transmitted light of transparent conductive laminate ^* When the value exceeds 2.0, the transmitted light tends to have a yellowish coloration and the appearance tends to deteriorate, and when the negative value is less than 0, the total light transmittance of the laminate is remarkable. This is because it tends to decrease.
[0012]
In the present invention, the type of light used for color measurement of the transmitted light is standard light D defined in Japanese Industrial Standard Z8720. ₆₅ It is assumed that a simple average value that does not perform visibility correction is used for the average reflectance.
[0013]
These colors and the reflectance of the surface of the transparent conductive layer indicate the mutual interference of reflected light generated at each interface between the transparent conductive layer and the optical interference layer when the laminate is highly transparent, that is, when the light absorption of the laminate is low. It varies depending on the above conditions, that is, the film thickness and refractive index of each layer, the stacking order of each layer, and the like.
[0014]
Specifically, in order to realize the preferable color, it is preferable that the visible light transmittance of the transmitted light of the transparent conductive laminate has a maximum point in the wavelength range of 450 to 530 nm, and at the same time high transmittance. From the viewpoint of obtaining a rate, it is more preferable to have a maximum point in the wavelength range of 470 to 530 nm.
[0015]
In order to obtain such a spectrum of transmitted light, the reflectance of the surface of the transparent conductive layer is preferably 430 to 510 nm, and more preferably has a minimum point in the region of 450 to 510 nm. The transparent conductive laminate of the present invention has an optical interference layer on a substrate made of an organic polymer, and further has a transparent conductive layer formed thereon. That is, at least from the substrate side, (A1) H ₁ Layer: Refractive index is 1.7 or more and 0.3 or less than the refractive index of the transparent conductive layer, and the film thickness is in the range of 20 to 90 nm, (B1) L ₁ Layer: The refractive index is in the range of 1.35 to 1.5 and the film thickness is in the range of 30 to 110 nm. (C) Transparent conductive layer: The film thickness is in the range of 12 to 30 nm. They are stacked in order. H ₁ Layer and L ₁ If the refractive index of the layer is out of the above range, L ₁ Since the effect of reducing the reflectance of the surface of the transparent conductive layer laminated on the layer is lowered, it is not preferable.
[0016]
In the transparent conductive laminate, (D) the sum of the optical thicknesses of the three layers is 180 to 230 nm. Here, the optical film thickness is a value obtained by multiplying the refractive index of the layer by the film thickness. ₁ Layer and L ₁ By laminating the three layers in such a combination that the sum of the optical film thicknesses of the layer and the transparent conductive layer is 180 to 230 nm, a transparent conductive laminate having good color and low reflectance can be obtained.
[0017]
L ₁ The reflectance of the surface of the layer preferably has a minimum point in the region of a wavelength of 260 to 390 nm.
[0018]
As the transparent conductive layer in the transparent conductive laminate of the present invention, a layer mainly composed of a metal oxide is preferably used. From the viewpoint of reduction in power consumption of the tablet and circuit processing, etc. It is preferable to use a transparent conductive layer having a surface resistance value of 100 to 2000 Ω / □, more preferably 150 to 2000 Ω / □. If the thickness of the transparent conductive layer is less than 12 nm, the resistance stability with time tends to be inferior, and if it exceeds 30 nm, the reflectance of the transparent conductive layer is significantly increased even when an optical interference layer is laminated. .
[0019]
Specifically, for example, a layer made of tin oxide, indium oxide, zinc oxide, gallium oxide or the like and a layer made of a material in which they are mixed in an appropriate ratio are preferably used, and silicon oxide, titanium oxide, A layer made of a material in which one or more of aluminum oxide, zirconium oxide and the like are added at a ratio of several weight percent is preferably used.
[0020]
These transparent conductive layers can be laminated using a known vacuum film forming process such as sputtering, ion plating, vacuum deposition, or CVD. Among these, the sputtering method is preferable from the viewpoints of film thickness uniformity and composition uniformity in the width direction and length direction.
[0021]
The optical interference layer in the transparent conductive laminate is the H ₁ Layer and L ₁ And the above H is formed on the substrate. ₁ Layer and L ₁ Layers are laminated in order. H ₁ The layer (A) has a refractive index in the range of 1.7 to 0.3 larger than the refractive index of the transparent conductive layer, and has a film thickness of 20 to 90 nm. ₁ The layer (B) has a refractive index in the range of 1.35 to 1.5 and a film thickness in the range of 30 to 110 nm. Such H ₁ Layer and L ₁ In addition to what is formed by laminating layers, for example, H ₁ Layer and L ₁ H in addition to layer stacking ₁ A layer having a refractive index of about 1.5 or less and a thickness of 30 to 100 nm (L ′ layer) on the substrate side in contact with the layer, or H ₁ A three-layer structure may be provided by providing an optical interference layer such as a layer (M layer) having an intermediate refractive index between the layer and the substrate (the layer serving as the base of the optical interference layer) and having a thickness of 30 to 100 nm.
[0022]
The difference in refractive index between the substrate of the organic polymer serving as a base of the optical interference layer, a protective layer described later, and the layer used in contact with the base among the optical interference layers is preferably 0. It is preferably 1 or more, more preferably 0.15 or more, for high optical interference effect expression of the optical interference layer and low reflection of the transparent conductive layer surface.
[0023]
These optical interference layers are typified by various vacuum film forming processes such as sputtering, vapor deposition, ion plating, and CVD, micro gravure coating, Mayer bar coating, and direct club coating. It can be prepared by various roll coating methods, knife coating methods, curtain coating methods, spin coating methods, wet coating methods such as spray coating methods, and combinations thereof.
