JP2004014335A - Organic electroluminescent (el) element, display device, light emitting method, and display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element having high luminous efficiency and a wide visual field angle without causing color variation depending on an angle, to provide its light emitting method, to provide a display device and its display method using the organic EL element, and to provide a transparent substrate suitable for portage, having low moisture permeability and applicable to the organic EL element. <P>SOLUTION: An organic electroluminescent part having an optical fine resonator structure and emitting light having color in a bluish-violet region, and a color conversion part emitting fluorescence of visible light by absorbing light emitted from the organic electroluminescent part are each characteristically an inorganic phosphor having particle diameters of 0.05-1.0 μm. <P>COPYRIGHT: (C)2004,JPO

Description

【００８９】
【化２】

【００９０】
【化３】

【００９１】
【化４】

【００９２】
【化５】

【００９３】
【化６】

【００９４】
尚、上記発光材料ＢＰ−９の合成例を以下に示す。
【００９５】
【化７】

【００９６】
２，５−ジメチルアニリン２．３７ｇと、２，５−ジメチルヨードベンゼン１０ｇと、銅粉１．２５ｇと炭酸カリウム２．９８ｇを撹拌しながら２００度で３０時間加熱した。反応溶液にテトラヒドロフランと酢酸エチルと水を加えた後セライトを用いて濾過し、水層を除去し、残りの有機層を飽和食塩水で洗った後硫酸マグネシウムで乾燥し、濃縮、カラム精製後、酢酸エチルで再結晶することで５ｇのトリフェニルアミン（Ａ）を得た。次に塩化メチレン２５ｍｌに（Ａ）２．０ｇを加え、これに０度で２．９ｇの臭素を滴下し、１時間撹拌後濃縮、精製することで２．７ｇのトリス（４−ブロモ−２，５−ジメチルフェニル）アミン（Ｂ）を得た。（Ｂ）１．００ｇをテトラヒドロフラン５０ｍｌ−水５ｍｌ２層系の溶媒中、炭酸カリウム、パラジウム触媒の存在下、１．００ｇナフチルボロン酸と反応させることで６９０ｍｇの本発明の例示化合物（３）を得た。ＮＭＲ及びマススペクトルにより目的物であることを確認した。
【００９７】
ＢＰ−９のデータ：^１Ｈ−ＮＭＲ（４００ＭＨｚ，ＣＤＣｌ_３）δ／ｐｐｍ１．９６（ｓ，９Ｈ），２．０５（ｓ，９Ｈ），６．９０（ｓ，３Ｈ），７．０９（ｓ，３Ｈ），７．４０（ｔ，Ｊ＝６．８Ｈｚ，３Ｈ），７．４１（ｔ，Ｊ＝６．８Ｈｚ，３Ｈ），７．４７（ｔ，Ｊ＝６．８Ｈｚ，３Ｈ），７．５２（ｔ，Ｊ＝８．１Ｈｚ，３Ｈ），７．５４（ｍ，３Ｈ），７．８４（ｄ，Ｊ＝８．１Ｈｚ，３Ｈ），７．８９（ｄ，Ｊ＝８．１Ｈｚ，３Ｈ）
ＭＳ（ＦＡＢ）ｍ／ｚ７０７（Ｍ^＋）
また、必要に応じて設けられる正孔輸送層は、陽極より注入された正孔を発光層に伝達する機能を有し、この正孔輸送層を陽極と発光層の間に介在させることにより、より低い電界で多くの正孔が発光層に注入され、その上、発光層に陰極又は電子輸送層より注入された電子は、発光層と正孔輸送層の界面に存在する電子の障壁により発光層内の界面に累積され、発光効率が向上するなど、発光性能の優れた素子となる。
【００９８】
この正孔輸送層の材料（以下、正孔輸送材料という）については、上記の好ましい性質を有するものであれば特に制限はなく、従来、光導伝材料において、正孔の電荷輸送材料として慣用されているものや、ＥＬ素子の正孔輸送層に使用される公知のものの中から任意のものを選択して用いることができる。
【００９９】
上記正孔輸送材料は、正孔の注入、電子の障壁性の何れかを有するものであり、有機物，無機物の何れであってもよい。この正孔輸送材料としては、例えば、トリアゾール誘導体、オキサジアゾール誘導体、イミダゾール誘導体、ポリアリールアルカン誘導体、ピラゾリン誘導体及びピラゾロン誘導体、フェニレンジアミン誘導体、アリールアミン誘導体、アミノ置換カルコン誘導体、オキサゾール誘導体、スチリルアントラセン誘導体、フルオレノン誘導体、ヒドラゾン誘導体、スチルベン誘導体、シラザン誘導体、アニリン系共重合体、又、導電性高分子オリゴマー、特にチオフェンオリゴマー等が挙げられる。
【０１００】
正孔輸送材料としては、上記のものを使用することができるが、例えば、ポルフィリン化合物、芳香族第３級アミン化合物及びスチリルアミン化合物、特に芳香族第３級アミン化合物を用いることが好ましい。上記芳香族第３級アミン化合物及びスチリルアミン化合物の代表例としては、Ｎ，Ｎ，Ｎ′，Ｎ′−テトラフェニル−４，４′−ジアミノフェニル；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）；２，２−ビス（４−ジ−ｐ−トリルアミノフェニル）プロパン；１，１−ビス（４−ジ−ｐ−トリルアミノフェニル）シクロヘキサン；Ｎ，Ｎ，Ｎ′，Ｎ′−テトラ−ｐ−トリル−４，４′−ジアミノビフェニル；１，１−ビス（４−ジ−ｐ−トリルアミノフェニル）−４−フェニルシクロヘキサン；ビス（４−ジメチルアミノ−２−メチルフェニル）フェニルメタン；ビス（４−ジ−ｐ−トリルアミノフェニル）フェニルメタン；Ｎ，Ｎ′−ジフェニル−Ｎ，Ｎ′−ジ（４−メトキシフェニル）−４，４′−ジアミノビフェニル；Ｎ，Ｎ，Ｎ′，Ｎ′−テトラフェニル−４，４′−ジアミノジフェニルエーテル；４，４′−ビス（ジフェニルアミノ）クオードリフェニル；Ｎ，Ｎ，Ｎ−トリ（ｐ−トリル）アミン；４−（ジ−ｐ−トリルアミノ）−４′−〔４−（ジ−ｐ−トリルアミノ）スチリル〕スチルベン；４−Ｎ，Ｎ−ジフェニルアミノ−（２−ジフェニルビニル）ベンゼン；３−メトキシ−４′−Ｎ，Ｎ−ジフェニルアミノスチルベンゼン；Ｎ−フェニルカルバゾール、更には、米国特許５，０６１，５６９号に記載されている２個の縮合芳香族環を分子内に有するもの、例えば、４，４′−ビス〔Ｎ−（１−ナフチル）−Ｎ−フェニルアミノ〕ビフェニル（ＮＰＤ）、特開平４−３０８６８８号に記載されるトリフェニルアミンユニットが三つスターバースト型に連結された４，４′，４″−トリス〔Ｎ−（３−メチルフェニル）−Ｎ−フェニルアミノ〕トリフェニルアミン（ＭＴＤＡＴＡ）等が挙げられる。
【０１０１】
さらに、これらの材料を高分子鎖に導入した、またはこれらの材料を高分子の主鎖とした高分子材料を用いることもできる。
【０１０２】
又、ｐ型−Ｓｉ，ｐ型−ＳｉＣ等の無機化合物も正孔輸送材料として使用することができる。以上の正孔輸送材料のほかに、特に本発明の好ましい形態である青紫領域の発光を得るためには、溶液中での蛍光極大波長が４２０ｎｍ以下の化合物、または、非蛍光性化合物（蛍光量子収率が０．０１未満の化合物）であることが好ましく、その代表例としては以下が挙げられる。
【０１０３】
【化８】

