JP3710901B2

JP3710901B2 - Plate for manufacturing light control film and method for manufacturing light control film

Info

Publication number: JP3710901B2
Application number: JP32591696A
Authority: JP
Inventors: 忠宏真崎
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 1996-11-22
Filing date: 1996-11-22
Publication date: 2005-10-26
Anticipated expiration: 2016-11-22
Also published as: JPH10153966A

Description

【０００１】
【発明の属する技術分野】
本発明は、液晶ディスプレイ、広告板、案内板等の表示体の照明手段等に用い、光の集光、拡散、指向性変更等の光の進行方向制御を行う光制御フィルムについて、その製造に用いる光制御フィルム製造用版と、該版を用いた光制御フィルムの製造方法に関する。
【０００２】
【従来の技術】
液晶ディスプレイが各種用途で使われ、透過型ディスプレイでは、光源からの光を有効利用し、必要充分な方向にのみ均一に光を導く背面光源として、各種方式のバックライトが使われている。バックライトには、光源自身が面光源でない光源を面光源に変換する方式により、エッジライト型と直下型とがある。
【０００３】
エッジライト型の面光源とは、例えば、透明樹脂板からなる導光体の少なくとも一つの側端面に隣接して、点又は線光源を配置し、導光体の下方の裏面側には例えば白色インクをドット状に印刷等した光拡散反射体を配置し、また導光体上方の出光面側には、微小凹凸の梨地表面を有する透明樹脂板等からなる拡散板を配置し、更に拡散板の上に、拡散した光を適度に集光する為に、微小レンズを多数有する透明樹脂板等からなる集光板を配置した構成とする。
この様な構成により、導光体の側端面から入射した光は、導光体内部で多重反射して内部全体に行き渡り、導光体裏面側の光拡散反射体で拡散反射される光が主として導光体上面の出光面から出射し、更に拡散板によって拡散光となった後、更に集光板によって、広がりすぎた拡散光を適度に集光すると共に、光のピーク方向を所望の方向にすることで所望の指向性を持った光として、液晶表示素子等を背面から照明する。
【０００４】
また、直下型の面光源では、例えば、上方が開口し内面が光反射面のランプハウスに点光源又は線光源を内蔵させ、上方の開口部に微小凹凸の梨地表面を有する透明樹脂板等からなる拡散板を配置し、更に拡散板の上に、光を適度に集光する為に、微小レンズを多数有する透明樹脂板等からなる集光板を配置した構成とする。この様な構成により、ランプハウス上方の開口部から出光する光は、光源からの直接光と、ランプハウス内面の光反射面で反射した間接光との合成光となり、この合成光が拡散板によって均一化された拡散光となった後、更に集光板によって、広がりすぎた拡散光を適度に集光すると共に、光のピーク方向を所望の方向にすることで所望の指向性を持った光として、液晶表示素子等を背面から照明する。
【０００５】
また、光制御フィルムは、反射型の液晶ディスプレイでも使われている。反射型液晶ディスプレイでは、外部照明光を任意の方向に進路変更する、すなわち指向性の制御に使われる。反射型液晶ディスプレイでは、表裏に偏光板を有する液晶表示素子の裏面側に、液晶表示素子を通過してきた外光を反射して液晶表示素子に戻す反射体が配置される。反射体ではある程度拡散光して反射する拡散反射板等が使われる。反射体で反射し液晶表示素子を通過し外部に出射した光が信号光となる。しかし、平面的な反射体を用いると、液晶表示素子の表側の偏光板表面で反射した反射光と、前記信号光とは同一方向に進行し、表示が見づらくなってしまう。この為に、液晶表示素子と反射体との間に、鋸歯型の凹凸面を有する透明樹脂板を指向性レンズとして介在させたり、或いは反射体の反射面そのものを鋸歯型とした指向性反射体として、反射体から液晶表示素子に入射する光の方向を、正反射の方向からずらすことが行われる。
【０００６】
この様に、光制御フィルムは、透過型の液晶ディスプレイにおいては、微細凹凸を有する拡散板や、微小レンズを有する集光体等として使われ、また、反射型液晶ディスプレイにおいても、拡散反射板として、或いは、光の指向性を変更する為の指向性レンズや、光反射機能も兼用した指向性反射体として使われる。
また、以上の様な拡散板、集光板、指向性レンズ、指向性反射板等は液晶ディスプレイ以外の広告板、案内板等の表示体用途でも使用できるものである。
【０００７】
これら、拡散板、集光板、指向性レンズ、拡散反射板、指向性反射板等は、基材フィルムの少なくとも片面に凹凸を有する光制御層が積層された光制御フィルムとして製造すると、大量に、且つ安価に効率的に製造することができる。（なお、指向性反射板や拡散反射板の場合は凹凸面に更にアルミニウムの真空蒸着膜等を光反射層として設ける。）この方法は、例えば、特開平５−１６９０１５号公報に開示されている方法である。すなわち、光制御層の凹凸形状と逆凹凸形状のロール凹版を光制御フィルム製造用版として用い、これに電離放射線硬化性樹脂液を塗工し充填した後、基材フィルムを版に供給し、基材フィルムが版に接触している間に電離放射線照射して樹脂液を固め、次いで基材フィルムを版から剥がして、基材フィルム上に凹凸を有する光制御層を形成する方法である。
【０００８】
【発明が解決しようとする課題】
しかしながら、上記の電離放射線硬化性樹脂液と光制御フィルム製造用版を用いる、光制御フィルムの製造方法では、基材フィルムを光制御フィルム製造用版から剥離する時に、電離放射線硬化性樹脂の硬化物からなる光制御層が基材フィルムに密着して基材フィルムと共に綺麗に剥離せずに、基材フィルムの幅方向両端の光制御層部分で版側に残留することがあった。版側に光制御層が残留すると、版の凹部が埋まる版詰まりとなり、版が一回転して次の電離放射線硬化性樹脂液が充填される時に、正常な形状の光制御層の形成が困難となる。また、版側に硬化した樹脂が残り易いと、硬化した樹脂と共に基材フィルムを版から容易に剥離することが難しくなり、光制御層が破断したり、基材フィルムが版に張り付き巻き付いたりして、安定的な連続生産が不可能になる場合があった。特に、硬化により固化した電離放射線硬化性樹脂が版面から剥離しにくい、凹凸形状や樹脂材料の時は発生し易かった。
【０００９】
【課題を解決するための手段】
