JP4003388B2 - Electroluminescence element and color conversion filter - Google Patents

Description

〔式中、Ｘ₁およびＹ₁はそれぞれ酸素原子を表し、Ｒ₁₁ は水素原子又は一価の置換基を表し、Ｚ₁は置換又は無置換のベンゼン環を形成するのに必要な原子群を表す。〕
【化Ｊ】

〔式中、Ｒ₂₁、Ｒ₂₂およびＲ₂₃はそれぞれ水素原子又は一価の置換基を表す。〕
【化Ｋ】

〔式中、Ｒ₃₁およびＲ₃₃は水素原子又はσｍ値が正の一価の置換基を表し、Ｒ₃₂は水素原子又はσｐ値が正の一価の置換基を表し、Ｒ₃₄およびＲ₃₆は水素原子又はσｍ値が負の一価の置換基を表し、Ｒ₃₅は水素原子又はσｐ値が負の一価の置換基を表す。ただし、Ｒ₃₁、Ｒ₃₂およびＲ₃₃が同時に水素原子であることはなく、Ｒ₃₄、Ｒ₃₅およびＲ₃₆が同時に水素原子であることはない。〕
【化Ｌ】

〔式中、Ｒ₄₁およびＲ₄₂は水素原子又は一価の置換基を表し、Ｚ₄は五員環の複素芳香環を形成するのに必要な原子群を表し、ｍ４およびｎ４は１〜５を表す。〕
【化Ｍ】

〔式中、Ｒ₅₁、Ｒ₅₂およびＲ₅₃は一価の置換基を表し、Ｘ₅は酸素原子又は硫黄原子を表す。〕
【化Ｎ】

〔式中、Ｒ₆₁およびＲ₆₂は一価の置換基を表す。〕
【化Ｏ】

〔式中、Ｒ₇₁、Ｒ₇₂およびＲ₇₃は水素原子又は一価の置換基をあらわす。〕
【００９５】
以下、一般式（１）について説明する。
一般式（１）において、Ｘ₁及びＹ₁はそれぞれ酸素原子、硫黄原子又はＮ−Ｒ₁₂を表し、Ｒ₁₁およびＲ₁₂はそれぞれ水素原子又は一価の置換基、Ｚ₁は芳香族環（以下、単に芳香環ともいう）を形成するのに必要な原子群を表す。Ｒ₁₁およびＲ₁₂で表される一価の置換基としては、例えばアルキル基、アルケニル基、アルキニル基、アリール基、複素環基、４級化された窒素原子を含むヘテロ環基（例えばピリジニウム基）、ヒドロキシ基、アルコキシ基（例えばエチレンオキシ基もしくはプロピレンオキシ基単位を繰り返し含む基を含む）、アリールオキシ基、アシルオキシ基、アシル基、アルコキシカルボニル基、アリールオキシカルボニル基、カルバモイル基、ウレタン基、カルボキシル基、イミド基、アミノ基、カルボンアミド基、スルホンアミド基、ウレイド基、チオウレイド基、スルファモイルアミノ基、セミカルバジド基、チオセミカルバジド基、ヒドラジノ基、４級のアンモニオ基、（アルキル、アリール又はヘテロ環）チオ基、メルカプト基、（アルキル又はアリール）スルホニル基、（アルキル又はアリール）スルフィニル基、スルホ基、スルファモイル基、アシルスルファモイル基、（アルキル又はアリール）スルホニルウレイド基、（アルキル又はアリール）スルホニルカルバモイル基、ハロゲン原子、シアノ基、ニトロ基、リン酸アミド基などが挙げられる。
【００９６】
Ｚ₁により形成される芳香族環としてはベンゼン環、ナフタレン環、ピリジン環、ピリミジン環、トリアジン環、ピロール環、フラン環、チアゾール環等が挙げられ、これら芳香族環はさらに置換基を有していても良く、置換基同士が環を形成しても良い。Ｚ₁で形成される芳香環が有する置換基の例としては、前述のＲ₁₁およびＲ₁₂で述べた一価の置換基と同様の置換基が挙げられる。
【００９７】
発光効率の点で、好ましくは、Ｚ₁により形成される芳香環が置換又は無置換のベンゼン環であり、Ｘ₁およびＹ₁が酸素原子であり、Ｒ₁₁が水素原子、炭化水素芳香環又は含窒素芳香環の場合である。炭化水素芳香環としてはベンゼン環、ナフタレン環又はアントラセン環等が挙げられ、含窒素芳香環としては、ピロール環、オキサゾール環、ピリジン環、ピリミジン環又はベンズイミダゾール環等が挙げられる。より好ましくは、Ｚ₁により形成される芳香環が置換、無置換のベンゼン環であり、Ｘ₁およびＹ₁が酸素原子であり、Ｒ₁が水素原子の場合である。
【００９８】
一般式（１）で表される化合物のアニオン体（化合物が脱水素化された陰イオン）とともに、錯体を形成する希土類金属としてＣｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ等の陽イオンが挙げられる。好ましくはＣｅ、ＴｂおよびＥｕの陽イオンであり、より好ましくは赤色において良好な色純度を示すＥｕ³⁺である。
【００９９】
以下に一般式（１）で表される化合物および化合物のアニオン体とともに形成される希土類錯体系蛍光体の具体例を示すが、本発明はこれらに限定されるものではない。
【０１００】
【化８】

【０１０１】
【化９】

【０１０２】
【化１０】

【０１０３】
【化１１】

【０１０４】
次に一般式（２）について説明する。
一般式（２）において、Ｒ₂₁、Ｒ₂₂およびＲ₂₃はそれぞれ水素原子又は一価の置換基を表す。Ｒ₂₁、Ｒ₂₂およびＲ₂₃で表される一価の置換基としては、前述のＲ₁₁およびＲ₁₂で述べた一価の置換基と同様の置換基が挙げられ、それぞれの置換基はお互いに結合して環を形成しても良い。
【０１０５】
発光効率の観点から本発明においては、一般式（２）が、好ましくはＲ₂₃が水素原子、Ｒ₂₁およびＲ₂₂が共に芳香族環の時であり、より好ましくはＲ₂₁のσｐ値が正、Ｒ₂₂のσｐ値が負の時、一般式（３）又は一般式（４）で表される時である。
【０１０６】
一般式（３）においてＲ₃₁およびＲ₃₃は水素原子又はσｍ値が正の一価の置換基を表し、Ｒ₃₂は水素原子又はσｐ値が正の一価の置換基を表し、Ｒ₃₄およびＲ₃₆は水素原子又はσｍ値が負の一価の置換基を表し、Ｒ₃₅は水素原子又はσｐ値が負の一価の置換基を表す。ただし、Ｒ₃₁、Ｒ₃₂およびＲ₃₃が同時に水素原子であることはなく、Ｒ₃₄、Ｒ₃₅およびＲ₃₆が同時に水素原子であることはない。Ｒ₃₁、Ｒ₃₂、Ｒ₃₃、Ｒ₃₄、Ｒ₃₅およびＲ₃₆で表される一価の置換基としては、前述のＲ₁₁およびＲ₁₂で述べた一価の置換基と同様の置換基が挙げられ、σｐ値又はσｍ値によって適宜選択される。それぞれの置換基はお互いに結合して環を形成しても良い。一般式（４）においてＲ₄₁およびＲ₄₂は水素原子又は一価の置換基を表し、Ｚ₄は五員複素芳香環を形成するのに必要な原子群を表し、ｍ４およびｎ４は１〜５を表す。Ｒ₄₁およびＲ₄₂で表される一価の置換基としては、前述のＲ₁₁およびＲ₁₂で述べた一価の置換基と同様の置換基が挙げられ、それぞれの置換基はお互いに結合して環を形成しても良い。Ｚ₄により形成される芳香族環としては、前述のＺ₁により形成される芳香族環で例示した中の五員複素芳香環が挙げられ、これら芳香族環はさらに置換基を有していても良く、置換基同士が環を形成しても良い。Ｚ₄で形成される芳香族環が有する置換基の例としては、前述のＲ₁₁およびＲ₁₂で述べた一価の置換基と同様の置換基が挙げられる。
【０１０７】
本発明における置換基のσｐ値およびσｍ値とは、Ｈａｍｍｅｔによって定義された置換基定数であり、例えば「薬物の構造活性相関：化学の領域，増刊１２２号，９６〜１０３頁，南江堂社刊」に記載されている。
【０１０８】
一般式（２）、（３）および（４）で表される化合物のアニオン体（化合物が脱水素化された陰イオン）とともに、錯体を形成する希土類金属としてＣｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ等の陽イオンが挙げられる。好ましくはＣｅ、ＴｂおよびＥｕの陽イオンであり、より好ましくは赤色において良好な色純度を示すＥｕ³⁺である
以下に一般式（２）、（３）および（４）で表される化合物および、化合物のアニオン体とともに形成される希土類錯体系蛍光体の具体例を示すが、本発明はこれらに限定されるものではない。
【０１０９】
【化１２】

【０１１０】
【化１３】

【０１１１】
【化１４】

【０１１２】
【化１５】

【０１１３】
【化１６】

【０１１４】
【化１７】

【０１１５】
次に一般式（５）、（６）および（７）について説明する。
一般式（５）においてＲ₅₁、Ｒ₅₂およびＲ₅₃は一価の置換基を表し、Ｘ₅は酸素原子又は硫黄原子を表す。Ｒ₅₁、Ｒ₅₂およびＲ₅₃で表される一価の置換基としては、前述のＲ₁₁およびＲ₁₂で述べた一価の置換基と同様の置換基が挙げられ、発光効率の点で、好ましくは、アルコキシ基又はアルキル基であり、より好ましくは、フッ素置換アルキル基である。
【０１１６】
一般式（６）において、Ｒ₆₁およびＲ₆₂は一価の置換基を表す。Ｒ₆₁およびＲ₆₂で表される一価の置換基としては、前述のＲ₁₁およびＲ₁₂で述べた一価の置換基と同様の置換基が挙げられ、発光効率の点で、好ましくは、アルコキシ基又はアルキル基であり、より好ましくは、フッ素置換アルキル基である。
【０１１７】
一般式（７）において、Ｒ₇₁、Ｒ₇₂およびＲ₇₃は水素原子又は一価の置換基をあらわす。Ｒ₇₁、Ｒ₇₂およびＲ₇₃で表される一価の置換基としては前述のＲ₁₁及びＲ₁₂で述べた一価の置換基が挙げられ、発光効率の点で好ましくは、Ｒ₇₂およびＲ₇₃がお互いの結合して含窒素芳香族環を形成する場合であり、具体的に形成される含窒素芳香族環としては、ピリジン環、ピリダジン環、ピリミジン環、ピラジン環、イミダゾール環、オキサゾール環、チアゾール環およびキノリン環等が挙げられ、これら含窒素芳香族環はさらに置換基を有していても良く、置換基同士が環を形成しても良く、中でもピリジン環が好ましい。
【０１１８】
一般式（５）、（６）および（７）で表される化合物とともに、錯体を形成する希土類金属としてＣｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ等の陽イオンが挙げられる。好ましくはＣｅ、ＴｂおよびＥｕの陽イオンであり、より好ましくは赤色において良好な色純度を示すＥｕ³⁺である。
【０１１９】
更に好ましくは、一般式（５）、（６）および（７）で表される化合物とともに形成される希土類錯体系蛍光体は、更に一般式（１）又は（２）で表される化合物のアニオン体の少なくとも１つを配位子として有する時である。この場合に併用される一般式（１）又は（２）の好ましい例は、前述と同様である。
【０１２０】
以下に一般式（５）、（６）および（７）で表される配位子および希土類錯体系蛍光体の具体例を示すが、本発明はこれらに限定されるものではない。
【０１２１】
【化１８】