【０１０４】
この正孔輸送層は、上記正孔輸送材料を、真空蒸着法、スピンコート法、キャスト法、ＬＢ法など、公知の方法により薄膜化することで形成することができる。正孔輸送層の膜厚については、特に制限はないが、通常は５ｎｍ〜５μｍ程度である。
【０１０５】
この正孔輸送層は、上記材料の１種又は２種以上からなる１層構造であってもよく、同一組成又は異種組成の複数層からなる積層構造であってもよい。
【０１０６】
更に、必要に応じて用いられる電子輸送層は、陰極より注入された電子を発光層に伝達する機能を有していればよく、その材料としては、従来公知の化合物の中から任意のものを選択して用いることができる。
【０１０７】
この電子輸送層に用いられる材料（以下、電子輸送材料と称する）の例としては、例えば、ニトロ置換フルオレン誘導体，ジフェニルキノン誘導体，チオピランジオキシド誘導体，ナフタレンペリレン等の複素環テトラカルボン酸無水物，カルボジイミド，フルオレニリデンメタン誘導体，アントラキノジメタン及びアントロン誘導体，オキサジアゾール誘導体などが挙げられる。又、特開昭５９−１９４３９３号に記載される一連の電子伝達性化合物は、該公報では発光層を形成する材料として開示されているが、本発明者らが検討の結果、電子輸送材料として用い得ることが判った。更に、上記オキサジアゾール誘導体において、オキサジアゾール環の酸素原子を硫黄原子に置換したチアジアゾール誘導体、電子吸引性基として知られているキノキサリン環を有するキノキザリン誘導体なども、電子輸送材料として用いることができる。
【０１０８】
さらにこれらの材料を高分子鎖に導入した、またはこれらの材料を高分子の主鎖とした高分子材料を用いることもできる。
【０１０９】
又、８−キノリノール誘導体の金属錯体、例えば、トリス（８−キノリノール）アルミニウム（Ａｌｑ）、トリス（５，７−ジクロロ−８−キノリノール）アルミニウム、トリス（５，７−ジブロモ−８−キノリノール）アルミニウム、トリス（２−メチル−８−キノリノール）アルミニウム、トリス（５−メチル−８−キノリノール）アルミニウム、ビス（８−キノリノール）亜鉛（Ｚｎｑ）等、及びこれらの金属錯体の中心金属がＩｎ、Ｍｇ、Ｃｕ、Ｃａ、Ｓｎ、Ｇａ又はＰｂに置き替わった金属錯体も電子輸送材料として用いることができる。その他、メタルフリーもしくはメタルフタロシアニン、又はそれらの末端がアルキル基やスルホ基などで置換されているものも、電子輸送材料として好ましく用いることができる。又、発光層の材料として例示したジスチリルピラジン誘導体も、電子輸送材料として用いることができるし、正孔輸送層と同様に、ｎ型−Ｓｉ，ｎ型−ＳｉＣ等の無機半導体も電子輸送材料として用いることができる。
【０１１０】
電子輸送材料も正孔輸送層と同様に、特に青紫領域の発光を得る場合には、短波長の蛍光発光を持つ化合物が好ましく、目安としては溶液中での蛍光極大波長が４２０ｎｍ以下の化合物が好ましい。また、非蛍光性化合物（蛍光量子収率が０．０１未満）であってもよい。
【０１１１】
この電子輸送層は、上記化合物を、例えば、真空蒸着法，スピンコート法，キャスト法，ＬＢ法などの公知の薄膜化法により製膜して形成することができる。電子輸送層としての膜厚は特に制限はないが、通常は５ｎｍ〜５μｍの範囲で選ばれる。この電子輸送層は、これらの電子輸送材料１種又は２種以上からなる１層構造でもよいし、同一組成又は異種組成の複数層から成る積層構造でもよい。
【０１１２】
陽極と発光層または正孔輸送層の間及び陰極と発光層または電子輸送層との間には、バッファー層（電極界面層ともいう）を存在させてもよい。
【０１１３】
バッファー層とは、駆動電圧低下や発光効率向上のために、電極と有機層間に設けられる層のことで、「有機ＥＬ素子とその工業化最前線（１９９８年１１月３０日　エヌ・ティー・エス社発行）」の第２編第２章「電極材料」（第１２３頁〜第１６６頁）に詳細に記載されており、具体的には、陽極バッファー層と陰極バッファー層とがある。
【０１１４】
陽極バッファー層は、特開平９−４５４７９号、同９−２６００６２号、同８−２８８０６９号等に詳細が記載されており、具体例として、銅フタロシアニンに代表されるフタロシアニンバッファー層、酸化バナジウムに代表される酸化物バッファー層、アモルファスカーボンバッファー層、ポリアニリン（エメラルディン）やポリチオフェン等の導電性高分子を用いた高分子バッファー層等が挙げられる。
【０１１５】
陰極バッファー層は、特開平６−３２５８７１号、同９−１７５７４号、同１０−７４５８６号等に詳細が記載されており、具体的にはストロンチウムやアルミニウム等に代表される金属バッファー層、フッ化リチウムに代表されるアルカリ金属化合物バッファー層、フッ化マグネシウムに代表されるアルカリ土類金属化合物バッファー層、酸化アルミニウムに代表される酸化物バッファー層等が挙げられる。
【０１１６】
上記バッファー層は、ごく薄い膜であることが望ましく、素材にもよるが、その膜厚は０．１〜１００ｎｍの範囲が好ましい。
【０１１７】
さらに、上記基本構成層の他に、必要に応じてその他の機能を有する層を積層してもよく、例えば特開平１１−２０４２５８号、同１１−２０４３５９号、および「有機ＥＬ素子とその工業化最前線（１９９８年１１月３０日　エヌ・ティー・エス社発行）」の第２３７頁等に記載されている正孔阻止（ホールブロック）層などのような機能層を有していても良い。
【０１１８】
誘電体ミラーは、屈折率の異なる層を積層したものであって、酸化ケイ素層（ＳｉＯ_２）を主成分とする層と酸化チタン層（ＴｉＯ_２）を主成分とする層とを複数層積層したものを好ましく用いることが出来る。例えば、ＴｉＯ_２（屈折率ｎ＝２．４０）とＳｉＯ_２（屈折率ｎ＝１．４６）の３回交互積層のスタックミラーを用いることができ、この場合、波長５５０ｎｍ付近で６０％程度の反射率が得られる。反射波長域（ストップバンド幅）は、λ／４の条件を満たす膜厚にすることで自由に設計できる。
【０１１９】
また、上記酸化物（ＳｉＯ_２、ＴｉＯ_２）には必要に応じて、特にガスバリア性をさらに向上させたい場合には、成膜時に窒素を加え、部分的に窒化物にしてもよく、その場合には、ＳｉＯ_ｘＮ_ｙ、ＴｉＯ_ｘＮ_ｙという組成で表される酸窒化物となる。窒素の比率を上昇させるとガスバリア性が増強されるが、逆に透過率が低下するため、ｘおよびｙは、０．４≦ｘ／（ｘ＋ｙ）≦０．８であることが好ましい。
【０１２０】
透明基体としては、ガラス、石英、透明樹脂フィルムを挙げることができる。本発明において透明基体は、透明樹脂フィルムを好ましく用いることができ、例えば、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリエーテルスルホン（ＰＥＳ）、ポリエーテルイミド、ポリエーテルエーテルケトン、ポリフェニレンスルフィド、ポリアリレート、ポリイミド、ポリカーボネート（ＰＣ）、セルローストリアセテート（ＴＡＣ）、セルロースアセテートプロピオネート（ＣＡＰ）等からなるフィルム等が挙げられる。
【０１２１】
本発明の誘電体ミラー構造を有する透明基板は、屈折率の異なる層を積層した構造であれば特に限定はないが、上記のような透明基体の上側に、上記誘電体ミラー層を有するものが好ましい。
【０１２２】
本発明の誘電体ミラー構造を有する透明基板は、もちろん本発明の有機ＥＬ素子に用いることが可能であるが、それ以外の用途としては、半透過型の液晶表示装置、空間光変調器等、電気光学装置応用が考えられる。
【０１２３】
本発明の誘電体ミラー構造を有する透明基板を、本発明の有機ＥＬ素子に適用する場合には、場合によって、透明基体と誘電体ミラー層の間に後述の色変換部を設けてもよいし、誘電体ミラー層の上にさらに保護層を設けてもよい。
【０１２４】
尚、本発明の誘電体ミラー構造を有する透明基板において、透明基体の上側に誘電体ミラー層を設ける方法としては、蒸着法、スパッタリング法等が適用できる。
【０１２５】
色変換部としては、色変換層であることが好ましい。色変換部は、有機ＥＬ部からの発光を吸収して、波長変換し、可視光の蛍光を発光する蛍光色素を含有するものである。
【０１２６】
本発明では、蛍光色素として、無機蛍光体を用いる。本発明で用いることのできる無機蛍光体は液相合成法で合成することが好ましい。
【０１２７】
本発明における液相合成法とは、液体の存在下または液中で無機蛍光体、無機蛍光体前駆体を合成する事であり、冷却晶析をはじめとするあらゆる晶析法や共沈法を含むが反応晶析法であることが好ましい。
【０１２８】
反応晶析法とは、液相中または気相中で原料溶液または原料ガスを混合する事によって無機蛍光体または無機蛍光体前駆体を合成する方法である。本願の反応晶析法は好ましくは液相中での反応であり、より好ましくは液相中での原料溶液の反応である。
【０１２９】
無機蛍光体前駆体結晶とは、無機蛍光体の中間生成物であり、前記無機蛍光体前駆体結晶を所定の温度で焼成することにより、無機蛍光体が得られる。
【０１３０】
液相法で前駆体を合成した後、必要に応じてろ過、蒸発乾固、遠心分離等の方法で回収した後に好ましくは洗浄を行い、更に乾燥、焼成等の諸工程を施してもよく、分級してもよい。
【０１３１】
本発明の無機蛍光体の製造方法では、焼成工程に先立って脱塩工程を経ることにより、前駆体から副塩などの不純物を取り除くことが好ましい。前駆体脱塩後の電気伝導度が０．０１〜２０ｍＳ／ｃｍの範囲であることが好ましく、更に好ましくは０．０１〜１０ｍＳ／ｃｍであり、特に好ましくは０．０１〜５ｍＳ／ｃｍである。０．０１ｍＳ／ｃｍ未満の電気伝導度にしても特に効果は大きくならないが、生産性が低くなってしまう。また２０ｍＳ／ｃｍを超えると副塩や不純物が充分に除去できていない為に粒子の粗大化や粒子径分布が広くなり、発光強度が劣化してしまう。
【０１３２】
本発明において、上記記載の電気伝導度の測定方法はどのような方法を用いることも可能であるが、市販の電気伝導度測定器を使用すればよい。
【０１３３】
本発明における脱塩工程としては、各種膜分離法、凝集沈降法、電気透析法、イオン交換樹脂を用いた方法、ヌーデル水洗法などを適用することが好ましい。また、原料溶液の一つ以上または全部に保護コロイドを混合してもかまわない。本発明で用いられる保護コロイドは、粒子同士の凝集を防ぐために機能しており、特開２００１−３２９２６２の晶癖制御に用いられている有機ポリマーとは明らかに機能が異なる。本願の保護コロイドは、天然、人工を問わず各種高分子化合物を用いる事ができる。その際、保護コロイドの平均分子量は、１０，０００以上が好ましく、１０，０００以上３００，０００以下がより好ましく、１０，０００以上３０，０００以下が特に好ましい。また、本願の保護コロイドは、タンパク質が好ましく、ゼラチンが特に好ましい。また、単一の組成である必要はなく、各種バインダーを混合してもよい。
【０１３４】
ここで言う平均粒径とは、粒子が立方体あるいは八面体の所謂、正常晶の場合には、粒子の稜の長さを言う。又、正常晶でない場合、例えば球状、棒状あるいは平板状粒子の場合には、粒子の体積と同等な球を考えた時の直径を言う。
【０１３５】
又、粒子は単分散であることが好ましい。ここで言う単分散とは、下記式で求められる単分散度が４０％以下の場合を示す。本発明において、単分散度としては３０％以下が更に好ましく、０．１〜２０％が特に好ましい。
【０１３６】
単分散度＝（粒径の標準偏差／粒径の平均値）×１００
本発明においては、無機蛍光体前駆体の乾燥方法には特に限定はなく、真空乾燥、気流乾燥、流動層乾燥、噴霧乾燥等、あらゆる方法が用いられる。
【０１３７】
本発明においては、無機蛍光体前駆体の焼成温度、時間に特に限定はなく、無機蛍光体の種類に応じて適宜選択できる。更に、焼成時のガス雰囲気は、酸化性雰囲気、還元性雰囲気又は不活性雰囲気の何れでもよく、目的に応じて適宜選択できる。焼成装置としても特に限定はなく、あらゆる装置を使用することができる。例えば箱型炉や坩堝炉、ロータリーキルン等が好ましく用いられる。
【０１３８】
焼成時に焼結防止剤を添加しても添加しなくともよい。添加する場合は、前駆体形成時にスラリーとして添加してもよく、又、粉状のものを乾燥済前駆体と混合して焼成する方法も好ましく用いられる。更に、焼結防止剤に特に限定はなく、無機蛍光体の種類、焼成条件によって適宜選択される。例えば、無機蛍光体の焼成温度域によって８００℃以下での焼成にはＴｉＯ_２等の金属酸化物が、１０００℃以下での焼成にはＳｉＯ_２が、１７００℃以下での焼成にはＡｌ_２Ｏ_３が、それぞれ好ましく使用される。
【０１３９】
本発明で用いる無機蛍光体は、平均粒径は０．０５〜１．０μｍであるが、０．８μｍ以下であることが好ましい。ここで無機蛍光体の粒径は、球換算粒径を意味する。球換算粒径とは、粒子の体積と同体積の球を想定し、該球の粒径をもって表した粒径である。
【０１４０】
また、粒径分布も上記と同様の理由から予め狭い方が有利であり、具体的には、粒径分布の変動係数が１００％以下であることが好ましく、７０％以下であることが更に好ましい。ここで粒径分布の変動係数（粒子分布の広さ）とは、下式によって定義される値である。
【０１４１】
粒径分布の広さ（変動係数）［％］
＝（粒子サイズ分布の標準偏差／粒子サイズの平均値）×１００
上記無機系蛍光体は、必要に応じて表面改質処理を施してもよく、その方法としてはシランカップリング剤等の化学的処理によるものや、サブミクロンオーダーの微粒子等の添加による物理的処理によるもの、さらにはそれらの併用によるもの等が挙げられる。
【０１４２】
希土類錯体系蛍光体としては、希土類金属としてＣｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ等を有するものが挙げられ、錯体を形成する有機配位子としては、芳香族系、非芳香族系のどちらでも良く、好ましく下記一般式（Ｂ）で表される化合物が好ましい。
【０１４３】
一般式（Ｂ）　Ｘａ−（Ｌ_ｘ）−（Ｌ_ｙ）_ｎ−（Ｌ_ｚ）−Ｙａ
［式中、Ｌ_ｘ、Ｌ_ｙ、Ｌ_ｚはそれぞれ独立に２個以上の結合手を持つ原子を表わし、ｎは０または１を表わし、ＸａはＬ_ｘの隣接位に配位可能な原子を有する置換基を表わし、ＹａはＬ_ｚの隣接位に配位可能な原子を有する置換基を表わす。さらにＸａの任意の部分とＬ_ｘとは互いに縮合して環を形成してもよく、Ｙａの任意の部分とＬ_ｚとは互いに縮合して環を形成してもよく、Ｌ_ｘとＬ_ｚとは互いに縮合して環を形成してもよく、さらに分子内に芳香族炭化水素環または芳香族複素環が少なくとも一つ存在する。ただし、Ｘａ−（Ｌ_ｘ）−（Ｌ_ｙ）_ｎ−（Ｌ_ｚ）−Ｙａがβ−ジケトン誘導体やβ−ケトエステル誘導体、β−ケトアミド誘導体又は前記ケトンの酸素原子を硫黄原子又は−Ｎ（Ｒ_２０１）−に置き換えたもの、クラウンエーテルやアザクラウンエーテルまたはチアクラウンエーテルまたはクラウンエーテルの酸素原子を任意の数硫黄原子または−Ｎ（Ｒ_２０１）−に置き換えたクラウンエーテルを表わす場合には芳香族炭化水素環または芳香族複素環は無くてもよい。−Ｎ（Ｒ_２０１）−において、Ｒ_２０１は、水素原子、置換または無置換のアルキル基、置換または無置換のアリール基を表す。］
一般式（Ｂ）において、ＸａおよびＹａで表される配位可能な原子とは、具体的には酸素原子、窒素原子、硫黄原子、セレン原子、テルル原子であり、特に酸素原子、窒素原子、硫黄原子であることが好ましい。
【０１４４】
一般式（Ｂ）において、Ｌ_ｘ、Ｌ_ｙ、Ｌ_ｚで表される２個以上の結合手を持つ原子としては、特に制限はないが、代表的には炭素原子、酸素原子、窒素原子、シリコン原子、チタン原子等が挙げられるが、このましいものは炭素原子である。
【０１４５】
以下に一般式（Ｂ）で表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。
【０１４６】
【化９】

