JP4287598B2 - Photoreactive chiral agent, liquid crystal composition, liquid crystal color filter, optical film, recording medium, and method for changing twisted structure of liquid crystal - Google Patents

Description

【００１４】
〔式中、Ｒは、水素原子、炭素数１〜１５のアルコキシ基、総炭素数３〜１５のアクリロイルオキシアルキルオキシ基、総炭素数４〜１５のメタクリロイルオキシアルキルオキシ基を表す。〕
【００１５】
＜２＞ 一般式（Ｉ）で表される化合物において、Ｒが、総炭素数３〜１５のアクリロイルオキシアルキルオキシ基、総炭素数４〜１５のメタクリロイルオキシアルキルオキシ基である前記＜１＞に記載の光反応型カイラル剤である。
＜３＞ 一般式（Ｉ）で表される化合物において、Ｒが、水素原子、炭素数１〜１５のアルコキシ基である前記＜１＞に記載の光反応型カイラル剤である。
【００１６】
＜４＞ 前記＜１＞〜＜３＞のいずれかに記載の光反応型カイラル剤より選択される少なくとも一種を含有することを特徴とする液晶組成物である。
＜５＞ 光反応型カイラル剤とコレステリック液晶性化合物と界面活性剤とを少なくとも含有する前記＜４＞に記載の液晶組成物である。前記界面活性剤としては、ノニオン系界面活性剤が好ましい。
【００１７】
＜６＞ 前記＜４＞又は＜５＞に記載の液晶組成物に光照射して液晶の捻れ力を変化させることを特徴とする液晶の捻れ構造を変化させる方法である。
＜７＞ 前記＜１＞〜＜３＞のいずれかに記載の光反応型カイラル剤より選択される少なくとも一種を含有することを特徴とする液晶カラーフィルタである。
【００１８】
＜８＞ 前記＜１＞〜＜３＞のいずれかに記載の光反応型カイラル剤より選択される少なくとも一種を含有することを特徴とする光学フィルムである。
＜９＞ 前記＜１＞〜＜３＞のいずれかに記載の光反応型カイラル剤より選択される少なくとも一種を含有することを特徴とする記録媒体である。
【００１９】
【発明の実施の形態】
以下、本発明について順に説明する。
＜光反応型カイラル剤＞
本発明の光反応型カイラル剤は、下記一般式（Ｉ）で表される化合物からなり、液晶性化合物の配向構造を制御し得ると共に、光の照射により液晶の螺旋ピッチ、即ち螺旋構造の捻れ力（ＨＴＰ：ヘリカルツイスティングパワー）を変化させることができる特質を有する。即ち、液晶性化合物、好ましくはネマチック液晶化合物に誘起する螺旋構造の捻れ力の変化を光照射（紫外線〜可視光線〜赤外線）によって起こさせる化合物であり、必要な部位（分子構造単位）として、カイラル部位（キラル部位）と光の照射によって構造変化を生じる部位とを有する。
しかも、下記一般式（Ｉ）で表される光反応型カイラル剤は、特に液晶分子のＨＴＰを大きく変化させることができる。したがって、例えば、液晶性化合物にネマチック液晶化合物を用いたコレステリック液晶（液晶相）の場合には、Ｂ(青色)、Ｇ(緑色)、Ｒ(赤色)の３原色を含む広範囲の波長領域にわたる選択反射が可能となる。即ち、光の波長の選択反射特性は、液晶分子の螺旋構造の捻れ角により決まるので、その角度が大きく変化するほど選択反射する色幅が広範となり有用となる。
【００２０】
尚、前記ＨＴＰは、液晶の螺旋構造の捻れ力、即ち、ＨＴＰ＝１／（ピッチ×キラル剤濃度〔質量分率〕）を表し、例えば、ある温度での液晶分子の螺旋ピッチ（螺旋構造の一周期；μｍ）を測定し、この値をカイラル剤（キラル剤）の濃度から換算〔μｍ^-1〕して求めることができる。
光反応型カイラル剤により光の照度により選択反射色を形成する場合、前記ＨＴＰの変化率（＝照射前のＨＴＰ／照射後のＨＴＰ）としては、照射後にＨＴＰがより小さくなる場合には１．５以上が好ましく、更に２．５以上がより好ましく、照射後にＨＴＰがより大きくなる場合には０．７以下が好ましく、更に０．４以下がより好ましい。
【００２１】
次に、一般式（Ｉ）で表される化合物について説明する。
【化３】

【００２２】
前記式中、Ｒは、水素原子、炭素数１〜１５のアルコキシ基、総炭素数３〜１５のアクリロイルオキシアルキルオキシ基、総炭素数４〜１５のメタクリロイルオキシアルキルオキシ基を表す。
前記炭素数１〜１５のアルコキシ基としては、例えば、メトキシ基、エトキシ基、プロポキシ基、ブトキシ基、ヘキシルオキシ基、ドデシルオキシ基等が挙げられ、中でも、炭素数１〜１２のアルコキシ基が好ましく、炭素数１〜８のアルコキシ基が特に好ましい。
【００２３】
前記総炭素数３〜１５のアクリロイルオキシアルキルオキシ基としては、例えば、アクリロイルオキシエチルオキシ基、アクリロイルオキシブチルオキシ基、アクリロイルオキシデシルオキシ基等が挙げられ、中でも、炭素数５〜１３のアクリロイルオキシアルキルオキシ基が好ましく、炭素数５〜１１のアクリロイルオキシアルキルオキシ基が特に好ましい。
【００２４】
前記総炭素数４〜１５のメタクリロイルオキシアルキルオキシ基としては、例えば、メタクリロイルオキシエチルオキシ基、メタクリロイルオキシブチルオキシ基、メタクリロイルオキシデシルオキシ基等が挙げられ、中でも、炭素数６〜１４のメタクリロイルオキシアルキルオキシ基が好ましく、炭素数６〜１２のメタクリロイルオキシアルキルオキシ基が特に好ましい。
【００２５】
前記一般式（Ｉ）で表される光反応型カイラル剤の分子量としては、３００以上が好ましい。また、後述する液晶性化合物との溶解性の高いものが好ましく、その溶解度パラメータＳＰ値が、液晶性化合物に近似するものがより好ましい。
【００２６】
以下、前記一般式（Ｉ）で表される化合物の具体例（例示化合物（１）〜（１５））を示すが、本発明においてはこれらに制限されるものではない。
【００２７】
【化４】

【００２８】
【化５】

【００２９】
【化６】

【００３０】
次に、本発明の光反応型カイラル剤（一般式（Ｉ）で表される化合物）の合成例を挙げる。尚、光反応型カイラル剤のカッコ内の番号は、前記［化４］〜［化６］に例示した光反応型カイラル剤（例示化合物）の番号を表す。
【００３１】
−光反応型カイラル剤（２）の合成−
４−メトキシ桂皮酸（１５ｇ，０．０８４ｍｏｌｅ）及びジメチルホルムアミド（２〜３滴）をテトラヒドロフラン（１００ｍＬ）に溶解し、これに更に塩化オキザリル（１０ｍＬ，０．１３ｍｏｌｅ）をテトラヒドロフラン（５０ｍＬ）に溶解させたものを滴下し２時間反応させた。反応液中の溶媒及び過剰の塩化オキザリルを減圧留去した後、テトラヒドロフラン（１００ｍＬ）で希釈し、イソソルビッド（５．５ｇ，０．０３８ｍｏｌｅ）を加えた。更に撹拌しながら、テトラヒドロフラン（５０ｍＬ）に溶解したピリジン（２７ｍＬ，０．３３ｍｏｌｅ）を滴下し３時間撹拌した。その後、反応液に１０％塩酸（１００ｍＬ）及び酢酸エチル（２００ｍＬ）を加えて撹拌し、分液した。得られた有機層を飽和食塩水（１００ｍＬ）で１回、飽和重曹水（１００ｍＬ）で２回、飽和食塩水（１００ｍＬ）で２回の順で洗浄し、硫酸マグネシウム上で乾燥した。更に有機溶媒を減圧留去した後、ｎ-ヘキサン−酢酸エチル（３：２ ｖ／ｖ）の混合溶液を展開溶媒とするシリカゲルカラムトグラフィーにより精製し、再結晶（ｎ-ヘキサン−酢酸エチル）を行い、無色結晶（９．８ｇ，５６％）を得た。
【００３２】
上記より得られた無色結晶を同定した結果（データ）を以下に示す。
融点Ｔｍ＝１１３．７℃、 [α]_D ²⁵-１５８°(ｃ０．５０，ＥｔＯＡｃ)．
¹Ｈ−ＮＭＲ（ＣＤＣｌ₃）： δ(in ppm from tetramethylsilane)７．７５−７．６０（２Ｈ，ｄｄ），７．５０−７．４５（４Ｈ，ｄｄ），６．９４−６．８８（４Ｈ，ｄｄ），６．４０−６．２５（２Ｈ，ｄｄ），５．３６−５．２６（２Ｈ，ｍ），４．９５（１Ｈ，ｔ），４．６０（１Ｈ，ｄ），４．１５−３．９０（８Ｈ，ｍ），３．８５（６Ｈ，ｓ）．
【００３３】
−光反応型カイラル剤（５）の合成−
トランス−４−クマル酸（２０ｇ，０．１２ｍｏｌｅ）及び炭酸カリウム（３３ｇ，０．２４ｍｏｌｅ）をジメチルホルムアミド（１００ｍＬ）に分散させ、油浴上で加温しながらｎ−ブロモブタン（５０ｇ，０．３７ｍｏｌｅ）を滴下した。３時間の撹拌の後、不溶分を濾別し、酢酸エチル（４００ｍＬ）で希釈し、飽和食塩水（２００ｍＬ）で洗浄した。更に有機溶媒を減圧留去した後、エタノール（１００ｍＬ）及び水酸化カリウム（２０ｇ，０．３６ｍｏｌｅ）を水（５０ｍＬ）に溶解したものを加え、１時間還流させた。反応液を希塩酸にあけ、析出した結晶を濾別し、クロロホルム（５００ｍＬ）に溶解させた。得られた有機層を飽和食塩水で洗浄し、硫酸マグネシウム上で乾燥した。更に有機溶媒を減圧留去した後、再結晶（ｎ−ヘキサン−酢酸エチル）を行い、無色結晶の４−ｎ−ブトキシ桂皮酸（２２．７ｇ，８４％）を得た。
【００３４】
得られた４−ｎ−ブトキシ桂皮酸（５ｇ，０．０２３ｍｏｌｅ）及びジメチルホルムアミド（２〜３滴）をテトラヒドロフラン（５０ｍＬ）に溶解し、これに更に塩化オキザリル（２．９ｍＬ，０．０３４ｍｏｌｅ）をテトラヒドロフラン（３０ｍＬ）に溶解させたものを滴下し、２時間反応させた。反応液の溶媒及び過剰の塩化オキザリルを減圧留去した後、テトラヒドロフラン（５０ｍＬ）で希釈し、イソソルビッド（１．５ｇ，０．０１０ｍｏｌｅ）を加えた。更に撹拌しながら、テトラヒドロフラン（２０ｍＬ）に溶解したピリジン（１１ｍＬ，０．１４ｍｏｌｅ）を滴下し、３時間撹拌した。その後、反応液に１０％塩酸（５０ｍＬ）及び酢酸エチル（１００ｍＬ）を加えて撹拌し、分液した。得られた有機層を飽和食塩水（５０ｍＬ）で１回、飽和重曹水（５０ｍＬ）で２回、飽和食塩水（５０ｍＬ）で２回の順で洗浄し、硫酸マグネシウム上で乾燥した。更に有機溶媒を減圧留去した後、ｎ-ヘキサン−酢酸エチル（２：１ ｖ／ｖ）の混合溶液を展開溶媒とするシリカゲルカラムトグラフィーにより精製し、再結晶（ｎ-ヘキサン−酢酸エチル）を行い、無色結晶性粉末（１．４ｇ，２５％）を得た。
【００３５】
上記より得られた無色結晶性粉末を同定した結果（データ）を以下に示す。
融点Ｔｍ＝１３２．４℃、 [α]_D ²⁵-１１５．０°（ｃ０．１０，ＥｔＯＡｃ）．
¹Ｈ−ＮＭＲ（ＣＤＣｌ₃）： δ（in ppm from tetramethylsilane）７．７５−７．６５（２Ｈ，ｄｄ），７．５０−７．４５（４Ｈ，ｄｄ），６．９０−６．８５（４Ｈ，ｄｄ），６．４０−６．２６（２Ｈ，ｄｄ），５．３５−５．２５（２Ｈ，ｍ），４．９４（１Ｈ，ｔ），４．６０（１Ｈ，ｄ），４．１３−３．９５（８Ｈ，ｍ），１．９４−１．６５（４Ｈ，ｍ），１．５５−１．４４（４Ｈ，ｍ），０．９５（６Ｈ，ｔ）．
【００３６】
−光反応型カイラル剤（１２）の合成−
トランス−４−クマル酸（２０ｇ，０．１２ｍｏｌｅ）、ヨウ化カリウム（２４ｇ，０．１４ｍｏｌｅ）及び炭酸カリウム（８５ｇ，０．６２ｍｏｌｅ）を、ジメチルホルムアミド（２００ｍＬ）及び水（１００ｍＬ）の混合液に分散させ、油浴で加温しながら６−クロロヘキサノール（６８ｇ，０．５０ｍｏｌｅ）を滴下した。３時間撹拌した後、酢酸エチル（４００ｍＬ）で希釈し、飽和食塩水（４００ｍＬ）で洗浄した。更に有機溶媒を減圧留去した後、エタノール（２００ｍＬ）及び水酸化カリウム（２０ｇ，０．３６ｍｏｌｅ）を水（５０ｍＬ）に溶解したものを加え、１時間還流させた。反応液を希塩酸にあけ、析出した結晶を濾別した後に乾燥し、無色結晶性粉末の４−（６−ヒドロキシヘキシルオキシ）桂皮酸（２２ｇ，６４％）を得た。
【００３７】
得られた４−（ヒドロキシヘキシルオキシ）桂皮酸（６ｇ，０．０２３ｍｏｌｅ）及びＮ，Ｎ−ジメチルアニリン（６．６ｇ，０．０５４ｍｏｌｅ）をテトラヒドロフラン（５０ｍＬ）に溶解させ、これに更に、室温下でテトラヒドロフラン（２０ｍＬ）に溶解させた塩化アクロイル（４．４ｇ，０．０４９ｍｏｌｅ）を滴下した。滴下後４時間撹拌した後、反応液を１０％塩酸にあけ、析出した結晶を濾別した。得られた粗結晶を酢酸エチル（１００ｍＬ）に溶解させ有機層を飽和食塩水で洗浄し、硫酸マグネシウム上で乾燥した。有機溶媒を減圧留去した後、粗結晶を再結晶（ｎ-ヘキサン−酢酸エチル）し、無色結晶性粉末の４−（６−アクロイルオキシヘキシルオキシ）桂皮酸（３．９ｇ，５４％）を得た。
【００３８】
得られた４−（６−アクロイルオキシヘキシルオキシ）桂皮酸（３ｇ，９．４ｍｍｏｌｅ）及びジメチルホルムアミド（２〜３滴）をテトラヒドロフラン（５０ｍＬ）に溶解し、これに更に微塩化オキザリル（１．２ｍＬ，０．０１４ｍｏｌｅ）をテトラヒドロフラン（１０ｍＬ）に溶解させたものを滴下し、２時間反応させた。反応液の溶媒及び過剰の塩化オキザリルを減圧留去した後、テトラヒドロフラン（５０ｍＬ）で希釈し、イソソルビッド（０．６ｇ，４．１ｍｍｏｌｅ）を加えた。更に撹拌しながら、テトラヒドロフラン（２０ｍＬ）に溶解したピリジン（４．５ｍＬ，０．０５６ｍｏｌｅ）を滴下し、一晩撹拌した。その後、反応液に１０％塩酸（５０ｍＬ）及び酢酸エチル（１００ｍＬ）を加えて撹拌し、分液した。得られた有機層を飽和食塩水（５０ｍＬ）で１回、飽和重曹水（５０ｍＬ）で２回、飽和食塩水（５０ｍＬ）で２回の順で洗浄し、硫酸マグネシウム上で乾燥した。有機溶媒を減圧留去した後、ｎ-ヘキサン−酢酸エチル（３：２ ｖ／ｖ）の混合溶液を展開溶媒とするシリカゲルカラムトグラフィーにより精製し、無色結晶性粉末（１．１ｇ，３８％）を得た。
【００３９】
上記より得られた無色結晶性粉末を同定した結果（データ）を以下に示す。
融点Ｔｍ＝７０．５℃、 [α]_D ²⁵-１０３．０°（ｃ０．１１，ＥｔＯＡｃ）．
¹Ｈ−ＮＭＲ（ＣＤＣｌ₃）： δ（in ppm from tetramethylsilane）７．７５−７．６５（２Ｈ，ｄｄ），７．５０−７．４５（４Ｈ，ｄｄ），６．９２−６．８８（４Ｈ，ｄｄ），６．４５−５．８８（８Ｈ，ｍ），５．３５−５．２５（２Ｈ，ｍ），４．９５（１Ｈ，ｔ），４．６０（１Ｈ，ｄ），４．２０−３．８５（８Ｈ，ｍ），１．９４−１．６５（４Ｈ，ｍ），１．８５−１．４５（１６Ｈ，ｍ）．
【００４０】
前記一般式（Ｉ）で表される光反応型カイラル剤は、液晶の螺旋構造の捻れ力を大きく変化させることができ、また、その構造中に重合性の結合基が１以上導入された構造の場合には、液晶組成物又はこれを含んでなる、例えば液晶カラーフィルタ、光学フィルム等、の耐熱性を向上させることができる。
【００４１】
また、本発明の光反応型カイラル剤は、捻れ力の温度依存性が大きいカイラル化合物など、光反応性のないカイラル剤と併用することもできる。前記光反応性のない公知のキラル剤としては、例えば、特開２０００−４４４５１号、特表平１０−５０９７２６号、ＷＯ９８／００４２８、特表２０００−５０６８７３号、特表平９−５０６０８８号、Ｌｉｑｕｉｄ Ｃｒｙｓｔａｌｓ（１９９６、２１、３２７）、Ｌｉｑｕｉｄ Ｃｒｙｓｔａｌｓ（１９９８、２４、２１９）等に記載のキラル剤が挙げられる。
【００４２】
＜液晶組成物＞
液晶組成物は、前記本発明の光反応型カイラル剤より選択される少なくとも一種を少なくとも含有してなり、更に少なくとも一種の液晶性化合物（好ましくはネマチック液晶化合物）を含む態様が好適であり、前記液晶性化合物は、重合性基を有していても有していなくてもよい。また、必要に応じて、重合性モノマー、重合開始剤や、バインダ樹脂、溶媒、界面活性剤、重合禁止剤、増粘剤、色素、顔料、紫外線吸収剤、ゲル化剤等の他の成分を含んでいてもよい。
本発明の液晶組成物は、特に界面活性剤を併用することが好ましい。例えば、塗布液状の液晶組成物を塗布し層形成する場合など、層表面の空気界面における配向状態を立体的に制御でき、より色純度の高い選択反射波長を得ることができる。
【００４３】
（光反応型カイラル剤）
光反応型カイラル剤としては、前述の本発明の光反応型カイラル剤を含み、液晶分子の配向構造を立体的に制御すると共に、所望のパターン及び光量で光照射することによって、共存する液晶性化合物、好ましくはネマチック液晶化合物の螺旋構造を変化させる。ネマチック液晶化合物を含む系では、広範な波長領域の選択反射色を発現させることができる。
液晶組成物中における光反応型カイラル剤の含有量としては、特に制限はなく適宜選択できるが、２〜３０質量％程度が好ましい。
【００４４】
（液晶性化合物）
液晶性化合物としては、その屈折率異方性Δｎが、０．１０〜０．４０の液晶化合物、高分子液晶化合物、重合性液晶化合物の中から適宜選択することができる。例えば、スメクティック液晶化合物、ネマチック液晶化合物などを挙げることができ、中でも、ネマチック液晶化合物が好ましい。例えば、液晶性化合物にネマチック液晶化合物を用い、これに前記一般式（Ｉ）で表される光反応型キラル剤を併用することによって、コレステリック液晶組成物（コレステリック液晶相）とすることができる。
前記液晶性化合物は、溶融時の液晶状態にある間に、例えばラビング処理等の配向処理を施した配向基板を用いる等により配向させることができる。また、液晶状態を固相にして固定化する場合には、冷却、重合等の手段を用いることができる。
【００４５】
前記液晶性化合物の具体例としては、下記化合物を挙げることができる。但し、本発明においては、これらに制限されるものではない。
【００４６】
【化７】