【０１２２】
【化１９】

【０１２３】
【化２０】

【０１２４】
【化２１】

【０１２５】
【化２２】

【０１２６】
【化２３】

【０１２７】
【化２４】

【０１２８】
【化２５】

【０１２９】
【化２６】

【０１３０】
【化２７】

【０１３１】
【化２８】

【０１３２】
【化２９】

【０１３３】
【化３０】

【０１３４】
本発明のエレクトロルミネッセンス素子に含有される希土類錯体系蛍光体は、発光材料から発せられる光によって４００〜７００ｎｍの領域に極大発光を有するものであることが好ましい。より好ましくは、従来技術では発光効率の低い６００ｎｍ〜７００ｎｍの領域に極大発光を有するものである。
【０１３５】
また、本発明のエレクトロルミネッセンス素子に含有される希土類錯体系蛍光体は、発光材料から発せられる極大発光波長に対して１８０ｎｍ以上長波側に極大発光波長を有するものを少なくとも１種含有することが好ましい。
【０１３６】
次に、色変換層の組成について説明する。色変換層は、希土類錯体系蛍光体を光硬化型又は熱硬化型樹脂硬化物および／又は非反応性樹脂等に代表されるバインダーやシリカゲル、アルミナ等に代表されるフィラー等で分散して作製してもよいし、ハイブリッドポリマーにコンポジットして作製してもよいし、単体をそのまま積層して作製してもよい。本発明の蛍光体を分散又はコンポジットして使用する場合には、バインダーやフィラー１ｋｇ当たり、０．０００１〜１００モルの割合で用いるのが好ましい。
【０１３７】
前記光硬化型又は熱硬化型樹脂硬化物について説明する。
これらの化合物は光硬化型の樹脂又は熱硬化型の樹脂組成物膜（レジスト又はペースト膜）に光又は熱処理を行って、ラジカル種やイオン種を発生させて重合又は架橋させ、不溶不融化させたものである。具体的にアクリレート系重合体とは、
（Ｉ）アクリル基やメタクリル基を複数有するアクリル系多官能モリマーおよびアクリレートオリゴマーと、光又は熱重合開始剤からなる組成物膜を光又は熱処理して、光ラジカルや熱ラジカルを発生させて重合させたもの、
（II）ポリビニル桂皮酸エステルと増感剤からなる組成物を光又は熱処理により二量化させて架橋したもの、
（III）鎖状又は環状オレフィンとビスアジドからなる組成物膜を光又は熱処理によりナイトレンを発生させ、オレフィンと架橋させたもの、
（IV）エポキシ基を有するモノマーと光酸発生剤からなる組成物膜を光又は熱処理により、酸（カチオン）を発生させて重合させたものなどがある。
【０１３８】
前記非反応性樹脂について説明すると、非反応性樹脂は、前記光硬化型または熱硬化型樹脂とは逆に、光や熱によってラジカル種やイオン種を発生しない、すなわち反応性を有しない樹脂である。具体的には、反応性ビニル基を有しない構造であって、重合開始剤や増感剤、ビスアジドや酸発生剤のように光や熱で分解してラジカル種やイオン種を発生する化合物を含有しない樹脂である。より具体的には、ポリメチルメタクリレート、ポリアクリレート、ポリカーボネート、ポリビニルアルコール、ポリビニルピロリドン、ポリ塩化ビニル、ポリ酢酸ビニル、ポリビニルブチラール、ポリエチレン、ポリプロピレン、ポリスチレン、ポリエステル、ポリピリジン、フッ素樹脂等の汎用ポリマーが挙げられる。
【０１３９】
発光効率の点で、好ましくは、低極性樹脂である。
ここで述べる低極性樹脂とは、ＪＩＳ−Ｋ−６９１１またはＡＳＴＭ Ｄ１５０に規定されている試験方法において測定される誘電率が３以下のものであり、具体例としては、「１９９８年版 プラスチック成形材料商取引便覧（化学工業日報社発行）」に記載されている樹脂の中で誘電率が３以下と記載されているものが挙げられ、ポリエチレン、ポリプロピレン、ポリスチレンおよびフッ素系樹脂のほとんどの誘電率は３以下である。
【０１４０】
色変換層は、用途によって様々な形態を採ることができる。本発明のエレクトロルミネッセンス素子は、少なくとも１種の希土類錯体系蛍光体を有しているが、必要に応じて無機系蛍光体を併用しても良い。
【０１４１】
例えば、白色の面状発光体にしたい場合には、青色に発光する蛍光体と黄色に発光する蛍光体の混合物を用いるか、又は、青色発光、緑色発光、赤色発光の３種の蛍光体の混合物を用いるが、その場合は特にパターニングする必要はなく、均一の厚みで塗設すれば良い。
【０１４２】
更に、フルカラー化の目的で、発光材料から発せられる光によって４００〜５００ｎｍに極大発光波長を有する無機系蛍光体又は希土類錯体系蛍光体の少なくとも１種、５０１〜６００ｎｍに極大発光波長を有する無機系蛍光体又は希土類錯体系蛍光体の少なくとも１種及び６０１〜７００ｎｍに極大発光波長を有する無機系蛍光体又は希土類錯体系蛍光体の少なくとも１種をそれぞれ有する色変換層を有することが好ましい。
【０１４３】
複数種の無機系蛍光体又は希土類錯体系蛍光体を使用して、複数の発光を得る場合、それぞれの蛍光体から発光する光の色調整をして色純度を高めることを目的としてカラーフィルターを重ね合わせて使用してもよい。また、各蛍光素子（蛍光色の異なる一画素）間隙に、ブラックマトリックスを配置し、発光の漏れ光を遮断して多色発光の視認性を高めることもできる。
【０１４４】
さらに前記色変換層上に、必要に応じて透明な保護膜を積層してもよい。各蛍光変換層の膜厚は通常０．１μｍ〜１００μｍ、好ましくは１μｍ〜６０μｍである。
【０１４５】
次に、色変換層の製造方法について説明する。
色変換層は、本発明の希土類錯体系蛍光体を分散又は溶液状にして、インクジェット法や印刷法を用いて直接モザイク状に本発明の蛍光体を塗設してもよいし、光硬化型又は熱硬化型樹脂組成物をバインダーとして用いることによりモザイクパターンを光や熱を利用して作製する、通常の印刷手法やフォトリソグラフィー法によってパターンを得てもよい。
【０１４６】
本発明で併用しても良い無機系蛍光体の組成は特に制限はないが、結晶母体であるＹ₂Ｏ₂Ｓ、Ｚｎ₂ＳｉＯ₄、Ｃａ₅（ＰＯ₄）₃Ｃｌ等に代表される金属酸化物及びＺｎＳ、ＳｒＳ、ＣａＳ等に代表される硫化物に、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ等の希土類金属のイオンやＡｇ、Ａｌ、Ｍｎ、Ｉｎ、Ｃｕ、Ｓｂ等の金属のイオンを賦活剤又は共賦活剤として組み合わせたものが好ましい。
【０１４７】
以下に本発明に好ましく使用される無機蛍光体を示すが、本発明はこれらの化合物に限定されるものではない。
【０１４８】
〔青色発光無機蛍光体〕
（ＢＬ−１）Ｓｒ₂Ｐ₂Ｏ₇：Ｓｎ⁴⁺
（ＢＬ−２）Ｓｒ₄Ａｌ₁₄Ｏ₂₅：Ｅｕ²⁺
（ＢＬ−３）ＢａＭｇＡｌ₁₀Ｏ₁₇：Ｅｕ²⁺
（ＢＬ−４）ＳｒＧａ₂Ｓ₄：Ｃｅ³⁺
（ＢＬ−５）ＣａＧａ₂Ｓ₄：Ｃｅ³⁺
（ＢＬ−６）（Ｂａ、Ｓｒ）（Ｍｇ、Ｍｎ）Ａｌ₁₀Ｏ₁₇：Ｅｕ²⁺
（ＢＬ−７）（Ｓｒ、Ｃａ、Ｂａ、Ｍｇ）₁₀（ＰＯ₄）₆Ｃｌ₂：Ｅｕ²⁺
（ＢＬ−８）ＢａＡｌ₂ＳｉＯ₈：Ｅｕ²⁺
（ＢＬ−９）Ｓｒ₂Ｐ₂Ｏ₇：Ｅｕ²⁺
（ＢＬ−１０）Ｓｒ₅（ＰＯ₄）₃Ｃｌ：Ｅｕ²⁺
（ＢＬ−１１）（Ｓｒ、Ｃａ、Ｂａ）₅（ＰＯ₄）₃Ｃｌ：Ｅｕ²⁺
（ＢＬ−１２）ＢａＭｇ₂Ａｌ₁₆Ｏ₂₇：Ｅｕ²⁺
（ＢＬ−１３）（Ｂａ，Ｃａ）₅（ＰＯ₄）₃Ｃｌ：Ｅｕ²⁺
（ＢＬ−１４）Ｂａ₃ＭｇＳｉ₂Ｏ₈：Ｅｕ²⁺
（ＢＬ−１５）Ｓｒ₃ＭｇＳｉ₂Ｏ₈：Ｅｕ²⁺
〔緑色発光無機蛍光体〕
（ＧＬ−１）（ＢａＭｇ）Ａｌ₁₆Ｏ₂₇：Ｅｕ²⁺，Ｍｎ²⁺
（ＧＬ−２）Ｓｒ₄Ａｌ₁₄Ｏ₂₅：Ｅｕ²⁺
（ＧＬ−３）（ＳｒＢａ）Ａｌ₂Ｓｉ₂Ｏ₈：Ｅｕ²⁺
（ＧＬ−４）（ＢａＭｇ）₂ＳｉＯ₄：Ｅｕ²⁺
（ＧＬ−５）Ｙ₂ＳｉＯ₅：Ｃｅ³⁺，Ｔｂ³⁺
（ＧＬ−６）Ｓｒ₂Ｐ₂Ｏ₇−Ｓｒ₂Ｂ₂Ｏ₅：Ｅｕ²⁺
（ＧＬ−７）（ＢａＣａＭｇ）₅（ＰＯ₄）₃Ｃｌ：Ｅｕ²⁺
（ＧＬ−８）Ｓｒ₂Ｓｉ₃Ｏ₈−₂ＳｒＣｌ₂：Ｅｕ²⁺
（ＧＬ−９）Ｚｒ₂ＳｉＯ₄、ＭｇＡｌ₁₁Ｏ₁₉：Ｃｅ³⁺，Ｔｂ³⁺
（ＧＬ−１０）Ｂａ₂ＳｉＯ₄：Ｅｕ²⁺
（ＧＬ−１１）Ｓｒ₂ＳｉＯ₄：Ｅｕ²⁺
（ＧＬ−１２）（ＢａＳｒ）ＳｉＯ₄：Ｅｕ²⁺
〔赤色発光無機蛍光体〕
（ＲＬ−１）Ｙ₂Ｏ₂Ｓ：Ｅｕ³⁺
（ＲＬ−２）ＹＡｌＯ₃：Ｅｕ³⁺
（ＲＬ−３）Ｃａ₂Ｙ₂（ＳｉＯ₄）₆：Ｅｕ³⁺
（ＲＬ−４）ＬｉＹ₉（ＳｉＯ₄）₆Ｏ₂：Ｅｕ³⁺
（ＲＬ−５）ＹＶＯ₄：Ｅｕ³⁺
（ＲＬ−６）ＣａＳ：Ｅｕ³⁺
（ＲＬ−７）Ｇｄ₂Ｏ₃：Ｅｕ³⁺
（ＲＬ−８）Ｇｄ₂Ｏ₂Ｓ：Ｅｕ³⁺
（ＲＬ−９）Ｙ（Ｐ，Ｖ）Ｏ₄：Ｅｕ³⁺
（ＲＬ−１０）Ｍｇ₄ＧｅＯ₅．₅Ｆ：Ｍｎ⁴⁺
（ＲＬ−１１）Ｍｇ₄ＧｅＯ₆：Ｍｎ⁴⁺
次に、本発明の色変換フィルターについて説明する。
【０１４９】
本発明の色変換フィルターは、光源の色（発光色）を所望の色に変換するのに用いられる波長変換素子のことであり、光源としては、本発明のエレクトロルミネッセンス素子以外にレーザー光等の任意の光源が挙げられる。基本的には光源の最大極大波長よりも１０ｎｍ以上長波長に波長を変換できる波長変換素子であり、具体的な用途としては、特開平３−１５２８９７号、同９−２４５５１１号、同１１−２９７４７７号等に記載されたフルカラーディスプレイ用フィルター（青色の光源から緑および赤に変換し、それらをストライプ状に配置することによって青、緑、赤の発光を可能とする色変換フィルター）、照明や液晶ディスプレイのバックライト用の白色発光用フィルター（４００〜７００ｎｍの可視領域の光を幅広く発光させる色変換フィルター）、ネオンサインや自動車の計器類の部分発光用フィルター（必要に応じた場所に必要な色を表示するための色変換フィルター）などがその代表例として挙げられる。
【０１５０】
液晶ディスプレイのカラーフィルターのような、多色化された色変換フィルターを得たい場合は、必要とする発光色の得られる蛍光体をストライプ状、ドット状又はモザイク状にパターニングすればよく、そのパターニング方法としては、従来の液晶ディスプレイ用カラーフィルターの製造方法がそのまま適用でき、具体的には顔料分散法、印刷法、インクジェット法等で作製することができる。
【０１５１】
【実施例】
以下、実施例をあげて本発明を具体的に説明するが、本発明の実施態様はこれに限定されるものではない。
【０１５２】
実施例１（有機ＬＥＤ素子の作製）
実施例（１−１）
陽極としてガラス上にＩＴＯを１５０ｎｍ成膜した基板（ＮＨテクノグラス社製ＮＡ−４５）にパターニングを行った後、このＩＴＯ透明電極を設けた透明支持基板をイソプロピルアルコールで超音波洗浄し、乾燥窒素ガスで乾燥し、ＵＶオゾン洗浄を５分間行なった。
【０１５３】
この透明支持基板を、市販の真空蒸着装置の基板ホルダーに固定し、一方、モリブデン製抵抗加熱ボートに、Ｎ，Ｎ’−ジフェニル−Ｎ，Ｎ’−ビス（３−メチルフェニル）〔１，１’−ビフェニル〕−４，４’−ジアミン（ＴＰＤ）２００ｍｇを入れ、別のモリブデン製抵抗加熱ボートにｐ−クウオーターフェニル（ＰＱＰ）２００ｍｇを入れ、さらに別のモリブデン製抵抗加熱ボートにトリス（８−ヒドロキシキノリナート）アルミニウム（Ａｌｑ３）を２００ｍｇ入れ、真空蒸着装置に取付けた。
【０１５４】
次いで、真空槽を４×１０^-4Ｐａまで減圧した後、ＴＰＤの入った前記加熱ボートに通電して、２２０℃まで加熱し、蒸着速度０．１〜０．３ｎｍ／ｓｅｃで透明支持基板に蒸着し、膜厚６０ｎｍの正孔注入層を設けた。さらに、ＰＱＰの入った前記加熱ボートを通電して２２０℃まで加熱し、蒸着速度０．１〜０．３ｎｍ／ｓｅｃで前記正孔注入層上に蒸着して膜厚４０ｎｍの発光層を設けた。さらに、Ａｌｑ３の入った前記加熱ボートを通電して２５０℃まで加熱し、蒸着速度０．１ｎｍ／ｓｅｃで前記発光層の上に蒸着して膜厚２０ｎｍの電子注入層を設けた。なお、蒸着時の基板温度は室温であった。次に、真空槽をあけ、電子注入層の上にステンレス鋼製の長方形穴あきマスクを設置し、一方、モリブデン製抵抗加熱ボートにマグネシウム３ｇを入れ、タングステン製の蒸着用バスケットに銀を０．５ｇ入れ、再び真空槽を２×１０^-4Ｐａまで減圧した後、マグネシウム入りのボートに通電して蒸着速度１．５〜２．０ｎｍ／ｓｅｃでマグネシウムを蒸着し、この際、同時に銀のバスケットを加熱し、蒸着速度０．１ｎｍ／ｓｅｃで銀を蒸着し、前記マグネシウムと銀との混合物からなる対向電極とすることにより、エレクトロルミネッセンス素子（ＵＶ−１）を作製した。
【０１５５】
この素子のＩＴＯ電極を陽極、マグネシウムと銀からなる対向電極を陰極として直流１０ボルトを印加したところ、極大発光波長３８０ｎｍの発光を得た。
【０１５６】
実施例（１−２）
実施例（１−１）の発光体ｐ−クウオーターフェニル（ＰＱＰ）を化合物Ａー１に置き換えた以外は実施例（１−１）と全く同じ方法で作製したエレクトロルミネッセンス素子（Ａ−１）を作製した。
【０１５７】
【化３１】

