JP2004175074A

JP2004175074A - Transparent substrate with multilayer film having electroconductivity

Info

Publication number: JP2004175074A
Application number: JP2002347236A
Authority: JP
Inventors: Yoshimitsu Uchida; 芳光内田; Masayoshi Osada; 雅義長田
Original assignee: Nidek Co Ltd
Current assignee: Nidek Co Ltd
Priority date: 2002-11-29
Filing date: 2002-11-29
Publication date: 2004-06-24
Anticipated expiration: 2022-11-29
Also published as: JP4245339B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent substrate with a multilayer film having electroconductivity and high scratch resistance (resistance to a sliding pen). <P>SOLUTION: This transparent substrate with the multilayer film having electroconductivity is composed by lamination of a thin transparent dielectric film and a thin transparent electroconductive film on the transparent substrate, where the electroconductive film has a first electroconductive film layer as the outermost layer comprising a transparent electroconductor containing zinc oxide as the principal component and a second electroconductive film layer comprising a transparent electroconductor formed under the first electroconductive film layer. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は導電性を有する多層膜付透明基板に関する。
【０００２】
【従来技術】
従来より、ガラス板やプラスチック板（プラスチックフィルム）等の透明基板にインジウム錫酸化物（ＩＴＯ）やＳｎＯ_２等の透明導電膜を形成して、太陽電池などの光電変換素子の電極や液晶等の表示装置またはタッチパネルの電極、静電防止フィルターや電磁波カットフィルターとして利用するものが知られている。特にタッチパネルとして使用される場合、耐擦傷性（タッチパネルにおいては耐ペン摺動性）に優れた導電性を有する多層膜付透明基板が望まれるようになっている。
このような背景において、基板上にハードコート層を設けるとともに最表面に透明導電膜を形成させることにより、導電性を有する多層膜付透明基板の耐ペン摺動性の向上を図ろうとする技術が知られている（例えば、特許文献１、特許文献２参照）。
【０００３】
【特許文献１】
特開２００１−２１６８４２号公報
【特許文献２】
特開２００２−１２２７０３号公報
【０００４】
【発明が解決しようとする課題】
しかしながら、上述したような基板上にハードコート層を形成するだけでは現在要望されている耐ペン摺動性を満足することが困難である。
【０００５】
本発明では上記従来技術の問題点に鑑み、高い耐擦傷性（耐ペン摺動性）を有する導電性を有する多層膜付透明基板を提供することを技術課題とする。
【０００６】
【課題を解決するための手段】
上記課題を解決するために、本発明は以下のような構成を備えることを特徴とする。
（１）透明基板上に透明誘電体の薄膜と透明導電体の薄膜とを積層する導電性を有する多層膜付透明基板において、最外層に主成分として酸化亜鉛を含有する透明導電体からなる第１導電膜層と、該第１導電膜層の下層に形成される透明導電体からなる第２導電膜層と、を有することを特徴とする。
（２）（１）の多層膜付透明基板において、前記第１導電膜層と第２導電膜層と合わせた光学膜厚は所望する表面抵抗値が得られるように決定されていることを特徴とする。
（３）（２）の多層膜付透明基板において、前記基板と第２導電膜層との間には反射防止効果をもたせるために屈折率の異なる複数の透明誘電体層からなる薄膜層帯が形成されていることを特徴とする。
（４）（２）の多層膜付透明基板において、前記第１導電膜層はアルミニウムドープ酸化亜鉛、ガリウムドープ酸化亜鉛又は酸化亜鉛から選ばれる少なくとも１種類の導電体にて形成されていることを特徴とする。
（５）（３）又は（４）の多層膜付透明基板において、前記複数の透明誘電体層からなる薄膜層帯は、基板側から順に、前記基板の屈折率より高い屈折率である透明誘電体からなる第１誘電膜層と、前記基板の屈折率より低い屈折率である透明誘電体からなる第２誘電膜層と、前記基板の屈折率より高い屈折率である透明誘電体からなる第３誘電膜層と、前記基板の屈折率より低い屈折率である透明誘電体からなる第４誘電膜層と、から形成されていることを特徴とする。