【００４７】
【化８】

【００４８】
【化９】

【００４９】
前記式中、ｎは、１〜１０００の整数を表す。
前記各例示化合物においては、芳香環の連結基が以下の構造に変わったものも同様に好適なものとして挙げることができる。
【００５０】
【化１０】

【００５１】
上記の中でも、十分な硬化性を確保し、層の耐熱性をする観点からは、分子内に重合性基あるいは架橋性基を有する液晶性化合物が好ましい。
【００５２】
前記液晶性化合物の含有量としては、液晶組成物の全固形分（質量）の３０〜９９．９質量％が好ましく、５０〜９５質量％がより好ましい。前記含有量が、３０質量％未満であると、配向が不十分となることがあり、特にコレステリック液晶の場合には所望の選択反射色が得られないことがある。
【００５３】
（重合性モノマー）
本発明の液晶組成物には、例えば膜強度等の硬化の程度を向上させる目的で、重合性モノマーを併用してもよい。該重合性モノマーを併用すると、光照射による液晶の捻れ力を変化（パターニング）させた後（例えば、選択反射波長の分布を形成した後）、その螺旋構造（選択反射性）を固定化し、固定化後の液晶組成物の強度をより向上させることができる。但し、前記液晶性化合物が同一分子内に不飽和結合を有する場合には、必ずしも添加する必要はない。
【００５４】
前記重合性モノマーとしては、例えば、エチレン性不飽和結合を持つモノマー等が挙げられ、具体的には、ペンタエリスリトールテトラアクリレート、ジペンタエリスリトールヘキサアクリレート等の多官能モノマーが挙げられる。
前記エチレン性不飽和結合を持つモノマーの具体例としては、以下に示す化合物を挙げることができる、但し、本発明においては、これらに限定されるものではない。
【００５５】
【化１１】