【０１５８】
この素子のＩＴＯ電極を陽極、マグネシウムと銀からなる対向電極を陰極として直流１０ボルトを印加したところ、極大発光４０５ｎｍの発光を得た。
【０１５９】
実施例（１−３）
（１−１）の発光体ｐ−クウオーターフェニル（ＰＱＰ）を４，４’−ビス（２，２’−ジフェニルビニル）ビフェニル（ＤＰＶＢｉ）に置き換えた以外は（１−１）と全く同じ方法で作製したエレクトロルミネッセンス素子（Ｂ−１）を作製した。
【０１６０】
この素子のＩＴＯ電極を陽極、マグネシウムと銀からなる対向電極を陰極として直流１０ボルトを印加したところ、極大発光４７５ｎｍの青色の発光を得た。
【０１６１】
実施例２（色変換層の作製）
実施例（２−１）
トルエン／エタノール＝１／１の混合溶液（３００ｇ）で溶解されたポリビニルブチラール（ＢＸ−１、積水化学工業（株）製）３０ｇに本発明の希土類錯体系蛍光体（ＣＬ−４）３ｇを溶解し、実施例（１−２）で作製したエレクトロルミネッセンス素子（Ａ−１）の基板上（発光層とは反対面）にＷｅｔ膜厚１５０μｍで塗布し、温風乾燥して、本発明の希土類錯体系蛍光体を含有するエレクトロルミネッセンス素子（ＮＯ．１）を作製した。
【０１６２】
また、これと同様に、エレクトロルミネッセンス素子および希土類錯体系蛍光体を表１に記載の素子および化合物に変更した以外は同様の方法によって、本発明の色希土類錯体系蛍光体を含有するエレクトロルミネッセンス素子（ＮＯ．２）〜（ＮＯ．２２）および（ＮＯ．２６）〜（ＮＯ．２７）を作製した。
【０１６３】
比較例（２−１）
実施例（２−１）のＣＬ−４の替わりに蛍光顔料ソルベントイエロー１１６を１．０ｇ、ベーシックバイオレット１１を０．５ｇおよびローダミン６Ｇを０．５ｇに替えた以外は実施例（２−１）と同様な方法で比較となる青色光励起赤色発光のエレクトロルミネッセンス素子（ＮＯ．２３）を作製した。更にエレクトロルミネッセンス素子をＢ−１、ＵＶ−１に変更したエレクトロルミネッセンス素子（ＮＯ．２４）および（ＮＯ．２５）を作製した。
【０１６４】
更に、実施例（２−１）のＣＬ−４の替わりに蛍光色素クマリン６、２．０ｇと蛍光顔料ソルベントイエロー１１６、０．５ｇに替えた以外は実施例（２−１）と同様な方法で比較となる青色光励起緑色発光のエレクトロルミネッセンス素子（ＮＯ．２８）を作製した。
【０１６５】
更にエレクトロルミネッセンス素子をＢ−１に変更したエレクトロルミネッセンス素子（ＮＯ．２９）を作製した。
【０１６６】
実施例３（評価）
実施例（３−１）（エレクトロルミネッセンス素子の発光効率、寿命および色調の評価）
エレクトロルミネッセンス素子ＮＯ．１〜ＮＯ．２９を、温度２３℃、乾燥窒素ガス雰囲気下で１２Ｖ直流電圧印加による連続点灯を行い、点灯開始時の発光効率（ｌｍ／Ｗ）および輝度の半減する時間を測定した。発光効率は試料Ｎｏ．１の発光効率を１００とした時の相対値で表し、輝度の半減する時間は試料Ｎｏ．１の輝度が半減する時間を１００とした相対値で表した。結果を表１、２に示す。
【０１６７】
【表１】

【０１６８】
【表２】

【０１６９】
表１、２より、赤色に発光する、本発明の希土類錯体系蛍光体を含有するエレクトロルミネッセンス素子は比較例に比べ発光効率が高く寿命も長いことがわかった。さらに発光色も本発明の試料の方が好ましい色調であった。
【０１７０】
また、緑色に発光する、本発明の希土類錯体系蛍光体を含有するエレクトロルミネッセンス素子は比較例に比べて発光効率が高く、寿命も長いことがわかった。さらに発光色も比較試料より好ましい色調であった。
【０１７１】
実施例（３−２）
実施例（３−１）で用いたエレクトロルミネッセンス素子の替わりに日亜化学（株）製紫外発光ＬＥＤ素子（ＵＶ ＬＥＤ Ｌａｍｐ）を用いて同様の評価を行ったところ、実施例（３−１）と同様の結果が得られた。
【０１７２】
実施例（３−３）（低極性バインダー）
塗料用フッ素樹脂（ルミフロン ＬＦ−２００、旭硝子（株）社製）３００ｇに本発明の希土類錯体系蛍光体（ＣＬ−５４）３ｇを溶解し、実施例（１−２）で作製したエレクトロルミネッセンス素子（Ａ−１）の基板上（発光層とは反対面）にＷｅｔ膜厚１５０μｍで塗布し、温風乾燥して、本発明の希土類錯体系蛍光体を含有するエレクトロルミネッセンス素子（ＮＯ．３０）を作製した。
【０１７３】
さらに、実施例（３−１）と同一条件において、発光効率および輝度の半減する時間を測定した。結果を表３に示す。
【０１７４】
なお、本実施例に使用したルミフロン ＬＦ−２００の誘電率は、ＡＳＴＭ−Ｄ５０に規定されている試験方法により実測した結果、２．２の値を示した。
【０１７５】
また、ポリビニルブチラール（積水化学工業（株）製）の誘電率は、３．１〜４．２とカタログに記載がある。
【０１７６】
【表３】

【０１７７】
表３より、本発明のエレクトロルミネッセンス素子（ＮＯ．２０）のバインダーをルミフロン ＬＦ−２００に変更することにより、更に発光効率が向上することが確認された。
【０１７８】
また、ルミフロン ＬＦ−２００を市販のポリエチレン、ポリプロピレンおよびポリスチレンに変更した場合も、発光効率の向上が確認されたことが分かる。
【０１７９】
実施例４
実施例（４−１）
特開平８−２７９３９７号に記載の方法により、透明基板上に色変換層を形成し、色変換層上に陽極、正孔注入層、発光層、電子注入層および陰極を順次積層するエレクトロルミネッセンス素子を作製し、実施例（３−１）と同様の評価を行ったところ、発光効率および寿命において、同様の効果が確認された。
【０１８０】
実施例５（色変換フィルター）
トルエン／エタノール＝１／１の混合溶液（３００ｇ）で溶解されたブチラール（ＢＸ−１）３０ｇに本発明の希土類錯体系蛍光体（ＣＬ−４）３ｇを溶解し、厚さ８０μｍのポリエーテルスルフォン（ＰＥＳ）フィルム上にＷｅｔ膜厚１５０μｍで塗布し、温風乾燥して、本発明の色変換フィルター（Ｆ−１）を作製した。
【０１８１】
また、これと同様に、ＣＬ−４の替わりに表４に記載の化合物を用いた以外は同様の方法によって、本発明の色変換フィルター（Ｆ−２）〜（Ｆ−５）を作製した。
【０１８２】
【表４】