（６）（５）の多層膜付透明基板において、前記第３誘電膜層を形成する透明誘電体の屈折率は前記第１誘電膜層を形成する透明誘電体の屈折率と同じかそれよりも高いことを特徴とする。
（７）（１）〜（６）の多層膜付透明基板において、前記基板上にはハードコート層が形成されていることを特徴とする。
【０００７】
【発明の実施の形態】
以下、本発明の実施の形態における導電性を有する多層膜付透明基板について、図面を参照しながら説明する。なお、本実施形態では、基板上に反射防止効果をもたせるための薄膜層帯を設けておき、その上に導電性を有する導電膜層を設けた導電性を有する多層膜付透明基板を例にとり、説明する。
【０００８】
図１は本発明の実施の形態における導電性を有する多層膜付透明基板の積層構成を示す概略図である。
１は透明の基板である。基板１は通常に入手できるものであればよく、屈折率は１．４８以上１．７以下程度のものを使用する。具体的に、基板材料としてはガラス類（屈折率１．４８〜１．７０）、プラスチック類（ポリカーボネイト（屈折率１．５９）、ポリエチレンテレフタラート（屈折率１．６３）等）が用いられ、光学的に透明であれば特に限定されない。また、本実施形態で述べる基板とは板状に限らず、フィルム基板を含むものとしている。
【０００９】
２は基板１上に多層膜の成膜前に事前に形成される薄膜層である。この薄膜層２は、多層膜を成膜する前に基板１にコーティングすることにより、基板１の表面を硬化させ、傷等から保護するためや、基板１と多層膜との間の密着力を上げるために形成される層である（以下、ハードーコート層と記す）。一般的に、ハードコート層２においては、基板１の表面を保護するとともに、基板１と多層膜との間の密着力を上げることが可能なアクリル系ハードコートがよく利用される。
【００１０】
また、基板１にハードコート層２を形成しないで、基板１上に直接多層膜を成膜することも可能であるが、前述したように多層膜の保護や密着力向上のために、基板１上に事前にハードコート処理を行なっておくことが好ましい。また、ハードコートではなく、単に基板１と多層膜との間での密着力向上のために真空蒸着等にて基板上にアンダーコートを行なうこともある。
何れの場合においても、ハードコート（アンダーコート）の膜厚は、光学的な阻害が起こらないように基板の屈折率と同程度の屈折率を有するようにしておくことが好ましい。
【００１１】
３はハードコート層２上に屈折率の異なる透明誘電体からなる誘電膜層を複数積層することにより反射防止効果をもたせるための反射防止層帯である。本実施形態における反射防止層帯３は４つの誘電膜層３ａ〜３ｄにより形成されている。
３ａは基板１の屈折率よりも高い屈折率をもつ透明誘電体からなる第１誘電膜層である。第１誘電膜層３ａに使用される透明誘電体は、使用する基板１に応じて適宜選択されるが、基板１の屈折率よりも高い屈折率が必要なため、基板１の最低屈折率１．４８より高い必要がある。また同時に、安価に入手可能でかつ安定した成膜が確認されているものが好ましいため、それらを考慮して屈折率が１．５０以上２．５０以下程度の範囲のものが使用される。具体的には、第１誘電膜層３ａの主成分にはＺｒＯ_２（屈折率１．９）や、ＴｉＯ_２（屈折率２．２）、Ａｌ_２Ｏ_３（屈折率１．６）等が挙げられる。第１誘電膜層３の光学的膜厚ｎｄ（以後、単に膜厚と記す）は１０ｎｍ以上６００ｎｍ以下が好ましく、より好ましくは５０ｎｍ以上５５０ｎｍ以下である。
【００１２】
３ｂは第１誘電膜層３ａ上に積層され、基板１の屈折率よりも低い屈折率をもつ透明誘電体からなる第２誘電膜層である。第２誘電膜層３ｂに使用される透明誘電体は、使用する基板１に応じて適宜選択されるが、基板１の屈折率よりも低い屈折率が必要なため、基板１の最高屈折率１．７０より低くする必要がある。また同時に、安価に入手可能でかつ安定した成膜が確認されているものが好ましいため、それらを考慮して屈折率が屈折率１．３５以上１．６０以下程度の範囲のものが使用される。具体的には、第２誘電膜層３ｂの主成分にはＳｉＯ_２（屈折率１．４６）やＭｇＦ_２（屈折率１．３８）が挙げられる。また、第２誘電膜層３ｂの膜厚は１０ｎｍ以上６００ｎｍ以下が好ましく、より好ましくは５０ｎｍ以上５５０ｎｍ以下である。膜厚がこれ以上薄くても厚くても、反射防止効果が得られにくい。
【００１３】
３ｃは第２誘電膜層３ｂ上に積層され、基板１の屈折率よりも高い屈折率をもつ透明誘電体からなる第３誘電膜層である。第３誘電膜層３ｃに使用される透明誘電体は、第１誘電膜層３ａと基本的に同じ材料のものが使用可能であるが、反射防止効果を向上させるためには第１誘電膜層３ａにて用いられる材料の屈折率と同じか、それより高い屈折率を有する材料を用いることが好ましい。第３誘電膜層３ｃの膜厚は１０ｎｍ以上６００ｎｍ以下が好ましく、より好ましくは５０ｎｍ以上５５０ｎｍ以下である。
【００１４】
３ｄは第３誘電膜層３ｃ上に積層され、基板１の屈折率よりも低い屈折率をもつ透明誘電体からなる第４誘電膜層である。第４誘電膜層３ｄに使用される透明誘電体は、第２誘電膜層３ｂと基本的に同じ材料のものが使用可能である。また、第４誘電膜層３ｄの膜厚は１０ｎｍ以上６００ｎｍ以下が好ましく、より好ましくは５０ｎｍ以上５５０ｎｍ以下である。
【００１５】
４は第４誘電膜層３ｄ上に積層され、導電性を有する第２導電膜層である。第２導電膜層４の透明導電体にはＩＴＯやＡＴＯ、ＳｎＯ_２、ＩＺＯ等の酸化亜鉛を主成分としない透明かつ導電性を有する材料が挙げられる。５は第２導電膜層４上に積層され、最表面となる導電性を有する第１導電膜層である。第１導電膜層５の透明導電体には、酸化亜鉛、ＡＺＯ（アルミニウムドープ酸化亜鉛）やＧＺＯ（ガリウムドープ酸化亜鉛）等の酸化亜鉛を主成分とする材料を用いることができる。
このように、ＩＴＯ等からなる第２導電膜層４の上に酸化亜鉛を主成分とする第１導電膜層５を形成することにより、従来の導電性を有する多層膜付透明基板に比べ、耐ペン摺動性の性能が格段に向上する。