【０１４７】
【化１０】

【０１４８】
【化１１】

【０１４９】
【化１２】

【０１５０】
【化１３】

【０１５１】
【化１４】

【０１５２】
【化１５】

【０１５３】
色変換部を設ける場所は、前記光学的微小共振器構造を有する有機ＥＬ部からの発光を吸収できる位置であれば特に限定はないが、透明電極と透明基体との間、または、透明基体の前記透明電極とは反対側（発光を取り出す前側）に設けることが好ましい。
【０１５４】
上記色変換部は、上記無機蛍光体を蒸着あるいはスパッタリング法による製膜や、適当な樹脂をバインダとしてその中に分散させた塗布膜等いずれの形態であっても構わない。膜厚は、１００ｎｍ〜５ｍｍ程度が適当である。ここで、適当な樹脂をバインダとしてその中に分散させた塗布膜とする場合、無機蛍光体の分散濃度は、蛍光の濃度消光を起こすことがなく、かつ、有機ＥＬ部からの発光を十分に吸収できる範囲であればよい。無機蛍光体の種類によるが、使用する樹脂１ｇに対して１０^−７〜１０^−３モル程度が適当である。無機蛍光体の場合は、濃度消光がほとんど問題とならないため、樹脂１ｇに対して０．１〜１０ｇ程度使用できる。
【０１５５】
本発明の有機ＥＬ素子は、照明用や露光光源のような一種のランプとして使用しても良いし、画像を投影するタイプのプロジェクション装置や、画像を直接視認するタイプの表示装置（ディスプレイ）として使用しても良い。動画再生用の表示装置として使用する場合の駆動方式は単純マトリクス（パッシブマトリクス）方式でもアクティブマトリクス方式でもどちらでも良い。
【０１５６】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されるものではない。
【０１５７】
＜無機蛍光体の作製＞
無機蛍光体１（赤色無機蛍光体　固相法）
赤色無機蛍光体は、原料として塩化カリウム（ＫＣｌ）と酸化ユウロピウム（Ｅｕ_２Ｏ_３）とタングステン酸ナトリウム（Ｎａ_３（ＷＯ_４））とをモル比で０．６：０．３：０．１：１．０となるように配合し、適量のフラックスと共にボールミルで混合し、１，４００℃酸化条件下で２時間焼成し無機蛍光体１（Ｋ_５Ｅｕ_２．５（ＷＯ_４）_６．２５）を得た。
【０１５８】
無機蛍光体２（赤色無機蛍光体　液相法）
水１０００ｍｌを溶液［Ａ］とした。水５００ｍｌにカリウムのイオン濃度が０．４６５９ｍｏｌ／ｌ、ユウロピウムのイオン濃度が０．０３８８ｍｏｌ／ｌとなるように塩化カリウム、硝酸ユウロピウム六水和物を溶解し溶液［Ｂ］とした。水５００ｍｌにタングステン酸のイオン濃度が０．７７６３ｍｏｌ／ｌとなるようにタングステン酸ナトリウムを溶解し溶液［Ｃ］とした。
【０１５９】
図１の反応容器に溶液［Ａ］（２１）を入れ温度を４０℃に保ち、攪拌翼を用いて攪拌を行った。その状態で同じく４０℃に保った溶液［Ｂ］（２２）、溶液［Ｃ］（２３）を溶液［Ａ］（２１）の入った反応容器下部ノズルより１００ｍｌ／ｍｉｎの速度で等速添加を行った。添加後１０分間熟成を行い、前駆体２を得た。その後前駆体２を濾過乾燥し乾燥前駆体２を得た。さらに乾燥前駆体２を１，４００℃酸化条件下で２時間焼成し無機蛍光体２を得た。
【０１６０】
無機蛍光体３（緑色無機蛍光体　固相法）
緑色無機蛍光体は、原料として酸化バリウム（ＢａＯ），酸化硅素（ＳｉＯ_２）をモル比で２対１に配合する。次に、この混合物に対して所定量の酸化ユウロピウム（Ｅｕ_２Ｏ_３）を添加し、ボールミルで混合後、１，０００℃　５％Ｈ_２−９５％Ｎ_２雰囲気条件下で２時間焼成し無機蛍光体３を得た。
【０１６１】
無機蛍光体４（緑色無機蛍光体　液相法）
水１０００ｍｌを溶液［Ａ］とした。水５００ｍｌにシリコンのイオン濃度が０．５０００ｍｏｌ／ｌとなるように、メタ珪酸ナトリウムを溶解し溶液［Ｂ］とした。水５００ｍｌにバリウムのイオン濃度が０．９５００ｍｏｌ／ｌ、マンガンのイオン濃度が０．０５００ｍｏｌ／ｌとなるように硝酸バリウムと硝酸ユウロピウム六水和物を溶解し溶液［Ｃ］とした。
【０１６２】
図１の反応容器に溶液［Ａ］を入れ温度を４０℃に保ち、攪拌翼を用いて攪拌を行った。その状態で同じく４０℃に保った溶液［Ｂ］、［Ｃ］を溶液［Ａ］の入った反応容器下部ノズルより１００ｍｌ／ｍｉｎの速度で等速添加を行った。添加後１０分間熟成を行い、前駆体４を得た。その後前駆体４を濾過乾燥し乾燥前駆体４を得た。
さらに乾燥前駆体４を１，０００℃　５％Ｈ_２−９５％Ｎ_２雰囲気条件下で２時間焼成し無機蛍光体４を得た。
【０１６３】
無機蛍光体５（青色無機蛍光体　固相法）
青色無機蛍光体は、まず、原料として炭酸バリウム（ＢａＣＯ_３），炭酸マグネシウム（ＭｇＣＯ_３），酸化アルミニウム（α−Ａｌ_２Ｏ_３）をモル比で１対１対５に配合する。次に、この混合物に対して、所定量の酸化ユウロピウム（Ｅｕ_２Ｏ_３）を添加する。そして、適量のフラックス（ＡｌＦ_２，ＢａＣｌ_２）と共にボールミルで混合し、１，６００℃還元条件下で２時間焼成し無機蛍光体５を得た。
【０１６４】
無機蛍光体６（青色無機蛍光体　液相法）
水１０００ｍｌを溶液［Ａ］とした。水５００ｍｌにバリウムのイオン濃度が０．０９００ｍｏｌ／ｌ、マグネシウムのイオン濃度が０．１０００ｍｏｌ／ｌ、ユウロピウムのイオン濃度が０．０１ｍｏｌ／ｌとなるように、塩化バリウム２水和物、塩化マグネシウム６水和物、塩化ユウロピウム６水和物を溶解し溶液［Ｂ］とした。水５００ｍｌにアルミニウムのイオン濃度が１．０００ｍｏｌ／ｌとなるように塩化アルミニウム６水和物を溶解し溶液［Ｃ］とした。
【０１６５】
図１の反応容器に溶液［Ａ］を入れ温度を４０℃に保ち、攪拌翼を用いて攪拌を行った。その状態で同じく４０℃に保った溶液［Ｂ］、［Ｃ］を溶液［Ａ］の入った反応容器下部ノズルより１００ｍｌ／ｍｉｎの速度で等速添加を行った。添加後１０分間熟成を行い、前駆体６を得た。その後前駆体６を濾過乾燥し乾燥前駆体６を得た。さらに乾燥前駆体６を１，６００℃還元条件下で２時間焼成し無機蛍光体６を得た。
【０１６６】
大塚電子（株）蛍光スペクトル測定装置を用いて、１４７ｎｍ励起における発光強度測定を行い、比較例である無機蛍光体の発光強度を１００％としたときの無機蛍光体の相対発光強度は以下のようになった。また、無機蛍光体の粒径を走査型電子顕微鏡で観察し、粒子５００個の平均粒径を測定した。
【０１６７】
【表１】

