JP3795598B2 - Liquid crystal display - Google Patents

Description

【００４８】
【化２】

【００４９】
【化３】

【００５０】
【化４】

【００５１】
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【化９】

【００５６】
【化１０】

【００５７】
（式中、Ｒ′、Ｘはそれぞれ単独してアルキル基、アルコキシ基、アルキルフェニル基、アルコキシアルキルフェニル基、アルコキシフェニル基、アルキルシクロヘキシル基、アルコキシアルキルシクロヘキシル基、アルキルシクロヘキシルフェニル基、シアノフェニル基、シアノ基、ハロゲン原子、フルオロメチル基、フルオロメトキシ基、アルキルフェニルアルキル基、アルコキシアルキルフェニルアルキル基、アルコキシアルキルシクロヘキシルアルキル基、アルキルシクロヘキシルアルキル基、アルコキシアルコキシシクロヘキシルアルキル基、アルコキシフェニルアルキル基、アルキルシクロヘキシルフェニルアルキル基を示し、Ｙは水素原子、ハロゲン原子を示し、さらにこれらのアルキル鎖およびアルコキシ鎖中に光学活性中心を有しても良い。また、Ｒ′、Ｘ中のフェニル基またはフェノキシ基はフッ素原子、塩素原子等のハロゲン原子で置換されていても良い。また、各式中のフェニル基は１個または２個のフッ素原子、塩素原子等のハロゲン原子で置換されていても良い。）
式中の液晶化合物はいずれも誘電異方性が正であるが、誘電異方性が負の公知の液晶化合物を誘電異方性が正の液晶化合物と混合して、全体として正の液晶化合物にして用いることができる。また、誘電異方性が負の液晶化合物でも、適切な素子構成および駆動方式を用いればそのまま使用することもできる。
【００５８】
本発明の液晶表示装置においては、液晶材料の構成要素の一つとして、コントラストを向上させる目的、およびカラー化の目的で二色性色素を用いてもよい。その場合、二色性色素としては、液晶化合物に対して相溶性があり、透明被膜を構成する高分子材料にはあまり溶解したり、吸着しないものを用いる必要がある。二色性色素を含有させる場合には、目的に応じた屈折率を考慮して透明被膜を構成する高分子材料および液晶材料を選択する必要がある。すなわち、光散乱を利用してコントラストを上げる場合には、屈折率異方性の大きい液晶材料を選択することが望ましい。しかしながら、この場合には、反射光の色が白っぽくなるという欠点が生じる。一方、屈折率異方性が小さく、低分子化合物の屈折率に近い場合には、二色性色素本来の色が得られる。二色性色素分子としては、例えば式（１１）〜（１９）に示すイエロー色素、式（２０）〜（２７）に示すマゼンタ色素、式（２８）〜（３１）に示すシアン色素を用いることができる。
【００５９】
【化１１】