【００１６】
また、第１導電膜層５と第２導電膜層４とを合わせた膜厚により表面抵抗値が決定される。したがって、表面抵抗値を低抵抗値に設定する場合には、一方の膜厚或いは両方の膜厚を厚くすればよい。また、表面抵抗値を高抵抗値に設定する場合には一方の膜厚或いは両方の膜厚を薄くすればよい。なお、第２導電膜層にＩＴＯ等の抵抗率の良い材料を用いた場合、第１導電膜層５の膜厚の増減に対して、第２導電膜層４の膜厚を増減させる方が、表面抵抗値の値が大きく変動する。このため、所望する表面抵抗値を得るために主として第２導電膜層４の膜厚を増減させることにより、導電膜層全体の膜厚を薄くさせることができるため、透過率の向上が期待できる。
【００１７】
また、表面抵抗値は使用目的に応じて適宜決定すれば良いが、電気光学素子用、光電変換素子用、液晶用、タッチパネル用等に用いるのであれば、好ましくは表面抵抗値が１００Ω／□以上５０００Ω／□以下であり、より好ましくは１００Ω／□以上１０００Ω／□以下である。また、表面抵抗値と対応する第１導電膜層５と第２導電膜層４との合計の膜厚は１０ｎｍ以上１０００ｎｍ以下が好ましく、より好ましくは１５ｎｍ以上１００ｎｍ以下である。
【００１８】
また、各層の最適な膜厚は以下の方法により決定される。
初めに、用途に応じて必要な表面抵抗値が得られるような導電膜層（ここでは第１導電膜層５及び第２導電膜層４）の膜厚を決定させておく。次に反射防止層帯３（誘電体層３ａ〜３ｄ）に使用する材料の屈折率を固定値とし、最適化アルゴリズムを用いながら誘電体層３ａ〜３ｄの物理膜厚を変化させていく。このような手法により、最も高い透過率若しくは最も低い反射率が得られるような各誘電体層３ａ〜３ｄの膜厚を求める。最適化アルゴリズムは例えば、ＡｄａｐｔｉｖｅＲａｎｄｏｍＳｅａｒｃｈやＭｏｄｉｆｉｅｄＧａｒｄｉｅｎｔ、ＭｏｎｔｅＣａｒｉｌｏｍｅｔｈｏｄ、ＳｉｍｕｒａｔｅｄＡｎｎｅａｌｉｎｇ等、メリット関数を使用した様々な最適化手法を基に与えられる。
【００１９】
上記で示した各薄膜層（導電膜層、誘電膜層）を基板１上に形成する方法としては、物理的気層成長方法（ＰＶＤ）では真空蒸着方法やスパッタ方法、イオンプレーティング方法等が挙げられる。また、化学的気層成長方法（ＣＶＤ）ではめっき方法や化学的気層成長方法等が挙げられる。これらの成膜方法は、本実施の形態としてすべて使用可能であるが、成膜に際して高温を伴うような方法では熱によるプラスチック基板の変形等が考えられるため、プラスチック基板での多層膜の成膜は高熱を必要としない真空蒸着方法やスパッタ方法が好適に用いられる。
【００２０】
なお、前述の実施形態では４層からなる反射防止層帯３の上に導電膜層を２層積層するものとしているが、これに限るものではない。例えば、導電性を有する多層膜付透明基板の透過率（反射率）を考慮する必要がなければ、このような反射防止層帯３を設けなくとも良い。また、反射防止層帯３を形成する場合であっても４層に限るものではなく、所望する透過率（反射率）が得られるような多層構造（例えば１層〜６層等）を形成すればよい。
【００２１】
＜実施例１＞
ハードコート付きポリカーボネイト基板（屈折率１．５９）を用意し、真空蒸着法により、誘電膜層を基板上に４層形成した。第１誘電膜層としては、オプトロン社製ＺｒＯ_２タブレットを使用し、アンダーコート層であるハードコート上にＺｒＯ_２を主成分とする薄膜層を形成した。このときの第１誘電体層の膜厚（光学膜厚ｎｄ）は７０ｎｍとした。第２誘電膜層としては、オプトロン社製ＳｉＯ_２顆粒を使用し、第１誘電膜層上にＳｉＯ_２を主成分とする薄膜層を形成した。このときの第２誘電膜層の膜厚は３５ｎｍとした。第３誘電膜層としては、オプトロン社製ＴｉＯ_２顆粒を使用し、第２誘電膜層上にＴｉＯ_２を主成分とする薄膜層を形成した。このときの第３誘電膜層の膜厚は９５ｎｍとした。第４誘電膜層としては、オプトロン社製ＳｉＯ_２顆粒を使用し、第３誘電膜層上にＳｉＯ_２を主成分とする薄膜層を形成した。このときの第４誘電膜層の膜厚は６５ｎｍとした。
【００２２】
次に真空治金（株）製ＩＴＯターゲットを使用し、第２導電膜層としてＩＴＯを主成分とする薄膜層をスパッタ法により第４誘電膜層上に形成した。このときの第２導電膜層の膜厚は２０ｎｍとした。最表面となる第１導電膜層としては、住友金属鉱山（株）製ＡＺＯターゲットを使用し、第２導電膜層上にＡＺＯの薄膜層を形成した。このときの第１導電膜層の膜厚は３０ｎｍとした。
【００２３】
このようにして得られた導電性を有する多層膜付透明基板の視感度透過率を測定した。測定装置は朝日分光社製視感度透過率計ＭＯＤＥＬ３０４を用いた。得られた視感透過率は９２．１％であった。また、表面抵抗値は５００Ω／□であった。
【００２４】
次に、物理膜厚１８８μｍのＩＴＯ付のＰＥＴ（ポリエチレンテレフタレート）フィルムのＩＴＯ形成面側と作成した多層膜付透明基板の膜形成面側とを張り合わせた後、耐ペン摺動性評価を行った。耐ペン摺動性評価は、張り合わせたＰＥＴフィルムのＩＴＯ電極面の裏面より、ポリアセタール製のペン（先端形状は、０．８ｍｍＲ）に２５０ｇの荷重を掛け、往復１０万回の摺動試験を行うことにより評価した。往復１０万回の摺動試験を行っても、目視にて多層膜付基板上に白濁が見られなければ○、白濁が生じていれば×とした。
以上の結果を表１に示す。
【００２５】
＜実施例２＞
基板、膜構成及び成膜材料を実施例１と同一条件にて多層膜付透明基板を作成した。ただし、第１導電膜層の膜厚を１５ｎｍに変えて成膜を行った。なお、得られる表面抵抗値を実施例１と同じ５００Ω／□とするために、第２導電膜層の膜厚を２３ｎｍとした。また、この条件にて多層膜付透明基板の透過率ができるだけ高く得られるように、最適化アルゴリズムを用いて各誘電膜層の膜厚を調整した。この結果、第１誘電膜層〜第４誘電膜層の各膜厚は順に７５ｎｍ、３５ｎｍ、９０ｎｍ、８０ｎｍとした。なお、実施例１と同様に誘電膜層の形成は真空蒸着法で行い、導電膜層の形成はスパッタ法にて行った。