【００５６】
前記重合性モノマーの添加量としては、液晶組成物の全固形分（質量）の０．５〜５０質量％が好ましい。前記添加量が、０．５質量％未満であると、十分な硬化性を得ることができないことがあり、５０質量％を越えると、液晶分子の配向を阻害し、十分な発色が得られないことがある。
【００５７】
（光重合開始剤）
本発明の液晶組成物は光重合開始剤を含有させることもでき、該光重合開始剤の併用により重合性基の重合反応を促進し、光照射により液晶の螺旋ピッチ（捻れ力）を変化させた後の螺旋構造を固定化して、固定化後の液晶組成物の強度をより向上させることができる。液晶の螺旋構造の固定化に、重合性の液晶性化合物による重合反応を利用した場合には光重合開始剤を添加することが好ましい。例えば、液晶相がコレステリック液晶相である場合には、所望の螺旋ピッチが安定的に得られ、色純度の高い選択反射色を確保することができる。
【００５８】
前記光重合開始剤としては、公知のものの中から適宜選択することができ、例えば、ｐ−メトキシフェニル−２，４−ビス（トリクロロメチル）−ｓ−トリアジン、２−（ｐ−ブトキシスチリル）−５−トリクロロメチル１，３，４−オキサジアゾール、９−フェニルアクリジン、９，１０−ジメチルベンズフェナジン、ベンゾフェノン／ミヒラーズケトン、ヘキサアリールビイミダゾール／メルカプトベンズイミダゾール、ベンジルジメチルケタール、チオキサントン／アミン、トリアリールスルホニウムヘキサフルオロホスフェート等、更にビス（２，４，６−トリメチルベンゾイル）−フェニルホスフィンオキシド等の特開平１０−２９９９７号公報に記載のビスアシルホスフィンオキシド類、Ｌｕｃｉｒｉｎ ＴＰＯ等のＤＥ４２３０５５５等に記載のアシルホスフィンオキシド類等が挙げられる。
【００５９】
前記光重合開始剤の添加量としては、液晶組成物の全固形分（質量）の０．１〜２０質量％が好ましく、０．５〜５質量％がより好ましい。前記添加量が、０．１質量％未満であると、光照射時の硬化効率が低いため長時間を要することがあり、２０質量％を越えると、紫外線領域から可視光領域での光透過率が劣ることがある。
【００６０】
（他の成分）
更に、他の成分として、バインダー樹脂、溶媒、界面活性剤、重合禁止剤、増粘剤、色素、顔料、紫外線吸収剤、ゲル化剤等を添加することもできる。
前記バインダー樹脂としては、例えば、ポリスチレン、ポリ−α−メチルスチレン等のポリスチレン化合物、メチルセルロース、エチルセルロース、アセチルセルロース等のセルロース樹脂、側鎖にカルボキシル基を有する酸性セルロース誘導体、ポリビニルフォルマール、ポリビニルブチラール等のアセタール樹脂、特開昭５９−４４６１５号、特公昭５４−３４３２７号、特公昭５８−１２５７７号、特公昭５４−２５９５７号、特開昭５９−５３８３６号、特開昭５９−７１０４８号に記載のメタクリル酸共重合体、アクリル酸共重合体、イタコン酸共重合体、クロトン酸共重合体、マレイン酸共重合体、部分エステル化マレイン酸共重合体等が挙げられる。
【００６１】
アクリル酸アルキルエステルのホモポリマー及びメタアクリル酸アルキルエステルのホモポリマーも挙げられ、これらについては、アルキル基がメチル基、エチル基、ｎ−プロピル基、ｎ−ブチル基、ｉｓｏ−ブチル基、ｎ−ヘキシル基、シクロヘキシル基、２−エチルヘキシル基等のものを挙げることができる。
その他、水酸基を有するポリマーに酸無水物を添加させたもの、ベンジル（メタ）アクリレート／（メタアクリル酸のホモポリマータ）アクリル酸共重合体やベンジル（メタ）アクリレート／（メタ）アクリル酸／他のモノマーの多元共重合体等が挙げられる。
【００６２】
液晶組成物中におけるバインダー樹脂の含有量としては、０〜５０質量％が好ましく、０〜３０質量％がより好ましい。前記含有量が５０質量％を超えると、液晶性化合物の配向が不十分となることがある。
【００６３】
本発明の液晶組成物においては、選択反射する色相の色純度をより向上させる観点から、光反応性カイラル剤及び液晶性化合物と共に界面活性剤を併用することが好ましい。該界面活性剤としては、排除体積効果を及ぼす界面活性剤が好ましい。ここで、排除体積効果を及ぼすとは、例えば塗布により液晶組成物を含む層を形成した際の、該層表面の空気界面での空間的な配向状態を立体的に制御することをいう。具体的には、ノニオン系の界面活性剤が好ましく、公知のノニオン系界面活性剤の中から適宜選択して使用することができる。
【００６４】
前記重合禁止剤は、保存性の向上の目的で添加され得る。例えば、ハイドロキノン、ハイドロキノンモノメチルエーテル、フェノチアジン、ベンゾキノン、及びこれらの誘導体等が挙げられる。該重合禁止剤の添加量としては、前記重合性モノマーに対して０〜１０質量％が好ましく、０〜５質量％がより好ましい。
【００６５】
本発明の液晶組成物は、前記各成分を適当な溶媒に溶解、分散して調製でき、これを任意の形状に成形し、あるいは支持体等の上に形成して用いることができる。ここで、前記溶媒としては、例えば、２−ブタノン、シクロヘキサノン、塩化メチレン、クロロホルム等が挙げられる。
【００６６】
＜液晶の捻れ構造を変化させる方法＞
前述の通り、本発明の液晶組成物は光反応性カイラル剤を含んでなり、本発明の液晶の捻れ構造を変化させる方法においては、前述の本発明の液晶組成物に光量を変えて光照射し液晶の捻れ力を変化させ、液晶の捻れ構造の異なる領域を形成する。即ち、液晶組成物に対して所望の光量で所望のパターン状に光照射することによって、液晶の捻れ構造、即ち、螺旋の捻れの程度（捻れ力；ＨＴＰ）を変化させることができ、その捻れ力に応じ液晶の示す選択反射色を任意に変化させることができる。
【００６７】
また、特に液晶相をコレステリック液晶相とする場合には、その捻れ力に応じ液晶の示す選択反射色を任意に変化させることができる。この捻れ力の変化率が大きい場合は、液晶が選択反射し得る選択反射色の色幅が拡く、３原色（Ｂ,Ｇ,Ｒ）を含む広範な波長域の選択反射を得ることが可能であり、このことは、特にＢＧＲの３原色を色純度の高く表示させることができる点で重要となる。この点において、特に既述の一般式（Ｉ）で表される光反応型カイラル剤は、液晶の螺旋構造の捻れ力を大きく変化させることができるので、該カイラル剤を含む液晶組成物を用いることにより、青(Ｂ)、緑(Ｇ)、赤(Ｒ)の３原色を含む広範な色相を色純度良く表示することができ、しかも色純度に優れた３原色を得ることができる。
【００６８】
具体的には、以下のようにして行える。即ち、
液晶組成物にある波長の光を照射すると、その照射強度に応じて共存する光反応型カイラル剤が感応して液晶の螺旋構造（捻れ角）を変化させ、この構造変化により異なる選択反射色を示し画像様のパターンが形成される（パターニング）。コレステリック液晶組成物の場合は、この構造変化により異なる選択反射色を示す。従って、所望の領域ごとに照射強度を変えて光照射すれば、照射強度に対応して配向し（複数色を呈し）、例えば、画像様に光透過率を変えて作成された露光用マスクを介して露光することにより、一回の光照射によって画像を、即ち異なる選択反射をする有色領域を同時形成することができる。
【００６９】
しかも、一般式（Ｉ）で表される化合物に依るので、液晶の螺旋ピッチを大きく変化させることが可能で、コレステリック液晶組成物の場合は、形成された有色領域は広範な選択反射色を示し、色純度に優れたＢＧＲの３原色を形成することができる。この光の照射は、露光用マスクによる方法のほか、所望の領域ごとに照射強度を変え得る方法であれば、特に制限なく行える。
後述の液晶カラーフィルタ、光学フィルム等を形成する場合には、前述のようにしてある波長の光を画像様に露光してパターニングした後、更に光照射して液晶組成物中の重合性基を光重合させて硬化し、所望の選択反射色に液晶の螺旋構造を固定化する。これらの形成方法の詳細は後述する。
【００７０】
前記一般式（Ｉ）で表される光反応型カイラル剤に起因し、光照射により液晶相に誘起する螺旋ピッチの変化率が大きいことを利用して、後述のように、光学フィルムである、円偏光分離膜、立体視用眼鏡、偏光マスク等を形成することができる。また、広帯域のスイッチャブルミラー、光書き込み型の記録媒体などへの応用も可能である。強誘電性液晶、反強誘電性液晶、ＴＧＢ相へドープすることによる分極状態のパターニング、螺旋ピッチのパターニングが可能となる。また、当然通常の光学活性化合物としての使用も可能であり、ＳＴＮ素子やＴＮ素子における螺旋構造誘起剤への適用も可能である。
また、本発明の液晶組成物には、非キラルなアゾ系やスチレン系の、光により異性化する化合物を配合させることもでき、光照射時における螺旋ピッチの変化率を更に増大させることができることがある。
【００７１】
光照射に用いる光源としては、エネルギーが高く、液晶化合物の構造変化及び重合反応が迅速に行える点で、紫外線を発する光源が好ましく、例えば、高圧水銀ランプ、メタルハライドランプ、Ｈｇ−Ｘｅランプ等が挙げられる。また、光量可変機能を備えることが好ましい。
【００７２】
上記のように、一般式（Ｉ）で表されるカイラル剤を含む液晶組成物を用いると、光量に対する液晶の螺旋構造の捻れ力を大きく変化させることができる。したがって、例えば液晶性化合物としてネマチック液晶化合物を用いたコレステリック液晶相の場合には、液晶が呈し得る選択反射色の色幅が拡がり、色純度に優れた青(Ｂ)、緑(Ｇ)、赤(Ｒ)の３原色を得ることができる。
【００７３】
＜液晶カラーフィルタ＞
本発明の液晶カラーフィルタは、前記本発明の光反応型カイラル剤より選択される少なくとも一種を少なくとも含有してなり、更に少なくとも一種の液晶性化合物を含む態様が好適であり、前記液晶性化合物としてはネマチック液晶化合物が最も好適である。また、必要に応じて、重合性モノマー、光重合開始剤、排除体積効果を及ぼす界面活性剤等の前記本発明の液晶組成物において列挙した他の成分等を含んでなる。前述した液晶の捻れ構造を変化させる方法に基づいて適宜選択された所望のパターン及び光量で光照射することにより作製できる。
【００７４】
以下、液晶カラーフィルタの製造方法の説明を通じて、本発明の液晶カラーフィルタについて詳述する。
本発明の液晶カラーフィルタは、前述の本発明の液晶組成物、及び公知の組成物に前記一般式（Ｉ）で表される化合物を含んでなるものの中から適宜選択して作製することができる。
この場合、前記液晶組成物のみから構成されたシート形態のものであってもよいし、所望の支持体や仮支持体上に液晶組成物含む層（液晶層）が設けられた態様のものであってもよく、更に配向膜や保護膜等の他の層（膜）が設けられていてもよい。後者の場合、液晶層を二層以上積層することもでき、この場合には後述する前記露光工程は複数回設けられる。
【００７５】
前記ネマチック液晶化合物、重合性モノマー、光重合開始剤及び他の成分としては、前記本発明の液晶組成物で使用可能なものと同様のものが使用でき、その含有量、好ましい範囲等も該液晶組成物の場合と同様である。排除体積効果を及ぼす界面活性剤を併用することが好ましい。
また、液晶カラーフィルタを構成する液晶組成物中における、前記一般式（Ｉ）で表される化合物の含有量も、既述の本発明の液晶組成物と同様である。
【００７６】
本発明の液晶カラーフィルタは、例えば、前記本発明の液晶組成物により好適に作製することができる。
また、液晶カラーフィルタを製造する方法としては、特に制限はなく、例えば、第一の光により画像様に露光してパターニングした後、第二の光により光重合させて硬化する工程（以下、「露光工程」ということがある。）を少なくとも一工程含んでなる製造方法であってもよい。また、選択する製造態様に応じて、適宜液晶組成物との接触面に配向処理を施す工程（配向処理工程）、密着・剥離により液晶層を転写形成する工程（転写工程）、コレステリック液晶組成物を塗布して液晶層を形成する工程（塗布工程）などを経て形成されてもよい。
【００７７】
以下に、前記露光工程を含む製造方法の例として、コレステリック液晶組成物を用いた具体的な一態様を示す。
−露光工程−
露光工程では、液晶化合物のパターニング及び固定化（重合硬化）のいずれをも光の照射によって行う。即ち、光反応型カイラル剤が高感度に感応しうる波長の第一の光により画像様に露光してパターニングした後、重合開始剤が高感度に感応しうる第二の光により光重合させて硬化し、所望の選択反射色に液晶化合物の螺旋構造を固定化する。
【００７８】
前記第一の光が液晶組成物に照射されると、その照度に応じて、共存する光反応型カイラル剤が感応して液晶化合物の螺旋構造が変化し、この構造変化により異なる選択反射色を示し画像様のパターンが形成される。従って、所望の領域ごとに照射強度を変えて光照射すれば、照射強度に対応して複数色を呈し、例えば、画像様に光透過率を変えて作成された露光用マスクを介して露光することにより、一回の光照射によって画像を、即ち異なる選択反射をする有色領域を同時形成することができる。これに更に、第二の光を照射して硬化（固定化）させることにより液晶カラーフィルタを作製できる。
【００７９】
前記第一の光の波長としては、光反応型カイラル剤の光感応波長域、特に光感応ピーク波長に近接する波長に設定することが、十分なパターニング感度が得られる点で好ましい。また、第二の光の波長としては、重合開始剤の光感応波長域、特に光感応ピーク波長に近接する波長に設定することが、十分な光重合感度が得られる点で好ましい。
また、第一及び第二の光の照度（照射強度）には特に制限はなく、パターニング時及び重合硬化時の光感度が十分得られるように、使用する材料に応じて適宜選択できる。前記第一及び第二の光の照射に用いる光源としては、前記液晶組成物の光照射に使用可能なものと同様の光源が使用できる。
【００８０】
更に具体的には、下記第１、第２の態様の製造方法であってもよく、これら２態様によって、より好適に作製することができる。
〔第１の態様〕
（１）仮支持体上に塗布液状の液晶組成物を設け、液晶層を少なくとも有する転写材料を形成する工程。
前記塗布液状の液晶組成物は、各成分を適当な溶媒に溶解、分散して調製できる。ここで、前記溶媒としては、例えば、２−ブタノン、シクロヘキサノン、塩化メチレン、クロロホルム等が挙げられる。液晶カラーフィルタの作製においては、コレステリック液晶組成物が好ましい。
前記液晶層と仮支持体との間には、被転写体上に異物等がある場合など、転写時における密着性を確保する観点から、熱可塑性樹脂等を含んでなるクッション層を設けることもでき、該クッション層等の表面には、ラビング処理等の配向処理（配向処理工程）を施すことも好ましい。
（２）前記転写材料を光透過性の基板上にラミネートする工程。
前記光透過性の基板のほか、基体上に受像層を有する受像材料を用いてもよい。また、前記転写材料を用いずに、基板上に直接液晶組成物を塗布形成してもよい（塗布工程）。塗布は、公知の塗布方法の中から適宜選択して行える。但し、材料ロス及びコストの点で転写による方法が好ましい。
【００８１】
（３）光透過性の基板から転写材料を剥離して、前記基板上にコレステリック液晶層を形成する工程（転写工程）。
該液晶層は、下記（４）を経た後、更に積層して複数層より構成することもできる。
（４）コレステリック液晶層に露光マスクを介して画像様に照度ν¹の紫外線を照射し選択反射色を示す画素パターンを形成し、これに更に照度ν²の紫外線を照射して層を硬化させる工程（露光工程）。
【００８２】
〔第２の態様〕
（１）カラーフィルタを構成する支持体上に直接液晶組成物を設けて液晶層を形成する工程。
ここで、液晶層は、上記同様に塗布液状に調製した液晶組成物をバーコーターやスピンコーター等を用いた公知の塗布方法により塗布形成することができる。
また、前記コレステリック液晶層と仮支持体との間には、上記同様の配向膜が形成されていてもよい。該配向膜等の表面には、ラビング処理等の配向処理（配向処理工程）を施すことも好ましい。
（２）前記第１の態様の工程（４）と同様の露光工程。
【００８３】
液晶カラーフィルタとして機能する液晶層（シート状の液晶組成物）の厚みとしては、１．５〜５μｍが好ましい。
【００８４】
更に、図１から図３を用いて以下に説明する。図１〜３は、本発明の液晶カラーフィルタを製造する工程の一形態を示す概略図である。
まず、既述の各成分を適当な溶媒に溶解し、塗布液状コレステリック液晶組成物を調製する。ここで、各成分及び溶媒は既述の通りである。
【００８５】
図１−（Ａ）のように、支持体１０（以下、「仮支持体」ともいう）を準備し、該支持体１０上に、例えばアクリル樹脂、ポリエステル、ポリウレタン等を塗布形成してクッション層（熱可塑性樹脂層）１２を設け、更にポリビニルアルコール等よりなる配向膜１４を積層する。この配向膜には、図１−（Ｂ）に示すようにしてラビング処理が施される。このラビング処理は、必ずしも必要ではないが、ラビング処理した方がより配向性を向上させることができる。
次に、図１−（Ｃ）に示すように、前記配向膜１４上に、塗布液状のコレステリック液晶組成物を塗布、乾燥しコレステリック液晶層１６を形成した後、このコレステリック液晶層１６上にカバーフィルム１８を設けて、転写材料を作製する。以下、該転写材料を転写シート２０と称する。
【００８６】
一方、図１−（Ｄ）に示すように、別の支持体２２を準備し、該支持体上に上記と同様にして配向膜２４を形成し、その表面にラビング処理を施す。以下、これをカラーフィルタ用基板２６と称する。
【００８７】
次いで、転写シート２０のカバーフィルム１８を剥がした後、図２−（Ｅ）に示すように、該転写シート２０のコレステリック液晶層１６の表面と、カラーフィルタ用基板２６の配向膜２４の表面とが接触するように重ね合わせ、図中の矢印方向に回転するロールを通してラミネートされる。その後、図２−（Ｆ）に示すように、転写シート２０の配向膜１４とクッション層１２との間で剥離され、カラーフィルタ用基板上に、コレステリック液晶層が配向膜１４と共に転写される。この場合、クッション層１２は、必ずしも仮支持体１０と共に剥離されなくてもよい。
【００８８】
転写後、図３−（Ｇ）に示すように、配向膜１４の上方に、光の透過率の異なる領域を複数有する露光マスク２８が配置され、このマスク２８を介して第一の光をコレステリック液晶層１６にパターン状に照射される。コレステリック液晶層１６には、光照射量によって螺旋ピッチが異なるように液晶化合物、カイラル化合物等が含まれており、螺旋ピッチが異なる構造が各パターン毎に、例えば、緑色（Ｇ）を反射し、青色（Ｂ）及び赤色（Ｒ）を透過させる領域、青色（Ｂ）を反射し、緑色（Ｇ）及び赤色（Ｒ）を透過させる領域、赤色（Ｒ）を反射し、緑色（Ｇ）及び青色（Ｂ）を透過させる領域を形成するように形成される。
【００８９】
次に、図３−（Ｈ）に示すように、コレステリック液晶層１６に対して、上記工程（Ｇ）における光照射と異なる照射強度で更に紫外線照射して、パターンを固定化する。その後、２−ブタノン、クロロホルム等を用いて、コレステリック液晶層１６上の不要部分（例えば、クッション層、中間層等の残存部、未露光部）を除去することにより、図３−（Ｉ）に示すように、ＢＧＲの反射領域を有するコレステリック液晶層を形成できる。
【００９０】
図１〜３に示す方法は、ラミネート方式によるカラーフィルタの製造方法の一形態であるが、カラーフィルタ用基板上に直接液晶層を塗布形成する塗布方式による製造方法であってもよい。この場合、上記態様に当てはめると、図１−（Ｄ）に示すカラーフィルタ用基板２６の配向膜２４上にコレステリック液晶層を塗布、乾燥した後、上記同様の図３−（Ｇ）〜（Ｉ）に示す工程が順次実施される。
【００９１】
これらの工程及び使用する転写材料、支持体等の材料については、本発明者らが先に提出した特願平１１−３４２８９６号及び特願平１１−３４３６６５号の各明細書に詳細に記載されている。
【００９２】
上記のように、一般式（Ｉ）で表される光反応型カイラル剤を含む液晶組成物を用いると、光量に対する液晶の螺旋構造の捻れ力の変化率が大きいので、液晶が呈し得る選択反射色の色幅が拡がり、色純度に優れた青(Ｂ)、緑(Ｇ)、赤(Ｒ)の３原色よりなる液晶カラーフィルタを得ることができる。
【００９３】
＜光学フィルム＞
本発明の光学フィルムは、前記本発明の光反応型カイラル剤より選択される少なくとも一種を少なくとも含有してなり、更に少なくとも一種の液晶性化合物（好ましくはネマチック液晶化合物）を含む態様が好適であり、広範な波長域から光学波長を任意に設定してなる。また、必要に応じて重合性モノマー、光重合開始剤、及び排除体積効果を及ぼす界面活性剤等の前記本発明の液晶組成物において列挙した他の成分等を含んでなり、前述の「液晶の捻れ構造を変化させる方法」に基づいて適宜選択された所望のパターン及び光量で光照射することにより作製できる。
【００９４】
本発明の光学フィルムは、前述した本発明の液晶組成物、及び公知の組成物に前記一般式（Ｉ）で表される化合物を含んでなるものの中から適宜選択して作製することができる。
光学フィルムの形態としては、特に制限はなく、前記液晶組成物のみから構成されたシート形態、所望の支持体や仮支持体上に液晶組成物含む層（液晶層）を設けた形態等のいずれであってもよく、更に配向膜や保護膜等の他の層（膜）が設けられていてもよい。
【００９５】
前記液晶性化合物、重合性モノマー、光重合開始剤及び他の成分としては、前記本発明の液晶組成物で使用可能なものと同様のものが使用でき、その含有量も該液晶組成物の場合と同様である。また、光学フィルムを構成する液晶組成物中における、前記一般式（Ｉ）で表される化合物の含有量も、既述の本発明の液晶組成物と同様である。
【００９６】
本発明の光学フィルムは、例えば、前記本発明の液晶組成物を用いて好適に作製することができる。
また、光学フィルムを製造する方法としては、前記液晶カラーフィルタとほぼ同様の方法により作製でき、前記露光工程を少なくとも一工程含んでなる方法であってもよい。また、選択する製造態様に応じて、前記配向処理工程、転写工程、塗布工程などの工程を経て形成されてもよい。
より具体的には、前記第１の態様、第２の態様の製造方法とほぼ同様にして作製することもできる。
【００９７】
上記のように、一般式（Ｉ）で表される光反応型カイラル剤を含む液晶組成物を用いると、光量に対する液晶の螺旋構造の捻れ力の変化率を大きく変化させることができ、非光吸収型の光学フィルムを得ることができる。例えば、液晶相をコレステリック液晶相とした場合には、液晶の選択反射する色幅が拡く、多彩な選択反射色よりなる光学フィルム、色純度に優れた原色（Ｂ,Ｇ,Ｒ)の光学フィルムなどを得ることができる。
【００９８】
＜記録媒体＞
本発明の記録媒体は、前記本発明の光反応型カイラル剤より選択される少なくとも一種を少なくとも含有してなり、更に少なくとも一種の液晶性化合物（好ましくはネマチック液晶化合物）を含む態様が好適である。また、必要に応じて、重合性モノマー、光重合開始剤、及び排除体積効果を及ぼす界面活性剤等の前記本発明の液晶組成物において列挙した他の成分等を含んでなる。
【００９９】
本発明の記録媒体は、その形態に制限はなく、液晶組成物のみからなるシート形態のものであってもよいし、所望の支持体や仮支持体（以下、「支持体等」という）上に光反応型カイラル剤を含有する液晶組成物を含む層（液晶層）が設けられた形態のものであってもよい。ここで、液晶組成物としては、前述した本発明の液晶組成物、及び公知の組成物に前記一般式（Ｉ）で表される化合物を含んでなるものの中から適宜選択できる。また更に、配向膜や保護膜等の他の層（膜）が設けられていてもよい。
【０１００】
前記液晶性化合物、重合性モノマー、光重合開始剤及び他の成分としては、前記液晶組成物で使用可能なものと同様のものが使用でき、その含有量も液晶組成物の場合と同様である。また、記録媒体を構成する液晶組成物中における、前記一般式（Ｉ）で表される化合物の含有量も、既述の本発明の液晶組成物と同様である。
【０１０１】
本発明の記録媒体は、例えば、前述した本発明の液晶組成物を支持体等上に設けることにより、好適に作製することができる。
液晶組成物を支持体等上に設ける方法としては、（１）仮支持体上に本発明の液晶組成物を含む液晶層が設けられた転写材料を用いて、支持体上に該液晶層を転写する方法、（２）支持体上に、塗布液状に調製した液晶組成物を直接塗布等する方法、等が挙げられる。
前記方法（１）及び（２）において、転写材料や塗布の方法などについては、前記本発明の液晶組成物において例示した態様（第１及び第２の態様）及び図１〜３の説明に準じて適応できる。
【０１０２】
上記のようにして作製された本発明の記録媒体は、適宜選択された所望のパターン及び光量で光照射することにより、液晶の捻れ力の変化率に応じて画像を、特にコレステリック液晶の場合には螺旋ピッチの変化率で決まる選択反射色から構成される有色画像を、形成することができる。画像の形成は、例えば、前述の「液晶の螺旋構造を変化させる方法」並びに「液晶の螺旋構造を固定化する方法」に基づいて行ってもよい。
【０１０３】
しかも、液晶構造を変化させるカイラル剤として前記一般式（Ｉ）で表される光反応型カイラル剤を用いると、光量に対する液晶の螺旋構造の捻れ力の変化率が大きいので、色再現範囲の広い画像を形成することができ、特にコレステリック液晶の場合には、液晶が選択反射する色相幅を拡げることができ、多彩で色純度の高い多色画像を形成することができる。また、捻れ力の変化率の大きいことは、画像形成の際の高感度化（高速化）にも大きく寄与する。
また、例えば、重合性の液晶性化合物や重合性モノマーを用いることにより、パターニング後の液晶を固定化することができ、十分な画像安定性に優れた画像を形成することができる。
【０１０４】
光照射する光源としては、前記本発明の液晶組成物において使用可能なものと同様の光源を用いて、好適に光記録を行うことができる。また、液晶の固定化のための光照射の場合も同様である。
【０１０５】
以上説明したように、液晶分子の螺旋構造を変化させるカイラル剤として、特に前記一般式（Ｉ）で表される光反応型カイラル剤を用いることにより、液晶の捻れ力（捻れ角）を大きく変化させることができる。特にネマチック液晶化合物を用いたコレステリック液晶の場合には、光照射により得られる選択反射波長域が拡がり、その結果、ＢＧＲの３原色の色純度をもより高めることができる。したがって、液晶の色相の選択性、鮮やかさが向上し、特に液晶カラーフィルタや光学フィルム等においては、クリアで鮮やかなカラー像の表示が可能となり、記録媒体においては、形成する画像の色相を多彩化することができる。
【０１０６】
【実施例】
以下、実施例により本発明を説明するが、本発明はこれらの実施例に限定されるものではない。尚、実施例中の「部」及び「％」は、全て「質量部」及び「質量％」を表す。
【０１０７】
（実施例１）：光照射による螺旋ピッチの変化の測定
前述した合成方法（光反応型カイラル剤（２）の合成）により合成した本発明の光反応型カイラル剤（例示化合物（２））２部をネマチック液晶組成物（ＺＬＩ−１１３２，メルク社製）９８部と混合し、ポリイミド配向膜で一軸配向処理を施したクサビ型セル（ガラス厚み１．１ｍｍ、青色板）に注入した。ここで、偏光顕微鏡を用いて室温での螺旋ピッチを測定したところ、１．１４μｍであった。これをヘリカルツイスティングパワー（ＨＴＰ）に換算すると、４４μｍ^-1となる。
【０１０８】
次いで、上記クサビ型セルに対して高圧水銀ランプから３００ｍＷ／ｃｍ²の照射強度で３分間紫外線を照射した。照射後、上記と同様にして室温での螺旋ピッチを測定したところ、３．６μｍに変化していた。これをＨＴＰに換算すると１４μｍ^-1となる。従って、ＨＴＰ変化率は３．１４であった。
上記のように、紫外線の照射により螺旋の捻れ力（ＨＴＰ）を大きく変化させることができた。尚、コンタクト法により、紫外線照射前後における捻れの向きを確認したところ、照射の前後とも右捻れであった。
【０１０９】
（実施例２）：広帯域円偏光反射板の作製
(1) 基板の準備
ガラス基板上に、ポリイミド配向膜（ＬＸ−１４００，日立化成デュポン（株）製）塗布液をスピンコーターにより塗布し、１００℃のオーブンで５分間乾燥した後、２５０℃のオーブンで１時間焼成して配向膜を形成した。更に、該膜の表面をラビング処理により配向処理して配向膜付ガラス基板を作製した。
【０１１０】
(2) 作製
上記より得た配向膜付ガラス基板の該配向膜上に、下記処方にて調製した塗布液をバーコーターにより塗布し、１１０℃のホットプレート上にて５分間保持した後、該温度下で３６５ｎｍに光源中心波長を持つバンドパスフィルタを介して、超高圧水銀灯により５分間光照射を行った。尚、下記本発明の光反応型カイラル剤（例示化合物（３））は、既述の合成方法と類似の方法により合成した。
【０１１１】
次いで、１１０℃に維持した状態で暗所に５分間保持し、その後バンドパスフィルタを取り除き、窒素ガスを吹き付けながら上記と同様の超高圧水銀灯により照射エネルギー５００ｍＪ／ｃｍ²で更に全面を露光し、重合硬化した。以上のようにして、円偏光反射板を作製した。
【０１１２】
【化１２】