【００６０】
【化１２】

【００６１】
【化１３】

【００６２】
【化１４】

【００６３】
【化１５】

【００６４】
【化１６】

【００６５】
【化１７】

【００６６】
【化１８】

さらに本発明の液晶表示装置においては、液晶材料の構成要素の一つとして、反射光の増白のために、もしくは紫外線吸収剤として蛍光色素を用いてもよい。その場合、蛍光色素は透明被膜に溶解し、液晶材料にはあまり溶解しないものであることが好ましい。
【００６７】
本発明において、二色性色素を用いる場合、液晶材料に対する重量比は、０．０１〜１０％、好ましくは０．１から５％であることが好ましい。重量比が低く過ぎるとコントラストが充分に向上せず、重量比が高過ぎると電圧印加時でも着色が残り、やはりコントラストが低下する。
【００６８】
本発明の液晶表示装置において、一対の基板は、少なくとも一方の基板が透明基板である必要がある。また、透明基板としては、ガラス基板、透明プラスチック基板、透明プラスチックフィルム等を用いることができ、透明でない基板としては、アルミニウム反射電極を有する基板等の不透明基板、半透明基板を用いることができる。
【００６９】
次に、本発明の効果を明確にするために行った実施例について説明する。
【００７０】
（参考例１）
正の誘電異方性を有するネマチック液晶ＺＬＩ−１８４０（メルク社製、商品名）を８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これに非イオン性界面活性剤エマルゲン１２０（花王社製、商品名）３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合させた。
【００７１】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径２〜４μｍの液晶マイクロカプセルを得た。
【００７２】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめ透明電極を設けたガラス基板表面にアプリケータを用いて塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートした。このようにして本発明の液晶表示装置を作製した。
【００７３】
得られた液晶表示装置を顕微鏡で観測した。その結果を図４に示す。図４（Ａ）は基板面に対して垂直な方向から見た構造模式図を示しており、図４（Ｂ）は基板面に対して水平な方向から見た構造模式図を示している。図４（Ａ）および図４（Ｂ）から分かるように、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。液晶分子の配向は基板面にほぼ平行であり、配向の方向はマイクロカプセル内では軸方向が一定の方向（一軸配向）であったが、マイクロカプセル間では軸方向がランダムであった。また、液晶マイクロカプセル層（調光層）の厚みは１０μｍであった。この液晶表示装置は白色不透明であり、５０Ｈｚで１０Ｖの交流電圧を印加すると透明となった。また、透過吸光度から求めたコントラスト比は２２であった。
【００７４】
（比較例１）
正の誘電異方性を有するネマチック液晶ＺＬＩ−１８４０を８０重量部、ポリメチルメタクリレート１５重量部をクロロホルムに溶解し、あらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて液晶層（調光層）を形成した。次いで、液晶層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートした。このようにして比較例の液晶表示装置を作製した。
【００７５】
得られた液晶表示装置を顕微鏡で観測した。その結果を図５に示す。図５（Ａ）は基板面に対して垂直な方向から見た構造模式図を示しており、図５（Ｂ）は基板面に対して平行な方向から見た構造模式図を示している。図５（Ａ）および図５（Ｂ）から分かるように、各液晶ドメインの大きさは種々であり、液晶ドメインは湾曲した界面を有していた。また、液晶層（調光層）の厚みは１０μｍであった。この液晶表示装置は白色不透明であり、５０Ｈｚで１２Ｖの交流電圧を印加すると透明となった。また、透過吸光度から求めたコントラスト比は１４であった。
【００７６】
（比較例２）
正の誘電異方性を有するネマチック液晶ＺＬＩ−１８４０を８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部を混合して溶解し、あらかじめセルギャップ１０μｍで組み立てた液晶セルに注入した。次いで、この液晶セルに波長２５４ｎｍを有する紫外線を照射して液晶組成物を硬化させた。
【００７７】
得られた液晶表示装置を顕微鏡で観測した。その結果を図６に示す。図６（Ａ）は基板面に対して垂直な方向から見た構造模式図を示しており、図６（Ｂ）は基板面に対して垂直な方向から見た構造模式図を示している。図６（Ａ）および図６（Ｂ）から分かるように、各液晶ドメインは網目状の構造をとっていた。また、液晶分子の配向はランダムであった。この液晶表示装置は白色不透明であり、５０Ｈｚで１１Ｖの交流電圧を印加すると透明となった。また、透過吸光度から求めたコントラスト比は１７であった。
【００７８】
（実施例１）
正の誘電異方性を有するネマチック液晶ＺＬＩ−１８４０を８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これに非イオン性界面活性剤エマルゲン１２０を３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合させた。
【００７９】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径４〜６μｍの液晶マイクロカプセルを得た。
【００８０】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめ透明電極を設けたガラス基板を重ね合わせた。次いで、これをポリアミド製の袋に入れ、袋内を減圧し、この状態で１２０℃の加熱処理を施してガラス基板を加熱密着させた。このようにして本発明の液晶表示装置を作製した。
【００８１】
得られた液晶表示装置を顕微鏡で観測した。その結果を図７に示す。図７（Ａ）は基板面に対して垂直な方向から見た構造模式図を示しており、図７（Ｂ）は基板面に対して水平な方向から見た構造模式図を示している。図７（Ａ）および図７（Ｂ）から分かるように、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた。液晶分子の配向は基板に対してほぼ平行であり、そのオーダーパラメータは実施例１の場合より高かった。また、液晶マイクロカプセル層（調光層）の厚みは８μｍであった。この液晶表示装置は白色不透明であり、５０Ｈｚで９．５Ｖの交流電圧を印加すると透明となった。また、透過吸光度から求めたコントラスト比は２５であった。
【００８２】
（参考例２）
黒色二色性色素Ｓ−４３５（三井東圧社製、商品名）を液晶ＺＬＩ−１６９５（メルク社製、商品名）に１重量％で溶解させたものを８０重量部、２，２，３，３−テトラフルオロプロピルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これにポリビニルアルコール３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【００８３】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径４〜６μｍの液晶マイクロカプセルを得た。
【００８４】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめアルミニウム反射電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートした。このようにして本発明の液晶表示装置を作製した。
【００８５】
得られた液晶表示装置を顕微鏡で観測した。その結果、液晶マイクロカプセル層（調光層）の構造は参考例１の場合（図４（Ａ），図４（Ｂ））と同様であった。また、液晶マイクロカプセル層（調光層）の厚みは１１μｍであった。この液晶表示装置は黒色であり、５０Ｈｚで１３Ｖの交流電圧を印加すると無色となった。また、反射濃度計で測定したコントラスト比は３．５であった。
【００８６】
（比較例３）
黒色二色性色素Ｓ−４３５を液晶ＺＬＩ−１６９５に１重量％で溶解させたものを８０重量部、ポリ（２，２，３，３−テトラフルオロプロピルメタクリレート）１５重量部をクロロホルムに溶解し、あらかじめアルミニウム反射電極を設けたガラス基板に塗布し、乾燥させてし、乾燥させて液晶層（調光層）を形成した。次いで、液晶層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートし、これを１２０℃で加圧密着させた。このようにして比較例の液晶表示装置を作製した。
【００８７】
得られた液晶表示装置を顕微鏡で観測した。その結果、液晶マイクロカプセル層（調光層）の構造は比較例１の場合（図５（Ａ），図５（Ｂ））と同様であった。また、液晶層（調光層）の厚みは１１μｍであった。この液晶表示装置は黒色であり、５０Ｈｚで１４Ｖの交流電圧を印加すると無色となった。また、反射濃度計で測定したコントラスト比は２．７であった。
【００８８】
（実施例２）
黒色二色性色素Ｓ−４３５を液晶ＺＬＩ−１６９５に１重量％で溶解させたものを８０重量部、２，２，３，３−テトラフルオロプロピルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これに界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【００８９】
次いで、この液晶組成物を目の大きさが１μｍ角のフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径４〜６μｍの液晶マイクロカプセルを得た。
【００９０】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめアルミニウム反射電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめ透明電極を設けたガラス基板を重ね合わせた。次いで、これをポリアミド製の袋に入れ、袋内を減圧し、この状態で１２０℃の加熱処理を施してガラス基板を加熱密着させた。このようにして本発明の液晶表示装置を作製した。
【００９１】
得られた液晶表示装置を顕微鏡で観測した。その結果、液晶マイクロカプセル層（調光層）の構造は、実施例１の場合（図７（Ａ），図７（Ｂ））と同様に、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた（多面体構造）。また、液晶マイクロカプセル層（調光層）の厚みは８μｍであった。この液晶表示装置は黒色であり、５０Ｈｚで８Ｖの交流電圧を印加すると無色となった。また、反射濃度計で測定したコントラスト比は４．５であった。
【００９２】
（実施例３）
負の誘電異方性を有するネマチック液晶ＺＬＩ−２６５９（メルク社製、商品名）を８０重量部、オクタデシルメタクリレートモノマー２０重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これに界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【００９３】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径４〜６μｍの液晶マイクロカプセルを得た。
【００９４】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめ透明電極を設けたガラス基板を重ね合わせた。次いで、これをポリアミド製の袋に入れ、袋内を減圧し、この状態で１００℃の加熱処理を施してガラス基板を加熱密着させた。このようにして本発明の液晶表示装置を作製した。
【００９５】
得られた液晶表示装置を顕微鏡で観測した。その結果、実施例２と同様に、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた。また、液晶マイクロカプセル層（調光層）の厚みは８μｍであった。また、液晶分子の配向は基板面に対してほぼ垂直であった。この液晶表示装置は透明であり、５０Ｈｚで９Ｖの交流電圧を印加すると白色となった。また、透過吸光度から求めたコントラスト比は２５であった。
【００９６】
（実施例４）
黒色二色性色素Ｓ−４３５を負の誘電異方性を有する液晶ＺＬＩ−２６５９に１重量％で溶解させたものを８０重量部、オクタデシルメタクリレートモノマー２０重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【００９７】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径４〜６μｍの液晶マイクロカプセルを得た。
【００９８】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめアルミニウム反射電極を設けたガラス基板を重ね合わせた。次いで、これをポリアミド製の袋に入れ、袋内を減圧し、この状態で１００℃の加熱処理を施してガラス基板を加熱密着させた。このようにして本発明の液晶表示装置を作製した。
【００９９】
得られた液晶表示装置を顕微鏡で観測した。その結果、実施例２と同様に、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた。また、液晶マイクロカプセル層（調光層）の厚みは９μｍであった。また、液晶分子の配向は基板面に対してほぼ垂直であった。この液晶表示装置は無色であり、５０Ｈｚで９．５Ｖの交流電圧を印加すると黒色となった。また、反射濃度計で測定したコントラスト比は５．０であった。
【０１００】
（実施例５）
黒色二色性色素Ｓ−４３５を液晶ＺＬＩ−１６９５に１重量％で溶解させたものを８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【０１０１】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径４〜６μｍの液晶マイクロカプセルを得た。
【０１０２】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめアルミニウム反射電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。次いで、液晶マイクロカプセル層に１２０℃でテフロン板を押し付けながら水平方向に僅かにずらした。室温にまで冷却した後、テフロン板を外し、あらかじめ透明電極を設けた高分子フィルムをラミネートした。このようにして本発明の液晶表示装置を作製した。
【０１０３】
得られた液晶表示装置を顕微鏡で観測した。その結果、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた。また、液晶マイクロカプセル層（調光層）の厚みは８μｍであった。また、液晶分子の配向方向は基板面に対してほぼ平行であり、テフロン板をずらした方向であった。この液晶表示装置は黒色であり、５０Ｈｚで８．８Ｖの交流電圧を印加すると無色となった。また、反射濃度計で測定したコントラスト比は４．６であった。
【０１０４】
（実施例６）
黒色二色性色素Ｓ−４３５を液晶ＺＬＩ−１６９５に１重量％で溶解させたものを８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【０１０５】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径２〜４μｍの液晶マイクロカプセルを得た。
【０１０６】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に５重量％で分散させ、これをあらかじめアルミニウム反射電極を設けたガラス基板表面に塗布し、乾燥させて第１の液晶マイクロカプセル層を形成した。次いで、第１の液晶マイクロカプセル層に１２０℃でテフロン板を押し付けながら水平方向に僅かにずらした。室温にまで冷却した後、テフロン板を外した。
【０１０７】
この状態で第１の液晶マイクロカプセル層を顕微鏡で観測した。その結果、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた。また、第１の液晶マイクロカプセル層の厚みは４μｍであった。また、液晶分子の配向方向は基板面に対してほぼ平行であり、テフロン板をずらした方向であった。
【０１０８】
次に、黒色二色性色素Ｓ−４３５を液晶ＺＬＩ−１６９５に１重量％で溶解させたものを８０重量部、メチルアクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【０１０９】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径２〜４μｍの液晶マイクロカプセルを得た。
【０１１０】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に５重量％で分散させ、上記メチルメタクリレートで被覆された第１の液晶マイクロカプセル層上に塗布し乾燥させて第２の液晶マイクロカプセル層を形成した。次いで、第２の液晶マイクロカプセル層に１００℃でテフロン板を押し付けながら前記ずれ方向とほぼ直交する方向に僅かにずらした。室温にまで冷却した後、テフロン板を外した。
【０１１１】
この状態で第２の液晶マイクロカプセル層を顕微鏡で観測した。その結果、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた。また、第２の液晶マイクロカプセル層の厚みは４μｍであった。また、液晶分子の配向方向は基板面に対してほぼ平行であり、テフロン板をずらした方向であった。
【０１１２】
次いで、第２の液晶マイクロカプセル層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートした。このようにして本発明の液晶表示装置を作製した。この液晶表示装置は黒色であり、５０Ｈｚで８．６Ｖの交流電圧を印加すると無色となった。また、反射濃度計で測定したコントラスト比は５．３であった。
（実施例７）
黒色二色性色素Ｓ−４３５を液晶ＺＬＩ−１６９５に１重量％で溶解させたものを８０重量部、フッ素化メタクリレートモノマー１５重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【０１１３】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、細かい液晶マイクロカプセルを除去し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径４〜６μｍの液晶マイクロカプセルを得た。次いで、この液晶マイクロカプセルとエポキシプレポリマー（エピコート）８重量部とを混合して、５重量％ゼラチン水溶液２００重量部に撹拌しながら滴下して微小滴を形成させ、アミン系硬化剤の３重量部を５０重量部の水に溶解してなる溶液を前記ゼラチン水溶液中に徐々に滴下しながら、約４０℃で１時間撹拌を続けた。
【０１１４】
次いで、この液晶組成物を目の大きさが１μｍ角であるフィルターで濾過し、細かい液晶マイクロカプセルを除去し、純水で３回洗浄した。このようにして、フッ素系メタクリレート膜とエポキシ樹脂膜の２層構造の透明被膜で液晶組成物を包含してなる外径５〜７μｍの液晶マイクロカプセルを得た。
【０１１５】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。次いで、液晶マイクロカプセル層にテフロン板を押し付けて１２０℃２時間の加熱処理を施して、ガラス基板に液晶マイクロカプセル層を加熱密着させると共に、エポキシ樹脂を硬化させた。その後、室温にまで冷却した後、テフロン板を外し、あらかじめ透明電極を設けた高分子フィルムをラミネートした。このようにして本発明の液晶表示装置を作製した。
【０１１６】
得られた液晶表示装置を顕微鏡で観測した。その結果、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっていた。また、液晶マイクロカプセル層（調光層）の厚みは８μｍであった。この液晶表示装置は黒色であり、５０Ｈｚで８．４Ｖの交流電圧を印加すると無色となった。また、反射濃度計で測定したコントラスト比は４．３であった。
【０１１７】
（実施例８）
黒色二色性色素Ｓ−４３５を液晶ＺＬＩ−１６９５に１重量％で溶解させたものを８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、ポリビニルアルコール３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。このようにして、透明被膜で液晶組成物を包含してなる外径１〜８μｍの液晶マイクロカプセル分散液を得た。
【０１１８】
次いで、あらかじめアルミニウム反射電極を設けたガラス基板を上記液晶マイクロカプセル分散液に浸漬し、引き上げ速度５ｍｍ／分でゆっくりと空気中に引き上げた。基板に付着した液は引き上げられたとき（空気中に露出したとき）に順次乾燥した。このようにして成膜された第１の液晶マイクロカプセル層内の液晶分子の配向は基板面に対してほぼ平行であり、かつ、液晶分子が基板引き上げ方向に対して垂直な方向にほとんど配向していた。
【０１１９】
次いで、基板を再び上記液晶マイクロカプセル分散液に浸漬し、基板の引き上げ方向を前記引き上げ方向と直交する方向に設定し、引き上げ速度５ｍｍ／分でゆっくりと空気中に引き上げた。このようにして、先に成膜された第１の液晶マイクロカプセル層上に次の第２の液晶マイクロカプセルを積層した。第２の液晶マイクロカプセル層内の液晶分子の配向は基板面に対してほぼ平行であり、かつ、第１の液晶マイクロカプセル層内のほとんどの液晶分子の配向と直交していた。
【０１２０】
さらに、第２の液晶マイクロカプセル層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートした。このようにして、液晶マイクロカプセル層（調光層）の厚みが１０μｍである本発明の液晶表示装置を作製した。この液晶表示装置は黒色であり、５０Ｈｚで１４Ｖの交流電圧を印加すると無色となった。また、反射濃度計で測定したコントラスト比は５．５であった。
【０１２１】
（実施例９）
図８（Ａ）は、本発明の液晶表示装置の一実施例を示す概略図であり、図８（Ｂ）は、図８（Ａ）に示す液晶表示装置の断面図である。図中１１はガラス基板を示す。ガラス基板１１上には、複数のＴＦＴ１２が形成されている。ガラス基板１１上には、絶縁膜を介してアルミニウムからなる反射板１３が配置されている。この反射板１３は画素電極を構成している。さらに、反射板１３上にイエロー液晶層１４ａ、透明電極層（画素電極）１５、マゼンダ液晶層１４ｂ、透明電極層（画素電極）１５、シアン液晶層１４ｃが順次積層されている。この液晶層１４ａ〜１４ｃは、それぞれの色（イエロー、マゼンダ、シアン）の色素分子を含むゲストホスト液晶を封じ込めたマイクロカプセルを含む分散液を塗布し、分散媒を揮発させることにより形成する。また、透明電極層１５は、透明導電材料をスパッタリングし、フォトリソグラフィーおよびエッチングによりパターニングすることにより形成する。なお、液晶層１４ａ〜１４ｃの積層の順序はいずれの場合でもよい。
【０１２２】
さらに、シアン液晶層１４ｃ上には、透明の対向電極１６を有するガラス基板が配置されている。なお、各ＴＦＴと、反射板１３または透明電極層１５とは電気的に接続されている。
【０１２３】
上記構成を有する液晶表示装置は、各液晶層１４ａ〜１４ｃおよび透明電極層１５には、非表示領域である能動素子および配線等が存在しないので開口率が広く、しかも透明電極層を薄膜で形成しておりガラス基板を使用していないので光利用効率が高い。
【０１２４】
この液晶表示装置でカラー表示を行う場合、各液晶層をそれぞれ挟持する４つの電極に印加する電圧は、演算回路であらかじめ決めておく。例えば、「白」を表示するときは、図９（Ａ）に示すように電圧を印加する。図中ＧはＧＮＤを意味し、ある基準となる電位である。ＶはＧＮＤに対する電位であり、前述のＶ−Ｔ特性において、Ｔを高い状態にある程度飽和させることができる電位である。なお、電圧印加を二通り示してあるのは、液晶層に交流波形を加える必要があるからである。ゲストホスト液晶の場合、「白」を表示するときは、光を透過させる都合上、液晶分子と色素分子をできるだけ電極面に対して垂直方向に立てる必要があるので、図９（Ａ）に示すように電圧をに印加する。他の色に関しては、図９（Ｂ）〜図９（Ｈ）に示すように各液晶層間の電圧を制御することにより表示することができた。
【０１２５】
（実施例１０）
正の誘電異方性を有するネマチック液晶Ｅ４８（メルク社製、商品名）６０重量％とコレステリック液晶ＣＢ１５（メルク社製、商品名）４０重量％とを混合した液晶材料を８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【０１２６】
次いで、この液晶組成物を目の大きさが０．５μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径２〜５μｍの液晶マイクロカプセルを得た。
【０１２７】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートした。さらに、これに１２０℃の加熱処理を施してガラス基板と液晶マイクロカプセル層とを加熱密着させた。このようにして本発明の液晶表示装置を作製した。
【０１２８】
得られた液晶表示装置を顕微鏡で観測した。その結果、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセル層（調光層）の厚みは５μｍであった。この液晶表示装置は緑色反射色であり、５０Ｈｚで矩形波４０Ｖの交流電圧を印加すると透明となった。
【０１２９】
（実施例１１）
ネマチック液晶Ｅ４８を６０重量％とコレステリック液晶ＣＢ１５を４０重量％とを混合した液晶材料を８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これに界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。
【０１３０】
次いで、この液晶組成物を目の大きさが０．５μｍ角であるフィルターで濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径２〜５μｍの液晶マイクロカプセルを得た。
【０１３１】
次いで、この液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％で分散させ、これをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて液晶マイクロカプセル層（調光層）を形成した。さらに、液晶マイクロカプセル層上に、あらかじめ透明電極を設けたガラス基板を重ね合わせた。次いで、これをポリアミド製の袋に入れ、袋内を減圧し、この状態で１２０℃の加熱処理を施してガラス基板を加熱密着させた。このようにして本発明の液晶表示装置を作製した。
【０１３２】
得られた液晶表示装置を顕微鏡で観測した。その結果、液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、液晶マイクロカプセルは、水平方向（基板面に対して平行な方向）に延伸された状態となっており、融合部分が基板面に対してほぼ平行な直線となっていた。また、液晶マイクロカプセル層（調光層）の厚みは５μｍであった。この液晶表示装置は緑色反射色であり、５０Ｈｚで矩形波３５Ｖの交流電圧を印加すると透明となった。
【０１３３】
（実施例１２）
正の誘電異方性を有するネマチック液晶Ｅ４８を６０重量％とコレステリック液晶ＣＢ１５とを混合した液晶材料を８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これに界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。なお、ＣＢ１５は右巻きのカイラル剤である。
【０１３４】
正の誘電異方性を有するネマチック液晶Ｅ４８を６０重量％とコレステリック液晶Ｃ１５（メルク社製、商品名）とを混合した液晶材料を８０重量部、メチルメタクリレートモノマー１５重量部、架橋剤としてジビニルベンゼン１重量部、ベンゾイルパーオキサイド０．２重量部を混合して溶解し、これに界面活性剤３重量部、純水３００重量部と共にホモジナイザーで乳化した後、上記液晶組成物を８５℃で１時間重合した。なお、Ｃ１５は右巻きのカイラル剤である。
【０１３５】
次いで、これらの液晶組成物を目の大きさが０．５μｍ角であるフィルターでそれぞれ濾過し、純水で３回洗浄した。このようにして、透明被膜で液晶組成物を包含してなる外径１〜３μｍの２種類の液晶マイクロカプセルを得た。
【０１３６】
次いで、これらの液晶マイクロカプセルを１０％イソプロピルアルコール水に１０重量％でそれぞれ分散させ、右巻きの構造を有する液晶マイクロカプセルをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて第１の液晶マイクロカプセル層（調光層）を形成した。続けて左巻きの構造を有する液晶マイクロカプセルをあらかじめ透明電極を設けたガラス基板表面に塗布し、乾燥させて第２の液晶マイクロカプセル層（調光層）を形成した。さらに、第２の液晶マイクロカプセル層上に、あらかじめ透明電極を設けた高分子フィルムをラミネートした。その後、これに１２０℃の加熱処理を施してガラス基板と液晶マイクロカプセル層とを加熱密着させた。このようにして本発明の液晶表示装置を作製した。
【０１３７】
得られた液晶表示装置を顕微鏡で観測した。その結果、第１および第２の液晶マイクロカプセル層中の液晶マイクロカプセルは互いに融合しており、融合部分が直線である多面体構造となっていた。また、第１および第２の液晶マイクロカプセル層（調光層）の厚みはそれぞれ２μｍであった。この液晶表示装置は緑色反射色であり、５０Ｈｚで矩形波３０Ｖの交流電圧を印加すると透明となった。
【０１３８】
（実施例１３）
マゼンタの二色性染料を溶解した液晶材料４０ｇにモノマーとしてメチルメタアクリレート８ｇ、ビニルメタアクリレート２ｇ、開始剤としてジクミルパーオキサイド０．１ｇを混合して溶解して液晶組成物を得た。次いで、媒質として、水５００ｇに乳化剤としてポリビニルアルコール５ｇを溶解した。
【０１３９】
次いで、孔粒径１μｍの乳化膜を介して液晶組成物を０．４ｋｇ／ｃｍ² の圧力で加圧して媒質中に押し出した。なお、このとき、媒質は循環させて乳化膜の表面に流れを与えた。押し出された液晶油滴は乳化膜表面から媒質に洗い落とされ、これにより粒径４〜５μｍの均一なモノマー含有液晶の油滴を得た。
【０１４０】
このようにして得られた油滴からなる乳化液を窒素雰囲気下で７５℃で１２時間重合して液晶マイクロカプセルを作製した。この液晶マイクロカプセルを含有した水溶液を透明電極付きガラス基板に塗布・乾燥して、厚さ１０μｍの液晶マイクロカプセル層を形成した。この液晶マイクロカプセル層を顕微鏡で表面から観察すると、液晶マイクロカプセルが融合してハニカム構造に近い大きさの揃っていることが確認できた。
【０１４１】
さらに、液晶マイクロカプセル層上に透明電極付きガラス基板を積層して液晶表示装置を完成させた。この液晶表示装置の駆動電圧を測定したところ、５Ｖであった。また、液晶表示装置に電圧を印加したところ、マゼンタ色から透明に変化した。この液晶表示装置においては、液晶マイクロカプセルの粒径がほぼ均一であるので、液晶マイクロカプセル層に段差が生じず、これにより散乱が少なかった。
【０１４２】
（実施例１４）
本発明においては、液晶マイクロカプセルのポリマー外壁上に露光粘着性発現体をコーティングし、これを基板上に均一に塗布して層形成を行い、この液晶マイクロカプセル層にパタ一ン露光を行い、基板表面の洗浄を行うことにより、液晶マイクロカプセル層に所望のパターンを形成することができることを見出した。
【０１４３】
すなわち、この態様における液晶マイクロカプセルは、例えば図１０に示すように、液晶分子２１と二色性色素２２を含む液晶材料をポリマー層２３で包含したカプセルの最表層に露光粘着性発現体層２４を設けたものである。なお、ポリマー層全体が露光粘着性発現体で構成されていても良い。
【０１４４】
この態様においては、まず、図１１（Ａ）に示すように、この液晶マイクロカプセルを、表面にＩＴＯ等からなる透明電極２６を有するガラス基板２７上に均一に塗布する。さらにこの基板にマスクを介してパターン露光する。このとき、露光した部分のみの露光粘着性発現体が粘着性を発現して液晶マイクロカプセルが下地に（基板や透明電極等）に吸着する。その後、基板を洗浄することにより、非露光部の液晶マイクロカプセルが洗い流されて所望のパターンを有する液晶マイクロカプセル層２５を形成することができる。このようにすることにより、図１１（Ｂ）に示すようなレッド、ブルー、グリーンのパターンを有する液晶マイクロカプセル層を得ることができる。その結果、液晶マイクロカプセルを用いても、構造が単純で低コストであり、しかも生産が可能であり、明るく鮮明な表示を得ることができる液晶表示装置を実現することができる。
【０１４５】
上記液晶マイクロカプセルに用いるイエローの二色性色素としては、例えばＧ−２３２（日本感光色素社製）、ＳＩ−２０９、Ｍ−３６１（三井東圧社製）等を挙げることができる。また、液晶マイクロカプセルに用いるシアンの二色性色素としては、ＳＩ−５０１、ＳＩ−４９７、Ｍ−４０３（三井東圧社製）、Ｇ−４７２（日本感光色素社製）等を挙げることができる。また、液晶マイクロカプセルに用いるマゼンタに二色性色素としては、Ｇ−２３９、Ｇ−４７１、Ｇ−２０２（日本感光色素社製）、ＳＩ−５１２、Ｍ−６１８、Ｍ−３７０（三井東圧社製）等を挙げることができる。