【０１６８】
以上のように本発明の無機蛍光体粒子は優れた特性を持つことが明らかとなった。また平均粒径が小さくなっても、相対発光強度が減少しないという長所を持つことがわかる。
【０１６９】
実施例１
サイズ２５ｍｍ×７５ｍｍ、厚さ０．１ｍｍの市販ＰＥＳ（ポリエーテルスルホン）フィルム（住友ベークライト（株）製スミライトＦＳ−１３００）上に、ＲＦマグネトロンスパッタ法で酸化ケイ素層（ＳｉＯ_２）、酸化チタン層（ＴｉＯ_２）の順で最後が酸化チタン層になるように、交互に各３層積層した誘電体ミラーを形成した。このとき、酸化ケイ素層、酸化チタン層の膜厚は、それぞれ、６９ｎｍ、４２ｎｍとした。
【０１７０】
なお、この誘電体ミラーは、素子から放出される光の波長を４０５ｎｍとして設計した。
【０１７１】
以上のようにして、透明樹脂フィルムを構成材料とし、誘電体ミラー構造を有する透明基板を作製することができた。
【０１７２】
誘電体ミラーを設けたことで、ＰＥＳフィルム単独の場合に比べて、防湿性は格段に向上した。
【０１７３】
実施例２
実施例１において、酸化ケイ素層を酸窒化ケイ素層に、酸化チタン層を酸窒化チタン層に変更した以外は、実施例１と同様にして、透明樹脂フィルムを構成材料とし、誘電体ミラー構造を有する透明基板を作製したところ、実施例１の透明基板に比べ、防湿性が更に向上した。
【０１７４】
実施例３
実施例１で作製した透明基板の誘電体ミラーの上にＲＦマグネトロンスパッタ法で、透明電極（陽極）として、透明導電層（ＩＴＯ）を５０ｎｍの厚さで形成した。これを有機溶剤で十分に洗浄後、真空蒸着装置内に固定した。まず、正孔輸送層として、ｍ−ＭＴＤＡＴＸＡを２０ｎｍ、発光層としてＤＭＰｈｅｎを２０ｎｍ、電子輸送層として、バソキュプロイン（ＢＣ）２０ｎｍ蒸着した。これにより、透明導電層と有機化合物薄膜との合計が１１０ｎｍとなった。ＤＭＰｈｅｎは、上述のＢＰ−１３である。以下にｍ−ＭＴＤＡＴＸＡとＢＣの構造式を示す。
【０１７５】
【化１６】

【０１７６】
この素子における光学的微小共振器の光学長は、透明導電層と有機化合物薄膜の厚さと屈折率及び誘電体ミラーへの浸み込み量から、上述の式（数１）により、目的とする波長４０５ｎｍの１．５倍になった。
【０１７７】
陰極としてＭｇＡｇ合金（１０：１）を１８０ｎｍ蒸着した。
＜無機蛍光体を用いた色変換フィルターの作製＞
平均粒径５ｎｍのエアロジル０．１６ｇにエタノール１５ｇおよびγ−グリシドキシプロピルトリエトキシシラン０．２２ｇを加えて開放系室温下１時間攪拌した。この混合物と無機蛍光体１の２０ｇとを乳鉢に移し、よくすり混ぜた後、７０℃のオーブンで２時間、さらに１２０℃のオーブンで２時間加熱し、表面改質した無機蛍光体１を得た。
【０１７８】
また、同様にして、無機蛍光体２〜６の表面改質も行った。
上記の表面改質を施した無機蛍光体１の１０ｇに、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を加え、攪拌した後、Ｗｅｔ膜厚２００μｍでガラス上に塗布した。得られた塗布済みガラスを１００℃のオーブンで４時間加熱乾燥し、本発明の色変換部としての赤色変換フィルター（Ｆ−１）を作製した。
【０１７９】
また、これと同じ方法で無機蛍光体３を塗設した緑色変換フィルター（Ｆ−３）および無機蛍光体５を塗設した青色変換フィルター（Ｆ−５）を作製した。同様にして、無機蛍光体２，４，６を塗設したフィルターＦ−２、Ｆ−４、Ｆ−６を作製した。
【０１８０】
続いて、透明樹脂フィルムの透明基体の下側に、色変換部として青色変換フィルター（Ｆ−５）をストライプ状に貼り付けた。本実施例の有機ＥＬ素子は、以下のような構成である。
【０１８１】
色変換部／透明基体／誘電体ミラー／透明電極／有機化合物薄膜／金属電極
以上により、光学的微小共振器構造を有する有機エレクトロルミネッセンス素子が作製された。
【０１８２】
この素子に８Ｖの電圧を印加したところ、鮮明な青色の発光が得られた。発光スペクトルの極大発光波長は４４８ｎｍ、ＣＩＥ色度座標上で、（０．１５，０．０６）となった。
【０１８３】
さらに、上記色変換部の青色変換フィルター（Ｆ−５）を、緑色変換フィルター（Ｆ−３）または赤色変換フィルター（Ｆ−１）に代えた有機ＥＬ素子を作製した。その結果、緑色変換フィルター（Ｆ−３）を設けた有機ＥＬ素子からは、極大発光波長５３２ｎｍ、ＣＩＥ色度座標上（０．２４，０．６３）の緑色光が、赤色変換フィルター（Ｆ−１）を設けた有機ＥＬ素子からは、極大発光波長６１５ｎｍ、ＣＩＥ色度座標上（０．６３，０．３３）の赤色光が、それぞれ得られた。
【０１８４】
また、以下のような色変換部の位置を透明基体の上側に変更した以下の層構成の有機ＥＬ素子を作製した。
【０１８５】
透明基体／色変換部／誘導体ミラー／透明電極／有機化合物薄膜／金属電極
この場合も、上記青、緑、赤色とほぼ同様の極大発光波長、ＣＩＥ色度座標の発光スペクトルが得られた。
【０１８６】
尚、使用した透明基板を実施例２で作製したものに変更しても同等の結果を得ることが出来た。
【０１８７】
比較例１
実施例１で作製した誘電体ミラーにおいて、ＳｉＯ_２層、ＴｉＯ_２層の膜厚を、それぞれ、７９ｎｍ、４８ｎｍとした以外は、実施例１と全く同様にして、誘電体ミラー構造を有する透明基板を作製した。
【０１８８】
この誘電体ミラー構造を有する透明基板上にＲＦマグネトロンスパッタ法で透明導電層（ＩＴＯ）を５０ｎｍ形成した。これら基板を有機溶剤で十分に洗浄後、真空蒸着装置内に固定した。まず、正孔輸送層として、ｍ−ＭＴＤＡＴＡを４０ｎｍ、発光層としてＤＰＶＢｉを２５ｎｍ蒸着、電子輸送層として、Ａｌｑ_３を１０ｎｍ蒸着した。これにより、透明導電層と有機化合物層の合計が１２５ｎｍとなった。
【０１８９】
以下に、ｍ−ＭＴＤＡＴＡ、ＤＰＶＢｉ、Ａｌｑ_３の構造式を示す。
【０１９０】
【化１７】