【００２６】
このようにして得られた導電性を有する多層膜付透明基板の視感度透過率は９３．３％であった。また、摺動性試験では白濁は見られなかった。以上の結果を表１に示す。
【００２７】
＜実施例３＞
基板、膜構成及び成膜材料を実施例１と同一条件にて多層膜付透明基板を作成した。ただし、第１導電膜層の膜厚を５ｎｍに変えて成膜を行った。なお、得られる表面抵抗値を実施例１と同じ５００Ω／□とするために、第２導電膜層の膜厚を２３．５ｎｍとした。また、この条件にて多層膜付透明基板の透過率ができるだけ高く得られるように、最適化アルゴリズムを用いて各誘電膜層の膜厚を調整した。この結果、第１誘電膜層〜第４誘電膜層の各膜厚は順に７５ｎｍ、３５ｎｍ、８６ｎｍ、９１ｎｍとした。なお、実施例１と同様に誘電膜層の形成は真空蒸着法で行い、導電膜層の形成はスパッタ法にて行った。
【００２８】
このようにして得られた導電性を有する多層膜付透明基板の視感度透過率は９３．９％であった。また、摺動性試験では白濁は見られなかった。以上の結果を表１に示す。
【００２９】
＜実施例４＞
基板、膜構成を実施例１と同一条件にて多層膜付透明基板を作成した。ただし、第１導電膜層の成膜材料をＧＺＯ（膜厚１５ｎｍ）として成膜を行った。なお、得られる表面抵抗値を実施例１と同じ５００Ω／□とするために、第２導電膜層の膜厚を２３ｎｍとした。また、この条件にて多層膜付透明基板の透過率ができるだけ高く得られるように、最適化アルゴリズムを用いて各誘電膜層の膜厚を調整した。この結果、第１誘電膜層〜第４誘電膜層の各膜厚は順に７５ｎｍ、３５ｎｍ、９０ｎｍ、８０ｎｍとした。なお、実施例１と同様に誘電膜層の形成は真空蒸着法で行い、導電膜層の形成はスパッタ法にて行った。
【００３０】
このようにして得られた導電性を有する多層膜付透明基板の視感度透過率は９３．３％であった。また、摺動性試験では白濁は見られなかった。以上の結果を表１に示す。
【００３１】
＜実施例５＞
実施例１と同一基板を用い、この基板上にＺｒＯ_２からなる第１誘電膜層とＳｉＯ_２からなる第２誘電膜層を形成した後、第２誘電膜層上にＩＴＯからなる第２導電膜層とＡＺＯからなる第１導電膜層とを順次積層し、多層膜付透明基板を作成した。第１導電膜層の膜厚は１５ｎｍとし、表面抵抗値を実施例１と同じ５００Ω／□とするために、第２導電膜層の膜厚を２３ｎｍとした。また、この条件にて多層膜付透明基板の透過率ができるだけ高く得られるように、最適化アルゴリズムを用いて各誘電膜層の膜厚を調整した。この結果、第１誘電膜層及び第２誘電膜層の各膜厚は順に１４０ｎｍ、９０ｎｍとした。なお、実施例１と同様に誘電膜層の形成は真空蒸着法で行い、導電膜層の形成はスパッタ法にて行った。
このようにして得られた導電性を有する多層膜付透明基板の視感度透過率は９２．５％であった。また、摺動性試験では白濁は見られなかった。以上の結果を表１に示す。
【００３２】
＜比較例１＞
導電膜層をＩＴＯの１層とした以外は、基板、誘電膜層の膜構成及び成膜材料は実施例１と同一条件として多層膜付透明基板を作成した。ただし、最表面のＩＴＯの導電膜層（表１では第２導電膜層としている）の膜厚は、表面抵抗値５００Ω／□が得られるように２４ｎｍとして成膜を行った。また、この条件にて多層膜付透明基板の透過率ができるだけ高く得られるように、最適化アルゴリズムを用いて各誘電膜層の膜厚を調整した。この結果、第１誘電膜層〜第４誘電膜層の各膜厚は順に８０ｎｍ、３５ｎｍ、８５ｎｍ、１００ｎｍとした。なお、実施例１と同様に誘電膜層の形成は真空蒸着法で行い、導電膜層の形成はスパッタ法にて行った。
【００３３】
このようにして得られた導電性を有する多層膜付透明基板の視感度透過率は９４．１％であった。また、摺動性試験では白濁が生じていた。以上の結果を表１に示す。
【００３４】
＜比較例２＞
実施例１と同一基板を用い、この基板上にＺｒＯ_２からなる第１誘電膜層とＳｉＯ_２からなる第２誘電膜層を形成した後、第２誘電膜層上にＩＴＯからなる導電膜層を形成し、多層膜付透明基板を作成した。ただし、最表面のＩＴＯの導電膜層（表１では第２導電膜層としている）の膜厚は、表面抵抗値５００Ω／□が得られるように２４ｎｍとして成膜を行った。また、この条件にて多層膜付透明基板の透過率ができるだけ高く得られるように、最適化アルゴリズムを用いて各誘電膜層の膜厚を調整した。この結果、第１誘電膜層及び第２誘電膜層の各膜厚は順に１４０ｎｍ、９０ｎｍとした。なお、実施例１と同様に誘電膜層の形成は真空蒸着法で行い、導電膜層の形成はスパッタ法にて行った。
【００３５】
このようにして得られた導電性を有する多層膜付透明基板の視感度透過率は９２．９％であった。また、摺動性試験では白濁が生じていた。以上の結果を表１に示す。
【００３６】
【表１】

【００３７】
＜結果＞
表１に示すように、実施例１〜５の多層膜付透明基板では、何れも視感度透過率が９０％と高透過率を示すとともに摺動性試験にて白濁が生じず、高い耐ペン摺動性を有することが確認された。
【００３８】
【発明の効果】
以上のように、本発明によれば高い耐擦傷性（耐ペン摺動性）を有する導電性を有する多層膜付透明基板を得ることができる。
【図面の簡単な説明】
【図１】本実施形態における膜構成を示した図である。
【符号の説明】
１基板
２ハードコート層
３反射防止層帯
４第２導電膜層
５第１導電膜層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transparent substrate with a multilayer film having conductivity.