【０１４６】
液晶マイクロカプセルの着色時の色相は、上記の二色性色素を混合することによって得ることができる。例えばレッドの液晶マイクロカプセルは、マゼンタとイエローの色素の混合によって調整することができ、ブルーの液晶マイクロカプセルは、マゼンタとシアンの色素の混合によって調整することができ、グリーンの液晶マイクロカプセルは、シアンとイエローの色素の混合によって得ること調整することができる。
【０１４７】
上記液晶マイクロカプセルに用いる液晶としては、ＴＣ−４３６８ＸＸ、ＺＬＩ−４２８１／２、ＺＬＩ−３８８９、ＺＬＩ−５５００−０００、ＭＬＣ−６０４１−０００、ＺＬＩ−４６２０、ＺＬＩ−５１００−０００、ＺＬＩ−１８４０、ＺＬＩ−２１１６−０００、ＺＬＩ−２２９３（メルクジャパン社製）、ＬＩＸ０Ｎ４０３３−０００ＸＸ、ＬＩＸ０Ｎ４０３４−０００ＸＸ．ＬＩＸＯＮ−５０５２（チッソ化学工業社製）等を用いることができるがこれらに限定されない。
【０１４８】
上記液晶マイクロカプセルの透明被膜（ポリマー外壁）の材料としては、ジビニルベンゼン、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸−ｎ−ブチル、（メタ）アクリル酸−２−ヒドロキシエチル、（メタ）アクリル酸グリシジル、エチレングリコール−ジ−（メタ）アクリル酸エステル、（メタ）アクリル酸トリブロモフェニル、（メタ）アクリロニトリル、（メタ）アクロレイン、（メタ）アクリルアミド、メチレンビス（メタ）アクリルアミド、Ｎ−メチロール−（メタ）アクリルアミド、塩化ビニル、塩化ビニリデン、ブ夕ジエン、イソプレン、（メタ）アクリル酸、イタコン酸、フマル酸等の共重合体等を挙げることができるが、これらに限定されるものではない。
【０１４９】
上記液晶マイクロカプセルの露光粘着性発現物質としては、１，４−ジヒドロピリジン等を挙げることができる。より具体的には、２，６−ジメチル−４− （２´−ニトロフェニル）−１、４−ジヒドロピリジン−３、５−ジカルボン酸ジメチルエステル；２、６−ジメチル−４−（２´−ニトロフェニル）−１，４−ジヒドロピリジン−３、５−ジカルボン酸ジエチルエステル；２，６−ジメチル−４−（２´−ニトロー４´，５´−ジメトキシフェニル）−１，４−ジヒドロピリジン−３，５−ジカルボン酸ジエチルエステル；２，６−ジメチル−４−（２´−ニトロフェニル）−１，４−ジヒドロピリジン−３，５−ジカルボン酸ジイソプロピルエステル；２，６−ジメチル−４−（２´−ニトロフェニル）−１）４−ジヒドロピリジン−３，５−ジカルボン酸ジ（β一エトキンエチル）エステル；２，６−ジメチル−４−（２´−ニトロフェニル）−１，４−ジヒドロピリジン−３，５−ジカルボン酸３−メチル−５−エチルエステル；２，６−ジメチル−４−（２´一ニトロフェニル）−１，４−ジヒドロピリジン−３，５−ジカルボン酸３−イソプロピル−５−メチルエステル；２，６−ジメチル−４−（２´−ニトロフェニル）一３−アセト−１，４−ジヒドロピリジン−５−カルボン酸エチルエステル；２，６−ジメチル−４−（２´´−ニトロフェニル）−３，５−ジアセト−１）４−ジヒドロピリジン、および２，６−ジメチル−４−（２´−ニトロフェニル）−３，５ージシアノ−１，４−ジヒドロピリジン等を挙げることができるが、これらに限定されるものではない。
【０１５０】
具体的には、上記液晶マイクロカプセルを有する液晶表示装置は、以下のように作製することができる。
【０１５１】
実施例１３と同様に乳化重合法により作製した平均粒径が約１０μｍのブルーの液晶マイクロカプセル（液晶材料：メルクジャパン社製ＴＣ−４３６８ＸＸ、色素材料：オージー社製ＳＩ−４９７＋日本感光色素社製Ｇ−２３９、外壁のポリマー材料：ジビニルベンゼン）の表面に、２，６−ジメチル−４−（２´´−ニトロフェニル）−１，４−ジヒドロピリジン−３，５−ジカルボン酸ジメチルエステルを１重量％含有するポリアクリル酸エステル層を形成した。
【０１５２】
この液晶マイクロカプセルを表面に透明電極としてＩＴＯ層を有するガラス基板に塗布し、超高圧水銀灯を光源とする露光機を用いて３６５ｎｍの波長の紫外線を２００ｍＪ／ｃｍ² のエネルギーで照射した。このとき、露光部分の液晶マイクロカプセルのみが基板に吸着した。次いで、この基板を水に浸して超音波洗浄を行って、露光部にのみ液晶マイクロカプセル層が残存するパターンを得た。
【０１５３】
次いで、レッド、グリーンに着色した液晶マイクロカプセルについて上記と同様の工程を施し、図１１（Ｂ）に示すようなレッド、グリーン、ブルーのデルタ配列のパターンを有する液晶マイクロカプセル層を形成した。
【０１５４】
さらに、液晶マイクロカプセル層上に透明電極付きガラス基板を積層して液晶表示装置を完成させた。この液晶表示装置の駆動電圧を測定したところ、１５Ｖであった。また、この液晶表示装置は、構造が簡単であり、白表示が明るく良好であり、色表示も鮮明であった。
【０１５５】
（実施例１５）
乳化重合法により作製した平均粒径が約１０μｍのブルーの液晶マイクロカプセル（液晶材料：メルクジャパン社製ＴＣ−４３６８ＸＸ）色素材料：オージー社製ＳＩ−４９７＋日本感光色素社製Ｇ−２３９、外壁のポリマー材料：ジビニルベンゼン）の表面に、直接２，６−ジメチル−４−（２´−ニトロフェニル）−１，４−ジヒドロピリジン−３，５−ジカルボン酸ジメチルエステルを吸着させ、紫外線照射エネルギーを５０ｍＪ／ｃｍ² とする以外は実施例１４と同様にして、図１１（Ｂ）に示すようなレッド、グリーン、ブルーのデルタ配列のパターンを有する液晶マイクロカプセル層を形成した。
【０１５６】
さらに、液晶マイクロカプセル層上に透明電極付きガラス基板を積層して液晶表示装置を完成させた。この液晶表示装置の駆動電圧を測定したところ、１５Ｖであった。また、この液晶表示装置の製造においては、実施例１６のものと比較して露光エネルギーを低減することができた。
【０１５７】
【発明の効果】
以上説明したように本発明の液晶表示装置は、それぞれの表面に電極を有し、前記電極が対向するようにして配置された一対の基板と、前記一対の基板間に挟持された調光層とを具備し、前記調光層が透明被膜中に液晶材料を含むマイクロカプセルを含有し、隣接する前記マイクロカプセルが密着している、または前記マイクロカプセルが多面体構造を有するので、明部の光透過率が高く、入射した光を有効に活用でき、かつ高いコントラストの表示が可能なものである。
【０１５８】
また、本発明の液晶表示装置の製造方法によれば、表面に電極を有する一対の基板の少なくとも一つの基板上に透明被膜中に液晶材料を含むマイクロカプセルからなる調光層を形成し、前記マイクロカプセル同士を融着させ、前記電極が対向するようにして前記一対の基板を配置して前記一対の基板間に調光層を挟持するので、上記液晶表示装置を効率よく得ることができる。
【図面の簡単な説明】
【図１】（Ａ）は本発明の液晶表示装置の液晶マイクロカプセル層の一例を示す模式平面図、（Ｂ）は（Ａ）に示す液晶マイクロカプセル層を示す模式断面図。
【図２】（Ａ）は従来の液晶マイクロカプセル層の一例を示す模式平面図、（Ｂ）は （Ａ）に示す液晶マイクロカプセル層を示す模式断面図。
【図３】（Ａ）は本発明の液晶表示装置における液晶マイクロカプセル中の液晶分子の配向を示す概略図、（Ｂ）は湾曲した界面を有する液晶マイクロカプセル中の液晶分子の配向を示す概略図。
【図４】（Ａ）は本発明の液晶表示装置の実施例１における液晶マイクロカプセル層を示す模式平面図、（Ｂ）は（Ａ）に示す液晶マイクロカプセル層を示す模式断面図。
【図５】（Ａ）は比較例１における液晶層を示す模式平面図、（Ｂ）は（Ａ）に示す液晶層を示す模式断面図。
【図６】（Ａ）は比較例２における液晶層を示す模式平面図、（Ｂ）は（Ａ）に示す液晶層を示す模式断面図。
【図７】（Ａ）は本発明の液晶表示装置の実施例２における液晶マイクロカプセル層を示す模式平面図、（Ｂ）は（Ａ）に示す液晶マイクロカプセル層を示す模式断面図。
【図８】（Ａ）は本発明の実施例１１の液晶表示装置を示す概略図、（Ｂ）は（Ａ）に示す液晶表示装置の断面図。
【図９】（Ａ）〜（Ｈ）は本発明の液晶表示装置の実施例１１における電位構成図。
【図１０】本発明の液晶表示装置の実施例１６における液晶マイクロカプセルを示す概略図。
【図１１】（Ａ）は液晶表示装置の実施例１６における液晶マイクロカプセル層を示す断面図、（Ｂ）は液晶表示装置の実施例１６における液晶マイクロカプセル層の配置を示す平面図。
【符号の説明】
１…透明被膜、２…液晶マイクロカプセル、３，１１，２７…ガラス基板、４…液晶分子、５…隙間、１２…ＴＦＴ、１３…反射板（画素電極）、１４ａ…イエロー液晶層、１４ｂ…マゼンタ液晶層、１４ｃ…シアン液晶層、１５…透明電極、１６…対向電極、２１…液晶分子、２２…二色性色素、２３…ポリマー層、２４…露光粘着性発現体層、２５…液晶マイクロカプセル層、２６…透明電極。[0001]
BACKGROUND OF THE INVENTION
  The present invention provides a liquid crystal displayAbout equipment.
[0002]
[Prior art]
Many liquid crystal display devices have been proposed as display elements for display of information equipment. At present, nematic liquid crystals such as a TN (twisted nematic) mode disclosed in, for example, JP-A-47-11737 and an STN (super twisted nematic) mode disclosed in, for example, JP-A-60-107020 are used. The type of liquid crystal display device used is widely used. The TN mode and STN mode assume an initial state of a structure in which the alignment of liquid crystal molecules is twisted around 90 ° or around 260 ° inside the device. Light incident on the element is emitted in a state where the polarization state is changed by the twisted structure and birefringence that the liquid crystal molecules take.
[0003]
When an electric field is applied to a liquid crystal cell including a liquid crystal layer having such a liquid crystal molecular alignment structure, the liquid crystal molecules are rearranged in the electrolysis direction so that the twisted structure is released, birefringence is lost, and the incident light is polarized. The light is emitted without changing. By utilizing this principle and adopting a structure in which the liquid crystal cell is sandwiched between two linear polarizers, the optical properties of the liquid crystal layer change due to voltage application, and this is observed as a change in light intensity. The liquid crystal display devices in the TN mode and the STN mode obtain bright and dark contrasts in this way.
[0004]
The liquid crystal display device of the above-described display method has an advantage that it consumes significantly less power than a CRT (cathode ray tube) display and can realize a thin display panel, and is widely used in OA information devices such as personal computers and word processors. ing.
[0005]
However, it is difficult to say that the type using a polarizer effectively uses incident light. Actually, in many displays, a light source (backlight) is provided behind the liquid crystal display device to ensure brightness. Further, in the type with the color filter attached, the light transmitted through the element is further reduced, and as a result, a more powerful light source is required. Since the power of the light source is comparable to the power consumption of the liquid crystal display device including the drive circuit, the liquid crystal display device with such a large power consumption is not suitable for a portable display that supplies power with a battery. In other words, not only liquid crystal color displays but also black and white displays, the conventional display system has a contradictory relationship between brighter and lower power consumption, and a bright display system that does not require a backlight. The development of is eagerly desired.
[0006]
Also, with respect to eye fatigue when the display is continued to be viewed, a backlight of a fluorescent lamp is not desirable, and a reflective bright display is required. In addition, such a bright display method that does not require a backlight contributes to a reduction in size, long life, and power saving of the entire device even when used as a projection display.
[0007]
In response to such a demand, a liquid crystal display device that does not use a polarizer has been proposed. Examples of such a device include a White-Taylor type guest / host device (J. Appl. Phys. Vol. 45, pp 4718-4723, 1974). This guest / host element uses a liquid crystal material in which a dichroic dye is mixed in a liquid crystal exhibiting a chiral nematic phase, and the liquid crystal molecules and the dichroic dye molecules are arranged substantially parallel to the substrate surface. Has a structured. In this guest / host element, the arrangement of liquid crystal molecules is changed by applying an electric field, and the light transmittance is changed by changing the direction of the dichroic dye molecules. In this case, since the liquid crystal molecules have a twisted structure due to the chiral nematic phase, light absorption by the dye occurs efficiently. Therefore, in this element, in principle, a high display contrast can be obtained without a polarizer.
[0008]
However, in order to achieve high contrast in this guest / host device, it is necessary to set the spiral pitch of the chiral nematic liquid crystal to the wavelength order of light, and if the spiral pitch is shortened to that extent, many disclination lines are generated. However, the display quality is deteriorated, and at the same time, a hysteresis phenomenon appears and the response to the electric field is extremely slow. Therefore, when compared with the TN mode and the STN mode, the practicality is poor.
[0009]
As another display method that does not use a polarizer, for example, there is a display method called PDLC (polymer dispersed liquid crystal) disclosed in Japanese Patent Application Laid-Open No. 58-501631. This display method is a method in which nematic liquid crystal having positive dielectric anisotropy is dispersed in a polymer matrix in the form of particles having a diameter of about several μm. In this PDLC, a liquid crystal material having a refractive index for ordinary light that is substantially the same as that of the polymer matrix and a refractive index for extraordinary light different from that of the polymer matrix is selected and used.
[0010]
In this display system, in the initial state, the liquid crystal molecules have an array structure in which the liquid crystal molecules are distorted, and the refractive index is between the liquid crystal particles and the polymer matrix due to variations in the alignment direction between the liquid crystal particles. Resulting in light scattering like ground glass. When a sufficient voltage is applied to this, the liquid crystal molecules in the liquid crystal grains are rearranged, and the refractive indexes of the liquid crystal and the polymer matrix become equal to the perpendicularly incident light. As a result, refraction and reflection at the interface between the liquid crystal and the polymer matrix disappear, and the state changes to a transparent state. In addition, incident light does not need to be linear light.
[0011]
Since this PDLC displays using such an operating principle, a polarizer is unnecessary, incident light can be used effectively, and a bright display can be obtained. However, in order to achieve a sufficient display contrast, the thickness of the element needs to be about several tens of μm, and as a result, the drive voltage becomes several tens of volts. Moreover, since it is a scattering type, it is effective for a projection display, but is not suitable for a direct-view display for OA equipment or the like.
[0012]
Reflective displays in which a dichroic dye is mixed in a nematic liquid crystal and the structure of the reflector or liquid crystal material is improved have been proposed in Japanese Patent Laid-Open Nos. 59-178429 and 59-178428. The requirements for direct-view displays for OA equipment are not fully satisfied.
[0013]
[Problems to be solved by the invention]
  The present invention has been made in view of such a point, and an object thereof is to provide a liquid crystal display device suitable for a direct-view information display for OA equipment. That is, the light transmittance of the bright part is high, the incident light can be used effectively, and a high contrast display is possible.Provide liquid crystal displayThe purpose is to do.
[0014]
[Means for Solving the Problems]
  The present invention comprises a substrate having an electrode on the surface and a light control layer provided on the substrate, the light control layer containing microcapsules containing a liquid crystal material in a transparent film,IndividualMicro capsulesSurrounded by multiple planesThere is provided a liquid crystal display device having a polyhedral structure and having an upper surface and a lower surface of the polyhedral structure substantially parallel to a substrate surface.
[0016]
In the present invention, the liquid crystal molecules of the liquid crystal material are arranged substantially parallel to the substrate surface, and are arranged in parallel and the microcapsules are laminated in a plurality of layers, and many of the liquid crystal molecules in the same layer are in the same direction. It is preferable that they are arranged substantially perpendicularly to the substrate surface. The liquid crystal material preferably contains a dichroic dye. Furthermore, in the present invention, the orientation of liquid crystal molecules in each microcapsule is preferably different from each other, and it is preferable that there are at least two kinds of materials for the transparent film constituting the microcapsule.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
The liquid crystal display device of the present invention is characterized in that a light control layer provided on a substrate having electrodes comprises microcapsules containing a liquid crystal material in a transparent film, and adjacent microcapsules are in close contact with each other. In this case, the liquid crystal display device has an electrode on each surface, and includes a pair of substrates disposed so that the electrodes face each other, and a light control layer sandwiched between the pair of substrates But it ’s okay. In addition, the microcapsule has a polyhedral structure. That is, as shown in FIG. 1A, the liquid crystal display device of the present invention has a light control layer having a structure in which liquid crystal microcapsules 2 including a liquid crystal material are placed in close contact with each other in a transparent film 1. It comprises. Further, the microcapsule has a polyhedral structure (in FIG. 1A, a hexahedral structure).
[0021]
By having such a structure, the liquid crystal microcapsules 2 can be gathered very densely, and a region in which light can be controlled with voltage per unit area can be increased. Further, the amount of the polymer material constituting the transparent film can be extremely reduced.
[0022]
Further, as shown in FIG. 1B, by adopting a planar structure in which the liquid crystal microcapsules are arranged substantially parallel to the substrate, the orientation of the liquid crystal molecules 4 is aligned with the substrate 3 as shown in FIG. Can be oriented substantially parallel to the surface of the substrate. For this reason, the difference in refractive index between the voltage applied state and the unapplied state can be made extremely large. As a result, light scattering can be enhanced and the contrast can be increased.
[0023]