[0024]
More specifically, various inorganic dielectric layers prepared using a vacuum film-forming process, such as MgF ₂ , SiO ₂ , CaF ₂ , NaF, Na ₃ AlF ₆ , LiF, Al ₂ O ₃ , CeF ₄ , LaF ₃ , NdF ₃ TiO ₂ , MgO, PbF ₃ , ThO ₂ , ZrO ₂ ZnS, SnO ₂ , In ₂ O ₃ , Sb ₂ O ₃ , CeO2, Nd ₂ O ₃ , La ₂ O ₃ Etc., and a layer composed of a mixture thereof, or a resin cross-linked layer prepared by using a wet coating method, for example, a simple substance or a mixture of metal alkoxides such as silicon, titanium, zirconium, tin, tantalum, indium, etc. Examples thereof include a resin cross-linked layer obtained by dehydration condensation and a resin cross-linked layer in which fine particles of various metal oxides having a particle size of several tens of nm or less are dispersed.
[0025]
Among these various optical interference layers exemplified above, from the viewpoint of obtaining high productivity, it is particularly preferable to use an optical interference layer formed of a resin cross-linked layer by the wet coating method, and further, a resin cross-linked layer formed by wet coating. Among them, from the viewpoint of excellent mechanical strength and stability of the layer, adhesion to a transparent conductive layer, a substrate, and the like, it is possible to use a cross-linked layer made of a metal alkoxide, particularly an alkoxide of titanium, zirconium or silicon. Most preferred. Here, the crosslinked layer of titanium and zirconium alkoxide functions as a high refractive index layer having a refractive index of about 1.6 or more, and in some cases about 1.7 or more in the optical interference layer. The crosslinked layer functions as a low refractive index layer having a refractive index of about 1.5 or less in the optical interference layer.
[0026]
Examples of the titanium alkoxide include titanium tetraisopropoxide, tetra-n-propyl orthotitanate, titanium tetra-n-butoxide, tetrakis (2-ethylhexyloxy) titanate, and the like, and examples of the zirconium alkoxide include zirconium tetraisopropoxy. And zirconium tetra-n-butoxide.
[0027]
Examples of the silicon alkoxide include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4 epoxy cyclohexyl) ethyltri Examples include methoxysilane, vinyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, and the like. .
[0028]
These silicon alkoxides are preferably used as a mixture of two or more from the viewpoint of mechanical strength, adhesion, solvent resistance, etc. of the layer, if necessary. It is preferable that the silicon alkoxide having an amino group in the molecule is contained within a ratio of 0.5 to 60%.
[0029]
These metal alkoxides may be used as monomers, or may be used after being hydrolyzed and dehydrated and condensed into appropriate oligomers. Usually, a coating solution dissolved and diluted in an appropriate organic solvent is applied onto the substrate. Work. The coating film formed on the substrate is hydrolyzed by moisture in the air and the like, and subsequently cross-linked by dehydration condensation.
[0030]
In general, an appropriate heat treatment is required to promote crosslinking, and it is preferable to perform a heat treatment for several minutes or more at a temperature of 100 ° C. or higher in the wet coating process. In some cases, the crosslinkability can be further improved by irradiating the coating film with actinic rays such as ultraviolet rays in parallel with the heat treatment.
[0031]
As the diluting solvent, alcohol-based or hydrocarbon-based solvents such as ethanol, isopropyl alcohol, butanol, 1-methoxy-2-propanol, hexane, cyclohexane, ligroin and the like are preferable, but in addition, xylene, Polar solvents such as toluene, cyclohexanone, methyl isobutyl ketone, and isobutyl acetate can also be used. These can be used alone or as a mixed solvent of two or more.
[0032]
The substrate made of the organic polymer constituting the transparent conductive laminate of the present invention is not particularly limited, but the substrate is preferably highly transparent, and specifically transmits in the wavelength region of 450 to 650 nm. The average rate is preferably at least 80% or more, more preferably 85% or more.
[0033]
When the transparent conductive laminate of the present invention is used for an input-side transparent electrode substrate (movable electrode substrate) of a pair of transparent electrode substrates constituting a transparent tablet, it is appropriately deformed with respect to an external input such as a pen. Organic polymers that provide a substrate with a certain degree of flexibility are preferred. For this reason, as such a substrate, a film-shaped molded substrate made of a thermoplastic polymer is preferably used. Specifically, for example, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polyether sulfone, triacetyl cellulose, diacetyl cellulose, various polyolefins, modified products thereof, or copolymers of these with different materials, etc. Preferably exemplified. These film-shaped molded substrates are preferably molded by a general melt extrusion method or solution casting method, etc., but mechanical strength is obtained by subjecting the molded film-shaped substrate to uniaxial stretching or biaxial stretching as necessary. It is also preferable to increase the optical performance and the optical function.
[0034]
The thickness of the substrate thus obtained and suitable as a movable electrode substrate is in the range of about 10 to 400 μm, more preferably 20 to 200 μm, from the viewpoint of tablet operating characteristics, lightness, lightness, etc. preferable.
[0035]
In addition, when the transparent conductive laminate of the present invention is used for a transparent electrode substrate (fixed electrode substrate) that is used relative to the movable electrode substrate, it is not necessarily required to have high flexibility. Rather, it may require a characteristic with little deformation against external force (high rigidity). In addition to the film-shaped molded substrate made of the thermoplastic polymer, the same thermoplastic polymer or epoxy system is used. Also, a sheet-shaped molded substrate made of a thermoset of various materials such as acrylic and / or an ultraviolet-cured product can be suitably used. Examples of a method for forming such a sheet-like molded substrate include a melt extrusion method, a solution casting method, an injection molding method, and a cast polymerization molding method.
[0036]
In some cases, the film-shaped molded substrate is backed by attaching a film-shaped or sheet-shaped molded substrate not formed with a transparent electrode on the surface opposite to the transparent electrode surface of the film-shaped molded substrate. An electrode substrate or the like is also preferably used.