【０１１３】
上記より得た円偏光反射板は、４５０〜６３０ｎｍに渡る広範な波長領域の選択反射を示し、広帯域円偏光反射板として十分な帯域特性を有していた。しかも、５５０ｎｍの選択反射波長での右円偏光反射率は９８％であった。
【０１１４】
（実施例３）：液晶カラーフィルタの作製
(1) フィルタ基板の準備
ガラス基板上にポリイミド配向膜（ＬＸ−１４００，日立化成デュポン（株）製）塗布液をスピンコーターにより塗布し、１００℃のオーブンで５分間乾燥した後、２５０℃のオーブンで１時間焼成して配向膜を形成した。更に、該膜の表面をラビング処理により配向処理して配向膜付ガラス基板を作製した。
【０１１５】
（２）フィルタ層の形成
上記より得た配向膜付ガラス基板の該配向膜上に、下記処方にて調製した感光性樹脂層用塗布液をスピンコーターにより塗布し、これを１１０℃のオーブンで２分間乾燥して感光性樹脂層を形成した。尚、下記本発明の光反応型カイラル剤（例示化合物（２））は、既述の合成方法にしたがって合成した。
【０１１６】
【化１３】

【０１１７】
次いで、ガラス基板の表面で接触するように１１０℃のホットプレート上に５分間保持し、感光性樹脂層を発色させた。更に、該感光性樹脂層上に、透過率が三段階に異なり（０％、４６％、９２％）、それぞれの領域が青色画素用、緑色画素用、赤色画素用に対応して配列されたフォトマスクと３６５ｎｍに中心を持つバンドパスフィルタとを介して超高圧水銀灯を配置し、このフォトマスク及びバンドパスフィルタを通して超高圧水銀灯により照射しパターニングした。このときの照射エネルギーは赤色画素用に対して３００ｍＪ／ｃｍ²であり、照射強度は３０ｍＷ／ｃｍ²であった。
【０１１８】
次に、フォトマスクとバンドパスフィルタとを取り除き、窒素ガスを吹き付けながら上記と同様の超高圧水銀灯により照射エネルギー５００ｍＪ／ｃｍ²で更に全面を露光し、重合硬化した。更に、フィルタ部（感光性樹脂層）の硬化度を促進するために、２２０℃のオーブンで２０分間焼成し、赤色画素、緑色画素、青色画素パターンが形成されたカラーフィルタを得た。
上記パターニング時において、照射によって液晶の螺旋ピッチ（液晶の捻れ力）を大きく変化させることができ、色純度の高い赤色、緑色、青色よりなる画素パターンを形成することができた。
【０１１９】
（実施例４）：ＳＴＮ素子用光学補償膜の作製
厚み８０μｍのトリアセチルセルロース（ＴＡＣ）上に、ケン化度９９．５％のポリエチレンビニルアルコール（ＰＶＡ）膜をバーコート法により形成し、１１０℃下で３分間加熱した。該ＰＶＡ膜上にラビング処理を施し、更に下記処方にて調製した塗布液をバーコーターにより加温塗布し、これを１２０℃のオーブンで３分間乾燥して成膜した。尚、下記本発明の光反応型カイラル剤（例示化合物（５））は、既述の合成方法にしたがって合成した。
【０１２０】
【化１４】

【０１２１】
次いで、温度１００℃の下、前記膜上から高圧水銀ランプを用いて紫外線照射（照射エネルギー１０００ｍＪ／ｃｍ²）を行って膜を重合硬化させ、ＳＴＮ素子用光学補償膜を作製した（以下、「ＳＴＮ補償膜」と称する。）。この時のＳＴＮ補償膜の膜厚を測定したところ５．０μｍであった。また、該ＳＴＮ補償膜の偏光透過スペクトルプロファイルから、液晶分子の配向（螺旋構造）が２４０度で膜厚方向に捻れ、その螺旋の捻れ角（回転角）が２４０度であることが判った。
また、この膜を該膜とは逆向きの捻れ角（−２４０度）を持つＳＴＮ補償膜を用意し、これらを合致した部分の液晶分子が直交するように重ね合わせ、互いに吸収軸が直交する２枚の偏光板の間に挿入して、目視により観察したところ良好な黒色を示した。したがって、上記より形成された膜（ＳＴＮ補償膜）は、ＳＴＮ素子用光学補償膜として作用していることが確認できた。
【０１２２】
（実施例５）：ＴＮ素子用のリバースツイストドメインの発生防止
ＩＴＯ膜付きのガラス基板の該ＩＴＯ膜上に、ポリイミド配向膜（ＬＸ−１４００，日立化成デュポン（株）製）塗布液をスピンコーターにより塗布し、１００℃のオーブンで５分間乾燥した後、２５０℃のオーブンで１時間焼成して配向膜を形成した。更に、該膜の表面にラビング処理を施してラビング角度が９０度になるように配向処理し、配向膜付ガラス基板を２枚作製した。
上記配向膜付ガラス基板の配向膜が互いに対向するように配置し、直径６μｍのスペーサビーズを混合した２液性エポキシ樹脂接着剤により貼り合わせ、駆動用セルを形成した。該セルの厚みを光干渉法により測定したところ５．４μｍであった。
【０１２３】
前記セル中に、下記組成よりなる組成物を注入した。尚、下記本発明の光反応型カイラル剤（例示化合物（２））は、既述の合成方法にしたがって合成した。
〔組成物〕
・ネマチック液晶組成物（ＺＬＩ−１１３２，メルク社製）・・・９９．９％
・本発明の光反応型カイラル剤（既述の例示化合物（２））・・・ ０．１％
【０１２４】
次に、互いに吸収軸が直交する二枚の偏光板の間に、注入後の駆動用セルを挿入して目視により観察したところ、リバースツイストドメインの発生は認められなかった。したがって、リバースツイストの発生によるコントラストの低下がなく、コントラスト、色純度に優れた画像表示が期待できる。
【０１２５】
【発明の効果】
本発明によれば、液晶性化合物の配向を制御し得、かつ光による液晶の捻れ力（捻れ角、螺旋ピッチ）の変化率（以下、「捻れ変化率」ということがある。）が大きく、例えばコレステリック液晶相の場合には、３原色（Ｂ、Ｇ、Ｒ）を含む広範な選択反射が可能で、色純度の高い３原色を表示させ得る光反応型カイラル剤を提供することができる。
本発明によれば、光により液晶の捻れ力を変化させ、且つその捻れ変化率の大きい光反応型カイラル剤を含み、光により液晶分子の配向状態を大きく立体的に制御して光学特性を変化しうる液晶組成物、例えばコレステリック液晶の場合には、光照射により３原色を含む広範な選択反射色を示し、しかも色純度に優れた３原色の表示が可能な液晶組成物を提供することができる。
本発明によれば、捻れ変化率の大きい光反応型カイラル剤を含む液晶組成物に光照射して液晶の捻れ力（捻れ角）を大きく変化させうる、液晶の捻れ構造を変化させる方法を提供することができる。
本発明によれば、光照射により液晶の捻れ力を大きく変化させ得る光反応型カイラル剤を含み、色純度の高い液晶カラーフィルタを提供することができる。
本発明によれば、光照射により液晶の捻れ力を大きく変化させ得る光反応型カイラル剤を含む非光吸収型の光学フィルム、例えばコレステリック液晶相の場合には、選択反射域が広範で色純度の高い光学フィルムを提供することができる。
本発明によれば、光照射により液晶の捻れ力を大きく変化させ得る光反応型カイラル剤を含み、画像様に光量を変化させることにより鮮明な画像を形成し得る記録媒体、例えば液晶相がコレステリック液晶相の場合には、色相が広範で色純度の高い選択反射色よりなる画像を形成し得る記録媒体を提供することができる。
【図面の簡単な説明】
【図１】 本発明の液晶カラーフィルタを製造する工程の一部を示す概略図である。
【図２】 本発明の液晶カラーフィルタを製造する工程の一部を示す概略図である。
【図３】 本発明の液晶カラーフィルタを製造する工程の一部を示す概略図である。
【符号の説明】
１０ 支持体（仮支持体）
１２ クッション層（熱可塑性樹脂層）
１４，２４ 配向膜
１６ 液晶層（液晶組成物）
１８ カバーフィルム
２０ 転写シート
２２ 基板
２６ カラーフィルタ用基板
２８ 露光マスク[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel photoreactive chiral agent that causes a change in the structure of liquid crystal, a liquid crystal composition containing the same, an optical film, a liquid crystal color filter and a recording medium, and a method for changing the twisted structure of a liquid crystal.
[0002]
[Prior art]
In recent years, liquid crystal materials such as cholesteric liquid crystals having a spiral structure and exhibiting various selective reflection colors due to the twisting force (twist angle) of the spiral have been attracting attention, and the materials have selective reflectivity and color purity of selectively reflected light. Therefore, it is widely used for optical films, liquid crystal color filters, recording media, and the like.
For example, a color filter used for a color liquid crystal display or the like generally includes red (R), green (G), and blue (B) pixels and a black matrix for improving display contrast in the gaps. Configured. Conventionally, such color filters are mainly used in which a pigment is dispersed in a resin or dyes are dyed, and the manufacturing method is also such that a colored resin solution is applied onto a glass substrate by spin coating or the like. In general, a color resist layer is formed and patterning is performed by a photolithography method to form a color filter pixel or a color pixel is directly printed on a substrate.
[0003]
However, for example, a manufacturing method using a printing method has a disadvantage that it is difficult to form a high-definition image pattern with a low pixel resolution. A manufacturing method using a spin coating method has a large material loss and a large-area substrate. There has been a drawback that the coating unevenness when applied to is large. Moreover, according to the electrodeposition manufacturing method, a color filter having a relatively high resolution and little unevenness of the colored layer can be obtained, but it has the disadvantage that the manufacturing process is complicated and the liquid management is difficult.
From the above, as a manufacturing process of the color filter, there has been a demand for a manufacturing method that can easily manufacture a high-quality color filter with low material loss and high efficiency.
[0004]
On the other hand, the performance of the color filter is required to have high transmittance and high color purity. In recent years, the method using a dye optimizes the type and dyeing resin of the dye, or the method using a pigment is more finely dispersed. Improvements to the above requirements have been achieved by using pigments. However, the demands on the transmittance and color purity of color filters in recent liquid crystal display (LCD) panels are extremely high. Especially in the color filters for reflective LCD, paper white white display, contrast and color reproducibility are compatible. However, in the conventional manufacturing method, the color filters manufactured by dyeing the resin in the resin or dispersing the pigment are all light absorption type color filters, so that the transmittance is further increased. The improvement of color purity due to the improvement almost reached the limit.
[0005]
In light of the above situation, a polarization-use color filter having a cholesteric liquid crystal as a main component is known. This polarization-based color filter displays an image by reflecting a certain amount of light and transmitting the other, so it has higher light utilization efficiency and is superior to light absorption color filters in terms of transmittance and color purity. Performance. On the other hand, from the viewpoint of obtaining a uniform thickness, a method of forming a film on a substrate using a spin coating method or the like has been generally performed as the manufacturing method, but there is a problem that material loss is large, and in terms of cost. It was disadvantageous.
[0006]
A method of using a photoreactive chiral compound (chiral compound) as a means for solving the above problems, ensuring the uniformity of color purity of the color filter film, and reducing the number of manufacturing steps. Is useful. In this method, when a liquid crystal composition containing a photoreactive chiral compound is irradiated in a pattern with light having a reaction wavelength of the chiral compound, the reaction of the chiral compound proceeds in accordance with the intensity of the irradiation energy. Since the spiral pitch (helical twist angle) changes, the principle that a selective reflection color is formed for each pixel only by pattern exposure with a light amount difference is used. That is, there is an advantage that the number of times of patterning at the time of forming the color filter can be completed by one mask exposure using masks having different amounts of transmitted light.
Therefore, after patterning by irradiating light like an image, a film functioning as a color filter can be formed by fixing the patterned cholesteric liquid crystal compound. This can also be applied to optical films and image recording.
[0007]
In particular, when a color filter is produced by a single mask exposure, it is desired that the three primary colors B (blue), G (green), and R (red) can be formed with high color purity by a single exposure. However, when the rate of change in the twist of the liquid crystal is small, sufficient color purity cannot be obtained. Therefore, from the viewpoint of displaying the three primary colors with high color purity in a single exposure, practically, as a photoreactive chiral compound to be used, the twist change rate that can greatly change the twisting force of the helical structure of the liquid crystal compound. It is necessary to use a chiral compound (chiral agent) having a large size. That is, by using a chiral compound having a large twist change rate, the width of the hue selectively reflected by the change in the amount of light is expanded.
[0008]
By the way, Japanese Patent Application Laid-Open No. 11-248943 discloses that a polymerizable mesogenic compound having an isosorbide skeleton in a chiral mother nucleus is used as a chiral compound constituting a broadband reflective polarizing plate. This polymerizable mesogenic compound can act on the liquid crystal compound to change the helical structure of the liquid crystal. However, when the reflection wavelength band of the polarizing plate described in the publication, that is, the helical structure (helical twisting force) of the liquid crystal is changed so as to exhibit a desired selective reflection, the change is adjusted with the mesogenic compound and non-chiral. It is carried out according to the mixing ratio (use amount) with the compound (liquid crystal), and light and its light quantity are not involved at all. That is, in the publication, there is no suggestion that the helical structure (helical twisting force) of the liquid crystal is changed by changing the amount of light, and the compounds exemplified in the publication are useful in terms of the rate of change of the twisting force with respect to light. There is no suggestion that it is.
[0009]
As described above, in the case of a cholesteric liquid crystal phase including a nematic liquid crystal compound, for example, it has photoreactivity capable of changing the alignment structure such as the helical pitch (twisting force, helical twist angle) of the liquid crystal depending on the amount of light to be irradiated. The wavelength range that can be selectively reflected is wide and shows a wide variety of selective reflections. In particular, the three primary colors (B, G, R) can be displayed with high color purity, and the helical pitch (twisting force) is greatly changed. At present, no photoreactive chiral agent (photoreactive chiral agent) that can be used has been provided.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to solve the conventional problems and achieve the following objects. That is,
In the present invention, first, the orientation of the liquid crystal compound can be controlled, and the change rate (hereinafter, referred to as “twist change rate”) of the twisting force (twist angle, spiral pitch) of the liquid crystal due to light. For example, in the case of a cholesteric liquid crystal phase, it is possible to provide a photoreactive chiral agent capable of displaying a wide range of selective reflections including three primary colors (B, G, R) and displaying three primary colors with high color purity. Objective.
Second, it includes a photoreactive chiral agent that changes the twisting force of the liquid crystal by light and has a large rate of change in twist, and can change the optical characteristics by controlling the orientation of the liquid crystal molecules largely and three-dimensionally by light. In the case of a liquid crystal composition, for example, a cholesteric liquid crystal, an object is to provide a liquid crystal composition that exhibits a wide range of selective reflection colors including three primary colors by light irradiation and is capable of displaying three primary colors with excellent color purity. To do.
[0011]
Thirdly, the present invention changes the twist structure of the liquid crystal, which can change the twist force (twist angle) of the liquid crystal by irradiating light to the liquid crystal composition containing the photoreactive chiral agent having a large twist change rate. It is an object of the present invention to provide a method. Fourthly, an object of the present invention is to provide a liquid crystal color filter having a high color purity, including a photoreactive chiral agent capable of greatly changing the twisting force of liquid crystal by light irradiation. Fifth, in the case of a non-light-absorbing optical film containing a photoreactive chiral agent that can greatly change the twisting power of liquid crystal by light irradiation, such as a cholesteric liquid crystal phase, the selective reflection range is wide and the color purity is high. An object is to provide an optical film. Sixth, a recording medium containing a photoreactive chiral agent that can change the twisting force of the liquid crystal by light irradiation and capable of forming a clear image by changing the amount of light like an image, for example, the liquid crystal phase is a cholesteric liquid crystal phase. In this case, an object of the present invention is to provide a recording medium capable of forming an image having a selective reflection color with a wide hue and high color purity.
[0012]
[Means for Solving the Problems]
Means for solving the above-mentioned problems are as follows. That is,
<1> A photoreactive chiral agent comprising a compound represented by the following general formula (I), wherein the twisting force of liquid crystal is changed by light irradiation.
[0013]
[Chemical formula 2]