On the other hand, a normal liquid crystal microcapsule having a curved surface has a gap 5 between the liquid crystal microcapsules as shown in FIGS. 2A and 2B, and a transparent film is formed between the liquid crystal microcapsules. This is disadvantageous from the viewpoint of contrast because the polymer material to be formed is considerably present and light scattering is weakened. In the so-called polymer-liquid crystal composite structure, the amount of the polymer material can be extremely reduced, but the initial alignment of the liquid crystal molecules is random and it is very difficult to align the alignment.
[0024]
Usually, in what is called a polymer-dispersed liquid crystal or a polymer-liquid crystal composite having a curved polymer-liquid crystal interface, the liquid crystal molecules are aligned along the curved surface. Therefore, the difference between the ordinary light refractive index and the extraordinary light refractive index of the liquid crystal cannot be increased as in a normal TN cell or STN cell. That is, when a nematic liquid crystal having a positive dielectric anisotropy is erected by applying a voltage, the ordinary refractive index is obtained. However, in the case of having a curved polymer-liquid crystal interface, as shown in FIG. The liquid crystal molecules are aligned along the curved interface when no voltage is applied, so that the refractive index is intermediate between the ordinary light refractive index and the extraordinary light refractive index. For this reason, contrast is poor and light leakage occurs.
[0025]
As shown in FIG. 1B, in the case where the liquid crystal microcapsule has a planar structure (including a laminated structure) in which the liquid crystal microcapsules are arranged substantially parallel to the substrate, a long chain alkyl group is used as a material constituting the transparent film in contact with the liquid crystal molecules. Etc., the alignment of the liquid crystal molecules can be made substantially perpendicular to the substrate surface. In addition, a liquid crystal material having a negative dielectric anisotropy is used as the liquid crystal material, and the liquid crystal molecules are aligned substantially perpendicular to the substrate surface as described above, thereby displaying a colorless positive display when no voltage is applied. be able to.
[0026]
Note that when the cell gap of the liquid crystal display device is too large, the driving voltage increases. On the other hand, when the cell gap is too small, the contrast is lowered. Therefore, in order to lower the driving voltage and increase the contrast, the cell gap is preferably 5 to 10 μm.
[0027]
If the particle size of the liquid crystal microcapsules is too small, light scattering increases and display characteristics deteriorate. On the other hand, if the particle size is too large, the strength of the microcapsule itself is undesirably lowered. Therefore, in order to reduce light scattering and increase strength, the particle size of the liquid crystal microcapsules is preferably 2 to 10 μm.
[0028]
If the thickness of the liquid crystal microcapsule wall is too thick, the ratio of liquid crystal and dye will be low, and the contrast will be low. On the other hand, if the thickness of the liquid crystal microcapsule wall is too thin, the mechanical strength is lowered. Therefore, in order to increase the contrast and mechanical strength, the thickness of the liquid crystal microcapsule wall is preferably 2 to 20%, particularly 5 to 20%, of the radius of the microcapsule grains.
[0029]
The present invention is particularly effective in a guest-host type liquid crystal display device using a liquid crystal material containing a dichroic dye. That is, the dichroic dye is generally difficult to dissolve in the liquid crystal material. In particular, the dichroic dye is difficult to dissolve in a fluorine-based liquid crystal material having excellent voltage holding characteristics. Since the dichroic dye has the property of being dissolved in the polymer material, the amount of the polymer material constituting the transparent film can be extremely reduced, and the amount of the dichroic dye in the liquid crystal material can be relatively increased. it can. Therefore, the structure of the liquid crystal display device of the present invention is extremely effective.
[0030]
Further, the dichroic dye can absorb light only with respect to the molecular axis. By arranging the dichroic dye substantially parallel to the substrate, the amount of light absorption can be maximized. In the liquid crystal display device of the present invention, as described above, the liquid crystal molecules can be arranged substantially parallel to the substrate surface, and the dichroic dye is also arranged substantially parallel to the substrate according to the orientation of the liquid crystal molecules. The amount of light absorption can be maximized.
[0031]
In the liquid crystal display device of the present invention, a plurality of liquid crystal microcapsules including a liquid crystal material included in a transparent film are stacked, and the orientations of liquid crystal molecules in the liquid crystal microcapsules that are in contact with each other are different from each other. it can. By doing so, light scattering can be enhanced, and in particular, when a dichroic dye is contained in the liquid crystal material, it is possible to absorb light of different polarization components. Therefore, a high contrast can be obtained without using a polarizing plate, which is suitable for a reflective display.
[0032]
In the liquid crystal display device of the present invention, the transparent film may be composed of two or more kinds of transparent polymer materials. In order to reduce the driving voltage of the liquid crystal material, it is necessary that the interaction between the polymer material constituting the transparent film in contact with the liquid crystal material and the liquid crystal material is not so large. On the other hand, the transparent film is required to have various properties such as heat resistance, solvent resistance, and a suitable refractive index. It is generally difficult to satisfy all of these requirements with only a transparent film made of one polymer material. As described above, these problems can be solved by configuring the transparent film with two or more transparent polymer materials.
[0033]
In the liquid crystal display device of the present invention, the thickness of the transparent film is preferably 30% or less of the thickness in the vertical direction of the liquid crystal material region included in the transparent film. The thickness of the transparent film is preferably thin, and if it is 30% or less of the thickness in the vertical direction of the included liquid crystal material region, it is acceptable in display performance. On the other hand, if the thickness is too thin, the mechanical and thermal resistance becomes weak, which is not preferable. Therefore, it is preferably 5% to 15% of the thickness of the included liquid crystal material region in the vertical direction.
[0034]
The light control layer of the liquid crystal display device of the present invention may be composed of a single layer of liquid crystal microcapsules or a plurality of layers. In the case of a single layer structure, the fusion condition of the liquid crystal microcapsules However, since the liquid crystal microcapsule may be damaged, it is preferable to have a laminated structure including a plurality of layers.
[0035]
In the liquid crystal display device of the present invention, a thin polymer layer may be formed between the light control layer containing the microcapsules and the electrode. This polymer layer can planarize the light control layer and can be used as a protective film, a moisture prevention film, or an ultraviolet ray prevention film during electrode formation.
[0036]
In the method for producing a liquid crystal display device of the present invention, a light control layer comprising microcapsules containing a liquid crystal material in a transparent film is formed on at least one of a pair of substrates having electrodes on the surface, and the microcapsules are fused. And a light control layer is sandwiched between a pair of substrates.
[0037]
By fusing the liquid crystal microcapsules in this way, the transparent film of the liquid crystal microcapsules is drawn to fill the gaps between the liquid crystal microcapsules. The transparent coating also extends to maintain the volume of the internal liquid crystal material. Therefore, the transparent coating is stretched in a direction parallel to the substrate surface (in-plane direction). In this way, the liquid crystal microcapsules have a layered structure. At this time, the liquid crystal molecules inside are aligned in the extending direction of the transparent film (direction parallel to the substrate surface), and the liquid crystal molecules in the liquid crystal microcapsules overlapped in layers are aligned in the extending direction. .
[0038]
The fusion of the liquid crystal microcapsules naturally occurs due to the self-fusion of the polymers constituting the capsule wall by evaporating the dispersion medium after applying the microcapsule dispersion onto the substrate. At that time, the fusion direction (stretching direction) between the microcapsules can be defined in one direction by changing the evaporation time of the dispersion medium on the substrate. An example of such a method is a dipping method in which the substrate is slowly pulled up from the microcapsule dispersion. Therefore, by changing the pulling direction of the substrate and performing dipping a plurality of times, the axial direction of the parallel aligned liquid crystal molecules can be changed between the microcapsule layers. This is suitable for a guest-host type liquid crystal display device that does not use a polarizing plate.
[0039]
When fusing liquid crystal microcapsules, the stretching action can be further increased by applying pressure in the direction perpendicular to the substrate surface (cell thickness direction), and parallel to the substrate surface. The area of the transparent coating surface in any direction increases. Moreover, a transparent film can be extended | stretched to a stress direction by melt | fusing it, applying a shift stress in the horizontal direction to a board | substrate. Therefore, the liquid crystal molecules in the liquid crystal microcapsule are also aligned in the stretching direction.
[0040]
Further, after the liquid crystal microcapsule is fused, the structure of the light control layer after the fusion can be more stably maintained by curing the transparent film by a heat treatment or a curing treatment using a reagent.
[0041]
In the method of the present invention, the transparent film of the liquid crystal microcapsule has a two-layer structure composed of an inner layer made of a material having a softening temperature and an outer layer made of a material having a softening temperature lower than that of the inner layer material. When fused at the softening temperature, only the outer layer softens and fuses together. In this case, since the polyhedral liquid crystal microcapsules are fused, the area of the transparent film tends to increase if the internal volume is constant. Therefore, the inner layer is stretched without melting. Thus, by making a transparent film into a multilayer structure (two-layer structure), it can fuse | melt at lower temperature.
[0042]
Liquid crystal microcapsules comprising a liquid crystal material with a transparent coating include microcapsules such as phase separation method, submerged drying method, interfacial polymerization method, in situ polymerization method, submerged cured film method, and spray drying method. The chemical method can be adopted.
[0043]
Examples of the polymer material constituting the transparent film include polyethylenes; ethylene copolymers such as chlorinated polyethylenes, ethylene-vinyl acetate copolymers, ethylene / acrylic acid / maleic anhydride copolymers; polybutadienes; Polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polypropylenes; polyisobutylenes; polyvinyl chlorides; natural rubbers; polyvinylidene chlorides; polyvinyl acetates; polyvinyl alcohols; Butyrals: ethylene tetrafluoride resin, ethylene trifluoride resin, ethylene fluoride / propylene resin, vinylidene fluoride resin, vinyl fluoride resin, tetrafluoroethylene / perfluoroalkoxyethylene copolymer, tetrafluoroethylene Fluoropolymers such as perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene / hexafluoropropylene copolymers, tetrafluoroethylene copolymers such as tetrafluoroethylene / ethylene copolymers, and fluorine-containing polybenzoxazoles Acrylic resins; methacrylic resins; acrylonitrile copolymers such as polyacrylonitrile, acrylonitrile / butadiene / styrene copolymers; polystyrene; styrene / acrylonitrile copolymers; acetal resins; polyamides such as nylon 66; polycarbonates; Polyester carbonates; Cellulose resins; Phenol resins; Urea resins; Epoxy resins; Unsaturated polyester resins; Alkyd resins; Melamine resins; Polyphenylene sulfides; Polysulfones; Polyphenylsulfones; Silicone resins; Polyimides; Bismaleimide triazine resins; Polyimide amides; Polyetherimides; Polyvinylcarbazoles; Norbornene amorphous polyolefins; Almost all polymer materials such as celluloses can be used.
[0044]
Further, if the glass transition temperature (Tg) of these polymer materials is too low, the microcapsules become unstable near room temperature, and the display characteristics deteriorate. On the other hand, if the glass transition temperature is too high, the temperature at which the microcapsules are fused becomes high, and the liquid crystal molecules and dye molecules inside are denatured or sublimated, which is not preferable. Therefore, the glass transition temperature is preferably 60 to 170 ° C. so that the microcapsules have sufficient strength near room temperature and do not affect the liquid crystal molecules and the dye molecules when the microcapsules are fused.
[0045]
As the liquid crystal material that can be used in the present invention, any liquid crystal material may be used as long as it has refractive index anisotropy and its orientation changes with voltage, but preferably nematic liquid crystal, cholesteric liquid crystal, etc. Is mentioned. In addition, when light scattering transparency is switched by voltage to cause transparency-white turbidity change, it is necessary to select the liquid crystal material so that the refractive index of the transparent film matches the refractive index when the liquid crystal material is transparent (ON). There is.
[0046]
Specifically, examples of the liquid crystal material used in the present invention include fluorine-based liquid crystal, cyano-based liquid crystal, and ester-based liquid crystal. Examples thereof include various liquid crystal compounds represented by the following structural formulas (1) to (10) and a mixed composition thereof.
[0047]
[Chemical 1]