[0037]
The thickness of the electrode substrate thus obtained and suitable as a fixed electrode substrate is preferably in the range of about 10 to 2000 μm, more preferably 50 to 1000 μm, and most preferably 70 to 700 μm.
[0038]
Recently, a new type of transparent tablet having a structure in which a polarizing plate is laminated on the input side (user side) of the tablet has been developed. The advantage of this configuration is that the reflectance of extraneous light inside the tablet can be reduced to less than half by the optical action of the polarizing plate.
[0039]
When the substrate is used for such a type of tablet, polarized light passes through the transparent electrode substrate. Therefore, it is preferable to use a substrate having a property superior in optical isotropy, specifically a substrate. The surface expressed by Re = (nx−ny) × d (nm) where nx is the refractive index in the slow axis direction, ny is the refractive index in the fast axis direction, and d is the thickness of the substrate. The inner retardation Re is more preferably at least 30 nm or less, more preferably 20 nm or less. Here, the in-plane retardation value of the substrate is represented by a measurement value at a wavelength of 590 nm using a multi-wavelength birefringence measuring apparatus (trade name “M-150”) manufactured by JASCO Corporation.
[0040]
Examples of these organic polymers exhibiting excellent optical isotropy include, for example, polycarbonate, amorphous polyarylate, polyether sulfone, triacetyl cellulose, diacetyl cellulose, amorphous polyolefin, and their modified or different materials. Preferred are thermosetting moldings and UV-curing moldings of organic materials such as epoxies and acrylics, but from the viewpoint of moldability, production cost, thermal stability, etc., polycarbonate, amorphous Most preferred are, for example, crystalline polyarylate, amorphous polyolefin and their modified products or copolymers with other materials.
[0041]
More specifically, examples of the polycarbonate include bisphenol A, 3,3,5-1,1-di (4-phenol) cyclohexylidene, and / or 3,3,5-trimethyl-1,1-di (4 -Average molecular weight consisting of homo- or copolymerization of bisphenol components such as -phenol) cyclohexylidene, fluorene-9,9-di (4-phenol), fluorene-9,9-di (3-methyl-4-phenol) Preferred examples include polycarbonate in the range of about 30,000 to 100,000 (product examples include “Panlite” manufactured by Teijin Chemicals and “Apec HT” manufactured by Bayer).
[0042]
Examples of the amorphous polyarylate include “Elmec” manufactured by Kaneka Chemical, “U polymer” manufactured by Unitika, “Isaril” manufactured by Isonova, and the like.
[0043]
Examples of the amorphous polyolefin include “Zeonex” manufactured by Nippon Zeon and “Arton” manufactured by Nippon Synthetic Rubber.
[0044]
Examples of a method for forming a substrate made of these organic polymer materials include methods such as a melt extrusion method, a solution casting method, and an injection molding method, but from the viewpoint of obtaining excellent optical isotropy, It is preferable to perform molding using a solution casting method.
[0045]
In the application of the type of tablet through which polarized light passes, the value of the in-plane retardation of the substrate is very important. In addition, the three-dimensional refractive index characteristic of the substrate, that is, the refractive index in the film thickness direction of the substrate. It is highly visible that the K value represented by K = {(nx + ny) / 2−nz} × d is at least −250 to +150 nm, more preferably −200 to +100 nm, where nz is nz This is preferable for obtaining viewing angle characteristics.
[0046]
By the way, when the solvent resistance and / or hard coat property of the substrate made of the organic polymer is insufficient for the performance required for the intended use, it has a function of improving the characteristics on one side or both sides of the substrate. It is preferable to laminate such a protective layer. Here, when the optical interference layer and the transparent conductive layer are laminated on the protective layer, the refractive index of the protective layer may have a refractive index difference of at least 0.1 or more at the interface contacting the optical interference layer as described above. It is preferable from the viewpoint of obtaining low reflectivity.
[0047]
Here, since solvent resistance is mainly necessary in the tablet production process, the standard of characteristics required for the production method is slightly different, but the following solvent resistance is required. That is, when a protective layer is laminated on a substrate as described above, it is preferable to laminate a protective layer exhibiting such solvent resistance on the substrate.
[0048]
Organic solvent resistance: A few drops of toluene (made by Wako Pure Chemical Industries, special grade), which is a typical solvent for silver paste that is printed on the transparent conductive layer during tablet production, is dropped on the sample surface for 3 minutes at 25 ° C. The appearance changes such as white turbidity, swelling, and dissolution of the surface after standing are visually observed, and when the change is not confirmed, it is determined to have organic solvent resistance.
[0049]
Alkali resistance aqueous solution: A few drops of 3.5 wt% sodium hydroxide aqueous solution used to dissolve the resist during patterning of the transparent conductive layer is dropped on the sample surface and left to stand at 25 ° C for 3 minutes. The external appearance change is visually observed, and when the change is not confirmed, it is determined that the aqueous solution has alkali resistance aqueous solution property.
[0050]
Acid resistant aqueous solution: A few drops of an etching solution (35 wt% ferric chloride aqueous solution, 35 wt% hydrochloric acid, water mixed at a ratio of 1: 1: 10) used for patterning the transparent conductive layer was dropped on the sample surface. Appearance changes such as white turbidity, swelling, and dissolution of the surface after standing at 25 ° C. for 3 minutes are visually observed, and if no change is confirmed, it is determined that the solution has acid resistance.
[0051]
In addition, hard coat is not an essential property item for transparent tablet applications, but it is intended to increase the durability against repeated input to the tablet, especially changes in resistance and linearity of the transparent conductive layer, and stable input load value of the tablet. It is often preferable that the hard coat property is high in order to suppress an increase in (ON load value) and damage or deformation of the substrate surface with respect to input to the tablet by a pen or the like.
[0052]
From the viewpoint of enhancing the durability, as the hard coat property, it is preferable that the pencil hardness as defined in Japanese Industrial Standard K5400 is at least 2B, more preferably F or more, and most preferably 2H or more. That is, when a protective layer is laminated on a substrate as described above, it is preferable to laminate a protective layer that exhibits such hard coat properties on the substrate.