【０１８３】
実施例６
実施例５で作製した色変換フィルターを用い、本発明で使用した光源（Ａ−１、Ｂ−１、ＵＶ−１）以外の光源（レーザー光等）を使用して、色変換効率を測定したところ、実施例３と同様に良好な色変換効率が得られた。
【０１８４】
【発明の効果】
実施例で実証した如く、本発明の希土類錯体系蛍光体は、良好な可視発光を確認でき、かつ良好な発光輝度、発光効率及び発光寿命に優れた効果を有する。本発明の希土類錯体系蛍光体を色変換フィルターは、エレクトロルミネッセンス素子以外の光源を用いた場合でも良好な可視発光が得られ、良好な発光輝度、発光効率及び発光寿命に優れた効果を有する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electroluminescence element (hereinafter also simply referred to as an EL element) and a color conversion filter, and specifically, suitable for consumer and industrial display devices such as light-emitting multi-color or full-color displays and display panels. The present invention relates to an electroluminescence element used and a color conversion filter.
[0002]
[Prior art]
The electronic display device includes a light emitting type and a light receiving type. Examples of the light emitting type include a CRT (cathode ray tube), a PDP (plasma display), an ELD (electroluminescence display), and a VFD (fluorescent display tube). .
[0003]
Among these, ELD will be described.
An ELD (electroluminescence display) is a light-emitting element made of a material that emits light by an electric field or an electric field, or a combination of a plurality of them. There are a carrier injection type using hole recombination and an accelerated electron type using collision energy of accelerated electrons. In general, inorganic materials have a longer life and are more stable than organic materials, but the development range of materials is narrow and molecular design is limited. In terms of mechanism, the recombination type generally has an advantage that the driving voltage is lower than that of the acceleration electron type. In recent years, the carrier injection type ELD has been actively studied due to the advantage.
[0004]
Specific examples of the light emitting element include the following three types.
Inorganic LED (Material is composed of an inorganic compound such as GaN or GaInN, and the light emission mechanism is a carrier injection type. It is also simply called LED (light emitting diode).)
Organic LED (Materials are composed of organic compounds such as triarylamine derivatives and stilbene derivatives, and light emission mechanism is carrier injection type. Also referred to as organic EL (electroluminescence) or OLED)
・ Inorganic EL (Materials are composed of inorganic compounds such as ZnS: Mn and ZnS: Tb, and the light emission mechanism is an accelerated electron type. Since it has an older history than organic LEDs, it may be simply called electroluminescence (EL). .)
In particular, carrier-injection organic LEDs that have attracted attention in recent years have come to have high emission intensities since thin films made of organic compounds have been used.
[0005]
For example, US Pat. No. 3,530,325 uses a single crystal anthracene or the like as a light emitter, and JP-A-59-194393 combines a hole injection layer and an organic light emitter layer. Japanese Kokai 63-295695 discloses a combination of a hole injection layer and an organic electron injection transport layer, Jpn. Journal of Applied Physics, vol 127, no. 2 pages 269-271 each disclose a combination of a hole transport layer, a light emitting layer, and an electron transport layer, and the light emission intensity has been improved by these.
[0006]
In addition, inorganic EL requires an alternating high voltage to drive a light emitting element, whereas organic LEDs can emit light at a voltage of several volts to several tens of volts, and are self-luminous. Therefore, it is rich in viewing angle dependency, has high visibility, and is a thin-film type complete solid-state device, and thus has attracted attention from the viewpoints of space saving and portability.
[0007]
On the other hand, a method of emitting multicolor fluorescence using a phosphor is applied to CRT, PDP, VFD, and the like.
[0008]
However, in this case, there is a problem that the light emission is high in energy, that is, the emission wavelength is a short wave, such as an electron beam or far ultraviolet rays. In other words, the above phosphors are specifically inorganic phosphors, and their stability is much higher than that of organic fluorescent dyes, and many are known to withstand long-term use. There was almost nothing that excited the long wavelength from the near ultraviolet to the visible region, and there was actually nothing that emitted red light at all.
[0009]
In addition, near-ultraviolet light that can be emitted from an electroluminescent material is estimated to be light having a maximum emission wavelength of about 350 nm to 400 nm. An organic fluorescent dye is used as a phosphor excited by such near-ultraviolet light. JP-A-3-152897, JP-A-9-245511, JP-A-5-258860 and the like are known.
[0010]
However, organic fluorescent dyes are generally susceptible to the surrounding environment. For example, depending on the type of medium such as a solvent or resin, the fluorescence wavelength may change (discolor) or quench, and light It is extremely unstable with respect to heat and, for example, most of them decompose in a few minutes to a few hours under strong light of about 100,000 lux, and there are no organic fluorescent dyes that can withstand long-term storage .
[0011]
In addition, the method described in the patent uses a fluorescent dye that absorbs light of a light emitter and converts the color to a green region or a red region, and a fluorescence conversion film that emits fluorescence in a green region is: The feature is that the Stokes shift (difference between the absorption wavelength and the emission wavelength) is small, and part of the light emission of the electroluminescent material can be transmitted, and the light of the light emitter can be converted with relatively high efficiency. However, since the fluorescence to the red region requires a large Stokes shift, the light from the illuminant can hardly be used, so that the conversion efficiency is remarkably low. Specifically, several types of fluorescent dyes with different excitation wavelengths are used in combination, for example, light-to-light conversion of a plurality of fluorescent dyes such as a fluorescent dye that turns yellow when it receives blue light and a fluorescent dye that glows red when it receives yellow light ( Photoluminescence) must be used in other stages, and in principle, high efficiency was not possible.
[0012]
[Problems to be solved by the invention]
In the prior art, including the problems of discoloration, low conversion efficiency, and quenching, the blue, green, and red light emission luminance is poorly balanced, especially the red luminance is low, and the overall visibility is low and low luminance. There was a problem that it had to be color display.
[0013]
An object of the present invention is to provide an electroluminescent device that improves the conversion efficiency by using a rare earth complex-based phosphor, has high brightness, and is excellent in storage stability, and uses a rare earth complex-based phosphor. Is to provide a color conversion filter with improved conversion efficiency, high brightness and excellent storage stability.
[0014]
[Means for Solving the Problems]
The object of the present invention is achieved by the following constitution.
[0015]
  1. In an electroluminescent device comprising a light emitting material and a rare earth complex phosphor that absorbs light emitted from the light emitting material and emits light at a maximum emission wavelength different from the maximum emission wavelength emitted from the light emitting material, the rare earth complex phosphor is General formula (1)soAn electroluminescent device comprising at least one anion of the compound represented as a ligand.
[0016]
2. The rare earth complex phosphor is represented by Z in the general formula (1).₁The aromatic ring formed by is a substituted or unsubstituted benzene ring, and X₁And Y₁Is an oxygen atom and R₁₁2. The electroluminescent device as described in 1 above, wherein the compound is an anionic ligand of a compound having a hydrogen atom, a hydrocarbon aromatic ring or a nitrogen-containing aromatic ring.
[0020]
  3.1 or 2 aboveIn the electroluminescence device, the rare earth complex-based phosphor is:MoreAn electroluminescent device comprising at least one selected from the compounds represented by the general formula (5), (6) or (7) as a ligand.
[0021]
  4. The rare earth complex phosphor is X in the general formula (5) or the general formula (6)._FiveIs an oxygen atom and R₅₁, R₅₂, R₅₃, R₆₁And R₆₂Containing at least one as a ligand of a compound each of which is an alkoxy group or an alkyl group3The electroluminescent device according to 1.
[0022]
  5. The rare earth complex phosphor is X in the general formula (5) or the general formula (6)._FiveIs an oxygen atom and R₅₁, R₅₂, R₅₃, R₆₁And R₆₂Containing at least one as a ligand of a compound each of which is a fluorine-substituted alkyl group4The electroluminescent device according to 1.
[0024]
  6. The rare earth complex phosphor is represented by Z in the general formula (1).₁The aromatic ring formed by is a substituted or unsubstituted benzene ring, and X₁And Y₁Is an oxygen atom and R₁₁Is contained as an anionic ligand of a compound in which is a hydrogen atomAny one of 3-5The electroluminescent element of description.
[0028]
  7. The above 1 characterized in that the binder used in the color conversion layer containing the rare earth complex phosphor is a low-polarity resin.Any one of -6The electroluminescent element according to item.
[0030]
  8. The maximum emission wavelength of the luminescent material is 430 nm or less,7The electroluminescent element according to any one of the above.
[0031]
  9. The maximum emission wavelength of the light-emitting material is 400 to 430 nm, 1 aboveAny one of ~ 7The electroluminescent element of description.
[0032]
  10. The light emitting material is an organic LED material,9The electroluminescent element according to any one of the above.
[0033]
  11. The general formula (1)soA color conversion filter comprising a rare earth complex-based phosphor containing at least one anion of the compound represented as a ligand.
[0034]
  12. The rare earth complex phosphor is represented by Z in the general formula (1).₁The aromatic ring formed by is a substituted or unsubstituted benzene ring, and X₁And Y₁Is an oxygen atom and R₁₁Is contained as an anionic ligand of a compound that is a hydrogen atom, a hydrocarbon aromatic ring or a nitrogen-containing aromatic ring.11The color conversion filter described in 1.
[0038]
  13. Rare earth complex phosphor having at least one of the compounds represented by the general formula (5), (6) or (7) as a ligandA color conversion filter, further comprising a rare earth complex-based phosphor containing, as a ligand, at least one anion of the compound represented by the general formula (1).
[0039]
  14. The rare earth complex-based phosphor is X in the general formula (5) or the general formula (6)._FiveIs an oxygen atom and R₅₁, R₅₂, R₅₃, R₆₁And R₆₂Containing at least one ligand of a compound each of which is an alkoxy group or an alkyl group13The color conversion filter described in 1.
[0040]
  15. The rare earth complex-based phosphor is X in the general formula (5) or the general formula (6)._FiveIs an oxygen atom and R₅₁, R₅₂, R₅₃, R₆₁And R₆₂Containing at least one ligand of a compound each of which is a fluorine-substituted alkyl group14The color conversion filter described in 1.
[0042]
  16. The rare earth complex phosphor is represented by Z in the general formula (1).₁The aromatic ring formed by is a substituted or unsubstituted benzene ring, and X₁And Y₁Is an oxygen atom and R₁₁Is contained as an anionic ligand of a compound that is a hydrogen atom, a hydrocarbon aromatic ring or a nitrogen-containing aromatic ring.Any one of 13-15The color conversion filter described in 1.
[0046]
The present invention is described in further detail below.
The light-emitting material of the present invention is a material that emits light by an electric field or an electric field, and specifically, a material that emits light or an accelerated electron when holes and electrons are injected from an anode and a cathode, respectively, and recombined. A material that emits light by the collision energy of the above can be mentioned.
[0047]
The light emission by an electric field or an electric field means that, for example, a light emitting material contained in the light emitting layer emits light by having a pair of counter electrodes with the light emitting layer interposed therebetween and passing a current through the electrodes. This is because recombination occurs in the light-emitting layer due to electrons injected from one electrode of a pair of counter electrodes sandwiching the light-emitting layer and holes injected from the other electrode, so that the light-emitting material has a higher energy level. It is presumed that this occurs by releasing energy as light when the excited luminescent material returns to its original ground state.
[0048]
The light emitting material of the present invention is not particularly limited as long as it emits light by an electric field or an electric field. For example, an inorganic light emitting material (also referred to as an inorganic LED material) such as gallium nitride (GaN), an organic light emitting material (organic LED) In the present invention, it is preferable to use an organic LED material from the viewpoint of luminous efficiency.
[0049]
Below, the electroluminescent element of this invention is demonstrated.
The “electroluminescence element” referred to in the present invention is the above-mentioned three types, and the “electroluminescence material” indicates a material constituting them.
[0050]
An electroluminescence element is usually configured to contain a single layer or a plurality of layers between two electrodes, and the constituent layers include a hole injection layer (or a charge injection layer, a hole injection layer, a charge transport layer) in addition to a light emitting layer. , A hole transport layer), an electron injection layer (also referred to as an electron transport layer), and the like.
[0051]
The hole injection layer and the electron injection layer may further have a laminated structure as necessary, for example, anode / first hole injection layer / second hole injection layer (hole transport layer) / light emission. A layer structure such as layer / second electron injection layer (electron transport layer) / first electron injection layer / cathode may be employed.
[0052]
Next, an example of the layer structure of the electroluminescent device of the present invention is shown (however, as described above, description of a plurality of hole injection layers and / or electron injection layers is omitted, but naturally a stack in which a plurality of compounds are stacked) A structure may be formed.)
(1) Substrate / color conversion layer / substrate / anode / light emitting layer / cathode
(2) Substrate / color conversion layer / substrate / anode / hole injection layer / light emitting layer / cathode
(3) Substrate / color conversion layer / substrate / anode / light emitting layer / electron injection layer / cathode
(4) Substrate / color conversion layer / substrate / anode / hole injection layer / light emitting layer / electron injection layer / cathode
(5) Substrate / anode / light emitting layer / cathode / color conversion layer / substrate
(6) Substrate / anode / hole injection layer / light emitting layer / cathode / color conversion layer / substrate
(7) Substrate / anode / light emitting layer / electron injection layer / cathode / color conversion layer / substrate