[0048]
[Chemical formula 2]

[0049]
[Chemical Formula 3]

[0050]
[Formula 4]

[0051]
[Chemical formula 5]

[0052]
[Chemical 6]

[0053]
[Chemical 7]

[0054]
[Chemical 8]

[0055]
[Chemical 9]

[0056]
[Chemical Formula 10]

[0057]
Wherein R ′ and X are each independently an alkyl group, an alkoxy group, an alkylphenyl group, an alkoxyalkylphenyl group, an alkoxyphenyl group, an alkylcyclohexyl group, an alkoxyalkylcyclohexyl group, an alkylcyclohexylphenyl group, a cyanophenyl group, Cyano group, halogen atom, fluoromethyl group, fluoromethoxy group, alkylphenylalkyl group, alkoxyalkylphenylalkyl group, alkoxyalkylcyclohexylalkyl group, alkylcyclohexylalkyl group, alkoxyalkoxycyclohexylalkyl group, alkoxyphenylalkyl group, alkylcyclohexylphenyl Represents an alkyl group, Y represents a hydrogen atom or a halogen atom, and is optically active in these alkyl and alkoxy chains. In addition, the phenyl group or phenoxy group in R ′ and X may be substituted with a halogen atom such as a fluorine atom or a chlorine atom, and one phenyl group in each formula or (It may be substituted with two halogen atoms such as fluorine atom and chlorine atom.)
All of the liquid crystal compounds in the formula have a positive dielectric anisotropy, but a known liquid crystal compound having a negative dielectric anisotropy is mixed with a liquid crystal compound having a positive dielectric anisotropy to form a positive liquid crystal compound as a whole. Can be used. Even a liquid crystal compound having a negative dielectric anisotropy can be used as it is by using an appropriate element configuration and driving method.
[0058]
In the liquid crystal display device of the present invention, a dichroic dye may be used as one of the constituent elements of the liquid crystal material for the purpose of improving the contrast and for the purpose of colorization. In that case, it is necessary to use a dichroic dye that is compatible with a liquid crystal compound and that does not dissolve or adsorb so much in the polymer material constituting the transparent film. When a dichroic dye is contained, it is necessary to select a polymer material and a liquid crystal material constituting the transparent film in consideration of the refractive index according to the purpose. That is, when increasing the contrast using light scattering, it is desirable to select a liquid crystal material having a large refractive index anisotropy. However, in this case, there is a drawback that the color of the reflected light becomes whitish. On the other hand, when the refractive index anisotropy is small and close to the refractive index of the low molecular weight compound, the original color of the dichroic dye can be obtained. As the dichroic dye molecule, for example, a yellow dye represented by formulas (11) to (19), a magenta dye represented by formulas (20) to (27), and a cyan dye represented by formulas (28) to (31) are used. Can do.
[0059]
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[0060]
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[0061]
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[0062]
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[0063]
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[0064]
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[0065]
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[0066]
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Furthermore, in the liquid crystal display device of the present invention, a fluorescent dye may be used as one of the components of the liquid crystal material for whitening of reflected light or as an ultraviolet absorber. In that case, the fluorescent dye is preferably dissolved in the transparent film and not so much dissolved in the liquid crystal material.
[0067]
In the present invention, when a dichroic dye is used, the weight ratio with respect to the liquid crystal material is preferably 0.01 to 10%, preferably 0.1 to 5%. If the weight ratio is too low, the contrast is not sufficiently improved. If the weight ratio is too high, coloring remains even when a voltage is applied, and the contrast is also lowered.
[0068]
In the liquid crystal display device of the present invention, at least one of the pair of substrates needs to be a transparent substrate. As the transparent substrate, a glass substrate, a transparent plastic substrate, a transparent plastic film, or the like can be used. As the non-transparent substrate, an opaque substrate such as a substrate having an aluminum reflective electrode, or a semitransparent substrate can be used.
[0069]
Next, examples performed for clarifying the effects of the present invention will be described.
[0070]
(referenceExample 1)
80 parts by weight of nematic liquid crystal ZLI-1840 (trade name, manufactured by Merck & Co.) having positive dielectric anisotropy, 15 parts by weight of methyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent, 0.2 part by weight of benzoyl peroxide And mixed with 3 parts by weight of the nonionic surfactant Emulgen 120 (trade name, manufactured by Kao Corporation) and 300 parts by weight of pure water, followed by emulsification with a homogenizer. Polymerized for hours.
[0071]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 2 to 4 μm were obtained which included the liquid crystal composition in a transparent film.
[0072]
Next, the liquid crystal microcapsules are dispersed in 10% by weight in 10% isopropyl alcohol water, and this is applied to a glass substrate surface provided with a transparent electrode in advance using an applicator and dried to obtain a liquid crystal microcapsule layer (light control). Layer). Further, a polymer film provided with a transparent electrode in advance was laminated on the liquid crystal microcapsule layer. Thus, the liquid crystal display device of the present invention was produced.
[0073]
  The obtained liquid crystal display device was observed with a microscope. The result is shown in FIG. FIG. 4A shows a structural schematic diagram viewed from a direction perpendicular to the substrate surface, and FIG. 4B shows the substrate surface.HorizontalThe structural schematic diagram seen from various directions is shown. As can be seen from FIGS. 4A and 4B, the liquid crystal microcapsules are fused to each other and have a polyhedral structure in which the fused portions are straight. The orientation of the liquid crystal molecules was almost parallel to the substrate surface, and the orientation direction was a constant axial direction (uniaxial orientation) in the microcapsules, but the axial direction was random between the microcapsules. The thickness of the liquid crystal microcapsule layer (light control layer) was 10 μm. This liquid crystal display device was white and opaque, and became transparent when an AC voltage of 10 V was applied at 50 Hz. The contrast ratio obtained from the transmission absorbance was 22.
[0074]
(Comparative Example 1)
80 parts by weight of nematic liquid crystal ZLI-1840 having a positive dielectric anisotropy and 15 parts by weight of polymethyl methacrylate are dissolved in chloroform, applied to a glass substrate surface provided with a transparent electrode in advance, and dried to prepare a liquid crystal layer (adjustment). Light layer) was formed. Next, a polymer film provided with a transparent electrode in advance was laminated on the liquid crystal layer. In this manner, a liquid crystal display device of a comparative example was produced.
[0075]
The obtained liquid crystal display device was observed with a microscope. The result is shown in FIG. FIG. 5A shows a structural schematic diagram viewed from a direction perpendicular to the substrate surface, and FIG. 5B shows a structural schematic diagram viewed from a direction parallel to the substrate surface. As can be seen from FIGS. 5A and 5B, the size of each liquid crystal domain was various, and the liquid crystal domain had a curved interface. The thickness of the liquid crystal layer (light control layer) was 10 μm. This liquid crystal display device was opaque white and became transparent when an AC voltage of 12 V was applied at 50 Hz. The contrast ratio determined from the transmission absorbance was 14.
[0076]
(Comparative Example 2)
A nematic liquid crystal ZLI-1840 having positive dielectric anisotropy, 80 parts by weight, 15 parts by weight of methyl methacrylate monomer, and 1 part by weight of divinylbenzene as a cross-linking agent are mixed and dissolved in a liquid crystal cell assembled in advance with a cell gap of 10 μm. Injected. Next, the liquid crystal composition was cured by irradiating the liquid crystal cell with ultraviolet rays having a wavelength of 254 nm.
[0077]
The obtained liquid crystal display device was observed with a microscope. The result is shown in FIG. FIG. 6A shows a structural schematic diagram viewed from a direction perpendicular to the substrate surface, and FIG. 6B shows a structural schematic diagram viewed from a direction perpendicular to the substrate surface. As can be seen from FIGS. 6A and 6B, each liquid crystal domain had a network structure. Further, the alignment of the liquid crystal molecules was random. This liquid crystal display device was opaque white and became transparent when an AC voltage of 11 V was applied at 50 Hz. The contrast ratio obtained from the transmission absorbance was 17.
[0078]
(Example 1)
  80 parts by weight of nematic liquid crystal ZLI-1840 having positive dielectric anisotropy, 15 parts by weight of methyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent and 0.2 part by weight of benzoyl peroxide are mixed and dissolved. After emulsifying the nonionic surfactant Emulgen 120 with 3 parts by weight and 300 parts by weight of pure water with a homogenizer, the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0079]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 4 to 6 [mu] m including the liquid crystal composition in a transparent film were obtained.
[0080]
Next, the liquid crystal microcapsules were dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with a transparent electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). . Further, a glass substrate provided with a transparent electrode in advance was overlaid on the liquid crystal microcapsule layer. Next, this was put in a polyamide bag, the inside of the bag was depressurized, and in this state, a heat treatment at 120 ° C. was performed to heat and adhere the glass substrate. Thus, the liquid crystal display device of the present invention was produced.
[0081]
The obtained liquid crystal display device was observed with a microscope. The result is shown in FIG. FIG. 7A shows a structural schematic diagram viewed from a direction perpendicular to the substrate surface, and FIG.HorizontalThe structural schematic diagram seen from various directions is shown. As can be seen from FIGS. 7A and 7B, the liquid crystal microcapsules are fused to each other and have a polyhedral structure in which the fused portions are straight. Further, the liquid crystal microcapsules were in a state of being stretched in the horizontal direction (direction parallel to the substrate surface), and the fused portion was a straight line substantially parallel to the substrate surface. The alignment of the liquid crystal molecules was almost parallel to the substrate, and the order parameter was higher than that in Example 1. The thickness of the liquid crystal microcapsule layer (light control layer) was 8 μm. This liquid crystal display device was white and opaque, and became transparent when an AC voltage of 9.5 V was applied at 50 Hz. The contrast ratio obtained from the transmission absorbance was 25.
[0082]
(Reference example 2)
  80 parts by weight of black dichroic dye S-435 (trade name, manufactured by Mitsui Toatsu Co., Ltd.) dissolved in liquid crystal ZLI-1695 (trade name, manufactured by Merck & Co., Ltd.) at 1% by weight, 2, 2, 3 , 3-tetrafluoropropyl methacrylate monomer 15 parts by weight, divinylbenzene 1 part by weight as a crosslinking agent, benzoyl peroxide 0.2 part by weight are mixed and dissolved, together with 3 parts by weight of polyvinyl alcohol and 300 parts by weight of pure water After emulsifying with a homogenizer, the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0083]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 4 to 6 [mu] m including the liquid crystal composition in a transparent film were obtained.
[0084]
Next, the liquid crystal microcapsules are dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with an aluminum reflective electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). did. Further, a polymer film provided with a transparent electrode in advance was laminated on the liquid crystal microcapsule layer. Thus, the liquid crystal display device of the present invention was produced.
[0085]
  The obtained liquid crystal display device was observed with a microscope. As a result, the structure of the liquid crystal microcapsule layer (light control layer) isReference example1 (FIGS. 4A and 4B). The thickness of the liquid crystal microcapsule layer (light control layer) was 11 μm. This liquid crystal display device was black and became colorless when an AC voltage of 13 V was applied at 50 Hz. The contrast ratio measured with a reflection densitometer was 3.5.
[0086]
(Comparative Example 3)
80 parts by weight of black dichroic dye S-435 dissolved in liquid crystal ZLI-1695 at 1% by weight and 15 parts by weight of poly (2,2,3,3-tetrafluoropropyl methacrylate) are dissolved in chloroform. Then, it was applied to a glass substrate provided with an aluminum reflective electrode in advance, dried, and dried to form a liquid crystal layer (light control layer). Next, a polymer film provided with a transparent electrode in advance was laminated on the liquid crystal layer, and this was pressed and adhered at 120 ° C. In this manner, a liquid crystal display device of a comparative example was produced.
[0087]
The obtained liquid crystal display device was observed with a microscope. As a result, the structure of the liquid crystal microcapsule layer (light control layer) was the same as that in Comparative Example 1 (FIGS. 5A and 5B). The thickness of the liquid crystal layer (light control layer) was 11 μm. This liquid crystal display device was black and became colorless when an AC voltage of 14 V was applied at 50 Hz. The contrast ratio measured by a reflection densitometer was 2.7.
[0088]
(Example 2)
  80 parts by weight of black dichroic dye S-435 dissolved in liquid crystal ZLI-1695 at 1% by weight, 15 parts by weight of 2,2,3,3-tetrafluoropropyl methacrylate monomer, divinylbenzene 1 as a crosslinking agent Part by weight and 0.2 part by weight of benzoyl peroxide are mixed and dissolved, and after emulsification with 3 parts by weight of a surfactant and 300 parts by weight of pure water with a homogenizer, the liquid crystal composition is polymerized at 85 ° C. for 1 hour. did.
[0089]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 4 to 6 [mu] m including the liquid crystal composition in a transparent film were obtained.
[0090]
Next, the liquid crystal microcapsules are dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with an aluminum reflective electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). did. Further, a glass substrate provided with a transparent electrode in advance was overlaid on the liquid crystal microcapsule layer. Next, this was put in a polyamide bag, the inside of the bag was depressurized, and in this state, a heat treatment at 120 ° C. was performed to heat and adhere the glass substrate. Thus, the liquid crystal display device of the present invention was produced.
[0091]
  The obtained liquid crystal display device was observed with a microscope. As a result, the structure of the liquid crystal microcapsule layer (light control layer) isExample 1In the case of (Fig. 7 (A), Fig. 7 (B)), it is in a state of being stretched in the horizontal direction (direction parallel to the substrate surface). It was a parallel straight line (polyhedral structure). The thickness of the liquid crystal microcapsule layer (light control layer) was 8 μm. This liquid crystal display device was black and became colorless when an AC voltage of 8 V was applied at 50 Hz. The contrast ratio measured with a reflection densitometer was 4.5.
[0092]
(Example 3)
  80 parts by weight of nematic liquid crystal ZLI-2659 (trade name, manufactured by Merck & Co., Inc.) having negative dielectric anisotropy, 20 parts by weight of octadecyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent, 0.2 part by weight of benzoyl peroxide Were mixed and dissolved, and emulsified with a homogenizer together with 3 parts by weight of a surfactant and 300 parts by weight of pure water, and then the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0093]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 4 to 6 [mu] m including the liquid crystal composition in a transparent film were obtained.
[0094]
Next, the liquid crystal microcapsules were dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with a transparent electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). . Further, a glass substrate provided with a transparent electrode in advance was overlaid on the liquid crystal microcapsule layer. Subsequently, this was put into a bag made of polyamide, the inside of the bag was decompressed, and in this state, a heat treatment at 100 ° C. was performed to heat and adhere the glass substrate. Thus, the liquid crystal display device of the present invention was produced.
[0095]
  The obtained liquid crystal display device was observed with a microscope. as a result,Example 2Similarly, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. Further, the liquid crystal microcapsules were in a state of being stretched in the horizontal direction (direction parallel to the substrate surface), and the fused portion was a straight line substantially parallel to the substrate surface. The thickness of the liquid crystal microcapsule layer (light control layer) was 8 μm. The alignment of the liquid crystal molecules was almost perpendicular to the substrate surface. This liquid crystal display device was transparent and turned white when an AC voltage of 9 V was applied at 50 Hz. The contrast ratio obtained from the transmission absorbance was 25.
[0096]
(Example 4)