[0053]
Protective layers having such properties include resin cross-linked layers such as radiation cross-linked layers of acrylic resins, heat cross-linked layers of phenoxy resins, heat cross-linked layers of epoxy resins, and heat cross-linked layers of silicon alkoxides. A crosslinked layer is mentioned. Among these, the radiation cross-linked layer of the acrylic resin is most preferably used because it has a feature that the load on the manufacturing process is small because a layer having a high degree of cross-linking can be obtained in a relatively short time by irradiation with radiation.
[0054]
The radiation-crosslinking resin refers to a resin that undergoes crosslinking by irradiation with radiation such as ultraviolet rays and electron beams, and is an acrylic resin containing a polyfunctional acrylate component having two or more acryloyl groups in the unit structure. Based resins. For example, trimethylolpropane triacrylate, trimethylolpropane ethylene oxide modified triacrylate, trimethylolpropane propylene oxide modified triacrylate, isocyanuric acid ethylene oxide modified triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, Various acrylate monomers such as dimethylol tricyclodecane diacrylate, polyester-modified, urethane-modified, and epoxy-modified polyfunctional acrylate oligomers are preferably used in this application. These resins may be used in a single composition or in a mixed composition of several kinds. In some cases, it is also preferable to add appropriate amounts of various hydrolyzed silicon alkoxides to the composition.
[0055]
When the resin layer is crosslinked by ultraviolet irradiation, an appropriate amount of a known photoreaction initiator is added. Examples of the photoinitiator include diethoxyacetophenone, 2-methyl-1- {4- (methylthio) phenyl} -2-morpholinopropane, 2-hydroxy-2-methyl-1-phenylpropan-1-one, Acetophenone compounds such as 1-hydroxycyclohexyl phenyl ketone; benzoin compounds such as benzoin and benzyldimethyl ketal; benzophenone compounds such as benzophenone and benzoylbenzoic acid; thioxanthone compounds such as thioxanthone and 2,4-dichlorothioxanthone Is mentioned.
[0056]
Examples of the thermally crosslinked layer of the phenoxy resin include a layer obtained by thermally crosslinking a phenoxy resin, a phenoxy ether resin, and a phenoxy ester resin represented by the following formula (1) with a polyfunctional isocyanate compound.
[0057]
[Chemical 1]

[0058]
Where R ¹ ~ R ⁶ Are the same or different hydrogen or an alkyl group having 1 to 3 carbon atoms, R ⁷ Represents an alkylene group having 2 to 5 carbon atoms, X represents an ether group or an ester group, m represents an integer of 0 to 3, and n represents an integer of 20 to 300. Especially R ¹ , R ² Is a methyl group, R ³ ~ R ⁶ Is hydrogen, R ⁷ Is preferably a pentylene group from the viewpoint of productivity because of easy synthesis.
[0059]
Moreover, as a polyfunctional isocyanate compound, what is necessary is just a compound which contains two or more isocyanate groups in 1 molecule, and the following are illustrated. 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, tolylene diisocyanate-trimethylolpropane adduct, t-cyclohexane-1,4-diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, hexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, hydrogenated diphenylmethane-4 , 4'-diisocyanate, lysine diisocyanate, lysine ester triisocyanate, triphenylmethane triisocyanate, tris ( Socyanate phenyl) thiophosphate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, bicycloheptane triisocyanate, Polyisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, mixtures thereof, polyhydric alcohol adducts and the like. Among these, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, tolylene diisocyanate-trimethylolpropane adduct and hexamethylene diisocyanate are particularly preferable from the viewpoint of versatility and reactivity.
[0060]
In addition, the crosslinking rate can be improved by adding an appropriate amount of a known tertiary amine such as triethylenediamine or an organic tin compound such as dibutyltin dilaurate as a reaction accelerator.
[0061]
In addition, various types of epoxy resin thermally crosslinked layers can be used, and among them, a layer obtained by thermally crosslinking a novolac type epoxy resin represented by the following formula (2) is preferable.
[0062]
[Chemical formula 2]

[0063]
Where R ⁸ Is hydrogen or methyl group, R ⁹ Represents hydrogen or a glycidyl phenyl ether group. In addition, q represents an integer from 1 to 50. In fact, the value of q generally has a distribution and is difficult to specify, but it is preferable that the average number is large, 3 or more, and 5 or more Is preferred.
[0064]
As the curing agent for crosslinking such an epoxy resin, known ones are applied. For example, curing agents such as amine-based polyaminoamides, acids and acid anhydrides, imidazoles, mercaptans, and phenol resins are used. Among these, acid anhydrides and alicyclic amines are preferably used, and acid anhydrides are more preferable. Examples of the acid anhydride include alicyclic acid anhydrides such as methylhexahydrophthalic anhydride and methyltetrahydrophthalic anhydride, aromatic acid anhydrides such as phthalic anhydride, and aliphatic acid anhydrides such as dodecenyl phthalic anhydride. Among them, methylhexahydrophthalic anhydride is particularly preferable. Examples of the alicyclic amine include bis (4-amino-3-methyldicyclohexyl) methane, diaminocyclohexylmethane, isophoronediamine, and the like, and bis (4-amino-3-methyldicyclohexyl) methane is particularly preferable.
[0065]
Here, when an acid anhydride is used as the curing agent, a reaction accelerator that accelerates the curing reaction between the epoxy and the acid anhydride may be added. Examples of the reaction accelerator include known second and third compounds such as bendimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, pyridine, 1,8-diazabicyclo (5,4,0) undecene-1. Examples thereof include curing catalysts such as amines and imidazoles.