(8) Substrate / anode / hole injection layer / light emitting layer / electron injection layer / cathode / color conversion layer / substrate
(9) Substrate / color conversion layer / anode / light emitting layer / cathode
(10) Substrate / color conversion layer / anode / hole injection layer / light emitting layer / cathode
(11) Substrate / color conversion layer / anode / light emitting layer / electron injection layer / cathode
(12) Substrate / color conversion layer / anode / hole injection layer / light emitting layer / electron injection layer / cathode
Here, the substrate in contact with the color conversion layer and the substrate in contact with the anode may be the same or different, and the outside of each element may be covered with the substrate.
[0053]
Note that a buffer layer (electrode interface layer) may exist between the anode and the light emitting layer or the hole injection layer and between the cathode and the light emitting layer or the electron injection layer.
[0054]
The substrate preferably used for the electroluminescent device of the present invention is not particularly limited in the kind of glass, plastic, etc., and is not particularly limited as long as it is transparent. Examples of the substrate preferably used for the electroluminescence device of the present invention include glass, quartz, and a light transmissive plastic film.
[0055]
Examples of the light transmissive plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, and polycarbonate (PC). And a film made of cellulose triacetate (TAC), cellulose acetate propionate (CAP), or the like.
[0056]
As the anode in this electroluminescence element, an electrode material made of a metal, an alloy, an electrically conductive compound or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, CuI, indium tin oxide (ITO), SnO.₂, ZnO, and conductive transparent materials such as zinc-doped indium oxide (IZO). The anode may be formed by forming a thin film by depositing these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or (100 μm) when pattern accuracy is not so required. As described above, a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered.
[0057]
When light emission is extracted from this anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is 10%.^ThreeΩ / □ or less is preferable. The film thickness of the anode can be appropriately selected depending on the material, but it is preferably about 10 nm to 1 μm, and more preferably 10 to 200 nm.
[0058]
On the other hand, as the cathode, a metal having a work function (less than 4 eV) metal (sometimes referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used. Specific examples of such electrode materials include potassium, sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al₂O_Three) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.
[0059]
Among these, from the point of durability against electron injection and oxidation, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al₂O_Three) A mixture of an electron injecting metal and a metal having a larger work function value, such as a mixture or a lithium / aluminum mixture, is preferable.
[0060]
However, when the cathode buffer layer as described above is used on the cathode surface, the work function limitation is removed, and for example, as described in JP-A No. 11-224783, In the patent specification, the cathode is made of ITO or SnO by using an alkali metal or alkaline earth metal fluoride for the electron injection layer).₂, In₂O_Three, ZnO: Al and other materials with a high work function that are normally used as anodes can also be used, and “Organic EL devices and their forefront of industrialization” November 30, 1998 issued by NTS Corporation As described in the 15th to 28th lines on page 145, aluminum can be used as a cathode material by using lithium fluoride (film thickness: 0.5 to 1 μm) as a cathode buffer layer. The cathode material in the case of using such a cathode buffer layer is defined as “metal” in the periodic table of silver, copper, platinum, gold, etc. in addition to the metal oxide and aluminum. Can be used.
[0061]
The cathode can be produced by forming a thin film from the electrode material by a method such as vapor deposition or sputtering. Further, it can be produced by a plating method as described in JP-A-11-8074.
[0062]
The sheet resistance as a cathode is 10^ThreeΩ / □ or less is preferable. Further, the film thickness of the cathode is preferably 10 nm to 100 μm, and more preferably 50 to 2000 nm.
[0063]
In order to transmit light, it is preferable that the electrode positioned between the light emitting layer and the color conversion layer of the electroluminescence element is transparent or translucent because the light emission efficiency is improved.
[0064]
Here, the electrode being transparent or translucent means that the visible light transmittance at 400 nm to 700 nm is 20% or more, preferably 50% or more, and more preferably 50 to 70%.
[0065]
Next, the light emitting layer will be described.
The light-emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, electron injection layer, or hole injection layer, and the light-emitting portion is adjacent to the light-emitting layer even within the light-emitting layer. It may be an interface with the layer.
[0066]
The material used for the light-emitting layer is a light-emitting material, preferably an organic compound or complex that emits fluorescence or phosphorescence, and an arbitrary material is selected from known materials used for the light-emitting layer of the organic EL element. Can be used.
[0067]
The light emitting material may have the hole injection function and the electron injection function in addition to the light emitting performance, and most of the hole injection material and the electron injection material can be used as the light emitting material.
[0068]
The light emitting material may be a polymer material such as p-polyphenylene vinylene or polyfluorene, and further using a polymer material in which the light emitting material is introduced into a polymer chain or the light emitting material is a polymer main chain. Also good.
[0069]
In addition, a dopant (guest material) may be used in combination with the light emitting layer, and an arbitrary one can be selected from known materials used as a dopant for an EL element.
[0070]
Specific examples of the dopant include quinacridone, DCM, coumarin derivatives, rhodamine, rubrene, decacyclene, pyrazoline derivatives, squarylium derivatives, europium complexes and the like.
[0071]
In the present invention, the luminescent material preferably has a maximum emission wavelength of 430 nm or less due to an electric field or an electric field, and further has a maximum emission wavelength of 400 to 430 nm from the viewpoint of both conversion efficiency and storage stability. Preferably there is.
[0072]
In addition, on the CIE chromaticity diagram, the new edition of Color Science Handbook, 4th edition, Japanese Color Society, edited by page 108, “Figure 4.16 Relationship between color name of color stimulus (color of light) and chromaticity coordinates” "Purple Blue, Blueish Purple, or Purple."
[0073]
Although the film thickness of a light emitting layer is not specifically limited, Usually, the thing of the range of 1 nm-5 micrometers is preferable, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm.
[0074]
The hole injection layer provided as necessary in the present invention has a function of transmitting holes injected from the anode to the light emitting layer, and this hole injection layer is interposed between the anode and the light emitting layer. As a result, many holes are injected into the light emitting layer with a lower electric field. In addition, light emission performance such as accumulation of electrons at the interface in the light emitting layer and improvement in light emission efficiency due to the barrier between electrons injected into the light emitting layer from the cathode or the electron injection layer and electrons present at the interface between the light emitting layer and the hole injection layer. It becomes an excellent element.
[0075]
The material used for the hole injection layer (hereinafter referred to as hole injection material) is not particularly limited as long as it has the above-mentioned function, and any conventionally selected one is used. be able to.
[0076]
The hole injection material has either hole injection or electron barrier properties, and may be either organic or inorganic.
[0077]
Examples of the organic hole injecting material include JP-A 63-295695, JP-A 2-191694, JP-A 3-792, JP-A-5-234681, and JP-A-5-239455. Various organic compounds described in JP-A-5-299174, JP-A-7-126225, JP-A-7-126226, JP-A-8-1001922, EP0650955A1, and the like are used. it can. For example, phthalocyanine derivatives, tetraarylbenzidine compounds, aromatic tertiary amines, hydrazone derivatives, carbazole derivatives, triazole derivatives, imidazole derivatives, oxadiazole derivatives having amino groups, polythiophenes, and the like. Two or more of these compounds may be used in combination, and when used together, they may be laminated as separate layers or mixed.
[0078]
When the hole injection layer is stacked and used (when the functions of hole injection and hole transport are properly used), a preferred combination can be selected from the above compounds. At this time, it is preferable to laminate in order of a compound layer having a small ionization potential from the anode (ITO or the like) side. Further, it is preferable to use a compound having a good thin film property (film forming property) (for example, a starburst type compound described in JP-A-4-308688 or the like is a typical example) for the anode surface.
[0079]
Moreover, p-type-Si, p-type-SiC, etc. can be used as an inorganic hole injection material.
[0080]
Although there is no restriction | limiting in particular about the film thickness of a positive hole injection layer, It is preferable that it is 5 nm-5 micrometers.
[0081]
Further, the electron injection layer used as necessary only has a function of transmitting electrons injected from the cathode to the light emitting layer, and facilitates injection of electrons from the cathode, and transports electrons. It has a function and a function of blocking holes. Note that the electron injecting and transporting layer may be provided separately for the layer having an injection function and the layer having a transport function.
[0082]
Examples of materials used in this electron injection layer (hereinafter referred to as electron injection materials) include heterocyclic tetracarboxylic anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, carbodiimide, Examples include fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. In addition, a series of electron transfer compounds described in JP-A-59-194393 is disclosed as a material for forming a light emitting layer in the publication, but can also be used as an electron injection material. Further, the oxadiazole derivative has a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, a triazole derivative substituted with an arylamino group or an alkylamino group, or a quinoxaline ring known as an electron withdrawing group. A quinoxaline derivative can also be used as an electron injection material.
[0083]
In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu Metal complexes replaced with Ca, Sn, Ga, or Pb can also be used as the electron injection material. In addition, the metal complex-based material described in the first edition, Chapter 3, pages 39 to 48 of the document A, metal-free metal phthalocyanine, or those whose ends are substituted with an alkyl group or a sulfonic acid group, etc. It can be preferably used as an electron injection material. Similarly to the hole injection layer, an inorganic semiconductor such as n-type Si or n-type SiC can also be used as the electron injection material.
[0084]
Although the film thickness as an electron injection layer does not have a restriction | limiting in particular, It is preferable that they are 5 nm-5 micrometers.
[0085]
The electron injection layer may have a single layer structure containing one or two or more of the above electron injection materials, or may have a multilayer structure having a plurality of layers having the same composition or different compositions.
[0086]
Note that a buffer layer (electrode interface layer) may exist between the anode and the light emitting layer or the hole injection layer and between the cathode and the light emitting layer or the electron injection layer.
[0087]
The buffer layer is a layer provided between the electrode and the organic layer in order to lower the driving voltage and improve the light emission efficiency. The second chapter, Chapter 2, “Electrode Material” (pages 123 to 166) of Document A The anode buffer layer and the cathode buffer layer are described in detail.
[0088]
As the anode buffer layer, a polymer using a phthalocyanine buffer layer typified by copper phthalocyanine, an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, or a conductive polymer such as polyaniline (emeraldine) or polythiophene. Examples include a buffer layer.
[0089]
As the cathode buffer layer, a metal buffer layer typified by strontium or aluminum, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, or aluminum oxide And oxide buffer layers.
[0090]
The buffer layer is preferably a very thin film, and depending on the material, the film thickness is preferably in the range of 0.1 to 100 nm.
[0091]
As a method for forming a light emitting layer, a hole injection layer, an electron injection layer, or a buffer layer, it can be formed by thinning by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Although it is possible, a molecular deposition film is particularly preferable. Here, the molecular deposited film is a thin film formed by deposition from a vapor phase state of a compound or a film formed by solidification from a molten state or a liquid phase state of a compound. Usually, this molecular deposited film can be distinguished from a thin film (molecular accumulated film) formed by the LB method, a difference in aggregation structure and higher order structure, and a functional difference resulting therefrom.
[0092]
Further, as described in JP-A-57-51781, this light emitting layer is prepared by dissolving the above light emitting material in a solvent together with a binder such as a resin, and then using a spin coating method or the like. It can be formed as a thin film. There is no restriction | limiting in particular about the film thickness of the light emitting layer formed in this way, Although it can select suitably according to a condition, It is preferable to use in the range of 5 nm-5 micrometers.
[0093]
The color conversion layer will be described.
The color conversion layer is a layer containing at least one rare earth complex-based phosphor according to the claims of the present invention, and absorbs light emitted from the light emitting material and has a maximum different from the maximum light emission wavelength of the light emitting material. It emits light at the emission wavelength.
[0094]
  Here, the emission wavelength different from the maximum emission wavelength emitted from the light emitting material means that the maximum emission wavelength of the rare earth complex-based phosphor is 10 nm or more away from the maximum emission wavelength emitted from the light emitting material.
  Moreover, although it becomes general formula (1) and another invention below, general formula (2)-(7) is demonstrated.
[Chemical I]