  80 parts by weight of black dichroic dye S-435 dissolved in liquid crystal ZLI-2659 having negative dielectric anisotropy at 1% by weight, 20 parts by weight of octadecyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent Then, 0.2 part by weight of benzoyl peroxide was mixed and dissolved. After emulsification with 3 parts by weight of a surfactant and 300 parts by weight of pure water with a homogenizer, the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0097]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 4 to 6 [mu] m including the liquid crystal composition in a transparent film were obtained.
[0098]
Next, the liquid crystal microcapsules were dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with a transparent electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). . Further, a glass substrate provided with an aluminum reflective electrode in advance was overlaid on the liquid crystal microcapsule layer. Subsequently, this was put into a bag made of polyamide, the inside of the bag was decompressed, and in this state, a heat treatment at 100 ° C. was performed to heat and adhere the glass substrate. Thus, the liquid crystal display device of the present invention was produced.
[0099]
  The obtained liquid crystal display device was observed with a microscope. as a result,Example 2Similarly, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. Further, the liquid crystal microcapsules were in a state of being stretched in the horizontal direction (direction parallel to the substrate surface), and the fused portion was a straight line substantially parallel to the substrate surface. The thickness of the liquid crystal microcapsule layer (light control layer) was 9 μm. The alignment of the liquid crystal molecules was almost perpendicular to the substrate surface. This liquid crystal display device was colorless and turned black when an AC voltage of 9.5 V was applied at 50 Hz. The contrast ratio measured with a reflection densitometer was 5.0.
[0100]
(Example 5)
  80 parts by weight of black dichroic dye S-435 dissolved in liquid crystal ZLI-1695 at 1% by weight, 15 parts by weight of methyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent, 0.2% by weight of benzoyl peroxide The components were mixed and dissolved, and emulsified with a homogenizer together with 3 parts by weight of a surfactant and 300 parts by weight of pure water, and then the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0101]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 4 to 6 [mu] m including the liquid crystal composition in a transparent film were obtained.
[0102]
Next, the liquid crystal microcapsules are dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with an aluminum reflective electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). did. Next, the liquid crystal microcapsule layer was slightly shifted in the horizontal direction while pressing a Teflon plate at 120 ° C. After cooling to room temperature, the Teflon plate was removed and a polymer film provided with a transparent electrode in advance was laminated. Thus, the liquid crystal display device of the present invention was produced.
[0103]
The obtained liquid crystal display device was observed with a microscope. As a result, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. Further, the liquid crystal microcapsules were in a state of being stretched in the horizontal direction (direction parallel to the substrate surface), and the fused portion was a straight line substantially parallel to the substrate surface. The thickness of the liquid crystal microcapsule layer (light control layer) was 8 μm. Further, the alignment direction of the liquid crystal molecules was substantially parallel to the substrate surface, and was a direction in which the Teflon plate was shifted. This liquid crystal display device was black and became colorless when an AC voltage of 8.8 V was applied at 50 Hz. The contrast ratio measured with a reflection densitometer was 4.6.
[0104]
(Example 6)
  80 parts by weight of black dichroic dye S-435 dissolved in liquid crystal ZLI-1695 at 1% by weight, 15 parts by weight of methyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent, 0.2% by weight of benzoyl peroxide The components were mixed and dissolved, and emulsified with a homogenizer together with 3 parts by weight of a surfactant and 300 parts by weight of pure water, and then the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0105]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 2 to 4 μm were obtained which included the liquid crystal composition in a transparent film.
[0106]
Next, the liquid crystal microcapsules were dispersed in 10% isopropyl alcohol water at 5% by weight, applied to a glass substrate surface provided with an aluminum reflective electrode in advance, and dried to form a first liquid crystal microcapsule layer. Next, the first liquid crystal microcapsule layer was slightly shifted in the horizontal direction while pressing a Teflon plate at 120 ° C. After cooling to room temperature, the Teflon plate was removed.
[0107]
In this state, the first liquid crystal microcapsule layer was observed with a microscope. As a result, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. Further, the liquid crystal microcapsules were in a state of being stretched in the horizontal direction (direction parallel to the substrate surface), and the fused portion was a straight line substantially parallel to the substrate surface. The thickness of the first liquid crystal microcapsule layer was 4 μm. Further, the alignment direction of the liquid crystal molecules was substantially parallel to the substrate surface, and was a direction in which the Teflon plate was shifted.
[0108]
Next, 80 parts by weight of a black dichroic dye S-435 dissolved in liquid crystal ZLI-1695 at 1% by weight, 15 parts by weight of a methyl acrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent, 0 of benzoyl peroxide 0 .2 parts by weight was mixed and dissolved, and emulsified with a homogenizer together with 3 parts by weight of a surfactant and 300 parts by weight of pure water, and then the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0109]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 2 to 4 μm were obtained which included the liquid crystal composition in a transparent film.
[0110]
Next, the liquid crystal microcapsules are dispersed in 10% isopropyl alcohol water at 5% by weight, applied onto the first liquid crystal microcapsule layer coated with methyl methacrylate and dried to form a second liquid crystal microcapsule layer. did. Next, the second liquid crystal microcapsule layer was slightly shifted in a direction substantially perpendicular to the shift direction while pressing a Teflon plate at 100 ° C. After cooling to room temperature, the Teflon plate was removed.
[0111]
In this state, the second liquid crystal microcapsule layer was observed with a microscope. As a result, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. Further, the liquid crystal microcapsules were in a state of being stretched in the horizontal direction (direction parallel to the substrate surface), and the fused portion was a straight line substantially parallel to the substrate surface. The thickness of the second liquid crystal microcapsule layer was 4 μm. Further, the alignment direction of the liquid crystal molecules was substantially parallel to the substrate surface, and was a direction in which the Teflon plate was shifted.
[0112]
  Next, a polymer film provided with a transparent electrode in advance was laminated on the second liquid crystal microcapsule layer. Thus, the liquid crystal display device of the present invention was produced. The liquid crystal display device was black and became colorless when an AC voltage of 8.6 V was applied at 50 Hz. The contrast ratio measured by a reflection densitometer was 5.3.
(Example 7)
  80 parts by weight of black dichroic dye S-435 dissolved in liquid crystal ZLI-1695 at 1% by weight, 15 parts by weight of fluorinated methacrylate monomer, and 0.2 parts by weight of benzoyl peroxide are mixed and dissolved. After emulsification with a homogenizer together with 3 parts by weight of a surfactant and 300 parts by weight of pure water, the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0113]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size, fine liquid crystal microcapsules were removed, and the resultant was washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 4 to 6 [mu] m including the liquid crystal composition in a transparent film were obtained. Next, this liquid crystal microcapsule and 8 parts by weight of epoxy prepolymer (Epicoat) were mixed and dropped into 200 parts by weight of a 5% by weight gelatin aqueous solution with stirring to form microdrops. Stirring was continued at about 40 ° C. for 1 hour while gradually dropping a solution obtained by dissolving 50 parts by weight of water into the gelatin aqueous solution.
[0114]
Next, this liquid crystal composition was filtered through a filter having a 1 μm square size, fine liquid crystal microcapsules were removed, and the resultant was washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 5 to 7 μm were obtained, including a liquid crystal composition with a transparent film having a two-layer structure of a fluorine-based methacrylate film and an epoxy resin film.
[0115]
Next, the liquid crystal microcapsules were dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with a transparent electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). . Next, a Teflon plate was pressed against the liquid crystal microcapsule layer and subjected to a heat treatment at 120 ° C. for 2 hours to heat and adhere the liquid crystal microcapsule layer to the glass substrate and to cure the epoxy resin. Thereafter, after cooling to room temperature, the Teflon plate was removed, and a polymer film provided with a transparent electrode in advance was laminated. Thus, the liquid crystal display device of the present invention was produced.
[0116]
The obtained liquid crystal display device was observed with a microscope. As a result, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. In addition, the liquid crystal microcapsules were stretched in the horizontal direction (direction parallel to the substrate surface). The thickness of the liquid crystal microcapsule layer (light control layer) was 8 μm. This liquid crystal display device was black and became colorless when an AC voltage of 8.4 V was applied at 50 Hz. The contrast ratio measured with a reflection densitometer was 4.3.
[0117]
(Example 8)
  80 parts by weight of black dichroic dye S-435 dissolved in liquid crystal ZLI-1695 at 1% by weight, 15 parts by weight of methyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent, 0.2% by weight of benzoyl peroxide The components were mixed and dissolved, emulsified with a homogenizer together with 3 parts by weight of polyvinyl alcohol and 300 parts by weight of pure water, and then the liquid crystal composition was polymerized at 85 ° C. for 1 hour. In this way, a liquid crystal microcapsule dispersion liquid having an outer diameter of 1 to 8 μm, which includes the liquid crystal composition in a transparent film, was obtained.
[0118]
Next, a glass substrate provided with an aluminum reflective electrode in advance was immersed in the liquid crystal microcapsule dispersion and slowly pulled up into the air at a pulling rate of 5 mm / min. The liquid adhering to the substrate was sequentially dried when pulled up (exposed to the air). The orientation of the liquid crystal molecules in the first liquid crystal microcapsule layer thus formed is substantially parallel to the substrate surface, and the liquid crystal molecules are almost aligned in a direction perpendicular to the substrate pulling direction. It was.
[0119]
Next, the substrate was immersed again in the liquid crystal microcapsule dispersion, the substrate was pulled up in the direction perpendicular to the pulling direction, and slowly pulled up into the air at a lifting speed of 5 mm / min. In this manner, the next second liquid crystal microcapsule was laminated on the first liquid crystal microcapsule layer formed in advance. The orientation of the liquid crystal molecules in the second liquid crystal microcapsule layer was substantially parallel to the substrate surface, and was orthogonal to the orientation of most of the liquid crystal molecules in the first liquid crystal microcapsule layer.
[0120]
Furthermore, a polymer film provided with a transparent electrode in advance was laminated on the second liquid crystal microcapsule layer. Thus, the liquid crystal display device of the present invention in which the thickness of the liquid crystal microcapsule layer (light control layer) was 10 μm was produced. This liquid crystal display device was black and became colorless when an AC voltage of 14 V was applied at 50 Hz. The contrast ratio measured with a reflection densitometer was 5.5.
[0121]
(Example 9)
  FIG. 8A is a schematic view showing an embodiment of the liquid crystal display device of the present invention, and FIG. 8B is a cross-sectional view of the liquid crystal display device shown in FIG. In the figure, 11 indicates a glass substrate. A plurality of TFTs 12 are formed on the glass substrate 11. On the glass substrate 11, a reflecting plate 13 made of aluminum is disposed via an insulating film. The reflector 13 constitutes a pixel electrode. Further, a yellow liquid crystal layer 14a, a transparent electrode layer (pixel electrode) 15, a magenta liquid crystal layer 14b, a transparent electrode layer (pixel electrode) 15, and a cyan liquid crystal layer 14c are sequentially stacked on the reflection plate 13. The liquid crystal layers 14a to 14c are formed by applying a dispersion liquid containing microcapsules containing a guest-host liquid crystal containing dye molecules of respective colors (yellow, magenta, cyan) and volatilizing the dispersion medium. The transparent electrode layer 15 is formed by sputtering a transparent conductive material and patterning it by photolithography and etching. The order of stacking the liquid crystal layers 14a to 14c may be any case.
[0122]
Further, a glass substrate having a transparent counter electrode 16 is disposed on the cyan liquid crystal layer 14c. Each TFT and the reflector 13 or the transparent electrode layer 15 are electrically connected.
[0123]
In the liquid crystal display device having the above configuration, each of the liquid crystal layers 14a to 14c and the transparent electrode layer 15 has a wide aperture ratio because there are no active elements and wirings that are non-display areas, and the transparent electrode layer is formed as a thin film. In addition, since a glass substrate is not used, light utilization efficiency is high.
[0124]
When performing color display with this liquid crystal display device, voltages to be applied to the four electrodes sandwiching each liquid crystal layer are determined in advance by an arithmetic circuit. For example, when “white” is displayed, a voltage is applied as shown in FIG. In the figure, G means GND and is a reference potential. V is a potential with respect to GND, and in the above-described VT characteristic, is a potential that can saturate T to some extent to a high state. The voltage application is shown in two ways because it is necessary to apply an AC waveform to the liquid crystal layer. In the case of a guest-host liquid crystal, when displaying “white”, it is necessary to stand liquid crystal molecules and dye molecules in a direction as perpendicular to the electrode surface as possible for the purpose of transmitting light, as shown in FIG. Apply a voltage to Other colors could be displayed by controlling the voltage between the liquid crystal layers as shown in FIGS. 9B to 9H.
[0125]
(Example 10)
  80 parts by weight of a liquid crystal material in which 60% by weight of nematic liquid crystal E48 having a positive dielectric anisotropy (trade name, manufactured by Merck) and 40% by weight of cholesteric liquid crystal CB15 (trade name, manufactured by Merck) is mixed, methyl methacrylate 15 parts by weight of monomer, 1 part by weight of divinylbenzene as a crosslinking agent and 0.2 part by weight of benzoyl peroxide are mixed and dissolved, and after emulsification with a homogenizer together with 3 parts by weight of surfactant and 300 parts by weight of pure water, the liquid crystal The composition was polymerized at 85 ° C. for 1 hour.
[0126]
Next, this liquid crystal composition was filtered through a filter having a mesh size of 0.5 μm square and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 2 to 5 μm were obtained which included the liquid crystal composition in a transparent film.
[0127]
Next, the liquid crystal microcapsules were dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with a transparent electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). . Further, a polymer film provided with a transparent electrode in advance was laminated on the liquid crystal microcapsule layer. Furthermore, the glass substrate and the liquid crystal microcapsule layer were heated and adhered to each other by heating at 120 ° C. Thus, the liquid crystal display device of the present invention was produced.
[0128]
The obtained liquid crystal display device was observed with a microscope. As a result, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. The thickness of the liquid crystal microcapsule layer (light control layer) was 5 μm. This liquid crystal display device has a green reflection color and becomes transparent when an alternating voltage of a rectangular wave of 40 V is applied at 50 Hz.
[0129]
(Example 11)
  80 parts by weight of a liquid crystal material prepared by mixing 60% by weight of nematic liquid crystal E48 and 40% by weight of cholesteric liquid crystal CB15, 15 parts by weight of methyl methacrylate monomer, 1 part by weight of divinylbenzene as a crosslinking agent, and 0.2 parts by weight of benzoyl peroxide Were mixed and dissolved, and emulsified with a homogenizer together with 3 parts by weight of a surfactant and 300 parts by weight of pure water, and then the liquid crystal composition was polymerized at 85 ° C. for 1 hour.
[0130]
Next, this liquid crystal composition was filtered through a filter having a mesh size of 0.5 μm square and washed three times with pure water. In this way, liquid crystal microcapsules having an outer diameter of 2 to 5 μm were obtained which included the liquid crystal composition in a transparent film.
[0131]