[0066]
In addition, as the thermal crosslinking layer of silicon alkoxide, it is preferable to use a mixture of 2 to 4 functional silicon alkoxides, more preferably 3 to 4 functional silicon alkoxides. Those that have been appropriately oligomerized by decomposition and dehydration condensation are also preferably used.
[0067]
Examples of usable silicon alkoxides include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4 epoxy). (Cyclohexyl) ethyltrimethoxysilane, vinyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, etc. Is exemplified.
[0068]
Crosslinking of these silicon alkoxide layers proceeds thermally, but the degree of crosslinking can be further increased by irradiating the coating with an actinic ray such as ultraviolet rays as necessary.
[0069]
These protective layers are laminated directly on a substrate made of an organic polymer or via an appropriate intermediate layer. As such an intermediate layer, for example, various phase compensation layers such as a layer having a function of improving the adhesion between the protective layer and the substrate, a layer having a negative three-dimensional refractive index characteristic described later, and a substrate are added. Layers with viscoelastic properties that relieve stress (vertical stress, horizontal stress), for example, storage elastic modulus around room temperature is about 1 kg / mm ² It has the following layers, a layer that prevents the permeation of moisture and air or a layer that absorbs moisture and air, a layer that absorbs ultraviolet rays and infrared rays, and a function that reduces the chargeability of the substrate. A layer etc. are mentioned preferably.
[0070]
As an actual coating method on the substrate of these protective layers, the above-mentioned resin crosslinked precursor composition and filler are dissolved in various organic solvents, and a coating liquid whose concentration and viscosity are adjusted is used. After coating on the layer, the layer is crosslinked by irradiation with radiation or heat treatment. Examples of the coating method include micro gravure coating method, Mayer bar coating method, direct gravure coating method, reverse roll coating method, curtain coating method, spray coating method, comma coating method, die coating method, knife coating method, spin coating method, etc. These various coating methods are used.
[0071]
In the present invention, it is also preferable that the surface of the substrate made of an organic polymer or the surfaces of various coating layers coated on the substrate is appropriately roughened as necessary.
[0072]
One purpose of this is to improve the slipperiness of the substrate or the laminated substrate on which the various coating layers and the transparent conductive layer are laminated, and to prevent the phenomenon that the substrate surface and the substrate surface or flat plate become stuck and move, so-called blocking phenomenon. Prevention of electrode seizure, improvement of substrate unwinding and roll-up in roll-to-roll process, or improvement of handling on processing table (flat plate) in single-wafer process. Can do.
[0073]
Another object is to appropriately scatter light reflected from the surface of the transparent conductive layer. That is, when the flatness of the surface of the transparent conductive layer is high, light interference fringes (Newton rings) caused by the mutual interference of the reflected light on the surface of the transparent conductive layer of the pair of transparent electrode substrates disposed as a transparent tablet. May be observed with the naked eye, and the visibility of the tablet may decrease, but if the surface of the transparent conductive layer has moderate irregularities, the light interference fringes become unclear and the visibility decreases. Can be suppressed.
[0074]
When the reflectance of the surface of the transparent conductive layer is reduced by laminating the optical interference layer as in the present invention, the light interference fringes are effectively produced even if the degree of the unevenness is relatively weak. There is a feature that is suppressed.
[0075]
Here, in the case of the transparent conductive laminate of the present invention, the surface roughness of the transparent conductive layer suitable for the above requirements is preferably in the range of about 0.02 to 0.05 μm in terms of the centerline surface roughness SRa. It is. When the SRa value is less than 0.02 μm, the effect of obscuring the light interference fringes tends to be insufficient. Conversely, when the SRa value exceeds 0.05 μm, light scattering on the surface of the transparent conductive layer is likely to occur. The reproducibility increases significantly, and disadvantages such as blurring of the display image and a decrease in the transmittance of the laminate are likely to occur.
[0076]
Yet another object is to impart anti-glare properties by appropriately scattering extraneous light (sunlight, indoor illumination light, etc.) reflected on the substrate surface on the side where input with a pen or the like is performed. In other words, when the substrate surface on which this input is made is flat and high, extraneous light is regularly reflected on the surface, so a so-called reflection phenomenon is likely to occur, and the tablet visibility may be reduced. Many. On the other hand, when the surface has moderate irregularities, extraneous light is appropriately scattered and reflected on the surface, and the reflection phenomenon is suppressed, that is, the antiglare property is exhibited.
[0077]
The reflection phenomenon can be reduced by laminating an optical interference layer having a function of reducing the reflectance mainly in the wavelength region of 450 to 650 nm on the surface of the substrate on which this input is performed. In some cases, such an optical interference layer is preferably laminated on the surface. In this case, the surface may be flat to some extent, but it is more preferable that the surface has relatively weak irregularities. As materials and forming methods for forming such an optical interference layer, the same materials and forming methods as those for the optical interference layer laminated as the base of the above-mentioned transparent conductive layer are preferably used.
[0078]
There are various methods for making the surface of the substrate made of organic polymer or the surface of the protective layer or optical interference layer coated on the substrate moderately uneven. For example, a mold with unevenness is used. A method of forming and shaping the substrate and various coating layers, a method of applying mechanical processing such as embossing and sandblasting, and mixing an appropriate amount of fine particles (filler) in a dispersed state in the substrate and various coating layers. Methods and the like.
[0079]
In particular, a method of mixing an appropriate amount of fine particles in a dispersed state in a protective layer or an optical interference layer coated on a substrate is most preferable from the viewpoints of process simplicity and stability.
[0080]
In this case, it is necessary to minimize the decrease in coating film strength, the increase in light scattering property, the deterioration of the coating film appearance, etc. due to the dispersion of the fine particles. About 1.0 to 2.0 times, more preferably about 1.0 to 1.5 times, and most preferably 1.1 to 1.3 times the average particle size as fine particles. And a method using a combination of a resin component and fine particles such that the fine particles are aggregated with an aggregate diameter of about 5 μm or less, more preferably 3 μm or less.