[0002]
[Prior art]
_2. Description of the Related Art Conventionally, a transparent conductive film such as indium tin oxide (ITO) or SnO ₂ is formed on a transparent substrate such as a glass plate or a plastic plate (plastic film) to form electrodes for a photoelectric conversion element such as a solar cell, a liquid crystal, or the like. There are known those used as electrodes of display devices or touch panels, antistatic filters and electromagnetic wave cut filters. In particular, when used as a touch panel, a transparent substrate with a multilayer film having conductivity excellent in abrasion resistance (pen touch resistance in a touch panel) has been desired.
Against such a background, a technique for improving the pen sliding resistance of a transparent substrate having a multilayer film having conductivity by providing a hard coat layer on the substrate and forming a transparent conductive film on the outermost surface has been developed. It is known (for example, see Patent Documents 1 and 2).
[0003]
[Patent Document 1]
JP 2001-216842 A [Patent Document 2]
JP-A-2002-122703
[Problems to be solved by the invention]
However, it is difficult to satisfy the currently required pen sliding resistance only by forming a hard coat layer on the substrate as described above.
[0005]
SUMMARY OF THE INVENTION In view of the above problems of the related art, an object of the present invention is to provide a conductive transparent substrate with a multilayer film having high scratch resistance (pen sliding resistance).
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is characterized by having the following configuration.
(1) In a transparent substrate having a multilayer film having conductivity in which a thin film of a transparent dielectric and a thin film of a transparent conductor are laminated on a transparent substrate, the outermost layer is made of a transparent conductor containing zinc oxide as a main component as a main component. A first conductive film layer and a second conductive film layer formed of a transparent conductor formed under the first conductive film layer.
(2) In the transparent substrate with a multilayer film according to (1), an optical film thickness of the first conductive film layer and the second conductive film layer is determined so that a desired surface resistance value is obtained. And
(3) In the transparent substrate with a multilayer film of (2), a thin film layer band composed of a plurality of transparent dielectric layers having different refractive indices is provided between the substrate and the second conductive film layer in order to provide an antireflection effect. It is characterized by being formed.
(4) In the transparent substrate with a multilayer film according to (2), the first conductive film layer is formed of at least one kind of conductor selected from aluminum-doped zinc oxide, gallium-doped zinc oxide, and zinc oxide. Features.
(5) In the transparent substrate with a multilayer film according to (3) or (4), the thin film layer band composed of the plurality of transparent dielectric layers has a refractive index higher than the refractive index of the substrate in order from the substrate side. A first dielectric film layer made of a body, a second dielectric film layer made of a transparent dielectric material having a refractive index lower than that of the substrate, and a second dielectric film layer made of a transparent dielectric material having a refractive index higher than the refractive index of the substrate. It is characterized by being formed of three dielectric film layers and a fourth dielectric film layer made of a transparent dielectric material having a refractive index lower than that of the substrate.
(6) In the transparent substrate with a multilayer film of (5), the refractive index of the transparent dielectric material forming the third dielectric film layer is equal to or higher than the refractive index of the transparent dielectric material forming the first dielectric film layer. It is also characterized by high.
(7) In the transparent substrate with a multilayer film according to (1) to (6), a hard coat layer is formed on the substrate.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a transparent substrate with a multilayer film having conductivity according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a transparent substrate with a multilayer film having conductivity, in which a thin film layer band for providing an anti-reflection effect is provided on a substrate and a conductive film layer having conductivity is provided thereon, is taken as an example. ,explain.
[0008]
FIG. 1 is a schematic view showing a laminated structure of a transparent substrate with a multilayer film having conductivity according to an embodiment of the present invention.
1 is a transparent substrate. The substrate 1 may be any commonly available substrate, and a substrate having a refractive index of about 1.48 to 1.7 is used. Specifically, as the substrate material, glass (refractive index: 1.48 to 1.70), plastics (polycarbonate (refractive index: 1.59), polyethylene terephthalate (refractive index: 1.63), and the like) are used. There is no particular limitation as long as it is optically transparent. Further, the substrate described in the present embodiment is not limited to a plate shape, but includes a film substrate.
[0009]
Reference numeral 2 denotes a thin film layer formed on the substrate 1 before forming a multilayer film. The thin film layer 2 is coated on the substrate 1 before forming the multilayer film, thereby hardening the surface of the substrate 1 to protect it from scratches and the like, and for reducing the adhesion between the substrate 1 and the multilayer film. This is a layer formed for raising the thickness (hereinafter, referred to as a hard coat layer). Generally, in the hard coat layer 2, an acrylic hard coat capable of protecting the surface of the substrate 1 and increasing the adhesion between the substrate 1 and the multilayer film is often used.
[0010]
It is also possible to form a multilayer film directly on the substrate 1 without forming the hard coat layer 2 on the substrate 1, but as described above, in order to protect the multilayer film and improve the adhesion, It is preferable to perform a hard coat treatment on the upper surface in advance. Further, an undercoat may be performed on the substrate by vacuum evaporation or the like, simply to improve the adhesion between the substrate 1 and the multilayer film, instead of the hard coat.
In any case, the thickness of the hard coat (undercoat) is preferably set to have a refractive index substantially equal to the refractive index of the substrate so that optical inhibition does not occur.
[0011]
Reference numeral 3 denotes an antireflection layer band for providing an antireflection effect by laminating a plurality of dielectric film layers made of transparent dielectric materials having different refractive indexes on the hard coat layer 2. The antireflection layer zone 3 in the present embodiment is formed by four dielectric film layers 3a to 3d.