そこで上記課題を解決する為に本発明では、基材フィルム上に凹凸を有する光制御層が積層され、該凹凸により指向性変更、拡散、集光等の光の進行方向を制御する光制御フィルムを製造する為に、前記光制御層と逆凹凸形状の凹凸を有するロール凹版からなる光制御フィルム製造用版であり、回転する該版の少なくとも凹部に、電離放射線硬化性樹脂液を充填し、次いで樹脂液が充填された版に長尺帯状の基材フィルムを接触させ、基材フィルムが版に接触している間に電離放射線を照射して、基材フィルムと版との間に介在する電離放射線硬化性樹脂液を硬化させて固化した樹脂を基材フィルムに密着させた後、硬化した樹脂と共に基材フィルムを版から剥離して、基材フィルム上に電離放射線硬化性樹脂からなる光制御層を有する光制御フィルムを製造する方法で用いる前記光制御フィルム製造用版において、前記光制御層と逆凹凸形状の凹凸を有する光制御層形成用版面と、その幅方向両側に隣接した底面が凹凸の無い平面から成る帯状の溝とを有する光制御フィルム製造用版とする。
そして、本発明の光制御フィルムの製造方法では、この光制御フィルム製造用版を用いて、塗工幅の両端を前記溝のそれぞれの溝幅内に納まる塗工幅として電離放射線硬化性樹脂液を光制御フィルム製造用版に塗工する。その結果、両側の溝はそれぞれその一部を残す様に電離放射線硬化性樹脂液が充填され、長尺帯状として得られる光制御フィルムの光制御層の幅方向両側には、ある程度の厚みの土手部が帯状に形成される為、土手部が基材フィルムと共に安定的に版から剥離され、ひいては土手部に連結した光制御層も土手部につられて安定的に版から剥離され、安定的な連続生産が可能となる。
【００１０】
【発明の実施の形態】
以下、図面に従って、本発明の光制御フィルム製造用版、及び該版を用いる本発明の光制御フィルムの製造方法を詳述する。
先ず、図１は溝２、２ａを有する本発明の光制御フィルム製造用版Ｐの説明図であり、図１（Ａ）は斜視図、図１（Ｂ）は軸芯を通る切断面による断面図、図１（Ｃ）は図１（Ｂ）の溝部分の拡大断面図である。また、図２は本発明で得られる光制御フィルムＦの一形態を示す斜視図、図３は、従来の光制御フィルム製造用版Ｐｏの軸芯を通る切断面による断面図、図４は本発明による光制御フィルムの製造方法の概念的説明図である。
【００１１】
図１の如く、本発明の光制御フィルム製造用版Ｐは、光制御層形成用版面１の幅方向両側に隣接して溝２及び２ａを有する。光制御層形成用版面１とは、光制御層の凹凸と逆凹凸形状の凹凸を有する版面部分である。そして、図２の斜視図に示す光制御フィルムＦの如く、溝２及び２ａに充填された電離放射線硬化性樹脂液が硬化して固化すると、基材フィルム４上の光制御層５の両側に隣接した帯状の土手部３及び３ａとなる。光制御フィルム製造用版Ｐが、光制御層形成用版面１を版全周にわたって有すれば、溝２及び２ａも版全周にわたって有する。従って、光制御フィルムとなった時の帯状の土手部３及び３ａも連続帯状となる。なお、土手部３及び３ａは、光制御フィルムＦの使用時に邪魔になる場合はカットして、中央の光制御層５の有る部分のみを用いる。
【００１２】
溝２及び２ａは、図１（Ｂ）及び図１（Ｃ）に示す如く、光制御フィルム製造用版Ｐに対する電離放射線硬化性樹脂液の塗工幅Ｗｃの両端が、それぞれ溝（幅）に納まる位置及び溝幅とする。塗工の際、電離放射線硬化性樹脂液は溝２及び２ａの内部の少なくとも一部に充填され、溝２と溝２ａの間で実質的な光制御フィルムが形成されることになる。塗工幅Ｗｃの両端部分は、版面への樹脂液供給量の変動等により、幅方向に微妙に振れるので、この振れがあっても溝内に両端が納まる程度の溝幅とする。したがって、溝の幅方向内側部分には樹脂液が充填されるが、溝の幅方向外側部分は樹脂液が充填されないことがある。その結果、得られる光制御フィルムＦに形成される土手部３及び３ａは、その幅方向外側では若干蛇行した様な不規則な曲線形状となる（内側は版面凹凸形状通りの形状となる）。
【００１３】
一方、図３に示す様な従来の光制御フィルム製造用版Ｐｏでは、光制御層形成用版面１は塗工幅Ｗｃよりも幅広に設定してあった。従って、塗工幅Ｗｃ両端部分の蛇行により、光制御フィルムの光制御層は、その幅方向両端部がシャープな直線を成さず、蛇行した様な不規則な曲線となり、しかも光制御層は凹凸を有する層である為に、光制御層の両端部分の強度に不規則な強弱が発生し、これが版から光制御フィルムを剥離する際に光制御層が版側に残ったりして、安定的な連続生産を困難にする原因となったと推定される。
【００１４】
ところで、溝２（及び２ａ）の溝深さｄは、図１（Ｃ）の如く、光制御層形成用版面１部分の深さＤよりも深い方が好ましい。例えば、溝深さｄは光制御層凹凸深さＤよりも５〜１０μｍ深くすると良い。具体的には、光制御層形成用版面１に、円周方向を断面三角柱の頂角が成す稜線とする三角柱プリズム形状の凹凸が有り、その深さ（三角形の高さ）が５０μｍであったなら、５５〜６０μｍに設定すると良い。溝深さｄを光制御層凹凸深さＤに対して前記の範囲を越えて深くすると、光制御層の厚みに対して土手部の厚みが厚くなりすぎて、光制御フィルムを巻き取った時に、直径が幅方向で不揃いとなり、綺麗に巻けない。逆に、溝深さｄが光制御層凹凸深さＤに対して前記の範囲未満であると、得られる土手部自身の厚みが光制御層の厚みと同程度がより薄く、土手部の補強効果が得られず、土手部、ひいては光制御層を基材フィルムに安定的に密着させて、基材フィルムを光制御フィルム製造用版から剥がすことができない。
【００１５】
また、溝２（及び２ａ）の溝の溝幅ｗは、実際の塗工幅Ｗｃがある程度蛇行しても、塗工幅Ｗｃが溝幅ｗ内に納まり、また土手部にある程度の強度を持たせられる幅を確保すれば良い。具体的には、１〜４ｃｍ程度である。また、溝２（及び２ａ）の溝の底面ｂは、溝内に充填され土手部となる電離放射線硬化性樹脂が溝から容易に剥離し易い様に、凹凸がない平面であることが好ましく、平滑面であることがより好ましい。
【００１６】
なお、以上の様な版面形状の光制御フィルム製造用版Ｐは円筒状のロール凹版である。これに所望の光制御層の凹凸形状と逆凹凸形状の凹凸及び溝２及び２ａを成す凹部７２を設けるには、円筒状の版材に直接旋盤加工したり、ミル加工法、電鋳法、あるいは、フォトエッチング法等により行う。光制御フィルム製造用版Ｐの材質としては、銅、クロム、鉄等の金属、ＮＢＲ、エポキシ樹脂、エボナイト等の合成樹脂、ガラス等のセラミックス等が使用できる。また、銅や鉄等の場合には、耐久性や剥離性を向上させる為に、表面にクロム等の金属メッキをしても良い。
【００１７】
次に、本発明の光制御フィルムの製造方法について説明する。本発明の光制御フィルムの製造方法は、上述した様な光制御フィルム製造用版を用いて光制御フィルムを製造する方法である。上述した特定の版を用いる点以外は、従来の特開平５−１６９０１５号公報に開示されている方法等と同様で良い。すなわち、光制御層の凹凸形状と逆凹凸形状のロール凹版を光制御フィルム製造用版として用い、これに電離放射線硬化性樹脂液を版の両側の溝内に納まる様な塗工幅で塗工し充填した後、基材フィルムを版に供給し、基材フィルムが版に接触している間に電離放射線照射して樹脂液を固め、次いで、硬化した樹脂と共に基材フィルムを版から剥がして、基材フィルム上に凹凸を有する光制御層を形成する方法である。