Next, the liquid crystal microcapsules were dispersed in 10% by weight in 10% isopropyl alcohol water, applied to a glass substrate surface provided with a transparent electrode in advance, and dried to form a liquid crystal microcapsule layer (light control layer). . Further, a glass substrate provided with a transparent electrode in advance was overlaid on the liquid crystal microcapsule layer. Next, this was put in a polyamide bag, the inside of the bag was depressurized, and in this state, a heat treatment at 120 ° C. was performed to heat and adhere the glass substrate. Thus, the liquid crystal display device of the present invention was produced.
[0132]
The obtained liquid crystal display device was observed with a microscope. As a result, the liquid crystal microcapsules were fused with each other and had a polyhedral structure where the fused portions were straight. Further, the liquid crystal microcapsules were in a state of being stretched in the horizontal direction (direction parallel to the substrate surface), and the fused portion was a straight line substantially parallel to the substrate surface. The thickness of the liquid crystal microcapsule layer (light control layer) was 5 μm. This liquid crystal display device has a green reflection color, and becomes transparent when an AC voltage of a rectangular wave of 35 V is applied at 50 Hz.
[0133]
(Example 12)
  80 parts by weight of a liquid crystal material in which 60% by weight of nematic liquid crystal E48 having positive dielectric anisotropy and cholesteric liquid crystal CB15 are mixed, 15 parts by weight of methyl methacrylate monomer, 1 part by weight of divinylbenzene as a cross-linking agent, 0 of benzoyl peroxide .2 parts by weight was mixed and dissolved, and after emulsifying with 3 parts by weight of a surfactant and 300 parts by weight of pure water with a homogenizer, the liquid crystal composition was polymerized at 85 ° C. for 1 hour. CB15 is a right-handed chiral agent.
[0134]
80 parts by weight of a liquid crystal material obtained by mixing 60% by weight of nematic liquid crystal E48 having positive dielectric anisotropy and cholesteric liquid crystal C15 (trade name, manufactured by Merck), 15 parts by weight of methyl methacrylate monomer, and divinylbenzene as a crosslinking agent 1 part by weight and 0.2 part by weight of benzoyl peroxide are mixed and dissolved, and after emulsification with a homogenizer together with 3 parts by weight of a surfactant and 300 parts by weight of pure water, the liquid crystal composition is heated at 85 ° C. for 1 hour. Polymerized. C15 is a right-handed chiral agent.
[0135]
Next, these liquid crystal compositions were each filtered through a filter having a mesh size of 0.5 μm square and washed with pure water three times. In this way, two types of liquid crystal microcapsules having an outer diameter of 1 to 3 μm each including a liquid crystal composition with a transparent film were obtained.
[0136]
Next, these liquid crystal microcapsules are each dispersed in 10% by weight of 10% isopropyl alcohol water, and the liquid crystal microcapsules having a right-handed structure are applied to the glass substrate surface provided with a transparent electrode in advance and dried to be first. The liquid crystal microcapsule layer (light control layer) was formed. Subsequently, a liquid crystal microcapsule having a left-handed structure was applied in advance to a glass substrate surface provided with a transparent electrode and dried to form a second liquid crystal microcapsule layer (light control layer). Furthermore, a polymer film provided with a transparent electrode in advance was laminated on the second liquid crystal microcapsule layer. Thereafter, the glass substrate and the liquid crystal microcapsule layer were heated and adhered to each other by heat treatment at 120 ° C. Thus, the liquid crystal display device of the present invention was produced.
[0137]
The obtained liquid crystal display device was observed with a microscope. As a result, the liquid crystal microcapsules in the first and second liquid crystal microcapsule layers were fused with each other, resulting in a polyhedral structure in which the fused portions were straight. The thicknesses of the first and second liquid crystal microcapsule layers (light control layers) were 2 μm, respectively. This liquid crystal display device has a green reflection color, and becomes transparent when an AC voltage of a rectangular wave of 30 V is applied at 50 Hz.
[0138]
(Example 13)
  To 40 g of a liquid crystal material in which magenta dichroic dye was dissolved, 8 g of methyl methacrylate as a monomer, 2 g of vinyl methacrylate and 0.1 g of dicumyl peroxide as an initiator were mixed and dissolved to obtain a liquid crystal composition. Next, 5 g of polyvinyl alcohol as an emulsifier was dissolved in 500 g of water as a medium.
[0139]
Next, 0.4 kg / cm of the liquid crystal composition is passed through an emulsion film having a pore diameter of 1 μm.²And was extruded into the medium. At this time, the medium was circulated to give a flow to the surface of the emulsion film. The extruded liquid crystal oil droplets were washed off from the surface of the emulsified film into the medium, thereby obtaining uniform monomer-containing liquid crystal oil droplets having a particle size of 4 to 5 μm.
[0140]
The emulsion composed of oil droplets thus obtained was polymerized at 75 ° C. for 12 hours under a nitrogen atmosphere to prepare liquid crystal microcapsules. The aqueous solution containing the liquid crystal microcapsules was applied to a glass substrate with a transparent electrode and dried to form a liquid crystal microcapsule layer having a thickness of 10 μm. When this liquid crystal microcapsule layer was observed from the surface with a microscope, it was confirmed that the liquid crystal microcapsules were fused and had a size close to a honeycomb structure.
[0141]
Furthermore, a glass substrate with a transparent electrode was laminated on the liquid crystal microcapsule layer to complete a liquid crystal display device. The driving voltage of this liquid crystal display device was measured and found to be 5V. When a voltage was applied to the liquid crystal display device, the color changed from magenta to transparent. In this liquid crystal display device, since the liquid crystal microcapsules have almost uniform particle diameters, no steps are formed in the liquid crystal microcapsule layer, thereby reducing scattering.
[0142]
(Example 14)
  In the present invention, an exposure adhesive expression body is coated on the polymer outer wall of the liquid crystal microcapsule, and this is uniformly applied onto the substrate to form a layer, and pattern exposure is performed on the liquid crystal microcapsule layer, It has been found that a desired pattern can be formed on the liquid crystal microcapsule layer by cleaning the substrate surface.
[0143]
That is, the liquid crystal microcapsule in this embodiment is, for example, as shown in FIG. Is provided. In addition, the whole polymer layer may be comprised with the exposure adhesive expression body.
[0144]
In this embodiment, first, as shown in FIG. 11A, the liquid crystal microcapsules are uniformly applied on a glass substrate 27 having a transparent electrode 26 made of ITO or the like on the surface. Further, pattern exposure is performed on the substrate through a mask. At this time, only the exposed portion of the exposed tackiness-expressing substance develops tackiness, and the liquid crystal microcapsules are adsorbed to the base (substrate, transparent electrode, etc.). Thereafter, by washing the substrate, the liquid crystal microcapsules in the non-exposed area can be washed away to form the liquid crystal microcapsule layer 25 having a desired pattern. By doing so, a liquid crystal microcapsule layer having a red, blue, and green pattern as shown in FIG. 11B can be obtained. As a result, even when liquid crystal microcapsules are used, it is possible to realize a liquid crystal display device that is simple in structure and low in cost, can be produced, and can obtain a bright and clear display.
[0145]
Examples of the yellow dichroic dye used for the liquid crystal microcapsule include G-232 (manufactured by Nippon Photosensitive Dye), SI-209, M-361 (manufactured by Mitsui Toatsu), and the like. Examples of cyan dichroic dyes used for liquid crystal microcapsules include SI-501, SI-497, M-403 (manufactured by Mitsui Toatsu Co., Ltd.), G-472 (manufactured by Nippon Photosensitizer Co., Ltd.), and the like. it can. Moreover, as a dichroic dye for magenta used for the liquid crystal microcapsule, G-239, G-471, G-202 (manufactured by Nippon Photosensitizer), SI-512, M-618, M-370 (Mitsui Toatsu) For example).
[0146]
The hue at the time of coloring of the liquid crystal microcapsule can be obtained by mixing the above dichroic dye. For example, red liquid crystal microcapsules can be adjusted by mixing magenta and yellow dyes, blue liquid crystal microcapsules can be adjusted by mixing magenta and cyan dyes, and green liquid crystal microcapsules It can be adjusted by obtaining a mixture of cyan and yellow dyes.
[0147]
As the liquid crystal used for the liquid crystal microcapsule, TC-4368XX, ZLI-4281 / 2, ZLI-3889, ZLI-5500-000, MLC-6041-000, ZLI-4620, ZLI-5100-000, ZLI-1840, ZLI-2116-000, ZLI-2293 (manufactured by Merck Japan), LIX0N4033-000XX, LIX0N4034-000XX. LIXON-5052 (manufactured by Chisso Chemical Industries) or the like can be used, but is not limited thereto.
[0148]
As a material for the transparent film (polymer outer wall) of the liquid crystal microcapsule, divinylbenzene, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylate-n-butyl, (meth) acrylic acid-2 -Hydroxyethyl, glycidyl (meth) acrylate, ethylene glycol-di- (meth) acrylic acid ester, tribromophenyl (meth) acrylate, (meth) acrylonitrile, (meth) acrolein, (meth) acrylamide, methylenebis (meth) ) Copolymers such as acrylamide, N-methylol- (meth) acrylamide, vinyl chloride, vinylidene chloride, butyl diene, isoprene, (meth) acrylic acid, itaconic acid, fumaric acid, and the like. It is not limited.
[0149]
Examples of the exposure adhesive substance of the liquid crystal microcapsule include 1,4-dihydropyridine. More specifically, 2,6-dimethyl-4- (2′-nitrophenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid dimethyl ester; 2,6-dimethyl-4- (2′-nitro) Phenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester; 2,6-dimethyl-4- (2′-nitro-4 ′, 5′-dimethoxyphenyl) -1,4-dihydropyridine-3,5 -Dicarboxylic acid diethyl ester; 2,6-dimethyl-4- (2'-nitrophenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid diisopropyl ester; 2,6-dimethyl-4- (2'-nitro Phenyl) -1) 4-dihydropyridine-3,5-dicarboxylic acid di (β-ethoquinethyl) ester; 2,6-dimethyl-4- (2′-nitrophenyl)- , 4-Dihydropyridine-3,5-dicarboxylic acid 3-methyl-5-ethyl ester; 2,6-dimethyl-4- (2′-nitrophenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid 3- Isopropyl-5-methyl ester; 2,6-dimethyl-4- (2′-nitrophenyl) mono-3-aceto-1,4-dihydropyridine-5-carboxylic acid ethyl ester; 2,6-dimethyl-4- (2 ″ ″ -Nitrophenyl) -3,5-diacet-1) 4-dihydropyridine, 2,6-dimethyl-4- (2′-nitrophenyl) -3,5-dicyano-1,4-dihydropyridine, and the like. However, it is not limited to these.
[0150]
Specifically, the liquid crystal display device having the liquid crystal microcapsules can be manufactured as follows.
[0151]
  Example 13Blue liquid crystal microcapsules having an average particle diameter of about 10 μm prepared by the emulsion polymerization method (Liquid crystal material: TC-4368XX manufactured by Merck Japan, Dye material: SI-497 manufactured by Aussie Co., Ltd., and G-239 manufactured by Nippon Photosensitizer Co., Ltd.) And 1% by weight of 2,6-dimethyl-4- (2 ″ -nitrophenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid dimethyl ester on the surface of the outer wall polymer material: divinylbenzene) A polyacrylate layer was formed.
[0152]
This liquid crystal microcapsule is applied to a glass substrate having an ITO layer as a transparent electrode on the surface, and ultraviolet light having a wavelength of 365 nm is applied to 200 mJ / cm using an exposure machine having an ultrahigh pressure mercury lamp as a light source.²Irradiated with the energy of. At this time, only the liquid crystal microcapsules in the exposed portion were adsorbed on the substrate. Next, this substrate was immersed in water and subjected to ultrasonic cleaning to obtain a pattern in which the liquid crystal microcapsule layer remained only in the exposed portion.
[0153]
Next, liquid crystal microcapsules colored red and green were subjected to the same process as described above to form a liquid crystal microcapsule layer having a red, green, and blue delta arrangement pattern as shown in FIG.
[0154]
Furthermore, a glass substrate with a transparent electrode was laminated on the liquid crystal microcapsule layer to complete a liquid crystal display device. The driving voltage of this liquid crystal display device was measured and found to be 15V. The liquid crystal display device had a simple structure, white display was bright and good, and color display was clear.
[0155]
(Example 15)
Blue liquid crystal microcapsules (liquid crystal material: TC-4368XX manufactured by Merck Japan) having an average particle diameter of about 10 μm prepared by emulsion polymerization method Dye material: SI-497 manufactured by Aussie Co., Ltd. G-239 manufactured by Nippon Photosensitive Dye Co., Ltd. 2,6-dimethyl-4- (2′-nitrophenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid dimethyl ester is directly adsorbed on the surface of the polymer material (divinylbenzene), and the ultraviolet irradiation energy is 50 mJ. / Cm²ExceptExample 14In the same manner as above, a liquid crystal microcapsule layer having a red, green, and blue delta arrangement pattern as shown in FIG. 11B was formed.
[0156]
Furthermore, a glass substrate with a transparent electrode was laminated on the liquid crystal microcapsule layer to complete a liquid crystal display device. The driving voltage of this liquid crystal display device was measured and found to be 15V. Further, in the production of this liquid crystal display device, the exposure energy could be reduced as compared with that of Example 16.
[0157]
【The invention's effect】
As described above, the liquid crystal display device of the present invention has electrodes on each surface, a pair of substrates arranged so that the electrodes face each other, and a light control layer sandwiched between the pair of substrates And the light control layer contains microcapsules containing a liquid crystal material in a transparent film, and the adjacent microcapsules are in close contact with each other, or the microcapsules have a polyhedral structure. The transmittance is high, incident light can be used effectively, and high contrast display is possible.
[0158]
Further, according to the method for producing a liquid crystal display device of the present invention, a light control layer comprising a microcapsule containing a liquid crystal material in a transparent film is formed on at least one of a pair of substrates having electrodes on the surface, Since the microcapsules are fused to each other, the pair of substrates are arranged so that the electrodes face each other, and the light control layer is sandwiched between the pair of substrates, the liquid crystal display device can be obtained efficiently.
[Brief description of the drawings]
1A is a schematic plan view showing an example of a liquid crystal microcapsule layer of a liquid crystal display device of the present invention, and FIG. 1B is a schematic cross-sectional view showing a liquid crystal microcapsule layer shown in FIG.
2A is a schematic plan view showing an example of a conventional liquid crystal microcapsule layer, and FIG. 2B is a schematic cross-sectional view showing the liquid crystal microcapsule layer shown in FIG.
3A is a schematic diagram showing the orientation of liquid crystal molecules in a liquid crystal microcapsule in the liquid crystal display device of the present invention, and FIG. 3B is a schematic diagram showing the orientation of liquid crystal molecules in a liquid crystal microcapsule having a curved interface. Figure.
4A is a schematic plan view showing a liquid crystal microcapsule layer in Example 1 of the liquid crystal display device of the present invention, and FIG. 4B is a schematic cross-sectional view showing the liquid crystal microcapsule layer shown in FIG.
5A is a schematic plan view showing a liquid crystal layer in Comparative Example 1, and FIG. 5B is a schematic cross-sectional view showing the liquid crystal layer shown in FIG.
6A is a schematic plan view showing a liquid crystal layer in Comparative Example 2, and FIG. 6B is a schematic cross-sectional view showing the liquid crystal layer shown in FIG.
7A is a schematic plan view showing a liquid crystal microcapsule layer in Example 2 of the liquid crystal display device of the present invention, and FIG. 7B is a schematic cross-sectional view showing the liquid crystal microcapsule layer shown in FIG.
8A is a schematic diagram illustrating a liquid crystal display device according to an eleventh embodiment of the present invention, and FIG. 8B is a cross-sectional view of the liquid crystal display device illustrated in FIG. 8A.
9A to 9H are potential configuration diagrams in Embodiment 11 of the liquid crystal display device of the present invention.
10 is a schematic diagram showing liquid crystal microcapsules in Example 16 of the liquid crystal display device of the present invention. FIG.
11A is a cross-sectional view showing a liquid crystal microcapsule layer in a liquid crystal display device according to Example 16, and FIG. 11B is a plan view showing an arrangement of the liquid crystal microcapsule layer in Example 16 of the liquid crystal display device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Transparent film, 2 ... Liquid crystal microcapsule, 3, 11, 27 ... Glass substrate, 4 ... Liquid crystal molecule, 5 ... Gap, 12 ... TFT, 13 ... Reflecting plate (pixel electrode), 14a ... Yellow liquid crystal layer, 14b ... Magenta liquid crystal layer, 14c ... Cyan liquid crystal layer, 15 ... Transparent electrode, 16 ... Counter electrode, 21 ... Liquid crystal molecule, 22 ... Dichroic dye, 23 ... Polymer layer, 24 ... Exposure tackifier layer, 25 ... Liquid crystal micro Capsule layer, 26 ... transparent electrode.