[0081]
The amount of fine particles mixed is preferably about 0.05 to 5.0%, more preferably 0.1 to 3.0% by weight in the former method. When the mixing amount is less than 0.05%, sufficient slipperiness is often not obtained, and when it exceeds 5.0%, the light scattering property is remarkably increased and the tablet visibility may be lowered. Since there are many, it is not preferable.
[0082]
In the latter method, the mixing ratio of the fine particles is preferably about 0.5 to 30% by weight, more preferably 0.5 to 20%. When the mixing amount is less than 0.5%, sufficient slipperiness is often not obtained, and when it exceeds 30%, the light scattering property often increases remarkably, which may cause cracks in the coating film. This is not preferable.
[0083]
As the kind of the fine particles, it is preferable to use those in which precipitation of the fine particles hardly occurs in the coating liquid. Specifically, commercially available organic silicon fine particles, crosslinked acrylic fine particles, crosslinked polystyrene fine particles, and the like are preferably used.
[0084]
According to the present invention, by using the transparent conductive laminate as at least one electrode substrate, a tablet with less reflection and coloring and good transparency is provided. Here, when the transparent conductive laminate of the present invention is used for a pair of electrode substrates of a tablet, that is, both of the movable electrode substrate and the fixed electrode substrate, the effect intended by the present invention is particularly remarkable. The effect can be obtained even if it is used on only one of the fixed electrode substrate. For example, it is possible to obtain good visibility even in a tablet configuration using a transparent electrode laminate of the present invention for a movable electrode substrate and a glass electrode substrate in which a transparent electrode is formed on a conventional glass plate for a fixed electrode substrate. it can.
[0098]
Examples of the present invention will be described below. The various characteristics in the following examples and comparative examples were evaluated in the following manner.
[0099]
Total light transmittance and haze value: Measured using a measuring instrument (trade name “COH-300A”) manufactured by Nippon Denshoku Industries Co., Ltd.
[0100]
Transmission spectrum, reflection spectrum, reflectance measurement, and color (b ^* Value): Each spectrum was measured and the color was calculated using the integrating sphere measurement mode and calculation program of Hitachi spectrophotometer U3500. The incident angle of the measurement light to the sample is 0 degree in the transmission mode and 10 degrees in the reflection mode. In the measurement in the reflection mode, a light-shielding layer is formed on the back side of the sample using a commercially available black spray. The measurement was performed in a state where there was almost no light reflected from the back surface side or light incident from the back surface side. In the calculation of the reflected color, the standard light D defined in the Japanese Industrial Standard Z8720 is used as the light source. ₆₅ The measurement was performed under the condition of a two-degree visual field.
[0101]
Evaluation of solvent resistance: Performed by the method described above in the specification.
[0102]
Evaluation of hard coat properties: Pencil hardness was measured with a load of 1 kg in accordance with Japanese Industrial Standard K5400.
[0103]
Refractive index and film thickness of each layer: For the optical interference layer and the transparent conductive layer, a single layer is laminated under the same coating conditions on an appropriate thermoplastic film substrate having a refractive index different from those of the layers. Calculation was performed by optical simulation using the wavelength of the maximum peak or minimum peak of the reflectance expressed based on the light interference effect on the light reflection spectrum and the value of the peak reflectance. The refractive index of the protective layer was measured using an Abbe refractometer, and the thickness of the protective layer was determined by calculation using the same optical interference method as that of the optical interference layer.
[0104]
[Example 1]
A biaxially stretched polyethylene terephthalate (PET) film having a thickness of about 75 μm (Teijin HSL-75, in-plane refractive index: about 1.64, pencil hardness F) was laminated with two layers of optical interference layers.
[0105]
That is, first of all, tetrabutoxy titanate (trade name “B-4” manufactured by Nippon Soda Co., Ltd.) of ligroin (grade made by Wako Pure Chemical Industries, Ltd. is a first grade product) and butanol (grade made by Wako Pure Chemical Industries, Ltd. is a special grade product). Roll coating was performed using a coating solution diluted with a mixed solvent, and heat treatment was performed at 130 ° C. for 2 minutes to form a layer having a thickness of about 41 nm and a refractive index of about 1.82.
[0106]
Next, the layer was roll-coated using a coating liquid having the following composition, and heat-treated at 130 ° C. for 5 minutes to form a layer having a thickness of about 51 nm and a refractive index of about 1.47. That is, after mixing 720 parts by weight of water, 1080 parts by weight of 2-propanol and 46 parts by weight of acetic acid, 480 parts by weight of γ-glycidoxypropyltrimethoxysilane (trade name “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) and methyltrimethoxy 240 parts by weight of silane (trade name “KBM13” manufactured by Shin-Etsu Chemical Co., Ltd.) and 120 parts by weight of N-β (aminoethyl) γ-aminopropyltrimethoxysilane (trade name “KBM603” manufactured by Shin-Etsu Chemical) were sequentially mixed. The alkoxysilane mixed solution was hydrolyzed and partially condensed by stirring for 3 hours, and further diluted with a mixed solvent of isopropyl alcohol and 1methoxy-2-propanol in a weight ratio of 1: 1 to obtain a coating solution for forming the layer. .
In addition, the solvent resistance of the surface of the film on which this optical interference layer was laminated was good.
[0107]
Next, a transparent conductive film was produced by laminating a transparent conductive layer on the film surface on which the optical interference layer was laminated. As the transparent conductive layer, an indium-tin oxide (ITO) was used, and the layer was formed by DC magnetron sputtering so as to have a film thickness of about 22 nm. That is, an ITO target having a composition of 95: 5 by weight of indium oxide and tin oxide and a packing density of 98% was used as a target. After the film was set in the sputtering apparatus, it was evacuated to a pressure of 1.3 mPa. Ar and O ₂ A mixed gas having a volume ratio of 98.5: 1.5 was introduced to adjust the atmospheric pressure to 0.27 Pa. The film temperature is 50 ° C. and the input power density is 1 W / cm. ² Sputtering was performed under the above conditions, and a transparent conductive layer made of ITO was laminated on the optical interference layer. The surface resistance of this transparent conductive layer was about 230Ω / □, and the refractive index was about 2.0.