ここでは、基材フィルムの片面のみに光制御層を形成する方法について説明するが、両面に光制御層を設けた構成の光制御フィルムも、同一又は異なる光制御フィルム製造用版で光制御層を表裏に形成すれば良く、本発明の製造方法で得られることは勿論である。
【００１８】
図４に、本発明の光制御フィルムの製造方法で用いる装置の一例の概念図（側面図）を示す。同図において、Ｐは基材フィルム上に形成する光制御層の凹凸形状と逆凹凸形状の凹凸及び溝を成す凹部７２が設けられ軸芯を中心として矢印方向に回転駆動されるロール凹版である光制御フィルム製造用版、７３は電離放射線硬化性樹脂液、４は基材フィルム、７４は光制御フィルム製造用版に当接して基材フィルム４を光制御フィルム製造用版Ｐに押圧する押圧ロール、７５は剥離ロール、７６は電離放射線硬化性樹脂液を硬化するための電離放射線照射装置、７７は電離放射線硬化性樹脂液を光制御フィルム製造用版Ｐに塗工する為の塗工装置（塗工ノズル）、７８は塗工装置に該樹脂液を供給するポンプ、５は電離放射線硬化性樹脂液の硬化物として基材フィルム４上に形成された所望の凹凸形状を有する光制御層である（光制御層両側の土手部は図示せず）。
【００１９】
電離放射線照射装置７６は、電離放射線を照射して、電離放射線硬化性樹脂液の硬化反応を起こさせ固化させる装置である。電離放射線とは、電磁波又は荷電粒子線のうち分子を重合又は架橋し得るエネルギー量子を有するものを意味し、通常、紫外線（ＵＶ）又は電子線（ＥＢ）が用いられる。紫外線源としては、超高圧水銀灯、高圧水銀灯、低圧水銀灯、カーボンアーク灯、ブラックライト、メタルハライドランプ等の光源が使用される。紫外線の波長としては通常１９０〜３８０ｎｍの波長域が主として用いられる。電子線源としては、コッククロフトワルトン型、バンデグラフト型、共振変圧器型、絶縁コア変圧器型、或いは、直線型、ダイナミトロン型、高周波型等の各種電子線加速器を用い、１００〜１０００ｋｅＶ、好ましくは、１００〜３００ｋｅＶのエネルギーをもつ電子を照射するものを使用される。
なお、電離放射線の照射は、光制御フィルム製造用版Ｐから光制御フィルムＦを剥離後に更に行っても良い。光制御フィルム製造用版Ｐから光制御フィルムＦが剥離するときは、剥離できる程度の硬化度合いとして、その後で硬化を完結する方法である。
【００２０】
塗工装置７７は、電離放射線硬化性樹脂液７３を光制御フィルム製造用版Ｐに供給、塗工し、版の凹凸内に電離放射線硬化性樹脂液を充填するための装置で、具体的には図４に示す様なノズル塗工装置を用いることが好ましい。ノズル塗工装置は、長方形の開口を有する塗出口から樹脂液を塗出する装置であり、その塗出口の長手方向が光制御フィルム製造用版Ｐの幅方向となる様に設置し、光制御フィルム製造用版Ｐの全幅の内の所定幅Ｗｃに対して、樹脂液を塗工する。
【００２１】
なお、電離放射線硬化性樹脂液は無溶剤で用いることができるが、ある程度の溶剤を含有させた塗液として塗工することも可能である。この場合は、塗工装置７７と押圧ローラ７４間の光制御フィルム製造用版Ｐ上の電離放射線硬化性樹脂液に対して、溶剤乾燥させるべく、塗工装置７７と押圧ローラ７４間に溶剤乾燥装置を設けると良い。
【００２２】
次に、光制御フィルムＦに用いる材料について説明する。
【００２３】
基材フィルム４には、例えば、ポリエチレンテレフタレート、ポリブチレンテレフタレート等のポリエステル樹脂、ポリメチルメタクリレート等のアクリル樹脂、ポリカーボネート樹脂、ポリスチレン樹脂等のフィルムを用いることができる。基材フィルムの厚みは、用途にもよるが通常２０〜１０００μｍ程度である。レンズフィルム等として光透過性の光制御フィルムの場合は、透明樹脂フィルムが用いられるが、反射光を利用する形態の拡散板、反射板となる光制御フィルムでは、必ずしも透明樹脂フィルムとする必要はない。基材フィルムを透明フィルムとすると、基材フィルム側から電離放射線を照射できる点で好ましい。不透明の場合でも、光制御フィルム製造用版としてガラスやセラミックス等の透明体を用いれば、版内面側から電離放射線照射は可能である。
なお、基材フィルムの光制御層を設ける面には、光制御層と基材フィルムとの密着性向上の為に、コロナ放電処理や、プライマー層等からなる接着層を形成する等、従来公知の易接着処理を施しても良い。例えば、プライマー層は、アクリルポリオールを主剤としてイソシアネート系の硬化剤を用いる２液硬化型プライマー等を塗工形成する。もちろん、光制御層の基材フィルムへの接着性が充分な場合は、接着層は省略できる。
【００２４】
光制御層５は、電離放射線硬化性樹脂の硬化物で形成するが、硬化させる電離放射線硬化性樹脂液としては、例えば、ポリエステルアクリレート、エポキシアクリレート、シリコーンアクリレート、ウレタンアクリレート等のプレポリマー及び／又はアクリレート系等のモノマー等からなり、紫外線または電子線等の電離放射線で硬化する、従来公知の電離放射線硬化性樹脂を用いることがてきる。また、硬質で傷や外力に対して耐久性のある硬質の光制御層とするには、多官能モノマーを主成分とする高架橋型の電離放射線硬化性樹脂が好ましい。
もちろん、土手部２及び２ａも光制御層５と同一の電離放射線硬化性樹脂の硬化物として形成される。
【００２５】
以上の様な装置及び材料にて、光制御フィルムは次の様にして製造される。
【００２６】
先ず、形成する光制御層の所望の凹凸形状に対して逆形状の凹部（正確には凹凸形状）と、幅方向両側に溝を有する光制御フィルム製造用版Ｐを用意する。光制御フィルム製造用版Ｐに、ポンプ７８から供給される電離放射線硬化性樹脂液を塗工装置７７により塗工して版の凹部に充填する。次に、電離放射線硬化性樹脂液７３が充填された光制御フィルム製造用版Ｐに連続帯状の基材フィルム４を供給して押圧ロール７４により版面に押圧して接触させる。（なお、押圧力の調整により、基材フィルムと版面凸部との間に電離放射線硬化性樹脂液を残すことも可能であり、この場合も含めて、基材フィルムを版面に「接触」させるという。）そして、基材フィルム４が光制御フィルム製造用版Ｐに接触して移送される間に、紫外線や電子線の電離放射線を電離放射線照射装置７５により基材フィルム側から照射して（光制御フィルム製造用版がガラス等で透明な場合は版の内側から照射も可能）、電離放射線硬化性樹脂液の硬化反応を起こさせて固化させ、電離放射線硬化性樹脂液の硬化物を光制御層５並びに土手部３及び３ａとして基材フィルム４に密着させる。しかる後、基材フィルム４は、剥離ロール７５にて、硬化した樹脂と共に光制御フィルム製造用版Ｐから剥がされて、所望の凹凸形状の光制御層５と、その幅方向両側に土手部３及び３ａが基材フィルム４の片面に形成された、光制御フィルムＦとなる。なお、土手部３及び３ａが使用に支障を来す場合は、土手部は切り落として、実際に使用する光制御フィルムＦとする。
【００２７】
かくして、本発明によって、電離放射線硬化性樹脂液の版詰まりや、光制御層が幅方向両端部分で版に張り付いたり、光制御層が破断したりすることが起きずに、光制御フィルムが安定的に連続生産されることになる。
【００２８】