[Where X₁And Y₁Are oxygen fieldsChildR_{1 1} Is a hydrogen atom or a monovalent substituentRepresents Z₁IsSubstituted or unsubstituted benzene ringRepresents an atomic group necessary for forming. ]
[Chemical J]

[In the formula, R_{twenty one}, R_{twenty two}And R_{twenty three}Each represents a hydrogen atom or a monovalent substituent. ]
[Chemical K]

[In the formula, R₃₁And R₃₃Represents a hydrogen atom or a monovalent substituent having a positive σm value, and R₃₂Represents a hydrogen atom or a monovalent substituent having a positive σp value, and R₃₄And R₃₆Represents a hydrogen atom or a monovalent substituent having a negative σm value, and R₃₅Represents a hydrogen atom or a monovalent substituent having a negative σp value. However, R₃₁, R₃₂And R₃₃Are not simultaneously hydrogen atoms, R₃₄, R₃₅And R₃₆Are not simultaneously hydrogen atoms. ]
[Chemical L]

[In the formula, R₄₁And R₄₂Represents a hydrogen atom or a monovalent substituent, and Z_FourRepresents an atomic group necessary for forming a 5-membered heteroaromatic ring, and m4 and n4 represent 1 to 5. ]
[Chemical formula M]

[In the formula, R₅₁, R₅₂And R₅₃Represents a monovalent substituent and X_FiveRepresents an oxygen atom or a sulfur atom. ]
[Chemical N]

[In the formula, R₆₁And R₆₂Represents a monovalent substituent. ]
[Chemical O]

[In the formula, R₇₁, R₇₂And R₇₃Represents a hydrogen atom or a monovalent substituent. ]
[0095]
Hereinafter, the general formula (1) will be described.
In general formula (1), X₁And Y₁Are oxygen atom, sulfur atom or N—R, respectively.₁₂Represents R₁₁And R₁₂Are each a hydrogen atom or a monovalent substituent, Z₁Represents an atomic group necessary for forming an aromatic ring (hereinafter also simply referred to as an aromatic ring). R₁₁And R₁₂As the monovalent substituent represented by, for example, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a heterocyclic group containing a quaternized nitrogen atom (for example, a pyridinium group), a hydroxy group, Alkoxy groups (including groups containing repeating ethyleneoxy groups or propyleneoxy group units), aryloxy groups, acyloxy groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, carbamoyl groups, urethane groups, carboxyl groups, imide groups , Amino group, carbonamido group, sulfonamido group, ureido group, thioureido group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, quaternary ammonio group, (alkyl, aryl or heterocyclic) thio group , Mercapto groups, (alkyl or aryl ) Sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group, sulfamoyl group, acylsulfamoyl group, (alkyl or aryl) sulfonylureido group, (alkyl or aryl) sulfonylcarbamoyl group, halogen atom, cyano group, nitro group And phosphoric acid amide group.
[0096]
Z₁Examples of the aromatic ring formed by benzene ring, naphthalene ring, pyridine ring, pyrimidine ring, triazine ring, pyrrole ring, furan ring, thiazole ring, etc., and these aromatic rings further have a substituent. The substituents may form a ring. Z₁Examples of the substituent that the aromatic ring formed by₁₁And R₁₂And the same substituents as the monovalent substituent described in the above.
[0097]
In terms of luminous efficiency, preferably Z₁The aromatic ring formed by is a substituted or unsubstituted benzene ring, and X₁And Y₁Is an oxygen atom and R₁₁Is a hydrogen atom, a hydrocarbon aromatic ring or a nitrogen-containing aromatic ring. Examples of the hydrocarbon aromatic ring include a benzene ring, a naphthalene ring, and an anthracene ring. Examples of the nitrogen-containing aromatic ring include a pyrrole ring, an oxazole ring, a pyridine ring, a pyrimidine ring, and a benzimidazole ring. More preferably, Z₁The aromatic ring formed by is a substituted or unsubstituted benzene ring, and X₁And Y₁Is an oxygen atom and R₁Is a hydrogen atom.
[0098]
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy as a rare earth metal forming a complex together with the anion of the compound represented by the general formula (1) (anion obtained by dehydrogenating the compound) , Ho, Er, Tm, Yb, and the like. Preferably, it is a cation of Ce, Tb and Eu, more preferably Eu which shows good color purity in red³⁺It is.
[0099]
Specific examples of the rare earth complex phosphor formed together with the compound represented by the general formula (1) and the anion body of the compound are shown below, but the present invention is not limited thereto.
[0100]
[Chemical 8]

[0101]
[Chemical 9]

[0102]
[Chemical Formula 10]