3a is a first dielectric film layer made of a transparent dielectric having a refractive index higher than that of the substrate 1. The transparent dielectric used for the first dielectric film layer 3a is appropriately selected according to the substrate 1 to be used. However, since a refractive index higher than the refractive index of the substrate 1 is required, the minimum refractive index of the substrate 1 .48. At the same time, it is preferable to use a material which is inexpensive and has a stable film formation. Therefore, a material having a refractive index in the range of about 1.50 or more and 2.50 or less is used in consideration of these. Specifically, the main components of the first dielectric film layer 3a include ZrO ₂ (refractive index: 1.9), TiO ₂ (refractive index: 2.2), Al ₂ O ₃ (refractive index: 1.6), and the like. No. The optical thickness nd (hereinafter, simply referred to as a film thickness) of the first dielectric film layer 3 is preferably from 10 nm to 600 nm, more preferably from 50 nm to 550 nm.
[0012]
Reference numeral 3b denotes a second dielectric film layer laminated on the first dielectric film layer 3a and made of a transparent dielectric material having a refractive index lower than that of the substrate 1. The transparent dielectric used for the second dielectric film layer 3b is appropriately selected according to the substrate 1 to be used. However, since a refractive index lower than the refractive index of the substrate 1 is required, the maximum refractive index of the substrate 1 .70. At the same time, it is preferable to use a material which is available at a low cost and has a stable film formation. Therefore, a material having a refractive index in the range of about 1.35 to 1.60 is used in consideration of these. . Specifically, the main components of the second dielectric film layer 3b include SiO ₂ (refractive index 1.46) and MgF ₂ (refractive index 1.38). The thickness of the second dielectric film layer 3b is preferably from 10 nm to 600 nm, more preferably from 50 nm to 550 nm. Even if the film thickness is thinner or thicker, it is difficult to obtain the antireflection effect.
[0013]
A third dielectric film layer 3c is formed on the second dielectric film layer 3b and made of a transparent dielectric material having a refractive index higher than that of the substrate 1. As the transparent dielectric used for the third dielectric film layer 3c, the same material as that of the first dielectric film layer 3a can be basically used. However, in order to improve the anti-reflection effect, the first dielectric film layer is used. It is preferable to use a material having a refractive index equal to or higher than the refractive index of the material used in 3a. The thickness of the third dielectric film layer 3c is preferably from 10 nm to 600 nm, more preferably from 50 nm to 550 nm.
[0014]
A fourth dielectric film layer 3d is formed on the third dielectric film layer 3c and made of a transparent dielectric material having a lower refractive index than the refractive index of the substrate 1. As the transparent dielectric used for the fourth dielectric film layer 3d, the same material as that of the second dielectric film layer 3b can be used. The thickness of the fourth dielectric film layer 3d is preferably 10 nm or more and 600 nm or less, more preferably 50 nm or more and 550 nm or less.
[0015]
Reference numeral 4 denotes a second conductive film layer which is stacked on the fourth dielectric film layer 3d and has conductivity. Examples of the transparent conductor of the second conductive film layer 4 include transparent and conductive materials not containing zinc oxide as a main component, such as ITO, ATO, SnO ₂ , and IZO. Reference numeral 5 denotes a first conductive film layer having conductivity, which is laminated on the second conductive film layer 4 and is the outermost surface. As the transparent conductor of the first conductive film layer 5, a material containing zinc oxide as a main component, such as zinc oxide, AZO (aluminum-doped zinc oxide) or GZO (gallium-doped zinc oxide) can be used.
As described above, by forming the first conductive film layer 5 mainly composed of zinc oxide on the second conductive film layer 4 made of ITO or the like, compared with the conventional transparent substrate with a multilayer film having conductivity, The performance of pen sliding resistance is remarkably improved.
[0016]
The surface resistance is determined by the total thickness of the first conductive film layer 5 and the second conductive film layer 4. Therefore, when the surface resistance is set to a low resistance, one or both of the film thicknesses may be increased. When the surface resistance is set to a high resistance, one or both of the film thicknesses may be reduced. Note that when a material having a high resistivity such as ITO is used for the second conductive film layer, it is better to increase or decrease the film thickness of the second conductive film layer 4 with respect to increase or decrease of the film thickness of the first conductive film layer 5. , The value of the surface resistance greatly varies. For this reason, by increasing or decreasing the thickness of the second conductive film layer 4 mainly in order to obtain a desired surface resistance value, the thickness of the entire conductive film layer can be reduced, and an improvement in transmittance can be expected. .
[0017]
The surface resistance may be appropriately determined according to the purpose of use, but if it is used for an electro-optical element, a photoelectric conversion element, a liquid crystal, a touch panel, or the like, the surface resistance is preferably 100Ω / □ or more. It is 5000 Ω / □ or less, more preferably 100 Ω / □ or more and 1000 Ω / □ or less. Further, the total thickness of the first conductive film layer 5 and the second conductive film layer 4 corresponding to the surface resistance value is preferably 10 nm or more and 1000 nm or less, more preferably 15 nm or more and 100 nm or less.
[0018]
The optimum thickness of each layer is determined by the following method.
First, the film thickness of the conductive film layers (here, the first conductive film layer 5 and the second conductive film layer 4) that can obtain a required surface resistance value according to the application is determined. Next, the refractive index of the material used for the antireflection layer 3 (dielectric layers 3a to 3d) is set to a fixed value, and the physical thickness of the dielectric layers 3a to 3d is changed while using an optimization algorithm. By such a method, the film thickness of each of the dielectric layers 3a to 3d that obtains the highest transmittance or the lowest reflectance is obtained. The optimization algorithm is given based on various optimization methods using a merit function, such as Adaptive Random Search, Modified Gardant, Monte Carilo method, and Simulated Annealing.
[0019]
As a method of forming each of the thin film layers (conductive film layer, dielectric film layer) described above on the substrate 1, a physical vapor deposition method (PVD) includes a vacuum deposition method, a sputtering method, an ion plating method, and the like. No. The chemical vapor deposition method (CVD) includes a plating method, a chemical vapor deposition method, and the like. Although all of these film forming methods can be used in the present embodiment, a method involving high temperature during film formation may cause deformation of a plastic substrate due to heat. Preferably, a vacuum evaporation method or a sputtering method that does not require high heat is used.