なお、本発明で得られる光制御フィルムは、集光、散乱、指向性変更等の単独又は組合せによる各種の光制御に用いられる。例えば、集光板、拡散板、指向性レンズ、指向性反射板、拡散反射板等である。
光制御層の凹凸は、光制御の目的に合わせた形状となる。例えば、光制御フィルムが集光目的のレンズフィルムである場合は、三角柱単位レンズ、円柱単位レンズ、楕円柱単位レンズ等を多数１次元配列したレンズ構造を有する光制御層とする。三角柱単位レンズは断面が三角形を成す単位レンズである。断面形状は、例えば、頂角を光制御層の凸部稜線とする二等辺三角形である。円柱単位レンズとは、直径の丁度２分の１の半円、或いは直径の２分の１以下の部分円を断面形状とする柱体である。楕円柱単位レンズは、その長軸又は短軸に平行な平行線で楕円を切断した部分楕円を断面形状とする柱体である。楕円を切断する平行線の位置は、楕円を丁度半分にする長軸又は短軸の位置であるとは限らず、半分以下の部分楕円もある。また、蠅の目等の複眼状の半球状レンズ、三角錐状レンズ、四角錐状レンズ等を多数２次元配列したレンズ構造を光制御層とするものもある。また、散乱目的の光制御層の凹凸は、例えば、梨地等のランダムを凹凸とする。また、三角柱単位レンズ等でも、平面的には円や円弧を描く様に２次元配列したものもある。
また、指向性変更目的の光制御層の凹凸は、例えば、鋸歯型等の不等辺三角形を断面とする三角柱単位レンズを１次元配列したレンズ構造のものとする。
【００２９】
そして、拡散や指向性変更等で光反射機能を持たせた光制御フィルムの場合は、電離放射線硬化性樹脂の硬化物として得られた光制御層の凹凸面に、更にアルミニウム等の金属薄膜を真空蒸着等により形成する。反射面は外側、或いは内側（基材フィルム側）である。一方、光透過体としての光制御フィルムの場合は、光制御層は基材フィルムの片面のみでなく、両面に設ける構成もある。
【００３０】
【実施例】
次に、実施例及び比較例により本発明を更に詳述する。
【００３１】
（実施例）
図１に例示する様な光制御フィルム製造用版Ｐと、図４に例示する様な装置を用いて、透明な基材フィルムの片面に、三角柱単位レンズが多数１次元配列したレンズ構造を有する光制御層を、紫外線硬化性樹脂により積層したレンズフィルムとして、光制御用フィルムを作製した。
三角柱単位レンズの断面形状は、凸部となる頂角角度が５０°で底辺が５０μｍの二等辺三角形である。光制御層は、この単位レンズを頂角がなす稜線を互いに平行にして繰返しピッチ５０μｍで隣接して基材フィルムの幅方向に多数１次元配列して、前記稜線が基材フィルム長手方向に平行なレンズ構造とした。
透明な基材フィルムとしては、厚み１２５μｍで片面易接着処理済のポリエチレンテレフタレートフィルムを用いた。さらに、易接着処理面には、プライマー（ザ・インクテック株式会社製、ケミカルマットニス用メジウムとＸＥＬ硬化剤の重量比１０：１の混合物）をグラビア塗工して接着層を形成しておいた。
光制御フィルム製造用版は、上記した光制御層の凹凸と逆凹凸形状の凹凸からなる光制御層形成用版面と、光制御層形成用版面に隣接した幅方向両側の溝（溝深さ６０μｍ、溝幅３ｃｍ）とを、版全周にわたって、銅からなる版面に対して切削用バイトにて所望の凹凸形状に切削後、クロムめっきして作製した。
【００３２】
そして、紫外線硬化性樹脂液（日本合成ゴム工業株式会社製、Ｚ９００２Ａ）を、塗出孔を上向きに開口したＴダイ状の塗工ノズルから、回転する光制御フィルム製造用版に供給しつつ、前記基材フィルムを樹脂液が塗工された光制御フィルム製造用版に供給し、光制御フィルム製造用版上の基材フィルム側から、紫外線を照射して紫外線硬化性樹脂液の硬化反応を起こさせて固化させて、基材フィルムに密着した紫外線硬化性樹脂液の硬化物とした後、光制御層が積層した基材フィルムを剥離ロールにより光制御フィルム製造用版から剥離して、光制御フィルムを製造した。なお、紫外線照射には１６０Ｗ／ｃｍの高圧水銀灯を２灯用いた。
以上の結果、塗工幅の幅方向両端部分で、紫外線硬化性樹脂液の硬化物（土手部）が版に張り付くことは起きず、光制御層及び土手部が形成された光制御フィルムは、剥離ロールによって光制御フィルム製造用版から円滑に剥離し、安定的な連続生産ができた。
【００３３】
（比較例）
実施例１で用いた光制御フィルム製造用版の代わりに、図３の様に両端に溝が無く塗工幅Ｗｃよりも広幅の光制御層成形用版面１とした光制御フィルム製造用版を用いた以外は、実施例１同様にして光制御フィルムを製造した。
その結果、塗工幅の幅方向両端部分で、紫外線硬化性樹脂液の硬化物（光制御層）が版に張り付く現象が発生し、光制御層が形成された光制御フィルムを、剥離ロールによって光制御フィルム製造用版から円滑に剥離することが困難で、安定的な連続生産が出来なかった。
【００３４】
【発明の効果】
本発明の光制御フィルム製造用版及び光制御フィルムの製造方法によれば、塗工幅の幅方向両端部分で、紫外線硬化性樹脂液の硬化物（光制御層）が版に張り付く現象が発生せず、光制御層が形成された光制御フィルムを、剥離ロールによって光制御フィルム製造用版から円滑に剥離することができるので、光制御フィルムを安定的に連続生産できる。
【図面の簡単な説明】
【図１】本発明の光制御フィルム製造用版の説明図。図１（Ａ）は斜視図、図１（Ｂ）は軸芯を通る切断面による断面図、図１（Ｃ）は図１（Ｂ）の溝部分の拡大断面図。
【図２】本発明で得られる光制御フィルムの一形態を示す斜視図。
【図３】従来の光制御フィルム製造用版の軸芯を通る切断面による断面図。
【図４】本発明の光制御フィルムの製造方法の概念的説明図。
【符号の説明】
１光制御層形成用版面
２、２ａ溝
３、３ａ土手部
４基材フィルム
５光制御層
７２凹部
７３電離放射線硬化性樹脂液
７４押圧ロール
７５剥離ロール
７６電離放射線照射装置
７７塗工装置（塗工ノズル）
７８ポンプ
ｂ溝の底面
ｄ溝深さ
Ｄ光制御層凹凸深さ（光制御層形成用版面の深さ）
Ｐ光制御フィルム製造用版
Ｐｏ従来の光制御フィルム製造用版
Ｆ光制御フィルム
ｗ溝幅
Ｗｃ塗工幅[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light control film that is used for lighting means of a display body such as a liquid crystal display, an advertisement board, a guide board, etc., and performs light traveling direction control such as light collection, diffusion, and directivity change. The present invention relates to a plate for producing a light control film to be used and a method for producing a light control film using the plate.