【０１９１】
この素子における光学的微小共振器の光学長は、透明導電層と有機化合物薄膜の厚さと屈折率及び誘電体ミラーへの浸み込み量から、上述の式（数１）により、目的とする波長４６０ｎｍの１．５倍になった。最後に陰極としてＭｇＡｇ合金（１０：１）を１８０ｎｍ蒸着した。
【０１９２】
＜有機蛍光体を用いた色変換部の作製＞
有機蛍光体を用いた色変換部は、特開平３−１５２８９７号公報と同様にして作製した。具体的には、緑色変換部は前記公報に記載のクマリン１５３をポリメチルメタクリレート（ＰＭＭＡ）分散膜とし、赤色変換部は前記公報に記載のフェノキサジン９とピリジン１のＰＭＭＡ分散膜としたものを用いた。
【０１９３】
透明樹脂フィルムの透明基体の下側に、色変換部として緑色変換部をストライプ状に貼り付けた。この素子に８Ｖの電圧を印加したところ、緑色の発光が得られた。発光スペクトルの極大発光波長は５３２ｎｍ、ＣＩＥ色度座標上で、（０．２４，０．６３）となった。
【０１９４】
さらに、上記緑色変換部を、赤色変換部に代えた有機ＥＬ素子を作製した。この素子に８Ｖの電圧を印加したところ、赤色の発光が得られた。発光スペクトルの極大発光波長は６１５ｎｍ、ＣＩＥ色度座標上で（０．６３，０．３２）となった。
【０１９５】
以上により、光学的微小共振器構造を有する有機エレクトロルミネッセンス素子が作製されたが、発光層からの光が青紫色の場合の上記実施例２に比べると、緑色、及び赤色の発光輝度はいずれも低い値であった。また、この場合、発光層からの光が青色であるため色変換部を要さず、青色の光学的微小共振器構造を有する有機エレクトロルミネッセンス素子は、視野角が得られずに、作製が困難となる欠点がある。
【０１９６】
比較例２
上記実施例３において、ＳｉＯ_２、ＴｉＯ_２を各３層積層した誘電体ミラーを形成する工程を省いた以外は、実施例３と同様にして、有機エレクトロルミネッセンス素子を作製した。この時、本比較例の有機ＥＬ素子の層構成は、
色変換部／透明基体／透明電極／有機化合物薄膜／金属電極
である。
【０１９７】
青色光、緑色光、赤色光の強度はそれぞれ、実施例３の０．２７倍、０．３３倍、０．２４倍であった。
【０１９８】
比較例３
上記比較例１において、ＳｉＯ_２、ＴｉＯ_２を各３層積層した誘電体ミラーを形成する工程を省いた以外は、比較例１と同様に、有機エレクトロルミネッセンス素子を作製した。この時、本比較例の有機ＥＬ素子の層構成は、
色変換部／透明基体／透明電極／有機化合物薄膜／金属電極
である。
【０１９９】
緑色光、赤色光の強度はそれぞれ、比較例１の０．４０倍、０．３３倍であった。有機ＥＬ部からの青色発光を色変換した場合は、有機ＥＬ部からの青紫色発光を色変換した場合に比べると、光学的微小共振器構造を導入することによる発光強度の増大効果は小さいことがわかる。
【０２００】
比較例４
上記実施例３において、色変換部を作製する工程を省いた以外は、実施例３と同様に、有機エレクトロルミネッセンス素子を作製した。本比較例の発光スペクトルは、極大発光波長４０５ｎｍ、半値幅１２ｎｍ、ＣＩＥ色度座標（ｘ＝０．１６，ｙ＝０．０３６）の青紫色の発光を得ることができた。ところが、発光の放射パターンは、視野角が得られないため表示装置には適さないことがわかった。
【０２０１】
実施例４
以下、上記実施例３で作製した本発明の有機ＥＬ素子から構成される本発明の表示装置の一例を図面に基づいて以下に説明する。
【０２０２】
図２は、有機ＥＬ素子の発光により画像情報の表示を行う、例えば、携帯電話等のディスプレイの模式図である。
【０２０３】
ディスプレイ１は、複数の画素３を有する表示部Ａ、画像情報に基づいて表示部Ａの画像走査を行う制御部Ｂ等からなる。
【０２０４】
制御部Ｂは、表示部Ａと電気的に接続され、複数の画素３それぞれに外部からの画像情報に基づいて走査信号と画像データ信号を送り、走査信号により走査線毎の画素３が画像データ信号に応じて順次発光して画像走査を行って画像情報を表示部Ａに表示する。
【０２０５】
図３は、表示部Ａの模式図である。
表示部Ａは基体上に、複数の走査線５およびデータ線６を含む配線部と、複数の画素３等とを有する。表示部Ａの主要な部材の説明を以下に行う。
【０２０６】
図においては、画素３の発光した光が、白矢印方向（下方向）へ取り出される場合を示している。
【０２０７】
配線部の走査線５および複数のデータ線６は、それぞれ導電材料からなり、走査線５とデータ線６は格子状に直交して、直交する位置で画素３に接続している（詳細不図示）。
【０２０８】
画素３は、走査線５から走査信号が印加されると、データ線６から画像データ信号を受け取り、受け取った画像データに応じて発光する。発光の色が赤領域の画素、緑領域の画素、青領域の画素を、適宜、同一基体上に並置することによって、フルカラー表示が可能となる。
【０２０９】
次に、画素３の発光プロセスを説明する。
図４は、画素３の模式図である。
【０２１０】
画素３は、有機ＥＬ素子１０、スイッチングトランジスタ１１、駆動トランジスタ１２、コンデンサ１３等を備えている。
【０２１１】
図において、制御部Ｂからデータ線６を介してスイッチングトランジスタ１１のドレインに画像データ信号が印加される。そして、制御部Ｂから走査線５を介してスイッチングトランジスタ１１のゲートに走査信号が印加されると、スイッチングトランジスタ１１の駆動がオンし、ドレインに印加された画像データ信号がコンデンサ１３と駆動トランジスタ１２のゲートに伝達される。
【０２１２】
画像データ信号の伝達により、コンデンサ１３が画像データ信号の電位に応じて充電されるとともに、駆動トランジスタ１２の駆動がオンする。駆動トランジスタ１２は、ドレインが電源ライン７に接続され、ソースが有機ＥＬ素子１０の電極に接続されており、ゲートに印加された画像データ信号の電位に応じて電源ライン７から有機ＥＬ素子１０に電流が供給される。
【０２１３】
制御部Ｂの順次走査により走査信号が次の走査線５に移ると、スイッチングトランジスタ１１の駆動がオフする。しかし、スイッチングトランジスタ１１の駆動がオフしてもコンデンサ１３は充電された画像データ信号の電位を保持するので、駆動トランジスタ１２の駆動はオン状態が保たれて、次の走査信号の印加が行われるまで有機ＥＬ素子１０の発光が継続する。順次走査により次に走査信号が印加されたとき、走査信号に同期した次の画像データ信号の電位に応じて駆動トランジスタ１２の駆動して有機ＥＬ素子１０が発光する。
【０２１４】
すなわち、有機ＥＬ素子１０の発光は、複数の画素３それぞれの有機ＥＬ素子１０に対して、アクティブ素子であるスイッチングトランジスタ１１と駆動トランジスタ１２を設けて、複数の画素３それぞれの有機ＥＬ素子１０の発光を行っている。このような発光方法をアクティブマトリクス方式と呼んでいる。
【０２１５】
ここで、有機ＥＬ素子１０の発光は、複数の階調電位を持つ多値の画像データ信号による複数の階調の発光でも良いし、２値の画像データ信号による所定の発光量のオン、オフでも良い。
【０２１６】
また、コンデンサ１３の電位の保持は、次の走査信号の印加まで継続して保持しても良いし、次の走査信号が印加される直前に放電させても良い。
【０２１７】
本発明においては、上述したアクティブマトリクス方式に限らず、走査信号が走査されたときのみデータ信号に応じて有機ＥＬ素子を発光させるパッシブマトリクス方式の発光駆動でも良い。
【０２１８】
図５は、画素３の有機ＥＬ素子１０の部分のみ抜き出し、厚さ方向から見た断面図である。
【０２１９】
図５（ａ）と図５（ｂ）はそれぞれ色変換部の配置が異なる態様を表している。図５（ａ）において有機ＥＬ素子１０は、透明基体である透明樹脂フィルム１０ｅの上側に有機ＥＬ部Ｙを、下側に色変換部Ｘを積層した態様であり、図５（ｂ）において有機ＥＬ素子１０は、透明樹脂フィルム１０ｅの上側に色変換部Ｘと有機ＥＬ部Ｙをこの順序で積層した態様である。
【０２２０】
図中、参照符号の１０ａは金属電極、１０ｂは発光層を含む有機化合物薄膜、１０ｃは透明電極、１０ｄは誘電体ミラー、１０ｅは透明樹脂フィルム、１０ｆは色変換層である。
【０２２１】
金属電極１０ａおよび透明電極１０ｃを介して有機化合物薄膜１０ｂに電流が供給されると電流量に応じて発光する。このときの発光色は、本発明において好ましくは青紫領域の色である。そして、この青紫領域の色の発光は、誘電体ミラー１０ｄと、光反射部としての金属電極１０ａの間で増幅され、図中の下側方向へ指向性を有する光強度の高い光として取り出される。そして、透明樹脂フィルム１０ｅを介して、または、介さずに、色変換層１０ｆに吸収され、色変換層が赤色変換能を有する場合には赤領域の、緑色変換能を有する場合には緑領域の、青色変換能を有する場合には青領域の色の発光を、図中白矢印のような方向に取り出すことが出来る。
【０２２２】
図６は、パッシブマトリクス方式によるディスプレイＡの模式図である。
図において、複数の走査線５と複数の画像データ線６が画素３を挟んで対向して格子状に設けられている。
【０２２３】
順次走査により走査線５の走査信号が印加されたとき、印加された走査線５に接続している画素３が画像データ信号に応じて発光する。
【０２２４】
パッシブマトリクス方式では画素３にアクティブ素子が無く、製造コストの低減が計れる。
【０２２５】
【発明の効果】
高い発光効率を有し、視野角が広く、且つ、角度による色変化のない有機ＥＬ素子とその発光方法、前記有機ＥＬ素子を用いた表示装置とその表示方法、および、携帯適正があり、透湿性が低い、有機ＥＬ素子に適用可能な透明基板を提供することが出来た。
【図面の簡単な説明】
【図１】無機蛍光体の前駆体の製造装置の一例を示す概略図。
【図２】有機ＥＬ素子から構成される表示装置の一例を示した模式図である。
【図３】表示部の模式図である。
【図４】画素の模式図である。
【図５】有機ＥＬ素子を厚さ方向から見た断面図である。
【図６】パッシブマトリクス方式による表示装置の模式図である。
【符号の説明】
１　ディスプレイ
３　画素
５　走査線
６　データ線
７　電源ライン
１０　有機ＥＬ素子
１０ａ　金属電極
１０ｂ　有機化合物薄膜
１０ｃ　透明電極
１０ｄ　誘電体ミラー
１０ｅ　透明樹脂フィルム
１０ｆ　色変換層
１１　スイッチングトランジスタ
１２　駆動トランジスタ
１３　コンデンサ
Ａ　表示部（ディスプレイ）
Ｂ　制御部
Ｘ　色変換部
Ｙ　有機ＥＬ部
２１　溶液［Ａ］
２２　溶液［Ｂ］
２３　溶液［Ｃ］[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an organic electroluminescence (hereinafter, also simply referred to as “organic EL”) element, a display device, a light emitting method, and a display method.
[0002]
[Prior art]
Conventionally, an inorganic electroluminescent element has been used as a planar light source, but a high AC voltage is required to drive the light emitting element.
[0003]
A recently developed organic EL device has a configuration in which an organic compound thin film containing a fluorescent organic compound is sandwiched between a cathode and an anode, and electrons and holes are injected into the thin film and recombined to form an exciton. (Exciton), and emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated. Usually, in order to utilize this light emission, at least one of the electrodes sandwiching the organic compound thin film uses a transparent electrode such as ITO, and the transparent electrode is further supported by a transparent substrate such as glass.
[0004]
The organic EL element can emit light at a low voltage of about several volts to several tens of volts, and has a wide viewing angle and high visibility because it is a self-luminous type. , From the viewpoint of portability and the like.
[0005]
Various types of full-color display devices and projection devices using the organic EL element have been proposed. Among these, in Japanese Patent Application Laid-Open No. 3-15297, the blue-to-blue-green emission from the organic EL section is provided on an organic EL section in which an organic compound thin film including a light-emitting layer emitting blue to blue-green light is sandwiched between electrodes. By using an organic EL element provided with a fluorescent portion that absorbs light and emits green light, a fluorescent portion that emits red light, and a blue color filter portion that improves blue color purity. A display device that obtains full-color light emission is disclosed. The display device of this type is superior in that it can be easily manufactured, as compared with a display device in which three types of organic EL portions emitting blue, green and red light are separately provided. However, since the emission color of the organic EL section is blue to blue-green, there is a problem that it is difficult to obtain red light emission of sufficient light intensity when the light passes through the color conversion section.
[0006]
In addition, since the light emission of the light emitting layer has no directivity and is scattered in all directions, there is a large loss in guiding the light from the light emitting layer to the color conversion unit. In other words, the light emitted from the organic EL unit uses only the light that comes out to the color conversion unit side (forward direction), but the light is extracted in the forward direction derived from multiple reflection based on classical optics. Efficiency (luminous efficiency) is 1 / 2n ² , And is determined by the refractive index n of the light emitting layer. Assuming that the refractive index of the light emitting layer is about 1.7, the luminous efficiency from the organic EL section simply becomes about 20%. The remaining light propagates in the area direction of the light-emitting layer (spraying in the horizontal direction) or disappears at the metal electrode opposite to the transparent electrode with the light-emitting layer interposed therebetween (backward absorption). Therefore, there is a problem that the display screen becomes dark due to insufficient light intensity.
[0007]
The problem that the luminous efficiency is low is not limited to the invention disclosed in JP-A-3-152897, but is a common problem to be solved in an apparatus using an organic EL element.
[0008]
Further, since the half width of the emission spectrum from the fluorescent organic compound contained in the light emitting layer of the organic EL element is about 100 nm, it cannot be said that the color purity is necessarily high.
[0009]
Under these circumstances, as one of the methods for solving the above-mentioned problems of the luminous efficiency and the color purity of the organic EL element, an organic EL element having an optical micro-resonator structure has been proposed in JP-A-6-283271 and JP-A-7-283271. 282981, 9-180883, JP-A-2000-98931, and the like. These are provided with a dielectric mirror between a transparent anode and a transparent substrate. When light is emitted from a light emitting layer sandwiched between a metal cathode as a light reflecting mirror and the dielectric mirror, the mirror is formed. This utilizes a phenomenon in which amplification occurs using the interference effect of light between the two.
[0010]
An organic EL device having an optical micro-resonator structure can be freely designed by adjusting the thickness of a layer sandwiched between the mirrors so as to satisfy an interference condition at a wavelength (emission wavelength) of light to be extracted. In addition, since the light intensity of the designed emission wavelength is enhanced, but other wavelength components are suppressed, the half width of the emission spectrum is also reduced (narrow band), and as a result, the color purity can be increased. . In addition, a phenomenon in which the emission pattern of light emission strongly depends on the light emission wavelength appears, and the light of the light emission wavelength is significantly directed forward from the dielectric mirror, and the loss in the horizontal direction is reduced.
[0011]
The light emission mechanism of the organic EL device having the optical micro-resonator structure is described in terms of control of the light emission characteristics of the organic EL device (NHK Broadcasting Research Institute Shizutoki Tokito lecture material), Applied Physics Vol. 69, No. 11 No. (2000) Device structure and light emitting mechanism II of organic EL device (Akihiko Fujii and Katsumi Yoshino) have a detailed description.
[0012]
However, when an organic EL element having an optical microresonator structure is applied to a display device, a problem arises in that a viewing angle cannot be obtained due to the high directivity of light emission. There is a situation where only applications have been proposed. Also, there is a problem in color reproduction in which the emission color changes because the optical length changes depending on the angle.
[0013]
On the other hand, another problem of the organic EL element is low durability due to poor stability against moisture in the air. For the purpose of minimizing the influence of moisture in the air, transparent glass having low moisture permeability is used as the transparent substrate of the organic EL element, and the element is formed thereon by a dry film forming method such as an evaporation method. At present, it is sealed with a metal cap. However, this method is not only difficult to apply to a portable device such as a PDA because it is not only inefficient and expensive, but also fragile because of lack of flexibility, and because of its large mass.
[0014]
Therefore, it is conceivable to use a transparent resin film as the transparent substrate. For example, when a film such as polyester terephthalate (PET), polyester naphthalate (PEN), or cellulose triacetate (TAC) is used for these, they have moisture permeability. Due to its high cost, it cannot be used as it is as a transparent substrate of an organic EL device like transparent glass.