[0014]
[Wherein, R represents a hydrogen atom, an alkoxy group having 1 to 15 carbon atoms, an acryloyloxyalkyloxy group having 3 to 15 carbon atoms, or a methacryloyloxyalkyloxy group having 4 to 15 carbon atoms. ]
[0015]
<2> In the compound represented by the general formula (I), in the above <1>, R is an acryloyloxyalkyloxy group having 3 to 15 carbon atoms in total or a methacryloyloxyalkyloxy group having 4 to 15 carbon atoms in total. The photoreactive chiral agent described.
<3> The photoreactive chiral agent according to <1>, wherein in the compound represented by the general formula (I), R is a hydrogen atom or an alkoxy group having 1 to 15 carbon atoms.
[0016]
<4> A liquid crystal composition comprising at least one selected from the photoreactive chiral agent according to any one of <1> to <3>.
<5> The liquid crystal composition according to <4>, which contains at least a photoreactive chiral agent, a cholesteric liquid crystal compound, and a surfactant. As the surfactant, a nonionic surfactant is preferable.
[0017]
<6> A method for changing a twisted structure of liquid crystal, wherein the liquid crystal composition according to <4> or <5> is irradiated with light to change the twisting force of the liquid crystal.
<7> A liquid crystal color filter comprising at least one selected from the photoreactive chiral agent according to any one of <1> to <3>.
[0018]
<8> An optical film comprising at least one selected from the photoreactive chiral agent according to any one of <1> to <3>.
<9> A recording medium comprising at least one selected from the photoreactive chiral agent according to any one of <1> to <3>.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in order.
<Photoreactive chiral agent>
The photoreactive chiral agent of the present invention comprises a compound represented by the following general formula (I), can control the alignment structure of the liquid crystalline compound, and can also be used to control the helical pitch of the liquid crystal, that is, the twist of the helical structure, upon irradiation with light. It has the property that the force (HTP: helical twisting power) can be changed. That is, a compound that causes a change in the twisting force of a helical structure induced in a liquid crystal compound, preferably a nematic liquid crystal compound, by light irradiation (ultraviolet light to visible light to infrared light), and as a necessary site (molecular structural unit), chiral It has a site (chiral site) and a site that undergoes a structural change upon irradiation with light.
Moreover, the photoreactive chiral agent represented by the following general formula (I) can greatly change the HTP of liquid crystal molecules. Therefore, for example, in the case of a cholesteric liquid crystal (liquid crystal phase) using a nematic liquid crystal compound as a liquid crystal compound, selection over a wide wavelength range including three primary colors of B (blue), G (green), and R (red) Reflection is possible. That is, the selective reflection characteristic of the wavelength of light is determined by the twist angle of the helical structure of the liquid crystal molecules, so that the color width for selective reflection becomes wider and useful as the angle changes greatly.
[0020]
The HTP represents the twisting force of the helical structure of the liquid crystal, that is, HTP = 1 / (pitch × chiral agent concentration [mass fraction]). For example, the helical pitch of the liquid crystal molecules at a certain temperature (the helical structure One period; μm) is measured, and this value is converted from the concentration of the chiral agent (chiral agent) [μm^-1] Can be obtained.
When the selective reflection color is formed by the illuminance of light by the photoreactive chiral agent, the rate of change of the HTP (= HTP before irradiation / HTP after irradiation) is as follows. 5 or more is preferable, and 2.5 or more is more preferable. When HTP becomes larger after irradiation, 0.7 or less is preferable, and 0.4 or less is more preferable.
[0021]
Next, the compound represented by formula (I) will be described.
[Chemical 3]

[0022]
In the above formula, R represents a hydrogen atom, an alkoxy group having 1 to 15 carbon atoms, an acryloyloxyalkyloxy group having 3 to 15 carbon atoms, or a methacryloyloxyalkyloxy group having 4 to 15 carbon atoms.
Examples of the alkoxy group having 1 to 15 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a hexyloxy group, and a dodecyloxy group. Among these, an alkoxy group having 1 to 12 carbon atoms is preferable. An alkoxy group having 1 to 8 carbon atoms is particularly preferable.
[0023]
Examples of the acryloyloxyalkyloxy group having 3 to 15 carbon atoms include acryloyloxyethyloxy group, acryloyloxybutyloxy group, acryloyloxydecyloxy group and the like, and among them, acryloyloxy having 5 to 13 carbon atoms. An alkyloxy group is preferable, and an acryloyloxyalkyloxy group having 5 to 11 carbon atoms is particularly preferable.
[0024]
Examples of the methacryloyloxyalkyloxy group having 4 to 15 carbon atoms include a methacryloyloxyethyloxy group, a methacryloyloxybutyloxy group, and a methacryloyloxydecyloxy group, and among them, a methacryloyloxy group having 6 to 14 carbon atoms. An alkyloxy group is preferable, and a methacryloyloxyalkyloxy group having 6 to 12 carbon atoms is particularly preferable.
[0025]
The molecular weight of the photoreactive chiral agent represented by the general formula (I) is preferably 300 or more. Moreover, a thing with high solubility with the liquid crystalline compound mentioned later is preferable, and the thing whose solubility parameter SP value approximates to a liquid crystalline compound is more preferable.
[0026]
Hereinafter, although the specific example (Exemplary compound (1)-(15)) of a compound represented by the said general formula (I) is shown, it is not restrict | limited to these in this invention.
[0027]
[Formula 4]

[0028]
[Chemical formula 5]

[0029]
[Chemical 6]