Table 1 describes the optical characteristics of the transparent conductive film.
[0108]
[Example 2]
Example 1 is the same as Example 1 except that a protective layer is laminated on both sides of a biaxially stretched polyethylene terephthalate film (Teijin OFW-188, in-plane refractive index of around 1.65, pencil hardness F) having a thickness of about 188 μm. Similarly, a transparent conductive film was prepared.
[0109]
That is, on the side of the film on which the optical interference layer and the transparent conductive layer are laminated, 50 parts by weight of polyester acrylate (M8560 manufactured by Toagosei Co., Ltd.), 50 parts by weight of dipentaerythritol hexaacrylate (DPHA manufactured by Nippon Kayaku), and a photoinitiator (Ciba Geigy's Irgacure 184) Roll coating is performed using a coating solution consisting of 7 parts by weight, 0.03 part by weight of silicone oil (SH28PA manufactured by Toray Dow Chemical) as a leveling agent, and 200 parts by weight of 1 methoxy 2-propanol as a diluent solvent. , After drying the solvent at 60 ° C. for 1 minute, using a high pressure mercury lamp with a lamp intensity of 160 W / cm, the integrated light quantity is about 600 mJ / cm ² The coating layer was cured by irradiating ultraviolet rays under the conditions described above, and a protective layer having a smooth surface with a film thickness of about 4.3 μm was laminated.
[0110]
A coating liquid obtained by adding 2.0 parts by weight of silicone crosslinked fine particles having an average particle size of about 4.5 μm (Toshiba Silicone Tospearl 145) as a filler to the coating liquid composition is further added to the film surface on the opposite side. The coating was carried out in the same manner as described above, and a protective layer having a film thickness of about 4.1 μm and uniformly fine irregularities formed on the surface was laminated.
[0111]
The refractive index of these protective layers was about 1.53 according to the Abbe refractometer, the pencil hardness on the film was 2H, and the solvent resistance was also good. The surface of the protective layer on which the fine irregularities were formed had good antiglare properties.
[0112]
Furthermore, an optical interference layer and a transparent conductive layer were laminated on the protective layer having a smooth surface in the same manner as in Example 1 to prepare a transparent conductive film. Table 1 describes the optical properties of the film.
[0113]
[Example 3]
Except that protective layers were laminated on both sides of a biaxially stretched polyethylene terephthalate film (Teijin OFW-75, refractive index 1.64, pencil hardness F) having a thickness of about 75 μm, the same as in Example 1. A transparent conductive film was prepared.
[0114]
That is, on the side of the film on which the optical interference layer and the transparent conductive layer are laminated, 50 parts by weight of polyester acrylate (M8560 manufactured by Toagosei Co., Ltd.), 50 parts by weight of dipentaerythritol hexaacrylate (DPHA manufactured by Nippon Kayaku), and average as filler 1.0 parts by weight of silicone cross-linked fine particles (Toshiba Silicone Tospearl 130) having a particle size of about 3.0 μm, 7 parts by weight of a photoinitiator (Irgacure 184 made by Ciba Geigy), silicone oil as a leveling agent (SH28PA made by Toray Dow Chemical) ) Roll coating using a coating solution consisting of 0.03 parts by weight and 200 parts by weight of 1 methoxy 2-propanol as a diluting solvent, and after drying the solvent at 60 ° C. for 1 minute, a high pressure mercury lamp with a lamp intensity of 160 W / cm Using integrated light quantity of about 600mJ / cm ² The coating layer was cured by irradiating with ultraviolet rays under the conditions described above, and a protective layer having a film thickness of about 2.7 μm and having fine irregularities uniformly formed on the surface was laminated.
[0115]
On the other side of the film surface, coating is performed in the same manner as described above using a coating liquid having a composition in which the silicone crosslinked fine particles of the coating liquid composition are not mixed. A smooth protective layer was laminated.
[0116]
The pencil hardness of these protective layers on the film was either H or 2H, and the solvent resistance was good.
[0117]
Further, an optical interference layer and a transparent conductive layer were laminated in the same manner as in Example 1 on the protective layer having irregularities uniformly formed on the surface to prepare a transparent conductive film. The optical properties of this film are shown in Table 1.
[0118]
Using this transparent conductive film as a movable electrode substrate, and using a glass plate having a thickness of 1.1 mm and a transparent conductive layer made of ITO on one side as a fixed electrode substrate, a transparent tablet made by a known method is commercially available. When observed under a three-wavelength fluorescent lamp, no optical interference fringes (Newton rings) were observed, and the visibility was excellent.
[0119]
[Example 4]
A transparent conductive film was prepared in exactly the same manner as in Example 1 except that the thickness of the cured layer of titanium alkoxide laminated in Example 3 was 47 nm and the thickness of the cured layer of silicon alkoxide was 57 nm. The optical properties of this film are shown in Table 1.
[0120]
[Example 5]
A transparent conductive film was prepared in exactly the same manner as in Example 1 except that the thickness of the cured layer of titanium alkoxide laminated in Example 3 was 74 nm and the thickness of the cured layer of silicon alkoxide was 30 nm. The optical properties of this film are shown in Table 1.
[0121]
[Example 6]
A transparent conductive film was prepared in exactly the same manner as in Example 1 except that the thickness of the cured layer of titanium alkoxide laminated in Example 3 was 38 nm and the thickness of the cured layer of silicon alkoxide was 47 nm. The optical properties of this film are shown in Table 1.