[0020]
In the above-described embodiment, two conductive film layers are laminated on the four-layer antireflection layer strip 3, but the present invention is not limited to this. For example, if it is not necessary to consider the transmittance (reflectance) of a transparent substrate having a multilayer film having conductivity, the antireflection layer band 3 need not be provided. Further, even when the anti-reflection layer band 3 is formed, the number of layers is not limited to four, and a multilayer structure (for example, one to six layers) that can obtain a desired transmittance (reflectance) may be formed. Just fine.
[0021]
<Example 1>
A polycarbonate substrate with a hard coat (refractive index: 1.59) was prepared, and four dielectric film layers were formed on the substrate by a vacuum evaporation method. As the first dielectric film layer, a ZrO ₂ tablet manufactured by Optron was used, and a thin film layer mainly composed of ZrO ₂ was formed on a hard coat as an undercoat layer. At this time, the thickness (optical thickness nd) of the first dielectric layer was 70 nm. As the second dielectric film layer, SiO ₂ granules manufactured by Optron were used, and a thin film layer mainly composed of SiO ₂ was formed on the first dielectric film layer. At this time, the thickness of the second dielectric film layer was 35 nm. As the third dielectric film layer, TiO ₂ granules manufactured by Optron were used, and a thin film layer mainly composed of TiO ₂ was formed on the second dielectric film layer. At this time, the thickness of the third dielectric film layer was 95 nm. The fourth dielectric layer, using OPTRON manufactured SiO ₂ granules, to form a thin film layer mainly composed of SiO ₂ in the third dielectric film layer. At this time, the thickness of the fourth dielectric film layer was 65 nm.
[0022]
Next, using an ITO target manufactured by Vacuum Metallurgy Co., Ltd., a thin film layer mainly composed of ITO was formed as a second conductive film layer on the fourth dielectric film layer by a sputtering method. At this time, the thickness of the second conductive film layer was set to 20 nm. An AZO target manufactured by Sumitomo Metal Mining Co., Ltd. was used as an outermost first conductive film layer, and an AZO thin film layer was formed on the second conductive film layer. At this time, the thickness of the first conductive film layer was 30 nm.
[0023]
The luminous transmittance of the thus obtained transparent substrate with a multilayer film having conductivity was measured. As a measuring device, a luminous transmittance meter MODEL304 manufactured by Asahi Spectroscopy was used. The resulting luminous transmittance was 92.1%. The surface resistance was 500Ω / □.
[0024]
Next, after the ITO-formed side of the PET (polyethylene terephthalate) film with a physical film thickness of 188 μm and the film-formed side of the prepared transparent substrate with a multilayer film were stuck together, the pen sliding resistance was evaluated. . The pen sliding resistance was evaluated by applying a load of 250 g to a polyacetal pen (tip shape: 0.8 mmR) from the back side of the ITO electrode surface of the laminated PET film, and performing a 100,000 reciprocating sliding test. It was evaluated by: Even when the sliding test was performed 100,000 times in a reciprocating manner, it was evaluated as ○ if no white turbidity was visually observed on the substrate with the multilayer film, and × if white turbidity occurred.
Table 1 shows the above results.
[0025]
<Example 2>
A transparent substrate with a multilayer film was prepared under the same conditions as in Example 1 for the substrate, film configuration, and film forming material. However, the film was formed by changing the thickness of the first conductive film layer to 15 nm. The thickness of the second conductive film layer was set to 23 nm in order to obtain the same surface resistance value of 500 Ω / □ as in Example 1. In addition, the thickness of each dielectric film layer was adjusted by using an optimization algorithm so that the transmittance of the transparent substrate with a multilayer film was obtained as high as possible under these conditions. As a result, the thicknesses of the first to fourth dielectric film layers were set to 75 nm, 35 nm, 90 nm, and 80 nm, respectively. Note that, similarly to Example 1, the formation of the dielectric film layer was performed by a vacuum deposition method, and the formation of the conductive film layer was performed by a sputtering method.
[0026]
The luminous transmittance of the transparent substrate with a multilayer film having conductivity thus obtained was 93.3%. No turbidity was observed in the sliding property test. Table 1 shows the above results.
[0027]
<Example 3>
A transparent substrate with a multilayer film was prepared under the same conditions as in Example 1 for the substrate, film configuration, and film forming material. However, the film formation was performed by changing the thickness of the first conductive film layer to 5 nm. The thickness of the second conductive film layer was set to 23.5 nm in order to obtain the same surface resistance value of 500 Ω / □ as in Example 1. In addition, the thickness of each dielectric film layer was adjusted by using an optimization algorithm so that the transmittance of the transparent substrate with a multilayer film was obtained as high as possible under these conditions. As a result, the thicknesses of the first to fourth dielectric film layers were set to 75 nm, 35 nm, 86 nm, and 91 nm, respectively. Note that, similarly to Example 1, the formation of the dielectric film layer was performed by a vacuum deposition method, and the formation of the conductive film layer was performed by a sputtering method.
[0028]
The luminous transmittance of the transparent substrate with a multilayer film having conductivity thus obtained was 93.9%. No turbidity was observed in the sliding property test. Table 1 shows the above results.
[0029]
<Example 4>
A transparent substrate with a multilayer film was prepared under the same conditions as in Example 1 for the substrate and the film configuration. Note that the first conductive film layer was formed using GZO (film thickness: 15 nm) as a film forming material. The thickness of the second conductive film layer was set to 23 nm in order to obtain the same surface resistance value of 500 Ω / □ as in Example 1. In addition, the thickness of each dielectric film layer was adjusted by using an optimization algorithm so that the transmittance of the transparent substrate with a multilayer film was obtained as high as possible under these conditions. As a result, the thicknesses of the first to fourth dielectric film layers were set to 75 nm, 35 nm, 90 nm, and 80 nm, respectively. Note that, similarly to Example 1, the formation of the dielectric film layer was performed by a vacuum deposition method, and the formation of the conductive film layer was performed by a sputtering method.
[0030]
The luminous transmittance of the transparent substrate with a multilayer film having conductivity thus obtained was 93.3%. No turbidity was observed in the sliding property test. Table 1 shows the above results.