[0103]
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[0104]
Next, general formula (2) will be described.
In the general formula (2), R_{twenty one}, R_{twenty two}And R_{twenty three}Each represents a hydrogen atom or a monovalent substituent. R_{twenty one}, R_{twenty two}And R_{twenty three}As the monovalent substituent represented by₁₁And R₁₂The same substituent as the monovalent substituent described in the above can be mentioned, and each substituent may be bonded to each other to form a ring.
[0105]
From the viewpoint of luminous efficiency, in the present invention, the general formula (2) is preferably R_{twenty three}Is a hydrogen atom, R_{twenty one}And R_{twenty two}Are both aromatic rings, more preferably R_{twenty one}Σp value is positive, R_{twenty two}Is the time represented by the general formula (3) or the general formula (4).
[0106]
In the general formula (3), R₃₁And R₃₃Represents a hydrogen atom or a monovalent substituent having a positive σm value, and R₃₂Represents a hydrogen atom or a monovalent substituent having a positive σp value, and R₃₄And R₃₆Represents a hydrogen atom or a monovalent substituent having a negative σm value, and R₃₅Represents a hydrogen atom or a monovalent substituent having a negative σp value. However, R₃₁, R₃₂And R₃₃Are not simultaneously hydrogen atoms, R₃₄, R₃₅And R₃₆Are not simultaneously hydrogen atoms. R₃₁, R₃₂, R₃₃, R₃₄, R₃₅And R₃₆As the monovalent substituent represented by₁₁And R₁₂The same substituents as the monovalent substituent described in the above can be mentioned, and are appropriately selected depending on the σp value or σm value. Each substituent may be bonded to each other to form a ring. In the general formula (4), R₄₁And R₄₂Represents a hydrogen atom or a monovalent substituent, and Z_FourRepresents an atomic group necessary for forming a five-membered heteroaromatic ring, and m4 and n4 represent 1 to 5. R₄₁And R₄₂As the monovalent substituent represented by₁₁And R₁₂The same substituent as the monovalent substituent described in the above can be mentioned, and each substituent may be bonded to each other to form a ring. Z_FourAs the aromatic ring formed by₁Among the five-membered heteroaromatic rings exemplified as the aromatic ring formed by the above, these aromatic rings may further have a substituent, and the substituents may form a ring. Z_FourExamples of the substituents that the aromatic ring formed of₁₁And R₁₂And the same substituents as the monovalent substituent described in the above.
[0107]
The σp value and σm value of the substituent in the present invention are substituent constants defined by Hammett, for example, “Drug structure-activity relationship: Chemistry domain, extra number 122, pages 96-103, published by Nanedo” It is described in.
[0108]
Ce, Pr, Nd, Pm, Sm as a rare earth metal that forms a complex with the anion of the compounds represented by the general formulas (2), (3), and (4) (an anion obtained by dehydrogenating the compound) , Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and other cations. Preferably, it is a cation of Ce, Tb and Eu, more preferably Eu which shows good color purity in red³⁺Is
Specific examples of the compounds represented by the general formulas (2), (3) and (4) and rare earth complex-based phosphors formed together with the anion bodies of the compounds are shown below, but the present invention is limited to these. It is not a thing.
[0109]
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[0110]
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[0111]
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[0112]
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[0113]
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[0114]
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[0115]
Next, general formulas (5), (6) and (7) will be described.
In the general formula (5), R₅₁, R₅₂And R₅₃Represents a monovalent substituent and X_FiveRepresents an oxygen atom or a sulfur atom. R₅₁, R₅₂And R₅₃As the monovalent substituent represented by₁₁And R₁₂The same substituent as the monovalent substituent described in the above can be mentioned, and from the viewpoint of luminous efficiency, an alkoxy group or an alkyl group is preferable, and a fluorine-substituted alkyl group is more preferable.
[0116]
In the general formula (6), R₆₁And R₆₂Represents a monovalent substituent. R₆₁And R₆₂As the monovalent substituent represented by₁₁And R₁₂The same substituent as the monovalent substituent described in the above can be mentioned, and from the viewpoint of luminous efficiency, an alkoxy group or an alkyl group is preferable, and a fluorine-substituted alkyl group is more preferable.
[0117]
In the general formula (7), R₇₁, R₇₂And R₇₃Represents a hydrogen atom or a monovalent substituent. R₇₁, R₇₂And R₇₃As the monovalent substituent represented by₁₁And R₁₂In view of luminous efficiency, R is preferably a monovalent substituent described in the above.₇₂And R₇₃Are bonded to each other to form a nitrogen-containing aromatic ring. Specifically formed nitrogen-containing aromatic rings include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazole ring, an oxazole ring, Examples thereof include a thiazole ring and a quinoline ring. These nitrogen-containing aromatic rings may further have a substituent, and the substituents may form a ring, and among them, a pyridine ring is preferable.
[0118]
As a rare earth metal forming a complex with the compounds represented by the general formulas (5), (6) and (7), Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm And cations such as Yb. Preferably, it is a cation of Ce, Tb and Eu, more preferably Eu which shows good color purity in red³⁺It is.
[0119]
More preferably, the rare earth complex phosphor formed together with the compounds represented by the general formulas (5), (6) and (7) is further an anion of the compound represented by the general formula (1) or (2). It is time to have at least one body as a ligand. Preferred examples of general formula (1) or (2) used in this case are the same as described above.
[0120]
Specific examples of the ligands and rare earth complex phosphors represented by the general formulas (5), (6) and (7) are shown below, but the present invention is not limited thereto.
[0121]
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[0122]
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[0123]
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[0124]
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[0125]
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[0126]
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[0127]
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[0128]
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[0129]
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[0130]
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[0131]
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[0132]
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[0133]
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[0134]
The rare earth complex-based phosphor contained in the electroluminescent device of the present invention preferably has a maximum light emission in a region of 400 to 700 nm by light emitted from the light emitting material. More preferably, the conventional technique has a maximum light emission in a region of 600 nm to 700 nm where the light emission efficiency is low.
[0135]
In addition, the rare earth complex-based phosphor contained in the electroluminescence device of the present invention preferably contains at least one of those having a maximum emission wavelength on the long wave side of 180 nm or more with respect to the maximum emission wavelength emitted from the light emitting material. .
[0136]
Next, the composition of the color conversion layer will be described. The color conversion layer is prepared by dispersing a rare earth complex phosphor with a binder typified by a photo-curing or thermosetting resin and / or a non-reactive resin, a silica gel, a filler typified by alumina, or the like. Alternatively, it may be prepared by being composited with a hybrid polymer, or may be prepared by laminating a single substance as it is. When the phosphor of the present invention is used in a dispersed or composite form, it is preferably used at a ratio of 0.0001 to 100 mol per kg of binder or filler.
[0137]
The photocurable or thermosetting resin cured product will be described.
These compounds are subjected to light or heat treatment on a photocurable resin or a thermosetting resin composition film (resist or paste film) to generate radical species and ionic species to be polymerized or cross-linked to be insoluble and infusible. It is a thing. Specifically, the acrylate polymer is
(I) A composition film comprising an acrylic polyfunctional oligomer and acrylate oligomer having a plurality of acrylic groups or methacrylic groups and light or a thermal polymerization initiator is subjected to light or heat treatment to generate photo radicals or heat radicals for polymerization. Food,
(II) A composition comprising a polyvinyl cinnamate ester and a sensitizer, which is dimerized by light or heat treatment and crosslinked.
(III) A composition film composed of a chain or cyclic olefin and bisazide is generated by nitrene by light or heat treatment, and crosslinked with olefin,
(IV) A composition film made of a monomer having an epoxy group and a photoacid generator is polymerized by generating an acid (cation) by light or heat treatment.
[0138]
The non-reactive resin will be described. The non-reactive resin is a resin that does not generate radical species or ionic species by light or heat, that is, has no reactivity, contrary to the photo-curing or thermosetting resin. is there. Specifically, a compound having no reactive vinyl group, such as a polymerization initiator, a sensitizer, a bisazide or an acid generator, which decomposes with light or heat to generate radical species or ionic species. It is a resin that does not contain. More specifically, general-purpose polymers such as polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyethylene, polypropylene, polystyrene, polyester, polypyridine, and fluororesin are listed. It is done.
[0139]
From the viewpoint of luminous efficiency, a low polarity resin is preferable.
The low-polarity resin described here is one having a dielectric constant measured by a test method specified in JIS-K-6911 or ASTM D150 of 3 or less. Among the resins described in "Handbook (Chemical Industry Daily)", those having a dielectric constant of 3 or less can be mentioned. Most of the dielectric constants of polyethylene, polypropylene, polystyrene and fluororesins are 3 or less. It is.
[0140]
The color conversion layer can take various forms depending on the application. Although the electroluminescent element of the present invention has at least one rare earth complex-based phosphor, an inorganic phosphor may be used in combination as necessary.
[0141]
For example, when a white planar light emitter is desired, a mixture of a phosphor emitting blue light and a phosphor emitting yellow light is used, or three kinds of phosphors of blue light emission, green light emission, and red light emission are used. Although a mixture is used, in that case, it is not necessary to perform patterning, and it may be applied with a uniform thickness.
[0142]
Further, for the purpose of full color, at least one inorganic phosphor or rare earth complex phosphor having a maximum emission wavelength at 400 to 500 nm by light emitted from a light emitting material, and an inorganic system having a maximum emission wavelength at 501 to 600 nm. It is preferable to have a color conversion layer having at least one phosphor or rare earth complex phosphor and at least one inorganic phosphor or rare earth complex phosphor having a maximum emission wavelength at 601 to 700 nm.
[0143]
When multiple types of inorganic phosphors or rare earth complex phosphors are used to obtain multiple emissions, a color filter is used to increase the color purity by adjusting the color of the light emitted from each phosphor. They may be used in a superimposed manner. In addition, a black matrix can be arranged in the gap between each fluorescent element (one pixel having a different fluorescent color), and the leakage of emitted light can be blocked to improve the visibility of multicolor emission.
[0144]
Further, a transparent protective film may be laminated on the color conversion layer as necessary. The thickness of each fluorescence conversion layer is usually 0.1 μm to 100 μm, preferably 1 μm to 60 μm.
[0145]
Next, the manufacturing method of a color conversion layer is demonstrated.
The color conversion layer may be a dispersion or solution of the rare earth complex phosphor of the present invention, and the phosphor of the present invention may be applied directly in a mosaic form using an ink jet method or a printing method. Alternatively, a pattern may be obtained by a normal printing method or a photolithography method in which a mosaic pattern is produced using light or heat by using a thermosetting resin composition as a binder.
[0146]
The composition of the inorganic phosphor that may be used in the present invention is not particularly limited.₂O₂S, Zn₂SiO_Four, Ca_Five(PO_Four)_ThreeMetal oxides typified by Cl and the like and sulfides typified by ZnS, SrS, CaS, etc., Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, etc. A combination of rare earth metal ions and metal ions such as Ag, Al, Mn, In, Cu and Sb as activators or coactivators is preferred.
[0147]
The inorganic phosphors preferably used in the present invention are shown below, but the present invention is not limited to these compounds.
[0148]
[Blue light emitting inorganic phosphor]
(BL-1) Sr₂P₂O₇: Sn⁴⁺
(BL-2) Sr_FourAl₁₄O_{twenty five}: Eu²⁺
(BL-3) BaMgAl_TenO₁₇: Eu²⁺
(BL-4) SrGa₂S_Four: Ce³⁺
(BL-5) CaGa₂S_Four: Ce³⁺
(BL-6) (Ba, Sr) (Mg, Mn) Al_TenO₁₇: Eu²⁺
(BL-7) (Sr, Ca, Ba, Mg)_Ten(PO_Four)₆Cl₂: Eu²⁺
(BL-8) BaAl₂SiO₈: Eu²⁺
(BL-9) Sr₂P₂O₇: Eu²⁺
(BL-10) Sr_Five(PO_Four)_ThreeCl: Eu²⁺
(BL-11) (Sr, Ca, Ba)_Five(PO_Four)_ThreeCl: Eu²⁺
(BL-12) BaMg₂Al₁₆O₂₇: Eu²⁺
(BL-13) (Ba, Ca)_Five(PO_Four)_ThreeCl: Eu²⁺
(BL-14) Ba_ThreeMgSi₂O₈: Eu²⁺
(BL-15) Sr_ThreeMgSi₂O₈: Eu²⁺
[Green light-emitting inorganic phosphor]
(GL-1) (BaMg) Al₁₆O₂₇: Eu²⁺, Mn²⁺
(GL-2) Sr_FourAl₁₄O_{twenty five}: Eu²⁺
(GL-3) (SrBa) Al₂Si₂O₈: Eu²⁺
(GL-4) (BaMg)₂SiO_Four: Eu²⁺
(GL-5) Y₂SiO_Five: Ce³⁺, Tb³⁺
(GL-6) Sr₂P₂O₇-Sr₂B₂O_Five: Eu²⁺
(GL-7) (BaCaMg)_Five(PO_Four)_ThreeCl: Eu²⁺
(GL-8) Sr₂Si_ThreeO₈−₂SrCl₂: Eu²⁺
(GL-9) Zr₂SiO_Four, MgAl₁₁O₁₉: Ce³⁺, Tb³⁺
(GL-10) Ba₂SiO_Four: Eu²⁺
(GL-11) Sr₂SiO_Four: Eu²⁺
(GL-12) (BaSr) SiO_Four: Eu²⁺
[Red light emitting inorganic phosphor]
(RL-1) Y₂O₂S: Eu³⁺
(RL-2) YAlO_Three: Eu³⁺
(RL-3) Ca₂Y₂(SiO_Four)₆: Eu³⁺
(RL-4) LiY₉(SiO_Four)₆O₂: Eu³⁺
(RL-5) YVO_Four: Eu³⁺
(RL-6) CaS: Eu³⁺
(RL-7) Gd₂O_Three: Eu³⁺
(RL-8) Gd₂O₂S: Eu³⁺
(RL-9) Y (P, V) O_Four: Eu³⁺
(RL-10) Mg_FourGeO_Five._FiveF: Mn⁴⁺
(RL-11) Mg_FourGeO₆: Mn⁴⁺
Next, the color conversion filter of the present invention will be described.
[0149]
The color conversion filter of the present invention is a wavelength conversion element used to convert the color of the light source (emission color) to a desired color. As the light source, in addition to the electroluminescence element of the present invention, a laser beam or the like is used. Any light source may be mentioned. Basically, it is a wavelength conversion element capable of converting the wavelength to a wavelength longer by 10 nm or more than the maximum maximum wavelength of the light source. Specific applications include JP-A-3-152897, JP-A-9-245511, and JP-A-11-297477. Full color display filters (color conversion filters that convert blue light sources into green and red and arrange them in stripes to enable blue, green and red light emission), lighting and liquid crystals White light emission filters for display backlights (color conversion filters that emit a wide range of light in the visible range of 400 to 700 nm), partial light emission filters for neon signs and automobile instruments (necessary colors where needed) As a representative example, a color conversion filter for displaying “.
[0150]
When you want to obtain a multicolored color conversion filter such as a color filter for liquid crystal displays, you only need to pattern the phosphor to obtain the required emission color in stripes, dots or mosaics. As a method, a conventional method for producing a color filter for a liquid crystal display can be applied as it is, and specifically, it can be produced by a pigment dispersion method, a printing method, an ink jet method or the like.
[0151]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples, but the embodiments of the present invention are not limited thereto.
[0152]
Example 1 (Preparation of organic LED element)
Example (1-1)
After patterning a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) having a 150 nm ITO film on glass as an anode, the transparent support substrate provided with this ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol and dried nitrogen After drying with gas, UV ozone cleaning was performed for 5 minutes.
[0153]
This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while N, N′-diphenyl-N, N′-bis (3-methylphenyl) [1,1 200 mg of '-biphenyl] -4,4'-diamine (TPD), 200 mg of p-quarterphenyl (PQP) in another molybdenum resistance heating boat, and tris (8 -Hydroxyquinolinato) 200 mg of aluminum (Alq3) was added and attached to a vacuum deposition apparatus.
[0154]
The vacuum chamber is then 4 × 10^-FourAfter depressurizing to Pa, energize the heating boat containing TPD, heat to 220 ° C., deposit on a transparent support substrate at a deposition rate of 0.1 to 0.3 nm / sec, and inject holes with a thickness of 60 nm. A layer was provided. Furthermore, the heating boat containing PQP was energized and heated to 220 ° C., and deposited on the hole injection layer at a deposition rate of 0.1 to 0.3 nm / sec to provide a light emitting layer having a thickness of 40 nm. . Further, the heating boat containing Alq3 was energized and heated to 250 ° C., and deposited on the light emitting layer at a deposition rate of 0.1 nm / sec to provide an electron injection layer having a thickness of 20 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature. Next, a vacuum chamber is opened, and a stainless steel rectangular perforated mask is placed on the electron injection layer. On the other hand, 3 g of magnesium is put into a molybdenum resistance heating boat, and 0.02 of silver is put into a tungsten vapor deposition basket. Put 5g and again vacuum tank 2 × 10^-FourAfter depressurizing to Pa, power was applied to the magnesium-containing boat to deposit magnesium at a deposition rate of 1.5 to 2.0 nm / sec. At this time, the silver basket was heated at the same time, and the deposition rate was 0.1 nm / sec. An electroluminescent element (UV-1) was produced by vapor-depositing silver to form a counter electrode made of the mixture of magnesium and silver.
[0155]
When a direct current of 10 volts was applied using the ITO electrode of this element as the anode and the counter electrode made of magnesium and silver as the cathode, emission with a maximum emission wavelength of 380 nm was obtained.
[0156]
Example (1-2)
The electroluminescent device (A-1) produced in exactly the same manner as in Example (1-1) except that the phosphor p-quarterphenyl (PQP) in Example (1-1) was replaced with Compound A-1. Was made.
[0157]
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[0158]
When a direct current of 10 volts was applied using the ITO electrode of this element as the anode and the counter electrode made of magnesium and silver as the cathode, emission with a maximum emission of 405 nm was obtained.
[0159]
Example (1-3)
Exactly the same method as (1-1) except that the phosphor p-quarterphenyl (PQP) of (1-1) is replaced with 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi). The electroluminescent element (B-1) produced in (1) was produced.
[0160]
When a direct current of 10 volts was applied using the ITO electrode of this element as the anode and the counter electrode made of magnesium and silver as the cathode, blue light emission with a maximum light emission of 475 nm was obtained.
[0161]
Example 2 (Preparation of color conversion layer)
Example (2-1)
Dissolve 3 g of the rare earth complex phosphor (CL-4) of the present invention in 30 g of polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.) dissolved in a mixed solution (300 g) of toluene / ethanol = 1/1. Then, the electroluminescent element (A-1) produced in Example (1-2) was coated on the substrate (the surface opposite to the light emitting layer) with a wet film thickness of 150 μm, dried with hot air, and the rare earth of the present invention. An electroluminescence element (NO. 1) containing a complex phosphor was produced.
[0162]
Similarly, an electroluminescence element containing the color rare earth complex-based phosphor of the present invention is obtained in the same manner except that the electroluminescence element and the rare earth complex-based phosphor are changed to the elements and compounds described in Table 1. (NO.2) to (NO.22) and (NO.26) to (NO.27) were prepared.
[0163]
Comparative Example (2-1)
Example (2-1) except that instead of CL-4 in Example (2-1), 1.0 g of fluorescent pigment solvent yellow 116, 0.5 g of basic violet 11 and 0.5 g of rhodamine 6G were changed A blue-light-excited red light-emitting electroluminescence element (NO. 23) was produced by the same method as that described above. Furthermore, electroluminescent elements (NO.24) and (NO.25) were produced in which the electroluminescent elements were changed to B-1 and UV-1.
[0164]
Further, the same method as in Example (2-1) except that instead of CL-4 in Example (2-1), fluorescent dye coumarin 6, 2.0 g and fluorescent pigment solvent yellow 116, 0.5 g were used. A blue-light-excited green light-emitting electroluminescence element (NO. 28), which is a comparative example, was prepared.
[0165]
Further, an electroluminescence element (NO. 29) in which the electroluminescence element was changed to B-1 was produced.
[0166]
Example 3 (Evaluation)
Example (3-1) (Evaluation of Luminous Efficiency, Lifetime and Color Tone of Electroluminescent Element)
Electroluminescence element NO. 1-NO. No. 29 was continuously lit by applying a 12 V DC voltage in a dry nitrogen gas atmosphere at a temperature of 23 ° C., and the light emission efficiency (lm / W) at the start of lighting and the time for halving the luminance were measured. Luminous efficiency is measured according to Sample No. 1 is expressed as a relative value when the luminous efficiency is set to 100. The time when the luminance of 1 is halved is expressed as a relative value, where 100 is taken. The results are shown in Tables 1 and 2.
[0167]
[Table 1]