[0002]
[Prior art]
Liquid crystal displays are used in various applications, and in transmissive displays, various types of backlights are used as back light sources that effectively utilize light from a light source and uniformly guide light only in a necessary and sufficient direction. There are two types of backlights, an edge light type and a direct type, by converting a light source that is not a surface light source into a surface light source.
[0003]
An edge light type surface light source is, for example, a point or line light source arranged adjacent to at least one side end surface of a light guide made of a transparent resin plate, and white on the back side below the light guide. A light diffusive reflector made by printing ink in dots or the like is disposed, and a light diffusing plate made of a transparent resin plate having a fine uneven surface is disposed on the light exit surface above the light guide. A condensing plate made of a transparent resin plate or the like having a large number of microlenses is arranged on the top in order to appropriately condense the diffused light.
With such a configuration, the light incident from the side end surface of the light guide is multiple-reflected inside the light guide and spread throughout the interior, and the light diffused and reflected by the light diffuse reflector on the back side of the light guide is mainly used. After exiting from the light exit surface on the upper surface of the light guide and further becoming diffused light by the diffusion plate, the diffused light that has spread too much is appropriately condensed by the light collecting plate, and the peak direction of the light is set to a desired direction. As a result, the liquid crystal display element or the like is illuminated from the back as light having a desired directivity.
[0004]
In a direct surface light source, for example, a point light source or a line light source is built in a lamp house having an upper opening and an inner light reflection surface, and a transparent resin plate having a fine uneven surface on the upper opening. In order to condense light appropriately on the diffusion plate, a light collecting plate made of a transparent resin plate having a large number of microlenses is arranged. With such a configuration, the light emitted from the opening above the lamp house becomes the combined light of the direct light from the light source and the indirect light reflected by the light reflecting surface on the inner surface of the lamp house, and this combined light is reflected by the diffusion plate. After becoming uniformed diffused light, the diffused light that has spread too much is collected appropriately by the light collecting plate, and the light has the desired directivity by changing the peak direction of the light to the desired direction. The liquid crystal display element is illuminated from the back.
[0005]
Light control films are also used in reflective liquid crystal displays. In the reflective liquid crystal display, the direction of external illumination light is changed in an arbitrary direction, that is, used for directivity control. In the reflective liquid crystal display, a reflector that reflects external light that has passed through the liquid crystal display element and returns it to the liquid crystal display element is disposed on the back side of the liquid crystal display element having polarizing plates on the front and back sides. For the reflector, a diffuse reflector or the like that reflects and diffuses light to some extent is used. Light reflected by the reflector, passed through the liquid crystal display element, and emitted to the outside becomes signal light. However, if a planar reflector is used, the reflected light reflected on the surface of the polarizing plate on the front side of the liquid crystal display element and the signal light travel in the same direction, making it difficult to see the display. For this purpose, a transparent resin plate having a serrated irregular surface is interposed between the liquid crystal display element and the reflector as a directional lens, or the reflective surface of the reflector itself is a saw-tooth reflector. The direction of light incident on the liquid crystal display element from the reflector is shifted from the direction of regular reflection.
[0006]
In this way, the light control film is used as a diffuser plate having fine irregularities or a light collector having a microlens in a transmissive liquid crystal display, and also as a diffuse reflector in a reflective liquid crystal display. Alternatively, it is used as a directional lens for changing the directivity of light, or as a directional reflector that also serves as a light reflection function.
Further, the diffuser plate, the light collecting plate, the directional lens, the directional reflector, and the like as described above can be used for display bodies such as advertising boards and guide boards other than liquid crystal displays.
[0007]
These, a diffuser plate, a light collector, a directional lens, a diffuse reflector, a directional reflector, etc. are manufactured in large quantities when manufactured as a light control film in which a light control layer having irregularities is laminated on at least one side of a base film, And it can manufacture efficiently cheaply. (In the case of a directional reflector or a diffuse reflector, an aluminum vacuum deposition film or the like is further provided as a light reflecting layer on the concavo-convex surface.) This method is disclosed, for example, in JP-A-5-169015. Is the method. That is, using a roll intaglio of the uneven shape and reverse uneven shape of the light control layer as a plate for light control film production, after coating and filling the ionizing radiation curable resin liquid to this, supply the substrate film to the plate, While the base film is in contact with the plate, it is irradiated with ionizing radiation to solidify the resin liquid, and then the base film is peeled off the plate to form a light control layer having irregularities on the base film.
[0008]
[Problems to be solved by the invention]
However, in the light control film manufacturing method using the ionizing radiation curable resin liquid and the light control film manufacturing plate, the ionizing radiation curable resin is cured when the base film is peeled from the light control film manufacturing plate. In some cases, the light control layer made of a product adheres to the base film and does not peel cleanly together with the base film, but remains on the plate side at the light control layer portions at both ends in the width direction of the base film. If the light control layer remains on the plate side, it becomes a plate clogging that fills the concave portion of the plate, and it is difficult to form a light control layer having a normal shape when the plate is rotated and filled with the next ionizing radiation curable resin liquid. It becomes. In addition, if the cured resin tends to remain on the plate side, it becomes difficult to easily peel the base film from the plate together with the cured resin, the light control layer may be broken, or the base film may be stuck and wrapped around the plate. As a result, stable continuous production may become impossible. In particular, the ionizing radiation curable resin solidified by curing was not easily peeled off from the plate surface, and was easily generated when it was an uneven shape or a resin material.
[0009]
[Means for Solving the Problems]
Therefore, in order to solve the above-mentioned problems, in the present invention, a light control layer having unevenness is laminated on a base film, and the light control film controls the traveling direction of light such as directivity change, diffusion, and condensing by the unevenness. In order to produce a light control film production plate comprising a roll intaglio having irregularities of reverse irregularities with the light control layer, filling at least the depressions of the rotating plate with an ionizing radiation curable resin liquid, Next, the long belt-like base film is brought into contact with the plate filled with the resin liquid, and the substrate film is irradiated with ionizing radiation while being in contact with the plate, and is interposed between the base film and the plate. After the resin solidified by curing the ionizing radiation curable resin liquid is adhered to the base film, the base film is peeled off from the plate together with the cured resin, and the light made of the ionizing radiation curable resin on the base film. Light control with control layer In the light control film manufacturing plane used in the method for producing the film, The light control layer has irregularities with a reverse irregularity shape. Plate for light control layer formation And so of Width direction Adjacent to both sides A strip-shaped groove with a flat bottom surface A plate for producing a light control film is provided.
And in the manufacturing method of the light control film of this invention, using this light control film manufacturing plate, both ends of a coating width are set as the coating width which fits in each groove width of the said groove | channel, and ionizing radiation-curable resin liquid Is coated on a plate for manufacturing a light control film. As a result, the grooves on both sides are filled with an ionizing radiation curable resin liquid so that a part of each groove is left, and on the both sides in the width direction of the light control layer of the light control film obtained as a long strip, Since the part is formed in a band shape, the bank part is stably peeled off from the plate together with the base film, and as a result, the light control layer connected to the bank part is also attached to the bank part and is stably peeled off from the plate. Continuous production is possible.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, according to the drawings, a plate for producing a light control film of the present invention and a method for producing the light control film of the present invention using the plate will be described in detail.