Claims (8)

A substrate having electrodes on the surface; and a light control layer provided on the substrate, the light control layer containing microcapsules containing a liquid crystal material in a transparent film, and each microcapsule has a plurality of planes A liquid crystal display device having a polyhedral structure surrounded by a substrate, and an upper surface and a lower surface of the polyhedral structure being substantially parallel to a substrate surface.   The liquid crystal display device according to claim 1, wherein the adjacent microcapsules are in close contact with each other.   The liquid crystal display device according to claim 1, wherein the liquid crystal molecules of the liquid crystal material are arranged substantially parallel to the substrate surface.   2. The liquid crystal molecules of the liquid crystal material are arranged substantially parallel to the substrate surface, and the microcapsules are laminated in a plurality of layers, and most of the liquid crystal molecules in the same layer are arranged in the same direction. A liquid crystal display device according to 1.   The liquid crystal display device according to claim 1, wherein the liquid crystal molecules of the liquid crystal material are arranged substantially perpendicular to the substrate surface.   The liquid crystal display device according to claim 1, wherein the liquid crystal material contains a dichroic dye.   The liquid crystal display device according to claim 1, wherein the orientation of liquid crystal molecules in each microcapsule is different from each other.   The liquid crystal display device according to claim 1, wherein there are at least two types of materials for the transparent film constituting the microcapsule.

Images