[0168]
[Table 2]

[0169]
From Tables 1 and 2, it was found that the electroluminescent device containing the rare earth complex phosphor of the present invention that emits red light has higher luminous efficiency and longer life than the comparative example. Further, the luminescent color of the sample of the present invention was a preferable color tone.
[0170]
Moreover, it turned out that the electroluminescent element containing the rare earth complex type | system | group fluorescent substance of this invention which light-emits green is high luminous efficiency compared with a comparative example, and its lifetime is long. Furthermore, the luminescent color was a more preferable color tone than the comparative sample.
[0171]
Example (3-2)
When the same evaluation was performed using an ultraviolet light emitting LED element (UV LED Lamp) manufactured by Nichia Corporation instead of the electroluminescent element used in Example (3-1), Example (3-1) was performed. Similar results were obtained.
[0172]
Example (3-3) (low polarity binder)
Electroluminescent device produced in Example (1-2) by dissolving 3 g of rare earth complex phosphor (CL-54) of the present invention in 300 g of fluororesin for paint (Lumiflon LF-200, manufactured by Asahi Glass Co., Ltd.) An electroluminescent device (NO. 30) containing the rare earth complex-based phosphor of the present invention, coated on the substrate (A-1) (opposite to the light emitting layer) with a wet film thickness of 150 μm and dried with hot air. Was made.
[0173]
Furthermore, under the same conditions as in Example (3-1), the light emission efficiency and the time to reduce the luminance by half were measured. The results are shown in Table 3.
[0174]
In addition, the dielectric constant of Lumiflon LF-200 used for the present Example was measured by the test method prescribed | regulated to ASTM-D50, and showed the value of 2.2.
[0175]
The dielectric constant of polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd.) is described in the catalog as 3.1 to 4.2.
[0176]
[Table 3]

[0177]
From Table 3, it was confirmed that luminous efficiency was further improved by changing the binder of the electroluminescent element (NO. 20) of the present invention to Lumiflon LF-200.
[0178]
Moreover, it turns out that the improvement of luminous efficiency was confirmed also when Lumiflon LF-200 was changed into commercially available polyethylene, polypropylene, and polystyrene.
[0179]
Example 4
Example (4-1)
An electroluminescent device in which a color conversion layer is formed on a transparent substrate by the method described in JP-A-8-279979, and an anode, a hole injection layer, a light emitting layer, an electron injection layer, and a cathode are sequentially stacked on the color conversion layer Was produced and the same evaluation as in Example (3-1) was performed. As a result, the same effect was confirmed in luminous efficiency and lifetime.
[0180]
Example 5 (color conversion filter)
3 g of rare earth complex phosphor (CL-4) of the present invention was dissolved in 30 g of butyral (BX-1) dissolved in a mixed solution of toluene / ethanol = 1/1 (300 g), and a polyether sulfone having a thickness of 80 μm was dissolved. A (PES) film was applied with a wet film thickness of 150 μm and dried with warm air to prepare the color conversion filter (F-1) of the present invention.
[0181]
Similarly to this, the color conversion filters (F-2) to (F-5) of the present invention were produced by the same method except that the compounds shown in Table 4 were used instead of CL-4.
[0182]
[Table 4]

[0183]
Example 6
Using the color conversion filter produced in Example 5, the color conversion efficiency was measured using a light source (laser light, etc.) other than the light sources (A-1, B-1, UV-1) used in the present invention. However, good color conversion efficiency was obtained as in Example 3.
[0184]
【The invention's effect】
As demonstrated in the examples, the rare earth complex-based phosphor of the present invention can confirm good visible light emission, and has excellent light emission luminance, light emission efficiency, and light emission lifetime. The color conversion filter of the rare earth complex-based phosphor of the present invention can obtain good visible light emission even when a light source other than an electroluminescence element is used, and has excellent light emission luminance, light emission efficiency, and light emission lifetime.

Claims (16)

A light emitting material and an electroluminescence element containing a rare earth complex phosphor that emits light at a maximum emission wavelength different from the maximum emission wavelength emitted from the light emitting material by absorbing light emitted from the light emitting material, the rare earth complex phosphor is: An electroluminescent device comprising at least one anion of the compound represented by the general formula (1) as a ligand.

[Each wherein, X ₁ and Y ₁ represents an oxygen atom, R _{1 1} represents a water atom or a monovalent substituent, Z ₁ is necessary to form a substituted or unsubstituted benzene ring Represents an atomic group. ] In the rare earth complex phosphor, the aromatic ring formed by Z ₁ in the general formula (1) is a substituted or unsubstituted benzene ring, X ₁ and Y ₁ are oxygen atoms, and R ₁₁ is a hydrogen atom. The electroluminescent device according to claim 1, comprising an anionic ligand of a compound that is a hydrocarbon aromatic ring or a nitrogen-containing aromatic ring. 3. The electroluminescent device according to claim 1, wherein the rare earth complex phosphor further comprises at least one selected from compounds represented by the following general formula (5), (6) or (7) as a ligand: An electroluminescent device comprising:

[Wherein, R ₅₁ , R ₅₂ and R ₅₃ represent a monovalent substituent, and X ₅ represents an oxygen atom or a sulfur atom. ]

[Wherein R ₆₁ and R ₆₂ represent a monovalent substituent. ]

[Wherein, R ₇₁ , R ₇₂ and R ₇₃ represent a hydrogen atom or a monovalent substituent. ] In the rare earth complex-based phosphor, in general formula (5) or general formula (6), X ₅ is an oxygen atom, and R ₅₁ , R ₅₂ , R ₅₃ , R ₆₁ and R ₆₂ are each an alkoxy group or an alkyl group. The electroluminescent device according to claim 3, comprising at least one as a ligand of the compound. The rare earth complex-based phosphor is a compound in which X ₅ is an oxygen atom and R ₅₁ , R ₅₂ , R ₅₃ , R ₆₁ and R ₆₂ are each a fluorine-substituted alkyl group in the general formula (5) or (6) The electroluminescent device according to claim 4, wherein at least one of the ligands is contained. In the rare earth complex phosphor, the aromatic ring formed by Z ₁ in the general formula (1) is a substituted or unsubstituted benzene ring, X ₁ and Y ₁ are oxygen atoms, and R ₁₁ is a hydrogen atom. The electroluminescent element according to any one of claims 1 to 5, wherein the electroluminescent element is contained as an anionic ligand of the compound.   The electroluminescent device according to any one of claims 1 to 6, wherein the binder used in the color conversion layer containing the rare earth complex phosphor is a low-polarity resin.   The electroluminescent device according to any one of claims 1 to 7, wherein the luminescent material has a maximum emission wavelength of 430 nm or less.   The electroluminescent device according to any one of claims 1 to 7, wherein the luminescent material has a maximum emission wavelength of 400 to 430 nm.   The electroluminescent device according to claim 1, wherein the light emitting material is an organic LED material. A color conversion filter comprising a rare earth complex phosphor containing at least one anion of a compound represented by the following general formula (1) as a ligand.

Wherein, X ₁ and Y ₁ each represent an oxygen atom, R ₁₁ represents a water atom or a monovalent substituent, atoms necessary to Z ₁ to form a substituted or unsubstituted benzene ring Represents a group. ] In the rare earth complex phosphor, the aromatic ring formed by Z ₁ in the general formula (1) is a substituted or unsubstituted benzene ring, X ₁ and Y ₁ are oxygen atoms, and R ₁₁ is a hydrogen atom. The color conversion filter according to claim 11, which is contained as an anionic ligand of a compound which is a hydrocarbon aromatic ring or a nitrogen-containing aromatic ring. A rare earth complex-based phosphor having at least one compound represented by the following general formula (5), (6) or (7) as a ligand, and further a compound represented by the following general formula (1) A color conversion filter comprising a rare earth complex-based phosphor containing at least one of the above anion compounds as a ligand.

Wherein, X ₁ and Y ₁ each represent an oxygen atom, R ₁₁ represents a water atom or a monovalent substituent, atoms necessary to Z ₁ to form a substituted or unsubstituted benzene ring Represents a group. ]

[Wherein, R ₅₁ , R ₅₂ and R ₅₃ represent a monovalent substituent, and X ₅ represents an oxygen atom or a sulfur atom. ]

[Wherein R ₆₁ and R ₆₂ represent a monovalent substituent. ]

[Wherein, R ₇₁ , R ₇₂ and R ₇₃ represent a hydrogen atom or a monovalent substituent. ] In the rare earth complex-based phosphor, in general formula (5) or general formula (6), X ₅ is an oxygen atom, and R ₅₁ , R ₅₂ , R ₅₃ , R ₆₁ and R ₆₂ are each an alkoxy group or an alkyl group. The color conversion filter according to claim 13, comprising at least one ligand of the compound. The rare earth complex-based phosphor is a compound in which X ₅ is an oxygen atom and R ₅₁ , R ₅₂ , R ₅₃ , R ₆₁ and R ₆₂ are each a fluorine-substituted alkyl group in the general formula (5) or (6) The color conversion filter according to claim 14, comprising at least one of the following ligands. In the rare earth complex phosphor, the aromatic ring formed by Z ₁ in the general formula (1) is a substituted or unsubstituted benzene ring, X ₁ and Y ₁ are oxygen atoms, and R ₁₁ is a hydrogen atom. The color conversion filter according to any one of claims 13 to 15, which is contained as an anionic ligand of a compound which is a hydrocarbon aromatic ring or a nitrogen-containing aromatic ring.