First, FIG. 1 is explanatory drawing of the plate P for light control film manufacture of this invention which has the groove | channels 2 and 2a, FIG. 1 (A) is a perspective view, FIG.1 (B) is a cross section by the cut surface which passes along an axial center. FIG. 1 and FIG. 1C are enlarged cross-sectional views of the groove portion of FIG. 2 is a perspective view showing an embodiment of a light control film F obtained by the present invention, FIG. 3 is a cross-sectional view of a conventional light control film manufacturing plate Po through a cross section passing through the axis, and FIG. It is a conceptual explanatory drawing of the manufacturing method of the light control film by invention.
[0011]
As shown in FIG. 1, the plate P for manufacturing a light control film of the present invention has grooves 2 and 2a adjacent to both sides in the width direction of the plate surface 1 for forming a light control layer. The plate surface 1 for forming the light control layer is a plate surface portion having the unevenness of the light control layer and the unevenness of the reverse uneven shape. Then, as the light control film F shown in the perspective view of FIG. 2, when the ionizing radiation curable resin liquid filled in the grooves 2 and 2 a is cured and solidified, it is formed on both sides of the light control layer 5 on the base film 4. Adjacent belt-shaped bank portions 3 and 3a are formed. If the light control film manufacturing plate P has the light control layer forming plate surface 1 over the entire periphery of the plate, the grooves 2 and 2a also have the entire surface of the plate. Therefore, the strip-shaped bank portions 3 and 3a when the light control film is formed also have a continuous strip shape. The bank portions 3 and 3a are cut when they are in the way when the light control film F is used, and only the portion with the central light control layer 5 is used.
[0012]
As shown in FIGS. 1 (B) and 1 (C), the grooves 2 and 2a have both ends of the application width Wc of the ionizing radiation curable resin liquid applied to the light control film manufacturing plate P to the grooves (widths), respectively. It shall be the position to fit and the groove width. At the time of coating, the ionizing radiation curable resin liquid is filled into at least a part of the inside of the grooves 2 and 2a, and a substantial light control film is formed between the grooves 2 and 2a. Since both end portions of the coating width Wc slightly swing in the width direction due to fluctuations in the amount of resin liquid supplied to the plate surface, the groove width is set such that both ends can be accommodated in the groove even if this swing occurs. Accordingly, the resin liquid is filled in the inner part in the width direction of the groove, but the outer part in the width direction of the groove may not be filled in with the resin liquid. As a result, the bank portions 3 and 3a formed on the obtained light control film F have an irregular curved shape that is slightly meandered on the outer side in the width direction (the inner side has a shape corresponding to the concavo-convex shape of the plate surface).
[0013]
On the other hand, in the conventional light control film manufacturing plate Po as shown in FIG. 3, the light control layer forming plate surface 1 is set wider than the coating width Wc. Therefore, due to the meandering of both ends of the coating width Wc, the light control layer of the light control film does not form a sharp straight line at both ends in the width direction, and the light control layer has an irregular curve as if meandering. Because it is a layer with irregularities, irregular strength is generated in the strength of both ends of the light control layer. When the light control film is peeled off from the plate, the light control layer remains on the plate side and is stable. It is estimated that it became the cause that made continuous production difficult.
[0014]
Incidentally, the groove depth d of the groove 2 (and 2a) is preferably deeper than the depth D of the portion 1 of the light control layer forming plate surface as shown in FIG. For example, the groove depth d is preferably 5 to 10 μm deeper than the light control layer unevenness depth D. More specifically, the light control layer forming plate 1 has triangular prism-shaped irregularities with the circumferential direction being the ridgeline formed by the apex angle of the triangular prism, and the depth (the height of the triangle) was 50 μm. Then, it is good to set to 55-60 micrometers. When the groove depth d is deepened beyond the above range with respect to the light control layer unevenness depth D, the thickness of the bank portion becomes too thick with respect to the thickness of the light control layer, and the light control film is wound up. The diameters are uneven in the width direction and cannot be wound neatly. On the contrary, when the groove depth d is less than the above range with respect to the light control layer unevenness depth D, the thickness of the obtained bank portion itself is thinner than the light control layer, and the bank portion is reinforced. The effect cannot be obtained, and the bank portion and thus the light control layer can be stably adhered to the base film, and the base film cannot be peeled from the plate for manufacturing the light control film.
[0015]
Further, the groove width w of the groove 2 (and 2a) is such that, even if the actual coating width Wc meanders to some extent, the coating width Wc is within the groove width w, and the bank portion has a certain strength. Let Ru It is sufficient to secure the width. Specifically, it is about 1 to 4 cm. Further, the bottom surface b of the groove 2 (and 2a) is preferably a flat surface having no irregularities so that the ionizing radiation curable resin that fills the groove and becomes the bank portion is easily peeled off from the groove, A smooth surface is more preferable.
[0016]
The plate P for manufacturing a light control film having a plate shape as described above is a cylindrical roll intaglio. In order to provide the concave and convex portions of the desired light control layer and the concave and convex portions opposite to the concave and convex portions and the concave portions 72 forming the grooves 2 and 2a, the cylindrical plate material may be directly turned, milled, electroformed, Alternatively, it is performed by a photo etching method or the like. As the material of the plate P for manufacturing the light control film, metals such as copper, chromium and iron, synthetic resins such as NBR, epoxy resin and ebonite, ceramics such as glass, and the like can be used. In the case of copper or iron, the surface may be plated with metal such as chromium in order to improve durability and peelability.
[0017]
Next, the manufacturing method of the light control film of this invention is demonstrated. The method for producing a light control film of the present invention is a method for producing a light control film using a plate for producing a light control film as described above. Except for using the specific plate described above, the method may be the same as the method disclosed in the conventional Japanese Patent Application Laid-Open No. 5-169015. In other words, a roll intaglio with a concave and convex shape of the light control layer and a reverse concave and convex shape are used as a plate for manufacturing a light control film, and the ionizing radiation curable resin liquid is applied with a coating width that fits in the grooves on both sides of the plate. Then, the base film is supplied to the plate, and while the base film is in contact with the plate, it is irradiated with ionizing radiation to solidify the resin liquid, and then the base film is peeled off from the plate together with the cured resin. And a method of forming a light control layer having irregularities on a substrate film.
Here, a method for forming a light control layer only on one side of a base film will be described. However, a light control film having a light control layer provided on both sides may be the same or different light control film manufacturing plate. Of course, it can be obtained by the production method of the present invention.
[0018]
In FIG. 4, the conceptual diagram (side view) of an example of the apparatus used with the manufacturing method of the light control film of this invention is shown. In the same figure, P is a roll intaglio which is provided with a concave portion 72 having a concave and convex shape and a concave and convex shape opposite to the concave and convex shape of the light control layer formed on the base film, and is rotated in the direction of the arrow about the axis. Light control film manufacturing plate, 73 is an ionizing radiation curable resin solution, 4 is a base film, and 74 is a press that presses the base film 4 against the light control film manufacturing plate P in contact with the light control film manufacturing plate Roll, 75 is a peeling roll, 76 is an ionizing radiation irradiating device for curing the ionizing radiation curable resin solution, and 77 is a coating device for applying the ionizing radiation curable resin solution to the plate P for manufacturing the light control film. (Coating nozzle), 78 is a pump for supplying the resin liquid to the coating apparatus, and 5 is a light control layer having a desired uneven shape formed on the base film 4 as a cured product of an ionizing radiation curable resin liquid. (Light control layer Bank portion of the side is not shown).