[0015]
[Problems to be solved by the invention]
An object of the present invention is to provide an organic EL element having high luminous efficiency, a wide viewing angle, and having no color change depending on the angle, an emission method thereof, and an organic EL element. It is an object of the present invention to provide a display device, a display method thereof, and a transparent substrate which is portable and has low moisture permeability and which can be applied to an organic EL element.
[0016]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following configurations.
[0017]
1. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: An organic electroluminescent device, which is an inorganic phosphor having a diameter of 0.05 to 1.0 μm.
[0018]
2. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region; and a color conversion portion emitting fluorescent light of visible light by absorbing light emitted from the organic electroluminescent portion. An organic electroluminescent device comprising an inorganic phosphor containing Si and Si.
[0019]
3. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: An organic electroluminescent device comprising an inorganic phosphor containing Ba and Si having a diameter of 0.05 to 1.0 μm.
[0020]
4. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: Ba having a diameter of 0.05 to 1.0 μm _2-a Eu _a SiO ₄ An organic electroluminescence device characterized by the following.
[0021]
5. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region; and a color conversion portion emitting fluorescent light of visible light by absorbing light emitted from the organic electroluminescent portion. An organic electroluminescent device comprising an inorganic phosphor containing Mg and Mg.
[0022]
6. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing the light emitted from the organic electroluminescent portion are formed of particles. An organic electroluminescence device comprising an inorganic phosphor containing Ba and Mg having a diameter of 0.05 to 1.0 μm.
[0023]
7. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: Ba having a diameter of 0.05 to 1.0 μm _1-a Eu _a MgAl ₁₀ O ₁₇ An organic electroluminescence device characterized by the following.
[0024]
8. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region; and a color conversion portion emitting visible light fluorescence by absorbing the light emitted from the organic electroluminescent portion, comprises K And an inorganic phosphor containing W.
[0025]
9. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing the light emitted from the organic electroluminescent portion are formed of particles. An organic electroluminescent device comprising an inorganic phosphor containing K and W having a diameter of 0.05 to 1.0 μm.
[0026]
10. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: K with a diameter of 0.05 to 1.0 μm ₅ Eu _2.5 (WO ₄ ) _6.25 An organic electroluminescence device characterized by the following.
[0027]
11. An organic electroluminescent portion is provided above a transparent substrate, and has a half mirror portion, an organic compound thin film including a light emitting layer, and a light reflecting portion in this order from the transparent substrate side. The organic electroluminescence device according to any one of items 1 to 10.
[0028]
12. 12. The organic electroluminescence device according to any one of 1 to 11, wherein the half mirror section has a dielectric mirror and a transparent electrode in this order from the transparent base side.
[0029]
13. 13. The organic electroluminescence device according to any one of 1 to 12, wherein the light reflecting portion is a metal electrode.
[0030]
14． 14. The organic electroluminescence device according to any one of 1 to 13, wherein the color conversion unit is provided below the dielectric mirror.
[0031]
15. The organic electroluminescent device according to any one of the above items 1 to 14, wherein the dielectric mirror is formed by laminating a plurality of layers mainly composed of silicon oxide and a layer mainly composed of titanium oxide. Luminescent element.
[0032]
16. 16. The organic electroluminescence device according to the above 15, wherein at least one of the layer containing silicon oxide as a main component and the layer containing titanium oxide as a main component contains silicon oxynitride or titanium oxynitride.
[0033]
17. 17. The organic electroluminescent device according to any one of 1 to 16, wherein the transparent substrate is a transparent resin film.
[0034]
18. A display device comprising the organic electroluminescence element according to any one of the above items 1 to 17.
[0035]
19. A light emitting method having an optical micro-resonator structure, wherein visible light fluorescence is emitted by absorbing light emitted from an organic electroluminescence portion, which emits light in a blue-violet region, into a color conversion portion.
[0036]
20. The organic electroluminescent portion is provided on the upper side of the transparent substrate, and has a half mirror portion, an organic compound thin film including a light emitting layer, and a light reflecting portion in this order from the transparent substrate side. 20. The light emitting method according to 19.
[0037]
21. 21. The light emitting method according to the item 20, wherein the half mirror section has a dielectric mirror and a transparent electrode in this order from the transparent substrate side.
[0038]
22. 22. The light emitting method according to the above item 20 or 21, wherein the light reflecting portion is a metal electrode.
[0039]
23. 23. The light emitting method according to any one of 20 to 22, wherein the color conversion unit is provided below the dielectric mirror.
[0040]
24. 24. The light emitting method according to any one of the above items 20 to 23, wherein the dielectric mirror is formed by laminating a plurality of layers composed mainly of silicon oxide and a layer composed mainly of titanium oxide. .
[0041]
25. 25. The light-emitting method according to the above item 24, wherein at least one of the layer containing silicon oxide as a main component and the layer containing titanium oxide as a main component contains silicon oxynitride or titanium oxynitride.
[0042]
26. 26. The light emitting method according to any one of the above 20 to 25, wherein the transparent substrate is a transparent resin film.
[0043]
27. 27. A display method, wherein display is performed using light emission by the light emission method according to any one of 19 to 26.
[0044]
Hereinafter, the present invention will be described in detail. The organic EL device of the present invention has the advantage that the light emitted from the organic EL portion having the optical microresonator structure has a high light intensity by the above-described mechanism, but the viewing angle is narrow and the light emission color depends on the angle. Is completely solved by combining the color conversion unit with the color conversion unit and causing the color conversion unit to emit light as visible light fluorescence by absorbing the light emitted from the organic EL unit.
[0045]
That is, light with high light intensity from the organic EL unit is used only as excitation energy for the color conversion unit to emit light. Light emitted from the fluorescent compound contained in the color conversion portion has a wide viewing angle because of no directivity, and does not change color because the emission wavelength is unique to the fluorescent compound.
[0046]
At the same time, the organic EL element of the present invention has a light emission intensity of the organic EL element (having no optical micro-resonator structure) and the organic EL element having a color converter disclosed in Japanese Patent Application Laid-Open No. Hei 3-152897. This means that low problems have been solved at the same time.
[0047]
As a result, it is possible to provide an organic electroluminescent element excellent in application to a display device which can be directly viewed, a display device using the same, a light emitting method and a display method.
[0048]
Further, since the light emission of the light emitting layer of the organic EL element of the present invention is in the blue-violet region, the light emission layer emits light in the blue to blue-green region disclosed in JP-A-3-152897. As a result, it is possible to secure the light intensity of the emission of the color in the red region from the color conversion unit.
[0049]
Further, an organic compound thin film which emits light in the blue to blue-green region disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-152978 is used, and an optical micro-resonator structure is provided thereon. When the present invention is applied to the display device of (1), light emission of B (blue region color) is directly extracted without using a color conversion unit, and color emission of G (green region color) and R (red region color) is obtained. The light emitted from the phosphor is extracted through the converter. In other words, only the B emission uses the highly directional light amplified by the optical microresonator structure as it is, while the G and R emissions are amplified by the optical microresonator structure and then passed through the color converter. As a result, light having a wide viewing angle without directivity is used. Therefore, when the light emission intensity of the color in the red region is weak, and the organic compound thin film emitting light in the blue to blue-green region disclosed in Japanese Patent Application Laid-Open No. 3-152897 is applied to a full-color display device. In addition, visibility, emission intensity, and balance are poor. However, by using the organic EL unit that emits light in the blue-violet region of the present invention, it is possible to provide an excellent display device with a good BGR balance.
[0050]
Further, the transparent substrate having the dielectric mirror structure of the present invention can be applied to, for example, an electric engineering apparatus having a semi-transmissive reflective layer other than for an organic EL element, and the utilization efficiency of light emitted from a backlight. Can be improved.
[0051]
By using the transparent substrate of the present invention as the transparent base and the dielectric mirror of the above-described organic EL device of the present invention, an optical micro-resonator structure can be provided to the organic EL section. Furthermore, it has been found that the dielectric mirror structure has a synergistic effect of imparting moisture resistance to the transparent substrate and increasing the gas barrier properties of the entire organic EL element.
[0052]
In the case where the transparent substrate of the present invention has a structure in which a dielectric mirror layer is provided on a transparent resin film, the transparent substrate has flexibility, is hard to be broken, is light, and is suitable for portable devices such as PDAs. Excellent application.
[0053]
Hereinafter, each component of the present invention will be described.
The organic EL device of the present invention includes an organic EL unit having an optical microresonator structure, and a color conversion unit that emits visible light fluorescence by absorbing light emitted from the organic EL unit.
[0054]
The relative position between the organic EL unit and the color conversion unit is not particularly limited as long as the color conversion unit is arranged at a position where the light emission from the organic EL unit can be absorbed. It is preferable to stack the converters.
[0055]