[0030]
Next, synthesis examples of the photoreactive chiral agent of the present invention (compound represented by the general formula (I)) will be given. The numbers in parentheses of the photoreactive chiral agent represent the numbers of the photoreactive chiral agents (exemplary compounds) exemplified in the above [Chemical 4] to [Chemical 6].
[0031]
-Synthesis of photoreactive chiral agent (2)-
4-Methoxycinnamic acid (15 g, 0.084 mole) and dimethylformamide (2-3 drops) were dissolved in tetrahydrofuran (100 mL), and oxalyl chloride (10 mL, 0.13 mole) was further dissolved in tetrahydrofuran (50 mL). Was added dropwise and allowed to react for 2 hours. The solvent and excess oxalyl chloride in the reaction solution were distilled off under reduced pressure, diluted with tetrahydrofuran (100 mL), and isosorbide (5.5 g, 0.038 mole) was added. While stirring, pyridine (27 mL, 0.33 mole) dissolved in tetrahydrofuran (50 mL) was added dropwise and stirred for 3 hours. Thereafter, 10% hydrochloric acid (100 mL) and ethyl acetate (200 mL) were added to the reaction solution, and the mixture was stirred and separated. The obtained organic layer was washed once with saturated brine (100 mL), twice with saturated aqueous sodium bicarbonate (100 mL) and twice with saturated brine (100 mL), and dried over magnesium sulfate. Further, the organic solvent was distilled off under reduced pressure, and then purified by silica gel column chromatography using a mixed solution of n-hexane-ethyl acetate (3: 2 v / v) as a developing solvent, and recrystallized (n-hexane-ethyl acetate). To give colorless crystals (9.8 g, 56%).
[0032]
The results (data) of identifying colorless crystals obtained from the above are shown below.
Melting point Tm = 113.7 ° C. [α]_D ^{twenty five}-158 [deg.] (C 0.50, EtOAc).
¹H-NMR (CDCl_Three): Δ (in ppm from tetramethylsilane) 7.75-7.60 (2H, dd), 7.50-7.45 (4H, dd), 6.94-6.88 (4H, dd), 6. 40-6.25 (2H, dd), 5.36-5.26 (2H, m), 4.95 (1H, t), 4.60 (1H, d), 4.15-3.90 ( 8H, m), 3.85 (6H, s).
[0033]
-Synthesis of photoreactive chiral agent (5)-
Trans-4-coumaric acid (20 g, 0.12 mole) and potassium carbonate (33 g, 0.24 mole) were dispersed in dimethylformamide (100 mL) and heated on an oil bath while heating n-bromobutane (50 g, 0.37 mole). ) Was added dropwise. After stirring for 3 hours, the insoluble matter was filtered off, diluted with ethyl acetate (400 mL), and washed with saturated brine (200 mL). Furthermore, after distilling off the organic solvent under reduced pressure, ethanol (100 mL) and potassium hydroxide (20 g, 0.36 mole) dissolved in water (50 mL) were added and refluxed for 1 hour. The reaction solution was poured into dilute hydrochloric acid, and the precipitated crystals were separated by filtration and dissolved in chloroform (500 mL). The obtained organic layer was washed with saturated brine and dried over magnesium sulfate. Further, the organic solvent was distilled off under reduced pressure, and then recrystallization (n-hexane-ethyl acetate) was performed to obtain 4-n-butoxycinnamic acid (22.7 g, 84%) as colorless crystals.
[0034]
The obtained 4-n-butoxycinnamic acid (5 g, 0.023 mole) and dimethylformamide (2-3 drops) were dissolved in tetrahydrofuran (50 mL), and oxalyl chloride (2.9 mL, 0.034 mole) was further added thereto. What was dissolved in tetrahydrofuran (30 mL) was added dropwise and reacted for 2 hours. The solvent of the reaction solution and excess oxalyl chloride were distilled off under reduced pressure, diluted with tetrahydrofuran (50 mL), and isosorbide (1.5 g, 0.010 mole) was added. While stirring, pyridine (11 mL, 0.14 mole) dissolved in tetrahydrofuran (20 mL) was added dropwise and stirred for 3 hours. Thereafter, 10% hydrochloric acid (50 mL) and ethyl acetate (100 mL) were added to the reaction mixture, and the mixture was stirred and separated. The obtained organic layer was washed once with saturated brine (50 mL), twice with saturated aqueous sodium hydrogen carbonate (50 mL), twice with saturated brine (50 mL), and dried over magnesium sulfate. Further, the organic solvent was distilled off under reduced pressure, and then purified by silica gel column chromatography using a mixed solution of n-hexane-ethyl acetate (2: 1 v / v) as a developing solvent, and recrystallized (n-hexane-ethyl acetate). To obtain a colorless crystalline powder (1.4 g, 25%).
[0035]
The results (data) of identifying the colorless crystalline powder obtained above are shown below.
Melting point Tm = 132.4 ° C., [α]_D ^{twenty five}-115.0 ° (c0.10, EtOAc).
¹H-NMR (CDCl_Three): Δ (in ppm from tetramethylsilane) 7.75-7.65 (2H, dd), 7.50-7.45 (4H, dd), 6.90-6.85 (4H, dd), 6. 40-6.26 (2H, dd), 5.35-5.25 (2H, m), 4.94 (1H, t), 4.60 (1H, d), 4.13-3.95 ( 8H, m), 1.94-1.65 (4H, m), 1.55-1.44 (4H, m), 0.95 (6H, t).
[0036]
-Synthesis of photoreactive chiral agent (12)-
Trans-4-coumaric acid (20 g, 0.12 mole), potassium iodide (24 g, 0.14 mole) and potassium carbonate (85 g, 0.62 mole) were mixed in a mixture of dimethylformamide (200 mL) and water (100 mL). 6-Chlorohexanol (68 g, 0.50 mole) was added dropwise while being dispersed and heated in an oil bath. After stirring for 3 hours, the mixture was diluted with ethyl acetate (400 mL) and washed with saturated brine (400 mL). Further, after the organic solvent was distilled off under reduced pressure, ethanol (200 mL) and potassium hydroxide (20 g, 0.36 mole) dissolved in water (50 mL) were added, and the mixture was refluxed for 1 hour. The reaction solution was poured into dilute hydrochloric acid, and the precipitated crystals were filtered off and dried to obtain 4- (6-hydroxyhexyloxy) cinnamic acid (22 g, 64%) as a colorless crystalline powder.
[0037]
The obtained 4- (hydroxyhexyloxy) cinnamic acid (6 g, 0.023 mole) and N, N-dimethylaniline (6.6 g, 0.054 mole) were dissolved in tetrahydrofuran (50 mL), and this was further added at room temperature. Acroyl chloride (4.4 g, 0.049 mole) dissolved in tetrahydrofuran (20 mL) was added dropwise. After stirring for 4 hours after dropping, the reaction solution was poured into 10% hydrochloric acid, and the precipitated crystals were separated by filtration. The obtained crude crystals were dissolved in ethyl acetate (100 mL), and the organic layer was washed with saturated brine and dried over magnesium sulfate. After distilling off the organic solvent under reduced pressure, the crude crystals were recrystallized (n-hexane-ethyl acetate) to give colorless crystalline powder of 4- (6-acryloyloxyhexyloxy) cinnamic acid (3.9 g, 54%). Got.
[0038]
The obtained 4- (6-acryloyloxyhexyloxy) cinnamic acid (3 g, 9.4 mmole) and dimethylformamide (2-3 drops) were dissolved in tetrahydrofuran (50 mL), and further oxalyl chloride (1. 2 mL, 0.014 mole) dissolved in tetrahydrofuran (10 mL) was added dropwise and reacted for 2 hours. The solvent of the reaction solution and excess oxalyl chloride were distilled off under reduced pressure, diluted with tetrahydrofuran (50 mL), and isosorbide (0.6 g, 4.1 mmole) was added. While further stirring, pyridine (4.5 mL, 0.056 mole) dissolved in tetrahydrofuran (20 mL) was added dropwise and stirred overnight. Thereafter, 10% hydrochloric acid (50 mL) and ethyl acetate (100 mL) were added to the reaction mixture, and the mixture was stirred and separated. The obtained organic layer was washed once with saturated brine (50 mL), twice with saturated aqueous sodium hydrogen carbonate (50 mL), twice with saturated brine (50 mL), and dried over magnesium sulfate. After distilling off the organic solvent under reduced pressure, the mixture was purified by silica gel column chromatography using a mixed solution of n-hexane-ethyl acetate (3: 2 v / v) as a developing solvent, and colorless crystalline powder (1.1 g, 38% )
[0039]
The results (data) of identifying the colorless crystalline powder obtained above are shown below.
Melting point Tm = 70.5 ° C., [α]_D ^{twenty five}−103.0 ° (c 0.11, EtOAc).
¹H-NMR (CDCl_Three): Δ (in ppm from tetramethylsilane) 7.75-7.65 (2H, dd), 7.50-7.45 (4H, dd), 6.92-6.88 (4H, dd), 6. 45-5.88 (8H, m), 5.35-5.25 (2H, m), 4.95 (1H, t), 4.60 (1H, d), 4.20-3.85 ( 8H, m), 1.94-1.65 (4H, m), 1.85-1.45 (16H, m).
[0040]
The photoreactive chiral agent represented by the general formula (I) can greatly change the twisting force of the helical structure of the liquid crystal, and has a structure in which one or more polymerizable linking groups are introduced into the structure. In this case, the heat resistance of the liquid crystal composition or the liquid crystal composition, for example, a liquid crystal color filter or an optical film can be improved.
[0041]
In addition, the photoreactive chiral agent of the present invention can be used in combination with a chiral agent having no photoreactivity such as a chiral compound having a large temperature dependency of torsional force. Examples of the known chiral agent having no photoreactivity include, for example, JP-A No. 2000-44451, JP-T-10-509726, WO98 / 00428, JP-T 2000-506873, JP-T-9-506088, Liquid. Examples include chiral agents described in Crystals (1996, 21, 327), Liquid Crystals (1998, 24, 219) and the like.
[0042]
<Liquid crystal composition>
The liquid crystal composition preferably contains at least one selected from the photoreactive chiral agents of the present invention, and further includes at least one liquid crystalline compound (preferably a nematic liquid crystal compound). The liquid crystalline compound may or may not have a polymerizable group. If necessary, other components such as a polymerizable monomer, a polymerization initiator, a binder resin, a solvent, a surfactant, a polymerization inhibitor, a thickener, a dye, a pigment, an ultraviolet absorber, and a gelling agent are added. May be included.
In the liquid crystal composition of the present invention, it is particularly preferable to use a surfactant in combination. For example, when forming a layer by applying a coating liquid crystal composition, the orientation state at the air interface on the surface of the layer can be controlled three-dimensionally, and a selective reflection wavelength with higher color purity can be obtained.
[0043]
(Photoreactive chiral agent)
The photoreactive chiral agent includes the above-described photoreactive chiral agent of the present invention, and controls the alignment structure of the liquid crystal molecules in a three-dimensional manner. The helical structure of the compound, preferably a nematic liquid crystal compound, is changed. In a system including a nematic liquid crystal compound, selective reflection colors in a wide wavelength range can be developed.
There is no restriction | limiting in particular as content of the photoreactive chiral agent in a liquid-crystal composition, Although it can select suitably, About 2-30 mass% is preferable.
[0044]
(Liquid crystal compound)
The liquid crystal compound can be appropriately selected from liquid crystal compounds, polymer liquid crystal compounds, and polymerizable liquid crystal compounds having a refractive index anisotropy Δn of 0.10 to 0.40. For example, a smectic liquid crystal compound, a nematic liquid crystal compound, and the like can be given, and among them, a nematic liquid crystal compound is preferable. For example, a cholesteric liquid crystal composition (cholesteric liquid crystal phase) can be obtained by using a nematic liquid crystal compound as the liquid crystal compound and using it together with the photoreactive chiral agent represented by the general formula (I).
While the liquid crystalline compound is in a liquid crystal state at the time of melting, it can be aligned, for example, by using an alignment substrate that has been subjected to an alignment treatment such as a rubbing treatment. Further, when the liquid crystal state is fixed in a solid phase, means such as cooling and polymerization can be used.
[0045]
Specific examples of the liquid crystal compound include the following compounds. However, the present invention is not limited to these.
[0046]
[Chemical 7]

[0047]
[Chemical 8]

[0048]
[Chemical 9]

[0049]
In said formula, n represents the integer of 1-1000.
In each of the above exemplary compounds, those in which the aromatic ring linking group is changed to the following structure can be cited as suitable as well.
[0050]
[Chemical Formula 10]

[0051]
Among these, from the viewpoint of ensuring sufficient curability and heat resistance of the layer, a liquid crystalline compound having a polymerizable group or a crosslinkable group in the molecule is preferable.
[0052]
As content of the said liquid crystalline compound, 30-99.9 mass% of the total solid (mass) of a liquid crystal composition is preferable, and 50-95 mass% is more preferable. When the content is less than 30% by mass, alignment may be insufficient, and in particular in the case of a cholesteric liquid crystal, a desired selective reflection color may not be obtained.
[0053]
(Polymerizable monomer)
In the liquid crystal composition of the present invention, a polymerizable monomer may be used in combination for the purpose of improving the degree of curing such as film strength. When the polymerizable monomer is used in combination, the helical structure (selective reflectivity) is fixed and fixed after changing (patterning) the twisting force of the liquid crystal by light irradiation (for example, after forming the distribution of selective reflection wavelength). The strength of the liquid crystal composition after conversion can be further improved. However, when the liquid crystalline compound has an unsaturated bond in the same molecule, it is not necessarily added.
[0054]
Examples of the polymerizable monomer include monomers having an ethylenically unsaturated bond, and specific examples include polyfunctional monomers such as pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate.
Specific examples of the monomer having an ethylenically unsaturated bond include the compounds shown below, but the invention is not limited to these.
[0055]
Embedded image