[0019]
The ionizing radiation irradiation device 76 is a device that irradiates ionizing radiation to cause a curing reaction of the ionizing radiation curable resin liquid and solidify it. The ionizing radiation means an electromagnetic wave or charged particle beam having an energy quantum capable of polymerizing or cross-linking molecules, and usually ultraviolet (UV) or electron beam (EB) is used. As the ultraviolet light source, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light, a metal halide lamp or the like is used. As a wavelength of ultraviolet rays, a wavelength range of 190 to 380 nm is mainly used. As the electron beam source, various electron beam accelerators such as a cockcroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, a high frequency type, etc. are used, preferably 100 to 1000 keV. Is used to irradiate electrons having an energy of 100 to 300 keV.
In addition, you may further perform irradiation of ionizing radiation after peeling the light control film F from the plate P for light control film manufacture. When the light control film F is peeled from the light control film manufacturing plate P, it is a method of completing the curing after that as the degree of curing that can be peeled.
[0020]
The coating apparatus 77 is an apparatus for supplying and coating the ionizing radiation curable resin liquid 73 to the plate P for manufacturing the light control film, and filling the ionizing radiation curable resin liquid into the irregularities of the plate. It is preferable to use a nozzle coating apparatus as shown in FIG. The nozzle coating device is a device that coats a resin liquid from a coating outlet having a rectangular opening. The nozzle coating apparatus is installed so that the longitudinal direction of the coating outlet is the width direction of the plate P for manufacturing a light control film. A resin liquid is applied to a predetermined width Wc of the full width of the film manufacturing plate P.
[0021]
The ionizing radiation curable resin liquid can be used without a solvent, but can also be applied as a coating liquid containing a certain amount of solvent. In this case, solvent drying is performed between the coating device 77 and the pressure roller 74 in order to dry the solvent with respect to the ionizing radiation curable resin liquid on the light control film manufacturing plate P between the coating device 77 and the pressure roller 74. A device may be provided.
[0022]
Next, materials used for the light control film F will be described.
[0023]
For the base film 4, for example, a polyester resin such as polyethylene terephthalate or polybutylene terephthalate, an acrylic resin such as polymethyl methacrylate, a polycarbonate resin, or a polystyrene resin can be used. Although the thickness of a base film is based also on a use, it is about 20-1000 micrometers normally. In the case of a light-transmitting light control film as a lens film or the like, a transparent resin film is used. However, in a light control film that becomes a diffuser plate or a reflective plate using reflected light, it is not always necessary to use a transparent resin film. Absent. If the base film is a transparent film, it is preferable in that ionizing radiation can be irradiated from the base film side. Even in the case of being opaque, if a transparent body such as glass or ceramics is used as a plate for manufacturing a light control film, it is possible to irradiate ionizing radiation from the inner surface side of the plate.
In addition, in order to improve the adhesion between the light control layer and the base film, a corona discharge treatment, an adhesive layer made of a primer layer, or the like is formed on the surface of the base film on which the light control layer is provided. Easy adhesion treatment may be performed. For example, the primer layer is formed by coating a two-part curable primer using an isocyanate-based curing agent with acrylic polyol as the main component. Of course, the adhesive layer can be omitted when the adhesiveness of the light control layer to the substrate film is sufficient.
[0024]
The light control layer 5 is formed of a cured product of an ionizing radiation curable resin. Examples of the ionizing radiation curable resin liquid to be cured include prepolymers such as polyester acrylate, epoxy acrylate, silicone acrylate, and urethane acrylate and / or Conventionally known ionizing radiation curable resins made of acrylate monomers and the like, which are cured by ionizing radiation such as ultraviolet rays or electron beams, can be used. In order to obtain a hard light control layer that is hard and durable against scratches and external forces, a highly cross-linked ionizing radiation curable resin mainly composed of a polyfunctional monomer is preferable.
Of course, the bank portions 2 and 2 a are also formed as a cured product of the same ionizing radiation curable resin as the light control layer 5.
[0025]
With the apparatus and materials as described above, the light control film is manufactured as follows.
[0026]
First, a plate P for manufacturing a light control film having a concave portion (exactly concave and convex shape) opposite to a desired concave and convex shape of a light control layer to be formed and grooves on both sides in the width direction is prepared. The ionizing radiation curable resin liquid supplied from the pump 78 is applied to the light control film manufacturing plate P by the coating device 77 to fill the concave portions of the plate. Next, the continuous belt-shaped base film 4 is supplied to the plate P for manufacturing the light control film filled with the ionizing radiation curable resin liquid 73 and pressed against the plate surface by the pressing roll 74 to be brought into contact therewith. (It is also possible to leave the ionizing radiation curable resin liquid between the base film and the plate surface convex portion by adjusting the pressing force. In this case, the base film is "contacted" with the plate surface. And) while the base film 4 is transported in contact with the light control film manufacturing plate P, the ionizing radiation irradiation device 75 irradiates the ionizing radiation of ultraviolet rays or electron beams from the base film side ( If the plate for light control film production is transparent, such as glass, irradiation can also be performed from the inside of the plate), and the ionizing radiation curable resin liquid is allowed to cure and solidify to light the cured product of the ionizing radiation curable resin liquid. The control layer 5 and the bank portions 3 and 3a are adhered to the base film 4. Thereafter, the base film 4 is peeled off from the light control film production plate P together with the cured resin by a peeling roll 75, and the light control layer 5 having a desired concavo-convex shape and the bank portions 3 on both sides in the width direction thereof. And 3a becomes the light control film F formed on one side of the base film 4. In addition, when the bank parts 3 and 3a interfere with use, the bank part is cut off and it is set as the light control film F actually used.
[0027]
Thus, according to the present invention, it is possible to prevent the light control film from clogging the ionizing radiation curable resin liquid, the light control layer from sticking to the plate at both ends in the width direction, or the light control layer from being broken. It will be stably produced continuously.
[0028]
In addition, the light control film obtained by this invention is used for various light control by single or combination, such as condensing, scattering, and directivity change. For example, a light collecting plate, a diffusing plate, a directional lens, a directional reflecting plate, a diffusing reflecting plate, and the like.
The unevenness of the light control layer has a shape that matches the purpose of light control. For example, when the light control film is a condensing lens film, the light control layer has a lens structure in which a large number of triangular prism unit lenses, cylindrical unit lenses, elliptic cylinder unit lenses, and the like are arranged one-dimensionally. The triangular prism unit lens is a unit lens having a triangular cross section. The cross-sectional shape is, for example, an isosceles triangle whose apex angle is a convex ridge line of the light control layer. The cylindrical unit lens is a column having a cross-sectional shape of a semicircle having a diameter that is exactly half or a partial circle having a diameter that is not more than half. An elliptic cylinder unit lens is a column having a cross-sectional shape of a partial ellipse obtained by cutting an ellipse with a parallel line parallel to the major axis or minor axis. The position of the parallel line that cuts the ellipse is not necessarily the position of the major axis or minor axis that halves the ellipse, and there are partial ellipses that are less than half. In some cases, a light control layer has a lens structure in which a large number of compound eye-shaped hemispherical lenses such as eyelids, triangular pyramidal lenses, and quadrangular pyramidal lenses are two-dimensionally arranged. Moreover, the unevenness | corrugation of the light control layer for a scattering objective makes random, such as a satin, unevenness | corrugation, for example. Some triangular prism unit lenses and the like are two-dimensionally arranged so as to draw a circle or an arc on a plane.