The fact that the organic EL section has an optical microresonator structure means that light emission in the organic EL section is reflected in the organic EL section (due to a difference in the refractive index of the constituent layers, etc.) and causes an interference phenomenon. In order to cause reflection and take out amplified light, it is preferable that the light emitting layer has a structure sandwiched between a half mirror portion and a light reflecting portion.
[0056]
One is Au, Ag, Cu, Pt, Ni, Pd, Se, Te, Rh, Ir, Ge, Os, Ru, Cr, W, ITO, SnO. ₂ , ZnO or other thin film electrode having a film thickness such that the light reflectance is 30% or more, or a laminate of two or more thin film electrodes and having a reflectance of 50% or more and a transmittance. The film is compatible with 30% or more.
[0057]
The other is a laminate of a dielectric mirror and a transparent electrode, which are provided in this order from the transparent substrate side. The dielectric mirror is formed by laminating a plurality of films having different refractive indexes by 0.1 or more. The dielectric mirror is also referred to as a multilayer mirror.
[0058]
The preferred configuration of the half mirror section is the latter combination of a dielectric mirror and a transparent electrode.
[0059]
As a configuration of the light reflecting portion, a metal electrode can be considered, and the light reflectance is preferably 80% or more.
[0060]
In the organic EL device of the present invention, when the organic EL section has an optical micro-resonator structure, the organic compound thin film including the light emitting layer is sandwiched between the half mirror section and the light reflecting section. It is necessary to adjust the optical film thickness of the organic compound thin film and the optical film thickness of the half mirror portion so as to satisfy the condition that a standing wave of light having an emission wavelength can exist inside the body. A known method can be applied to the adjusting method.
[0061]
For example, JP-A-6-283271, JP-A-7-282981, JP-A-9-180883 and J. Tokito et al. Appl. Phys. , Vol. 86, No. 5, 1 September 1999 p. 2407-2411, Nakayama et al., Appl. Phys. Lett. 63 (5), 2 August 1993, p. 594-595, Takada et al., Appl. Phys. Lett. 63 (15), 11 October 1993, p. 2032-2034, etc., the adjustment method is described, and the present invention may use any of those methods.
[0062]
One example is the following optical length relational expression (Equation 1). When the optical length L becomes 1.5 or 2 times the target emission wavelength, the emission intensity is effectively increased and the emission is increased. A sharpening of the spectrum is observed.
[0063]
The formula in which the optical length L of the optical microresonator takes into account the amount of light permeated into the multilayer mirror (dielectric mirror) is as follows.
[0064]
(Equation 1) L = (λ / 2) × (n _eff / Δn) + Σn _i d _i cos θ
Where n _eff Is the effective refractive index of the multilayer mirror, Δn is the difference between the refractive indexes of the two layers of the multilayer mirror, n _i And d _i Is the refractive index and layer thickness of the organic compound thin film and the transparent conductive layer that is the transparent electrode, and θ is the light incident on each interface between the organic compound thin films or each interface between the organic compound thin film and the transparent conductive layer, and the normal to the interface. The ideal optical microresonator structure is obtained when the optical length L is 1.5 times or 2.0 times the target emission wavelength. The object of the present invention can be achieved if the ideal optical length is within ± 10%.
[0065]
In the above configuration, λ / 2 (n) in the first term of Expression (Equation 1) _eff / Δn) represents the depth at which the resonating light permeates the multilayer mirror. As can be seen from the first term, n _eff And Δn are constants determined by the material constituting the multilayer mirror, so that if the wavelength λ of light is determined, the depth of penetration will also be determined. Further, the refractive index n of each layer in the second term _i Is also a constant determined by the material, and the thickness of each layer of the multilayer mirror is set to λ / 4. Therefore, the optical length L is the thickness d of the transparent conductive layer and the organic compound thin film. _i Can be controlled by changing.
[0066]
The wavelength of light that resonates with the optical microresonator is determined by the optical length L described above. That is, light whose optical length L is equal to an integral multiple of 1/2 wavelength can resonate with the optical microresonator. Therefore, when the total thickness of the transparent conductive layer and the organic compound thin film is reduced and the optical length L is reduced, the wavelength of light emitted from the element resonating with the optical micro-resonator also changes to the shorter wavelength side. Go. In this case, light having an optical length L equal to 1.5 times the half wavelength is the longest wavelength as resonating light. Therefore, the light emitted from the device has a shorter wavelength. When the light emitted from the element has a short wavelength, light having high directivity in front of the element can be obtained. Further, when the optical length L is reduced, the light emission mode of the element can be set to a single mode.
[0067]
The organic EL section having an optical micro-resonator structure is provided on the upper side of the transparent substrate, and a dielectric mirror, a transparent electrode, an organic compound thin film including a light emitting layer, and a metal electrode are provided in this order from the transparent substrate side. Are preferred.
[0068]
Preferred layer constitutions of the organic EL device of the present invention include:
a. Transparent substrate / color converter / dielectric mirror / transparent electrode / organic compound thin film / metal electrode
b. Color converter / transparent substrate / dielectric mirror / transparent electrode / organic compound thin film / metal electrode
and so on.
[0069]
The structure of the organic compound thin film may be a single layer or a multi-layer structure. For example, in the case of a multi-layer structure, a layer other than an organic substance (for example, a layer of an inorganic metal salt such as lithium fluoride or magnesium fluoride, or May be arranged at any position.
[0070]
The structure of an electrode (anode / cathode) and an organic compound thin film is basically such that at least one light emitting layer is sandwiched between a pair of electrodes, and a hole transport layer or an electron transport layer is interposed as necessary. It has the structure made to be. In the present invention, one of the electrodes is preferably a transparent electrode that transmits light emitted from the light-emitting layer, and the other is a metal electrode (an electrode containing a metal) having a light reflecting ability.
[0071]
In particular,
1: anode / light-emitting layer / cathode
2: anode / hole transport layer / light-emitting layer / cathode
3: anode / light-emitting layer / electron transport layer / cathode
4: anode / hole transport layer / light-emitting layer / electron transport layer / cathode
There are such structures.
[0072]
As the anode, a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function (4 eV or more) as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au, CuI, indium tin oxide (ITO), and SnO. ₂ , ZnO and the like. The electrode composed of these is a transparent electrode. The anode may be formed by forming a thin film of these electrode materials by a method such as evaporation or sputtering, and forming a pattern of a desired shape by a photolithography method, or when the pattern accuracy is not required much (100 μm or more). To the extent), a pattern may be formed through a mask having a desired shape during the deposition or sputtering of the electrode material. When light is extracted from the anode, the transmittance is desirably greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / □ or less. Further, the film thickness is usually in the range of 10 nm to 1 μm, preferably 10 to 200 nm, though it depends on the material used.
[0073]
On the other hand, as a cathode, a metal having a small work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof are used as an electrode material. The electrode composed of these is a metal electrode.
[0074]
Specific examples of the electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among them, a mixture of an electron-injecting metal and a second metal, which is a metal having a large work function and a stable work function, such as a magnesium / silver mixture, from the viewpoint of durability against electron injection and oxidation. Magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, lithium / aluminum mixtures and the like are preferred.
[0075]
The cathode can be manufactured by forming a thin film from these electrode substances by a method such as vapor deposition or sputtering. Further, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 1 μm, preferably 50 to 200 nm.
[0076]
In order to transmit light, if either one of the anode and the cathode of the organic EL element is transparent (including semi-transparent), the luminous efficiency is advantageously improved.
[0077]
The light emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode or the electron transporting layer and the hole transporting layer, and the light emitting portion is a light emitting layer even in the light emitting layer. And an interface between the layer and the adjacent layer.
[0078]
The material used for the light-emitting layer (hereinafter, referred to as a light-emitting material) is preferably an organic compound or complex that emits fluorescence or phosphorescence, and is appropriately selected from known materials used for the light-emitting layer of the organic EL device. Can be used. Such a light-emitting material is mainly an organic compound, and according to a desired color tone, for example, Macromol. Synth. And the like, vol. 125, pp. 17-25.
[0079]
The light emitting material may have the hole transport function and the electron transport function in addition to the light emitting performance, and most of the hole transport material and the electron transport material can be used as the light emitting material.
[0080]
The light-emitting material may be a polymer material such as p-polyphenylenevinylene or polyfluorene. Further, a polymer material in which the light-emitting material is introduced into a polymer chain or a polymer material in which the light-emitting material is a polymer main chain is used. May be.
[0081]
Further, a dopant (guest material) may be used in combination in the light-emitting layer, and an arbitrary one can be selected from known ones used as dopants in EL devices. Specific examples of the dopant include, for example, quinacridone, DCM, coumarin derivatives, rhodamine, rubrene, decacyclene, pyrazoline derivatives, squarylium derivatives, europium complexes, and the like.
[0082]
This light emitting layer can be formed by forming the above compound into a thin film by a known thinning method such as a vacuum evaporation method, a spin coating method, a casting method, and an LB method. The thickness of the light emitting layer is not particularly limited, but is usually selected in the range of 5 nm to 5 μm. This light-emitting layer may have a single-layer structure composed of one or two or more of these light-emitting materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.
[0083]
Further, as described in JP-A-57-51781, this light-emitting layer is prepared by dissolving the light-emitting material together with a binder such as a resin in a solvent to form a solution, and then spin-coating the solution. It can be formed as a thin film. The thickness of the light emitting layer thus formed is not particularly limited and can be appropriately selected depending on the situation, but is usually in the range of 5 nm to 5 μm.