[0031]
<Example 5>
Using the same substrate as in Example 1, a first dielectric film layer made of ZrO ₂ and a second dielectric film layer made of SiO ₂ are formed on this substrate, and then a second conductive film made of ITO is formed on the second dielectric film layer. The film layer and the first conductive film layer made of AZO were sequentially laminated to form a transparent substrate with a multilayer film. The film thickness of the first conductive film layer was 15 nm, and the film thickness of the second conductive film layer was 23 nm so that the surface resistance value was 500 Ω / □, which is the same as that in Example 1. In addition, the thickness of each dielectric film layer was adjusted by using an optimization algorithm so that the transmittance of the transparent substrate with a multilayer film was obtained as high as possible under these conditions. As a result, the thicknesses of the first dielectric film layer and the second dielectric film layer were set to 140 nm and 90 nm, respectively. Note that, similarly to Example 1, the formation of the dielectric film layer was performed by a vacuum deposition method, and the formation of the conductive film layer was performed by a sputtering method.
The luminous transmittance of the thus obtained transparent substrate with a multilayer film having conductivity was 92.5%. No turbidity was observed in the sliding property test. Table 1 shows the above results.
[0032]
<Comparative Example 1>
A transparent substrate with a multilayer film was prepared under the same conditions as in Example 1 except that the conductive film layer was made of one layer of ITO, and the film configuration and the material of the dielectric film layer were the same as those in Example 1. However, the film thickness of the outermost ITO conductive film layer (in Table 1, the second conductive film layer) was set to 24 nm so that a surface resistance value of 500 Ω / □ was obtained. In addition, the thickness of each dielectric film layer was adjusted by using an optimization algorithm so that the transmittance of the transparent substrate with a multilayer film was obtained as high as possible under these conditions. As a result, the thicknesses of the first to fourth dielectric film layers were set to 80 nm, 35 nm, 85 nm, and 100 nm, respectively. Note that, similarly to Example 1, the formation of the dielectric film layer was performed by a vacuum deposition method, and the formation of the conductive film layer was performed by a sputtering method.
[0033]
The luminous transmittance of the thus-obtained transparent substrate with a multilayer film having conductivity was 94.1%. In addition, in the slidability test, cloudiness was generated. Table 1 shows the above results.
[0034]
<Comparative Example 2>
Using the same substrate as in Example 1, a first dielectric film layer made of ZrO ₂ and a second dielectric film layer made of SiO ₂ are formed on this substrate, and then a conductive film layer made of ITO is formed on the second dielectric film layer. Was formed to prepare a transparent substrate with a multilayer film. However, the film thickness of the outermost ITO conductive film layer (in Table 1, the second conductive film layer) was set to 24 nm so that a surface resistance value of 500 Ω / □ was obtained. In addition, the thickness of each dielectric film layer was adjusted by using an optimization algorithm so that the transmittance of the transparent substrate with a multilayer film was obtained as high as possible under these conditions. As a result, the thicknesses of the first dielectric film layer and the second dielectric film layer were set to 140 nm and 90 nm, respectively. Note that, similarly to Example 1, the formation of the dielectric film layer was performed by a vacuum deposition method, and the formation of the conductive film layer was performed by a sputtering method.
[0035]
The luminous transmittance of the thus-obtained transparent substrate with a multilayer film having conductivity was 92.9%. In addition, in the slidability test, cloudiness was generated. Table 1 shows the above results.
[0036]
[Table 1]

[0037]
<Result>
As shown in Table 1, all of the transparent substrates with multilayer films of Examples 1 to 5 exhibited a luminous transmittance of 90%, a high transmittance, did not cause white turbidity in a sliding property test, and had a high pen resistance. It was confirmed that it had slidability.
[0038]
【The invention's effect】
As described above, according to the present invention, a conductive transparent substrate with a multilayer film having high scratch resistance (pen sliding resistance) can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a film configuration in an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 2 Hard coat layer 3 Antireflection layer zone 4 Second conductive film layer 5 First conductive film layer

Claims

In a transparent substrate with a multilayer film having conductivity in which a thin film of a transparent dielectric and a thin film of a transparent conductor are laminated on a transparent substrate, a first conductive film made of a transparent conductor containing zinc oxide as a main component in an outermost layer A transparent substrate with a multilayer film having conductivity, comprising: a layer; and a second conductive film layer formed of a transparent conductor formed below the first conductive film layer.

2. The conductive substrate according to claim 1, wherein an optical film thickness of the first conductive film layer and the second conductive film layer is determined so as to obtain a desired surface resistance value. Transparent substrate with multi-layered film.

3. The transparent substrate with a multilayer film according to claim 2, wherein a thin film layer band including a plurality of transparent dielectric layers having different refractive indices is formed between the substrate and the second conductive film layer so as to have an antireflection effect. A transparent substrate with a multilayer film having conductivity.

3. The transparent substrate with a multilayer film according to claim 2, wherein the first conductive film layer is formed of at least one kind of conductor selected from aluminum-doped zinc oxide, gallium-doped zinc oxide, and zinc oxide. A transparent substrate with a multilayer film having conductivity.

5. The transparent substrate with a multilayer film according to claim 3 or 4, wherein the thin film layer band composed of the plurality of transparent dielectric layers is made of a transparent dielectric material having a refractive index higher than the refractive index of the substrate in order from the substrate side. A first dielectric film layer, a second dielectric film layer made of a transparent dielectric material having a refractive index lower than that of the substrate, and a third dielectric film made of a transparent dielectric material having a refractive index higher than that of the substrate. A transparent substrate with a multilayer film having conductivity, comprising: a layer; and a fourth dielectric film layer made of a transparent dielectric material having a refractive index lower than that of the substrate.

6. The transparent substrate with a multilayer film according to claim 5, wherein a refractive index of a transparent dielectric forming the third dielectric film layer is equal to or higher than a refractive index of a transparent dielectric forming the first dielectric film layer. A transparent substrate provided with a multilayer film having conductivity.

7. The transparent substrate with a multilayer film having conductivity according to claim 1, wherein a hard coat layer is formed on the substrate.