Further, the unevenness of the light control layer for changing the directivity is assumed to have a lens structure in which triangular prism unit lenses having a cross section of an unequal triangular shape such as a sawtooth shape are arranged one-dimensionally.
[0029]
In the case of a light control film having a light reflection function by diffusion or directivity change, a metal thin film such as aluminum is further provided on the uneven surface of the light control layer obtained as a cured product of ionizing radiation curable resin. It is formed by vacuum deposition or the like. The reflective surface is the outside or the inside (base film side). On the other hand, in the case of a light control film as a light transmissive body, there is a configuration in which the light control layer is provided not only on one side of the substrate film but also on both sides.
[0030]
【Example】
Next, the present invention will be described in more detail with reference to examples and comparative examples.
[0031]
(Example)
1 has a lens structure in which a large number of triangular prism unit lenses are one-dimensionally arranged on one side of a transparent base film using a plate P for producing a light control film as illustrated in FIG. 1 and an apparatus as illustrated in FIG. A light control film was produced as a lens film in which the light control layer was laminated with an ultraviolet curable resin.
The cross-sectional shape of the triangular prism unit lens is an isosceles triangle having an apex angle of 50 ° and a base of 50 μm. The light control layer has a plurality of one-dimensional arrangements in the width direction of the base film adjacent to each other at a pitch of 50 μm, with the ridge lines formed by the apex angles of the unit lenses being parallel to each other, and the ridge lines are parallel to the base film longitudinal direction. Lens structure.
As the transparent substrate film, a polyethylene terephthalate film having a thickness of 125 μm and subjected to one-side easy adhesion treatment was used. Further, a primer (a mixture of chemical mat varnish medium and XEL curing agent in a 10: 1 weight ratio) was gravure-coated on the easy adhesion treated surface to form an adhesive layer. .
The plate for manufacturing a light control film is composed of a light control layer forming plate surface having unevenness of the light control layer and a reverse uneven shape, and grooves on both sides in the width direction adjacent to the light control layer forming plate surface (groove depth 60 μm). And a groove width of 3 cm) were cut into a desired concavo-convex shape with a cutting bit on the plate surface made of copper over the entire circumference of the plate, and then chrome plated.
[0032]
Then, while supplying the ultraviolet curable resin liquid (Nippon Synthetic Rubber Industry Co., Ltd., Z9002A) from the T-die-shaped coating nozzle with the coating hole opened upward, to the rotating light control film manufacturing plate, The base film is supplied to a plate for manufacturing a light control film on which a resin liquid has been applied. From the base film side on the plate for manufacturing a light control film, ultraviolet rays are irradiated to cause a curing reaction of the UV curable resin liquid. After curing and solidifying to make a cured product of an ultraviolet curable resin liquid in close contact with the base film, the base film on which the light control layer is laminated is peeled off from the plate for manufacturing the light control film with a peeling roll, and light A control film was produced. Note that two 160 W / cm high-pressure mercury lamps were used for ultraviolet irradiation.
As a result of the above, the cured product of the UV curable resin liquid (bank portion) does not stick to the plate at both ends in the width direction of the coating width, and the light control film in which the light control layer and the bank portion are formed is The release roll smoothly peeled off the plate for manufacturing the light control film, and stable continuous production was possible.
[0033]
(Comparative example)
Instead of the light control film manufacturing plate used in Example 1, a light control film manufacturing plate having a light control layer forming plate surface 1 having no grooves at both ends and wider than the coating width Wc as shown in FIG. A light control film was produced in the same manner as in Example 1 except that it was used.
As a result, a phenomenon occurs in which the cured product (light control layer) of the ultraviolet curable resin liquid sticks to the plate at both ends in the width direction of the coating width, and the light control film on which the light control layer is formed is removed by the peeling roll. It was difficult to peel smoothly from the plate for manufacturing a light control film, and stable continuous production was not possible.
[0034]
【The invention's effect】
According to the plate for producing a light control film and the method for producing a light control film of the present invention, a phenomenon occurs in which a cured product (light control layer) of an ultraviolet curable resin liquid sticks to the plate at both ends in the width direction of the coating width. However, since the light control film on which the light control layer is formed can be smoothly peeled off from the plate for manufacturing the light control film by the peeling roll, the light control film can be stably and continuously produced.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a plate for producing a light control film of the present invention. 1A is a perspective view, FIG. 1B is a cross-sectional view of a cut surface passing through an axis, and FIG. 1C is an enlarged cross-sectional view of a groove portion of FIG. 1B.
FIG. 2 Light control obtained by the present invention the film The perspective view which shows one form.
FIG. 3 is a cross-sectional view of a conventional light control film manufacturing plate with a cut surface passing through the axis.
FIG. 4 is a conceptual explanatory diagram of a method for producing a light control film of the present invention.
[Explanation of symbols]
1 Plate for light control layer formation
2, 2a groove
3, 3a Bank
4 Base film
5 Light control layer
72 recess
73 Ionizing radiation curable resin liquid
74 Pressing roll
75 Peeling roll
76 Ionizing radiation irradiation equipment
77 Coating equipment (Coating nozzle)
78 pump
b Bottom of groove
d Groove depth
D Light control layer uneven depth (depth of plate for forming light control layer)
P Light control film production plate
Po Conventional light control film production plate
F Light control film
w Groove width
Wc coating width

Claims

A light control layer having unevenness is laminated on a base film, and the light control layer is used to produce a light control film that controls the traveling direction of light such as change in directivity, diffusion, and condensing by the unevenness. And a plate for light control film production comprising a roll intaglio having irregularities of reverse irregularities,
While at least the concave portion of the rotating plate is filled with an ionizing radiation curable resin liquid, and then the long belt-like substrate film is brought into contact with the plate filled with the resin solution, while the substrate film is in contact with the plate Is irradiated with ionizing radiation, the ionizing radiation curable resin liquid interposed between the substrate film and the plate is cured and solidified to adhere to the substrate film, and then the substrate film is bonded together with the cured resin. In the plate for light control film production used in the method of producing a light control film having a light control layer made of an ionizing radiation curable resin on a base film, peeled from the plate,
A light control layer forming plate surface having unevenness of the light control layer opposite uneven bottom surface adjacent to both sides in the width direction of their having a band-like groove consisting of free plane unevenness, the light control flow I Lum production Edition.

A method of manufacturing a light control film in which a light control layer having unevenness is laminated on a base film, and the direction of change of light, diffusion, condensing, etc. is controlled by the unevenness, wherein the light control Using a plate for producing a light control film comprising a roll intaglio having irregularities with a reverse irregularity shape, and filling at least a concave portion of the rotating plate with an ionizing radiation curable resin liquid, and then a plate filled with the resin liquid A long strip-shaped base film is brought into contact, and ionizing radiation is irradiated while the base film is in contact with the plate to cure the ionizing radiation curable resin liquid interposed between the base film and the plate. After the solidified resin is adhered to the base film, the base film is peeled off from the plate together with the cured resin to produce a light control film having a light control layer made of an ionizing radiation curable resin on the base film. How to smell ,
As a light control film manufacturing version, the light control layer forming plate surface having unevenness of the light control layer opposite uneven bottom surface adjacent to both sides in the width direction of their is a belt-shaped groove consisting of free plane unevenness Use the version you have,
Coating the ionizing radiation curing resin liquid as the coating width to fit within the respective groove widths of both ends the grooves of the coating width to the light control film manufacturing version, light control off I Lum manufacturing method.