[0122]
[Example 7]
Except that the thickness of the cured layer of titanium alkoxide laminated in Example 3 was 53 nm, the thickness of the cured layer of silicon alkoxide was 65 nm, and the thickness of the transparent conductive layer was 15 nm, it was exactly the same as Example 1. A transparent conductive film was prepared. The optical properties of this film are shown in Table 1.
[0123]
[Example 8]
A zirconium oxide layer having a thickness of about 34 nm and a refractive index of about 2.2 was formed by RF magnetron sputtering on the protective layer having unevenness formed uniformly on the surface in Example 3. That is, a titanium oxide target with a filling density of 90% is used as a target, the film is set in a sputtering apparatus, the air is evacuated to a pressure of 1 mPa, and then a mixed gas of Ar: O2 volume ratio 98: 2 is introduced. The atmospheric pressure was 0.27 Pa. The film temperature is 50 ° C. and the input power density is 1 W / cm. ² Sputtering was performed under the conditions described above to stack a zirconium oxide layer.
[0124]
Next, a silicon oxide layer having a thickness of 51 nm and a refractive index of about 1.46 was formed by DC magnetron sputtering. That is, a silicon target was used as a target, the film was set in a sputtering apparatus, the air was exhausted to a pressure of 1 mPa, and then Ar and O ₂ The mixed gas having a volume ratio of 70:30 was introduced, and the atmospheric pressure was set to 0.27 Pa. The film temperature is 50 ° C. and the input power density is 1 W / cm. ² Sputtering was performed under these conditions to stack a silicon oxide layer.
[0125]
Thereafter, in the same manner as in Example 1, a transparent conductive film having a thickness of 22 nm and a refractive index of 2.0 made of indium oxide was laminated to prepare a transparent conductive film. The optical properties of this film are shown in Table 1.
[0126]
[Example 9]
A protective layer was laminated on both sides of a polycarbonate film (Teijin Pure Ace, refractive index 1.586, pencil hardness 6B or less, in-plane retardation 10nm or less) as a substrate in exactly the same way as in Example 3 and further carried out. In the same manner as in Example 3, a transparent conductive film was prepared by laminating an optical interference layer and a transparent conductive layer on a protective layer on one side.
The pencil hardness of these protective layers on the film was B, and the solvent resistance was also good. The optical properties of this film are shown in Table 1.
[0127]
[Comparative Example 1]
A transparent conductive film was prepared in exactly the same manner as in Example 3 except that the cured layer of titanium alkoxide and the cured layer of silicon alkoxide were not laminated in Example 3, but a transparent conductive layer was laminated directly on the PET film. The optical properties of this film are shown in Table 1.
[0128]
[Comparative Example 2]
A transparent conductive film was prepared in exactly the same manner as in Example 3, except that the thickness of the cured layer of titanium alkoxide laminated in Example 3 was 55 nm and the thickness of the cured layer of silicon alkoxide was 66 nm. The optical properties of this film are shown in Table 1.
[0129]
[Comparative Example 3]
A transparent conductive film was prepared in exactly the same manner as in Example 3, except that the thickness of the cured layer of titanium alkoxide in Example 3 was 34 nm and the thickness of the cured layer of silicon alkoxide was 42 nm. The optical properties of this film are shown in Table 1.
[0130]
[Comparative Example 4]
In the same manner as in Comparative Example 1, except that a cured layer of titanium alkoxide and a cured layer of silicon alkoxide are not laminated, a transparent conductive layer is laminated directly on the PET film, and the thickness of the transparent conductive layer is 15 nm. A transparent conductive film was prepared in the same manner as in 1. The optical properties of this film are shown in Table 1.
[0133]
[Table 1]

[0134]
Note) The measured value of reflectivity tends to be slightly larger than the actual value due to the effects of stray light and back reflection of the sample. (Measurement error is within 0.3%)
[0135]
【The invention's effect】
The transparent conductive laminate of the present invention has a feature that the reflectance of the surface of the transparent conductive layer is low and the transmitted light of the laminate is less colored. In a transparent tablet made using this transparent conductive laminate, Very good visibility can be obtained.

Claims (5)

In a transparent conductive laminate in which a transparent conductive layer is laminated on the outermost surface of at least one surface of an organic polymer substrate, (A1) the refractive index is 1.7 to 1.7 range layers thickness is in the range of rates +0.3 is in the range of 20 to 90 nm (H ₁ layer), is located a thickness in the range of (B1) a refractive index from 1.35 to 1.5 of 30~110nm Layer (L ₁ layer), (C) a transparent conductive layer having a thickness of 12 to 30 nm, and (D) a sum of optical thicknesses of the three layers is in the range of 180 to 230 nm. (F) The average reflectance of the laminated surface of the transparent conductive layer at a wavelength of 450 to 650 nm is 5.5% or less, and (G) Japanese Industrial Standard No. Z8729 for the transmitted light of the laminate. L ^* a ^* b ^* chromaticness index b ^* values of the color system is in the range of 0-2 Transparent conductive laminate according to claim and. The transparent conductive laminate according to claim 1, wherein the H ₁ layer and / or the L ₁ layer is a layer formed mainly by hydrolysis and condensation of a metal alkoxide. The L ₁ layer is a layer formed mainly by hydrolysis and condensation of silicon alkoxide, and the H ₁ layer is a layer formed mainly by hydrolysis and condensation of titanium alkoxide and / or zirconium alkoxide. Or the transparent conductive laminated body in any one of 2. The transparent conductive laminate according to any one of claims 1 to 3, protective layer made of a resin cross-linked layer on one side or both sides of a substrate made of an organic polymer characterized in that it is laminated. In the transparent tablet in which two transparent electrode substrates are disposed so that the electrode surfaces are opposed to each other, the transparent conductive laminate according to any one of claims 1 to 4 is used as at least one transparent electrode substrate. .