[0056]
The addition amount of the polymerizable monomer is preferably 0.5 to 50% by mass of the total solid content (mass) of the liquid crystal composition. If the addition amount is less than 0.5% by mass, sufficient curability may not be obtained, and if it exceeds 50% by mass, the alignment of liquid crystal molecules is inhibited and sufficient color development cannot be obtained. Sometimes.
[0057]
(Photopolymerization initiator)
The liquid crystal composition of the present invention can also contain a photopolymerization initiator. The photopolymerization initiator is used in combination to promote the polymerization reaction of the polymerizable group, and the light irradiation changes the helical pitch (twisting force) of the liquid crystal. The strength of the liquid crystal composition after fixing can be further improved by fixing the spiral structure after the fixing. When a polymerization reaction by a polymerizable liquid crystalline compound is used for fixing the helical structure of the liquid crystal, it is preferable to add a photopolymerization initiator. For example, when the liquid crystal phase is a cholesteric liquid crystal phase, a desired helical pitch can be stably obtained, and a selective reflection color with high color purity can be ensured.
[0058]
The photopolymerization initiator can be appropriately selected from known ones such as p-methoxyphenyl-2,4-bis (trichloromethyl) -s-triazine, 2- (p-butoxystyryl)- 5-trichloromethyl 1,3,4-oxadiazole, 9-phenylacridine, 9,10-dimethylbenzphenazine, benzophenone / Michler's ketone, hexaarylbiimidazole / mercaptobenzimidazole, benzyldimethyl ketal, thioxanthone / amine, triaryl Bisacylphosphine oxides described in JP-A-10-29997, such as sulfonium hexafluorophosphate, and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and DE4230 such as Lucirin TPO And acylphosphine oxides described in 555 and the like.
[0059]
As addition amount of the said photoinitiator, 0.1-20 mass% of the total solid (mass) of a liquid crystal composition is preferable, and 0.5-5 mass% is more preferable. If the addition amount is less than 0.1% by mass, it may take a long time because the curing efficiency at the time of light irradiation is low. If it exceeds 20% by mass, the light transmittance from the ultraviolet region to the visible light region may be required. May be inferior.
[0060]
(Other ingredients)
Furthermore, as other components, a binder resin, a solvent, a surfactant, a polymerization inhibitor, a thickener, a dye, a pigment, an ultraviolet absorber, a gelling agent, and the like can be added.
Examples of the binder resin include polystyrene compounds such as polystyrene and poly-α-methylstyrene, cellulose resins such as methyl cellulose, ethyl cellulose, and acetyl cellulose, acidic cellulose derivatives having a carboxyl group in the side chain, polyvinyl formal, polyvinyl butyral, and the like. Acetal resin, described in JP-A-59-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54-25957, JP-A-59-53836, JP-A-59-71048 Methacrylic acid copolymers, acrylic acid copolymers, itaconic acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers, and the like.
[0061]
Also included are homopolymers of acrylic acid alkyl esters and homopolymers of methacrylic acid alkyl esters, in which the alkyl group is methyl, ethyl, n-propyl, n-butyl, iso-butyl, n- Examples thereof include a hexyl group, a cyclohexyl group, and a 2-ethylhexyl group.
In addition, a polymer having a hydroxyl group with an acid anhydride added, benzyl (meth) acrylate / (homopolymer of methacrylic acid) acrylic acid copolymer, benzyl (meth) acrylate / (meth) acrylic acid / other monomers And a multi-component copolymer.
[0062]
As content of binder resin in a liquid-crystal composition, 0-50 mass% is preferable, and 0-30 mass% is more preferable. When the content exceeds 50% by mass, the alignment of the liquid crystal compound may be insufficient.
[0063]
In the liquid crystal composition of the present invention, it is preferable to use a surfactant in combination with the photoreactive chiral agent and the liquid crystal compound from the viewpoint of further improving the color purity of the selectively reflected hue. As the surfactant, a surfactant having an excluded volume effect is preferable. Here, the effect of the excluded volume effect means that the spatial alignment state at the air interface on the surface of the layer is three-dimensionally controlled when, for example, a layer containing a liquid crystal composition is formed by coating. Specifically, a nonionic surfactant is preferable, and it can be appropriately selected from known nonionic surfactants.
[0064]
The polymerization inhibitor may be added for the purpose of improving storage stability. Examples thereof include hydroquinone, hydroquinone monomethyl ether, phenothiazine, benzoquinone, and derivatives thereof. As addition amount of this polymerization inhibitor, 0-10 mass% is preferable with respect to the said polymerizable monomer, and 0-5 mass% is more preferable.
[0065]
The liquid crystal composition of the present invention can be prepared by dissolving and dispersing each of the above components in a suitable solvent, and can be used by forming it into an arbitrary shape or forming it on a support or the like. Here, examples of the solvent include 2-butanone, cyclohexanone, methylene chloride, chloroform, and the like.
[0066]
<Method of changing the twisted structure of the liquid crystal>
As described above, the liquid crystal composition of the present invention contains a photoreactive chiral agent, and in the method of changing the twisted structure of the liquid crystal of the present invention, the liquid crystal composition of the present invention is irradiated with light by changing the amount of light. Then, the twisting force of the liquid crystal is changed to form regions having different liquid crystal twisting structures. That is, by irradiating the liquid crystal composition with a desired light amount in a desired pattern, the twisted structure of the liquid crystal, that is, the degree of twisting of the spiral (twisting force; HTP) can be changed. The selective reflection color indicated by the liquid crystal can be arbitrarily changed according to the force.
[0067]
In particular, when the liquid crystal phase is a cholesteric liquid crystal phase, the selective reflection color indicated by the liquid crystal can be arbitrarily changed according to the twisting force. When the rate of change of the twisting force is large, the color width of the selective reflection color that can be selectively reflected by the liquid crystal is widened, and it is possible to obtain selective reflection in a wide wavelength range including the three primary colors (B, G, R). This is particularly important in that the three primary colors of BGR can be displayed with high color purity. In this respect, the photoreactive chiral agent represented by the general formula (I) described above can greatly change the twisting force of the helical structure of the liquid crystal, and therefore a liquid crystal composition containing the chiral agent is used. Thus, a wide range of hues including the three primary colors of blue (B), green (G), and red (R) can be displayed with good color purity, and three primary colors with excellent color purity can be obtained.
[0068]
Specifically, it can be performed as follows. That is,
When the liquid crystal composition is irradiated with light of a certain wavelength, the coexisting photoreactive chiral agent responds according to the irradiation intensity and changes the helical structure (twisting angle) of the liquid crystal. An image-like pattern is formed (patterning). In the case of a cholesteric liquid crystal composition, different selective reflection colors are exhibited due to this structural change. Therefore, if the irradiation intensity is changed for each desired region and irradiated with light, the exposure mask is oriented corresponding to the irradiation intensity (provides a plurality of colors), for example, by changing the light transmittance like an image. By performing exposure through the image, it is possible to simultaneously form an image, that is, a colored region having different selective reflections by one light irradiation.
[0069]
Moreover, since it depends on the compound represented by the general formula (I), the helical pitch of the liquid crystal can be changed greatly. In the case of a cholesteric liquid crystal composition, the formed colored region shows a wide range of selective reflection colors. The three primary colors of BGR having excellent color purity can be formed. This light irradiation can be carried out without any limitation as long as it is a method that can change the irradiation intensity for each desired region in addition to the method using an exposure mask.
In the case of forming a liquid crystal color filter, an optical film, etc., which will be described later, after patterning by exposing light of a certain wavelength image-wise as described above, the light irradiation is further performed to remove the polymerizable group in the liquid crystal composition. It is cured by photopolymerization, and the liquid crystal helical structure is fixed to a desired selective reflection color. Details of these forming methods will be described later.
[0070]
Due to the photoreactive chiral agent represented by the general formula (I), the fact that the rate of change of the helical pitch induced in the liquid crystal phase by light irradiation is large, as described later, is an optical film. A circularly polarized light separation film, stereoscopic glasses, a polarization mask, and the like can be formed. Further, it can be applied to a broadband switchable mirror, an optical writing type recording medium, and the like. Patterning of a polarization state by doping into a ferroelectric liquid crystal, antiferroelectric liquid crystal, or TGB phase, and patterning of a helical pitch are possible. Naturally, it can also be used as a normal optically active compound, and can also be applied to a helical structure inducer in STN elements and TN elements.
In addition, the liquid crystal composition of the present invention can be blended with a non-chiral azo-based or styrene-based compound that is isomerized by light, and the rate of change of the helical pitch upon light irradiation can be further increased. There is.
[0071]
The light source used for light irradiation is preferably a light source that emits ultraviolet rays because it has high energy and can rapidly change the structure of the liquid crystal compound and the polymerization reaction, and examples thereof include a high-pressure mercury lamp, metal halide lamp, and Hg-Xe lamp. It is done. Moreover, it is preferable to have a light quantity variable function.
[0072]
As described above, when the liquid crystal composition containing the chiral agent represented by the general formula (I) is used, the twisting force of the spiral structure of the liquid crystal with respect to the amount of light can be greatly changed. Therefore, for example, in the case of a cholesteric liquid crystal phase using a nematic liquid crystal compound as a liquid crystal compound, the color width of the selective reflection color that can be exhibited by the liquid crystal is widened, and blue (B), green (G), red, which have excellent color purity. The three primary colors (R) can be obtained.
[0073]
<Liquid crystal color filter>
The liquid crystal color filter of the present invention preferably contains at least one selected from the photoreactive chiral agent of the present invention, and further contains at least one liquid crystalline compound. Is most preferably a nematic liquid crystal compound. If necessary, it contains other components listed in the liquid crystal composition of the present invention such as a polymerizable monomer, a photopolymerization initiator, and a surfactant having an excluded volume effect. It can be produced by irradiating light with a desired pattern and light amount appropriately selected based on the above-described method of changing the twisted structure of the liquid crystal.
[0074]
Hereinafter, the liquid crystal color filter of the present invention will be described in detail through the description of the method for producing the liquid crystal color filter.
The liquid crystal color filter of the present invention can be prepared by appropriately selecting from the liquid crystal composition of the present invention described above and a known composition containing the compound represented by the general formula (I). .
In this case, it may be in the form of a sheet composed only of the liquid crystal composition, or in a mode in which a layer (liquid crystal layer) containing the liquid crystal composition is provided on a desired support or temporary support. In addition, other layers (films) such as an alignment film and a protective film may be provided. In the latter case, two or more liquid crystal layers can be laminated. In this case, the exposure step described later is provided a plurality of times.
[0075]
As the nematic liquid crystal compound, polymerizable monomer, photopolymerization initiator, and other components, the same ones that can be used in the liquid crystal composition of the present invention can be used, and the content, preferred range, and the like of the liquid crystal composition can also be used. The same as in the case of the composition. It is preferable to use a surfactant having an excluded volume effect.
Further, the content of the compound represented by the general formula (I) in the liquid crystal composition constituting the liquid crystal color filter is the same as that of the liquid crystal composition of the present invention described above.
[0076]
The liquid crystal color filter of the present invention can be suitably produced, for example, with the liquid crystal composition of the present invention.
Further, the method for producing the liquid crystal color filter is not particularly limited. For example, the liquid crystal color filter is exposed and patterned imagewise with a first light, and then photopolymerized with a second light to be cured (hereinafter, “ It may also be referred to as an “exposure step”). Further, depending on the production mode to be selected, a step of appropriately aligning the contact surface with the liquid crystal composition (alignment processing step), a step of transferring and forming a liquid crystal layer by adhesion / peeling (transfer step), a cholesteric liquid crystal composition It may be formed through a step (coating step) for forming a liquid crystal layer by applying a liquid crystal.
[0077]
Below, the specific one aspect | mode using a cholesteric liquid crystal composition is shown as an example of the manufacturing method including the said exposure process.
-Exposure process-
In the exposure step, both patterning and immobilization (polymerization curing) of the liquid crystal compound are performed by light irradiation. That is, the photoreactive chiral agent is image-wise exposed and patterned with a first light having a wavelength sensitive to high sensitivity, and then photopolymerized with a second light sensitive to the polymerization initiator. Curing and fixing the helical structure of the liquid crystal compound to the desired selective reflection color.
[0078]
When the liquid crystal composition is irradiated with the first light, depending on the illuminance, the coexisting photoreactive chiral agent reacts to change the helical structure of the liquid crystal compound, and this structure change causes a different selective reflection color. An image-like pattern is formed. Therefore, if the irradiation intensity is changed for each desired region and light is irradiated, a plurality of colors are displayed corresponding to the irradiation intensity. For example, exposure is performed through an exposure mask created by changing the light transmittance like an image. Thus, an image can be formed simultaneously by a single light irradiation, that is, colored regions having different selective reflections can be formed simultaneously. Furthermore, a liquid crystal color filter can be produced by irradiating (immobilizing) the second light.
[0079]
The wavelength of the first light is preferably set to a light sensitive wavelength range of the photoreactive chiral agent, particularly a wavelength close to the light sensitive peak wavelength, from the viewpoint of obtaining sufficient patterning sensitivity. Further, the wavelength of the second light is preferably set to a light sensitive wavelength region of the polymerization initiator, particularly a wavelength close to the light sensitive peak wavelength, from the viewpoint of obtaining sufficient photopolymerization sensitivity.
Moreover, there is no restriction | limiting in particular in the illumination intensity (irradiation intensity) of 1st and 2nd light, According to the material to be used, it can select suitably so that the photosensitivity at the time of patterning and polymerization hardening may be acquired sufficiently. As the light source used for the first and second light irradiation, the same light source that can be used for the light irradiation of the liquid crystal composition can be used.
[0080]
More specifically, the production methods of the following first and second aspects may be used, and the production methods can be more suitably produced by these two aspects.
[First embodiment]
(1) A step of providing a coating liquid crystal composition on a temporary support and forming a transfer material having at least a liquid crystal layer.
The coating liquid crystal composition can be prepared by dissolving and dispersing each component in a suitable solvent. Here, examples of the solvent include 2-butanone, cyclohexanone, methylene chloride, chloroform, and the like. In the production of the liquid crystal color filter, a cholesteric liquid crystal composition is preferable.
A cushion layer containing a thermoplastic resin or the like may be provided between the liquid crystal layer and the temporary support from the viewpoint of ensuring adhesion during transfer, such as when there is a foreign matter on the transfer target. It is also possible to subject the surface of the cushion layer and the like to orientation treatment (orientation treatment step) such as rubbing treatment.
(2) A step of laminating the transfer material on a light-transmitting substrate.
In addition to the light-transmitting substrate, an image receiving material having an image receiving layer on a substrate may be used. In addition, the liquid crystal composition may be directly formed on the substrate without using the transfer material (application step). The application can be performed by appropriately selecting from known application methods. However, the transfer method is preferable in terms of material loss and cost.
[0081]
(3) A step of peeling the transfer material from the light transmissive substrate to form a cholesteric liquid crystal layer on the substrate (transfer step).
The liquid crystal layer may be composed of a plurality of layers by further laminating after the following (4).
(4) Illuminance ν in an image-like manner through an exposure mask on the cholesteric liquid crystal layer¹The pixel pattern showing the selective reflection color is formed by irradiating the ultraviolet ray with illuminance ν.²A step of exposing the ultraviolet ray to cure the layer (exposure step).
[0082]
[Second embodiment]
(1) The process of forming a liquid-crystal layer by providing a liquid-crystal composition directly on the support body which comprises a color filter.
Here, the liquid crystal layer can be formed by coating a liquid crystal composition prepared in a coating liquid as described above by a known coating method using a bar coater or a spin coater.
Further, an alignment film similar to the above may be formed between the cholesteric liquid crystal layer and the temporary support. It is also preferable to subject the surface of the alignment film or the like to an alignment treatment (orientation treatment step) such as a rubbing treatment.
(2) An exposure step similar to step (4) of the first aspect.
[0083]
The thickness of the liquid crystal layer (sheet-like liquid crystal composition) that functions as a liquid crystal color filter is preferably 1.5 to 5 μm.
[0084]
Furthermore, it demonstrates below using FIGS. 1-3. 1 to 3 are schematic views showing an embodiment of a process for producing a liquid crystal color filter of the present invention.
First, each component described above is dissolved in a suitable solvent to prepare a coating liquid cholesteric liquid crystal composition. Here, each component and solvent are as described above.
[0085]
As shown in FIG. 1- (A), a support 10 (hereinafter also referred to as a “temporary support”) is prepared, and an acrylic resin, polyester, polyurethane, or the like is applied and formed on the support 10, for example. (Thermoplastic resin layer) 12 is provided, and an alignment film 14 made of polyvinyl alcohol or the like is further laminated. This alignment film is rubbed as shown in FIG. This rubbing treatment is not always necessary, but the orientation can be improved more by the rubbing treatment.
Next, as shown in FIG. 1- (C), a coating liquid cholesteric liquid crystal composition is applied on the alignment film 14 and dried to form a cholesteric liquid crystal layer 16, and then the cholesteric liquid crystal layer 16 is covered. A film 18 is provided to produce a transfer material. Hereinafter, the transfer material is referred to as a transfer sheet 20.
[0086]
On the other hand, as shown in FIG. 1- (D), another support 22 is prepared, an alignment film 24 is formed on the support in the same manner as described above, and a rubbing process is performed on the surface thereof. Hereinafter, this is referred to as a color filter substrate 26.
[0087]
Next, after the cover film 18 of the transfer sheet 20 is peeled off, as shown in FIG. 2- (E), the surface of the cholesteric liquid crystal layer 16 of the transfer sheet 20 and the surface of the alignment film 24 of the color filter substrate 26 Are laminated so that they come into contact with each other and laminated through a roll rotating in the direction of the arrow in the figure. Thereafter, as shown in FIG. 2- (F), the film is peeled between the alignment film 14 of the transfer sheet 20 and the cushion layer 12, and the cholesteric liquid crystal layer is transferred together with the alignment film 14 onto the color filter substrate. In this case, the cushion layer 12 does not necessarily have to be peeled off together with the temporary support 10.
[0088]
After the transfer, as shown in FIG. 3G, an exposure mask 28 having a plurality of regions having different light transmittances is arranged above the alignment film 14, and the first light is cholesteric through the mask 28. The liquid crystal layer 16 is irradiated in a pattern. The cholesteric liquid crystal layer 16 includes a liquid crystal compound, a chiral compound, or the like so that the spiral pitch varies depending on the amount of light irradiation. A structure with a different spiral pitch reflects, for example, green (G) for each pattern, An area that transmits blue (B) and red (R), an area that reflects blue (B), an area that transmits green (G) and red (R), an area that reflects red (R), and the green (G) and blue It forms so that the area | region which permeate | transmits (B) may be formed.
[0089]
Next, as shown in FIG. 3- (H), the pattern is fixed by further irradiating the cholesteric liquid crystal layer 16 with ultraviolet rays at an irradiation intensity different from the light irradiation in the step (G). Thereafter, using 2-butanone, chloroform, or the like, unnecessary portions on the cholesteric liquid crystal layer 16 (for example, remaining portions such as a cushion layer and an intermediate layer, and unexposed portions) are removed, thereby obtaining FIG. As shown, a cholesteric liquid crystal layer having a BGR reflective region can be formed.
[0090]
The method shown in FIGS. 1 to 3 is an embodiment of a color filter manufacturing method using a laminate method, but may be a coating method manufacturing method in which a liquid crystal layer is directly formed on a color filter substrate. In this case, when applied to the above embodiment, a cholesteric liquid crystal layer is applied on the alignment film 24 of the color filter substrate 26 shown in FIG. 1- (D) and dried, and then the same as in FIGS. ) Are sequentially performed.
[0091]
These steps and materials such as a transfer material and a support to be used are described in detail in each specification of Japanese Patent Application Nos. 11-342896 and 11-343665 previously filed by the present inventors. ing.
[0092]
As described above, when the liquid crystal composition containing the photoreactive chiral agent represented by the general formula (I) is used, the rate of change in the twisting force of the spiral structure of the liquid crystal with respect to the amount of light is large. A liquid crystal color filter composed of three primary colors of blue (B), green (G), and red (R), which has a wide color width and excellent color purity, can be obtained.
[0093]
<Optical film>
The optical film of the present invention preferably contains at least one selected from the photoreactive chiral agent of the present invention and further contains at least one liquid crystalline compound (preferably a nematic liquid crystal compound). The optical wavelength is arbitrarily set from a wide wavelength range. Further, it contains other components listed in the liquid crystal composition of the present invention such as a polymerizable monomer, a photopolymerization initiator, and a surfactant having an excluded volume effect, if necessary. It can be produced by irradiating light with a desired pattern and light quantity appropriately selected based on the “method of changing the twisted structure”.
[0094]
The optical film of the present invention can be prepared by appropriately selecting from the liquid crystal composition of the present invention described above and a known composition containing the compound represented by the general formula (I).
There is no restriction | limiting in particular as a form of an optical film, Any of the form which provided the layer (liquid crystal layer) which contains the liquid crystal composition on the sheet form comprised only from the said liquid crystal composition, a desired support body, or a temporary support body etc. Further, another layer (film) such as an alignment film or a protective film may be provided.
[0095]
As the liquid crystal compound, polymerizable monomer, photopolymerization initiator and other components, the same ones that can be used in the liquid crystal composition of the present invention can be used, and the content thereof is also the case of the liquid crystal composition. It is the same. The content of the compound represented by the general formula (I) in the liquid crystal composition constituting the optical film is also the same as that of the liquid crystal composition of the present invention described above.
[0096]
The optical film of the present invention can be suitably produced using, for example, the liquid crystal composition of the present invention.
Moreover, as a method for producing an optical film, it may be produced by a method substantially the same as that of the liquid crystal color filter, and may be a method comprising at least one exposure step. Moreover, according to the manufacturing aspect to select, you may form through processes, such as the said alignment process process, a transfer process, and an application | coating process.
More specifically, it can be produced in substantially the same manner as in the manufacturing methods of the first and second aspects.
[0097]
As described above, when the liquid crystal composition containing the photoreactive chiral agent represented by the general formula (I) is used, the rate of change of the twisting force of the spiral structure of the liquid crystal with respect to the amount of light can be greatly changed. An absorption type optical film can be obtained. For example, when the liquid crystal phase is a cholesteric liquid crystal phase, the color width of the selective reflection of the liquid crystal is widened, an optical film composed of various selective reflection colors, and optical colors of primary colors (B, G, R) excellent in color purity. A film or the like can be obtained.
[0098]
<Recording medium>
The recording medium of the present invention preferably contains at least one selected from the photoreactive chiral agents of the present invention and further contains at least one liquid crystalline compound (preferably a nematic liquid crystal compound). . If necessary, it contains other components listed in the liquid crystal composition of the present invention such as a polymerizable monomer, a photopolymerization initiator, and a surfactant having an excluded volume effect.
[0099]
The recording medium of the present invention is not limited in its form, and may be in the form of a sheet composed only of a liquid crystal composition, or on a desired support or temporary support (hereinafter referred to as “support or the like”). Further, a layer provided with a layer (liquid crystal layer) containing a liquid crystal composition containing a photoreactive chiral agent may be used. Here, the liquid crystal composition can be appropriately selected from the liquid crystal composition of the present invention described above and a known composition containing the compound represented by the general formula (I). Furthermore, other layers (films) such as an alignment film and a protective film may be provided.
[0100]
As the liquid crystal compound, the polymerizable monomer, the photopolymerization initiator, and other components, the same ones that can be used in the liquid crystal composition can be used, and the content thereof is the same as in the case of the liquid crystal composition. . The content of the compound represented by the general formula (I) in the liquid crystal composition constituting the recording medium is also the same as that of the liquid crystal composition of the present invention described above.
[0101]
The recording medium of the present invention can be suitably produced, for example, by providing the above-described liquid crystal composition of the present invention on a support or the like.
As a method for providing a liquid crystal composition on a support or the like, (1) using a transfer material in which a liquid crystal layer containing the liquid crystal composition of the present invention is provided on a temporary support, the liquid crystal layer is formed on the support. Examples thereof include a transfer method, and (2) a method in which a liquid crystal composition prepared in a coating liquid is directly applied onto a support.
In the methods (1) and (2), the transfer material, the coating method, and the like are the same as in the embodiments (first and second embodiments) exemplified in the liquid crystal composition of the invention and the description of FIGS. Can adapt.
[0102]
The recording medium of the present invention produced as described above is irradiated with light with a desired pattern and light amount selected as appropriate, so that an image can be displayed according to the rate of change in the twisting force of the liquid crystal, particularly in the case of a cholesteric liquid crystal. Can form a colored image composed of selectively reflected colors determined by the rate of change of the helical pitch. The image formation may be performed based on, for example, the above-described “method for changing the helical structure of the liquid crystal” and “the method for fixing the helical structure of the liquid crystal”.
[0103]
In addition, when the photoreactive chiral agent represented by the general formula (I) is used as the chiral agent for changing the liquid crystal structure, the rate of change in the twisting force of the spiral structure of the liquid crystal with respect to the amount of light is large. An image can be formed. In particular, in the case of a cholesteric liquid crystal, the hue width selectively reflected by the liquid crystal can be widened, and a multicolor image with high color purity can be formed. Further, the large change rate of the twisting force greatly contributes to high sensitivity (high speed) at the time of image formation.
Further, for example, by using a polymerizable liquid crystalline compound or a polymerizable monomer, the liquid crystal after patterning can be fixed, and an image excellent in sufficient image stability can be formed.
[0104]
As the light source for irradiating light, the same light source as that which can be used in the liquid crystal composition of the present invention is used, and optical recording can be suitably performed. The same applies to light irradiation for fixing the liquid crystal.
[0105]
As described above, by using the photoreactive chiral agent represented by the general formula (I) as the chiral agent that changes the helical structure of the liquid crystal molecules, the twisting force (twisting angle) of the liquid crystal is greatly changed. Can be made. In particular, in the case of a cholesteric liquid crystal using a nematic liquid crystal compound, the selective reflection wavelength range obtained by light irradiation is expanded, and as a result, the color purity of the three primary colors of BGR can be further increased. Therefore, the selectivity and vividness of the hue of the liquid crystal are improved. In particular, the liquid crystal color filter and the optical film can display a clear and vivid color image, and the recording medium has various hues of the image to be formed. Can be
[0106]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, “parts” and “%” all represent “parts by mass” and “% by mass”.
[0107]
(Example 1): Measurement of change in helical pitch by light irradiation
A nematic liquid crystal composition (ZLI-1132, manufactured by Merck & Co., Inc.) The mixture was mixed with 98 parts and injected into a wedge-shaped cell (glass thickness 1.1 mm, blue plate) subjected to uniaxial alignment treatment with a polyimide alignment film. Here, when the helical pitch at room temperature was measured using a polarizing microscope, it was 1.14 μm. When converted to helical twisting power (HTP), it is 44 μm.^-1It becomes.
[0108]
Next, 300 mW / cm from the high pressure mercury lamp for the wedge type cell.²Ultraviolet rays were irradiated for 3 minutes at an irradiation intensity of. After irradiation, when the helical pitch at room temperature was measured in the same manner as described above, it was changed to 3.6 μm. This is 14μm when converted to HTP.^-1It becomes. Therefore, the HTP change rate was 3.14.
As described above, the helical twisting force (HTP) could be greatly changed by irradiation with ultraviolet rays. In addition, when the direction of twisting before and after the ultraviolet irradiation was confirmed by the contact method, it was a right twisting both before and after the irradiation.
[0109]
(Example 2): Production of a broadband circularly polarizing reflector
(1) Board preparation
A polyimide alignment film (LX-1400, manufactured by Hitachi Chemical DuPont Co., Ltd.) coating solution is applied onto a glass substrate with a spin coater, dried in an oven at 100 ° C. for 5 minutes, and then baked in an oven at 250 ° C. for 1 hour. Thus, an alignment film was formed. Further, the surface of the film was subjected to orientation treatment by rubbing treatment to produce a glass substrate with an orientation film.
[0110]
(2) Production
On the alignment film of the glass substrate with an alignment film obtained as described above, a coating solution prepared according to the following formulation was applied by a bar coater, held on a hot plate at 110 ° C. for 5 minutes, and then 365 nm at the temperature. Then, light was irradiated for 5 minutes with an ultra-high pressure mercury lamp through a bandpass filter having a light source center wavelength. The following photoreactive chiral agent (Exemplary Compound (3)) of the present invention was synthesized by a method similar to the synthesis method described above.
[0111]
Subsequently, it is kept at 110 ° C. in a dark place for 5 minutes, after which the band-pass filter is removed, and the irradiation energy is 500 mJ / cm with an ultrahigh pressure mercury lamp similar to the above while blowing nitrogen gas.²Then, the entire surface was exposed and polymerized and cured. As described above, a circularly polarized light reflector was produced.
[0112]
Embedded image

[0113]
The circularly polarized light reflector obtained from the above showed selective reflection in a wide wavelength range extending from 450 to 630 nm, and had sufficient band characteristics as a broadband circularly polarized light reflector. Moreover, the right circularly polarized light reflectance at a selective reflection wavelength of 550 nm was 98%.
[0114]
Example 3 Production of liquid crystal color filter
(1) Preparation of filter substrate
A polyimide alignment film (LX-1400, manufactured by Hitachi Chemical DuPont Co., Ltd.) coating solution is applied onto a glass substrate with a spin coater, dried in an oven at 100 ° C. for 5 minutes, and then baked in an oven at 250 ° C. for 1 hour. An alignment film was formed. Further, the surface of the film was subjected to orientation treatment by rubbing treatment to produce a glass substrate with an orientation film.
[0115]
(2) Formation of filter layer
On the alignment film of the glass substrate with an alignment film obtained as described above, a photosensitive resin layer coating solution prepared by the following formulation was applied by a spin coater, and this was dried in an oven at 110 ° C. for 2 minutes to be photosensitive. A resin layer was formed. The photoreactive chiral agent (Exemplary Compound (2)) of the present invention described below was synthesized according to the synthesis method described above.
[0116]
Embedded image

[0117]
Next, the photosensitive resin layer was colored by being held on a hot plate at 110 ° C. for 5 minutes so as to be in contact with the surface of the glass substrate. Further, on the photosensitive resin layer, the transmittance is different in three stages (0%, 46%, 92%), and the respective regions are arranged correspondingly for blue pixels, green pixels, and red pixels. An ultra-high pressure mercury lamp was placed through a photomask and a band-pass filter having a center at 365 nm, and irradiation and patterning were performed with the ultra-high-pressure mercury lamp through the photomask and the band-pass filter. The irradiation energy at this time is 300 mJ / cm for the red pixel.²The irradiation intensity is 30 mW / cm²Met.
[0118]
Next, the photomask and the band-pass filter are removed, and the irradiation energy is 500 mJ / cm with an ultra-high pressure mercury lamp similar to the above while blowing nitrogen gas.²Then, the entire surface was exposed and polymerized and cured. Further, in order to promote the degree of curing of the filter part (photosensitive resin layer), baking was performed in an oven at 220 ° C. for 20 minutes to obtain a color filter in which red pixel, green pixel, and blue pixel patterns were formed.
At the time of patterning, the helical pitch of the liquid crystal (twisting force of the liquid crystal) can be greatly changed by irradiation, and a pixel pattern composed of red, green, and blue with high color purity can be formed.
[0119]
Example 4 Production of Optical Compensation Film for STN Element
A polyethylene vinyl alcohol (PVA) film having a saponification degree of 99.5% was formed on a triacetyl cellulose (TAC) having a thickness of 80 μm by a bar coating method and heated at 110 ° C. for 3 minutes. The PVA film was subjected to a rubbing treatment, and a coating solution prepared according to the following formulation was heated and applied with a bar coater, and this was dried in an oven at 120 ° C. for 3 minutes to form a film. The following photoreactive chiral agent (Exemplary Compound (5)) of the present invention was synthesized according to the synthesis method described above.
[0120]
Embedded image

[0121]
Next, ultraviolet irradiation (irradiation energy: 1000 mJ / cm 2) using a high-pressure mercury lamp from above the film at a temperature of 100 ° C.²The film was polymerized and cured to produce an optical compensation film for an STN element (hereinafter referred to as “STN compensation film”). The thickness of the STN compensation film at this time was measured and found to be 5.0 μm. Further, from the polarization transmission spectrum profile of the STN compensation film, it was found that the orientation (helical structure) of the liquid crystal molecules was twisted in the film thickness direction at 240 degrees, and the twist angle (rotation angle) of the spiral was 240 degrees.
In addition, an STN compensation film having a twist angle (-240 degrees) opposite to that of the film is prepared, and the liquid crystal molecules of the matched portions are overlapped so that the absorption axes are orthogonal to each other. When inserted between two polarizing plates and visually observed, a good black color was shown. Therefore, it was confirmed that the film formed as described above (STN compensation film) acts as an optical compensation film for STN elements.
[0122]
(Example 5): Prevention of occurrence of reverse twist domain for TN device
On the ITO film of the glass substrate with the ITO film, a polyimide alignment film (LX-1400, manufactured by Hitachi Chemical DuPont) coating solution was applied with a spin coater and dried in an oven at 100 ° C. for 5 minutes, and then 250 An alignment film was formed by baking in an oven at 0 ° C. for 1 hour. Further, the surface of the film was subjected to a rubbing treatment so that the rubbing angle was 90 degrees, and two glass substrates with an alignment film were produced.
The alignment films of the glass substrate with an alignment film were arranged so as to face each other, and bonded together with a two-component epoxy resin adhesive mixed with spacer beads having a diameter of 6 μm to form a driving cell. The thickness of the cell was measured by an optical interference method and found to be 5.4 μm.
[0123]
A composition having the following composition was injected into the cell. The photoreactive chiral agent (Exemplary Compound (2)) of the present invention described below was synthesized according to the synthesis method described above.
〔Composition〕
-Nematic liquid crystal composition (ZLI-1132, manufactured by Merck & Co., Inc.) ... 99.9%
-Photoreactive chiral agent of the present invention (Exemplary Compound (2) already described) 0.1%
[0124]
Next, when a driving cell after injection was inserted between two polarizing plates whose absorption axes were orthogonal to each other and observed visually, the occurrence of a reverse twist domain was not observed. Accordingly, there is no reduction in contrast due to the occurrence of reverse twist, and an image display excellent in contrast and color purity can be expected.
[0125]
【The invention's effect】
According to the present invention, the orientation of the liquid crystal compound can be controlled, and the change rate (hereinafter, also referred to as “twist change rate”) of the twisting force (twist angle, spiral pitch) of the liquid crystal due to light is large. For example, in the case of a cholesteric liquid crystal phase, it is possible to provide a photoreactive chiral agent that can display a wide range of selective reflections including three primary colors (B, G, R) and can display three primary colors with high color purity.
According to the present invention, a photoreactive chiral agent that changes the twisting force of liquid crystal by light and has a large rate of change in twist is used, and the optical properties are changed by controlling the orientation state of liquid crystal molecules greatly and three-dimensionally by light. In the case of a liquid crystal composition that can be used, for example, a cholesteric liquid crystal, it is possible to provide a liquid crystal composition that exhibits a wide range of selective reflection colors including three primary colors by light irradiation and that can display three primary colors with excellent color purity. it can.
According to the present invention, there is provided a method for changing the twisted structure of a liquid crystal, which can significantly change the twisting force (twist angle) of the liquid crystal by irradiating a liquid crystal composition containing a photoreactive chiral agent having a high twist change rate. can do.
According to the present invention, it is possible to provide a liquid crystal color filter having a high color purity, including a photoreactive chiral agent capable of greatly changing the twisting force of liquid crystal by light irradiation.
According to the present invention, in the case of a non-light-absorbing optical film containing a photoreactive chiral agent capable of greatly changing the twisting force of liquid crystal by light irradiation, for example, a cholesteric liquid crystal phase, the selective reflection range is wide and the color purity. High optical film can be provided.
According to the present invention, a recording medium that includes a photoreactive chiral agent capable of greatly changing the twisting force of liquid crystal by light irradiation and capable of forming a clear image by changing the amount of light in an image-like manner, for example, the liquid crystal phase is cholesteric. In the case of the liquid crystal phase, it is possible to provide a recording medium capable of forming an image having a selective reflection color with a wide hue and high color purity.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a part of a process for producing a liquid crystal color filter of the present invention.
FIG. 2 is a schematic view showing a part of a process for producing a liquid crystal color filter of the present invention.
FIG. 3 is a schematic view showing a part of a process for producing a liquid crystal color filter of the present invention.
[Explanation of symbols]
10 Support (temporary support)
12 Cushion layer (thermoplastic resin layer)
14,24 Alignment film
16 Liquid crystal layer (Liquid crystal composition)
18 Cover film
20 Transfer sheet
22 Substrate
26 Color filter substrate
28 Exposure mask

Claims (8)

A photoreactive chiral agent comprising a compound represented by the following general formula (I), wherein the twisting force of liquid crystal is changed by light irradiation.

[Wherein, R represents a hydrogen atom, an alkoxy group having 1 to 15 carbon atoms, an acryloyloxyalkyloxy group having 3 to 15 carbon atoms, or a methacryloyloxyalkyloxy group having 4 to 15 carbon atoms. ] 2. The photoreaction according to claim 1, wherein in the compound represented by the general formula (I), R is an acryloyloxyalkyloxy group having 3 to 15 carbon atoms or a methacryloyloxyalkyloxy group having 4 to 15 carbon atoms. Type chiral agent. The photoreactive chiral agent according to claim 1, wherein in the compound represented by the general formula (I), R is a hydrogen atom or an alkoxy group having 1 to 15 carbon atoms. A liquid crystal composition comprising at least one selected from the photoreactive chiral agents according to claim 1. A method for changing a twisted structure of a liquid crystal, wherein the liquid crystal composition according to claim 4 is irradiated with light to change the twisting force of the liquid crystal. A liquid crystal color filter comprising at least one selected from the photoreactive chiral agent according to claim 1. An optical film comprising at least one selected from the photoreactive chiral agent according to claim 1. A recording medium comprising at least one selected from the photoreactive chiral agent according to claim 1.

Images