[0084]
In the present invention, the light emitted from the light emitting layer has a color in the blue-violet region.
In the organic EL device of the present invention, the color in the blue-violet region, which is the light emitted from the light-emitting layer, is measured by a measuring device such as a spectral radiance meter CS-1000 (manufactured by Minolta). When applied to the coordinates (FIG. 4.16 (Edited by the Japan Society of Color Science, University of Tokyo Press, 1985) on page 108 of the “New Color and Color Science Handbook”), the values of Purplish Blue (purple blue) or Blue Purple (purplish blue) were obtained. It means that it is in the area.
[0085]
As a general feature of the compound that emits light in the blue-violet region, those having a fluorescence maximum wavelength in a solution of 350 nm or more and 420 nm or less are preferable, and those having a fluorescence quantum yield of 0.1 or more are preferable.
[0086]
Specific examples of such a light emitting material are described in JP-A-2000-203091 (corresponding EP published: EP1067165A), JP-A-2001-160488, JP-A-2001-81453, JP-A-2001-93670, JP-A-2002-56975, and the like. I have.
[0087]
Some specific examples are shown below, but are not limited thereto.
[0088]
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[0089]
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[0090]
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[0091]
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[0092]
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[0093]
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[0094]
An example of the synthesis of the light emitting material BP-9 is shown below.
[0095]
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[0096]
2.37 g of 2,5-dimethylaniline, 10 g of 2,5-dimethyliodobenzene, 1.25 g of copper powder and 2.98 g of potassium carbonate were heated at 200 ° C. for 30 hours with stirring. After adding tetrahydrofuran, ethyl acetate and water to the reaction solution, the mixture was filtered using celite, the aqueous layer was removed, the remaining organic layer was washed with brine, dried over magnesium sulfate, concentrated, and purified by column purification. By recrystallizing with ethyl acetate, 5 g of triphenylamine (A) was obtained. Next, 2.0 g of (A) was added to 25 ml of methylene chloride, 2.9 g of bromine was added dropwise at 0 ° C, and the mixture was stirred for 1 hour, concentrated and purified to obtain 2.7 g of tris (4-bromo-2). , 5-Dimethylphenyl) amine (B) was obtained. (B) 690 mg of Exemplified Compound (3) of the present invention was obtained by reacting 1.00 g with 1.00 g naphthylboronic acid in a two-layer solvent of 50 ml of tetrahydrofuran and 5 ml of water in the presence of potassium carbonate and a palladium catalyst. Was. NMR and mass spectrum confirmed that the product was the desired product.
[0097]
BP-9 data: ¹ H-NMR (400 MHz, CDCl ₃ ) Δ / ppm 1.96 (s, 9H), 2.05 (s, 9H), 6.90 (s, 3H), 7.09 (s, 3H), 7.40 (t, J = 6.8 Hz) , 3H), 7.41 (t, J = 6.8 Hz, 3H), 7.47 (t, J = 6.8 Hz, 3H), 7.52 (t, J = 8.1 Hz, 3H), 7 .54 (m, 3H), 7.84 (d, J = 8.1 Hz, 3H), 7.89 (d, J = 8.1 Hz, 3H)
MS (FAB) m / z 707 (M ⁺ )
In addition, the hole transport layer provided as needed has a function of transmitting holes injected from the anode to the light emitting layer, by interposing this hole transport layer between the anode and the light emitting layer, At a lower electric field, many holes are injected into the light emitting layer, and furthermore, electrons injected from the cathode or the electron transport layer into the light emitting layer emit light due to an electron barrier present at the interface between the light emitting layer and the hole transport layer. An element having excellent light-emitting performance, for example, accumulating at the interface in the layer and improving the light-emitting efficiency, is obtained.
[0098]
The material of the hole transport layer (hereinafter, referred to as a hole transport material) is not particularly limited as long as it has the above-mentioned preferable properties. Conventionally, it is commonly used as a charge transport material for holes in photoconductive materials. And any known materials used in the hole transport layer of the EL element.
[0099]
The hole transport material has any of a hole injection property and an electron barrier property, and may be an organic substance or an inorganic substance. Examples of the hole transport material include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene Derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers, and conductive polymer oligomers, particularly thiophene oligomers, are mentioned.
[0100]
As the hole transporting material, those described above can be used. For example, it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound. Representative examples of the aromatic tertiary amine compound and styrylamine compound include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N' -Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1- Bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ', N'-tetra-p-tolyl-4,4'-diaminobiphenyl; 1,1-bis (4-di-p- Tolaminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N -Di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadri Phenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenyl Amino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two amino acids described in U.S. Pat. No. 5,061,569. Those having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-30868 No. 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which triphenylamine units described in No. 3 are linked in a three-star burst type Is mentioned.
[0101]
Further, a polymer material in which these materials are introduced into a polymer chain, or a polymer material in which these materials are used as a polymer main chain can be used.
[0102]
In addition, inorganic compounds such as p-type Si and p-type SiC can be used as the hole transport material. In addition to the above hole transport materials, in order to obtain light emission in the blue-violet region, which is a preferred embodiment of the present invention, a compound having a fluorescence maximum wavelength of 420 nm or less in a solution or a non-fluorescent compound (fluorescent quantum (A compound having a yield of less than 0.01), and typical examples thereof include the following.
[0103]
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[0104]
This hole transport layer can be formed by thinning the above hole transport material by a known method such as a vacuum evaporation method, a spin coating method, a casting method, and an LB method. The thickness of the hole transport layer is not particularly limited, but is usually about 5 nm to 5 μm.
[0105]
The hole transport layer may have a single-layer structure composed of one or more of the above materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.
[0106]
Further, the electron transporting layer used as necessary may have a function of transmitting electrons injected from the cathode to the light emitting layer, and the material may be any of conventionally known compounds. Can be selected and used.
[0107]
Examples of the material used for the electron transport layer (hereinafter, referred to as an electron transport material) include, for example, heterocyclic tetracarboxylic anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, and naphthalene perylene. , Carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Also, a series of electron-transporting compounds described in JP-A-59-194393 are disclosed as materials for forming a light-emitting layer in the publication, but as a result of investigations by the present inventors, they have been reported as electron-transporting materials. It has been found that it can be used. Further, in the oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group, and the like may also be used as the electron transporting material. it can.
[0108]
Further, a polymer material in which these materials are introduced into a polymer chain, or a polymer material in which these materials are used as a polymer main chain, can also be used.
[0109]
Also, metal complexes of 8-quinolinol derivatives, for example, 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), and the like; A metal complex replaced with Cu, Ca, Sn, Ga or Pb can also be used as an electron transport material. In addition, metal-free or metal phthalocyanine, or those whose terminals are substituted with an alkyl group, a sulfo group, or the like can be preferably used as the electron transporting material. Also, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can be used as the electron transporting material, and similarly to the hole transporting layer, inorganic semiconductors such as n-type Si and n-type SiC can be used as the electron transporting material. Can be used as
[0110]
In the case where the electron transporting material also emits light in the blue-violet region, similarly to the hole transporting layer, a compound having short-wavelength fluorescence is preferred, and as a guide, a compound having a fluorescence maximum wavelength of 420 nm or less in a solution is used as a guide. preferable. Further, it may be a non-fluorescent compound (fluorescence quantum yield is less than 0.01).
[0111]
This electron transporting layer can be formed by forming the above compound by a known thinning method such as a vacuum evaporation method, a spin coating method, a casting method, and an LB method. The thickness of the electron transport layer is not particularly limited, but is usually selected in the range of 5 nm to 5 μm. The electron transport layer may have a single layer structure composed of one or more of these electron transport materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.
[0112]
A buffer layer (also referred to as an electrode interface layer) may be present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer.
[0113]
The buffer layer is a layer provided between an electrode and an organic layer in order to reduce driving voltage and improve luminous efficiency, and is referred to as “Organic EL device and the forefront of its industrialization (NTS, November 30, 1998) Issue 2), Vol. 2, Chapter 2, “Electrode Materials” (pages 123 to 166), specifically, an anode buffer layer and a cathode buffer layer.
[0114]
The anode buffer layer is described in detail in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. Specific examples thereof include a phthalocyanine buffer layer represented by copper phthalocyanine and a vanadium oxide represented by vanadium oxide. Oxide buffer layer, amorphous carbon buffer layer, polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.
[0115]
The cathode buffer layer is described in detail in JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specifically, a metal buffer layer represented by strontium, aluminum, or the like; Examples include an alkali metal compound buffer layer represented by lithium, an alkaline earth metal compound buffer layer represented by magnesium fluoride, and an oxide buffer layer represented by aluminum oxide.
[0116]
The buffer layer is desirably a very thin film, and the thickness is preferably in the range of 0.1 to 100 nm, depending on the material.
[0117]
Further, in addition to the above-mentioned basic constituent layers, layers having other functions may be laminated as necessary. For example, JP-A-11-204258, JP-A-11-204359, and "Organic EL Device and Its Industrialization Front page (November 30, 1998, published by NTTS Corporation) ", page 237, etc., may have a functional layer such as a hole blocking (hole block) layer.
[0118]
The dielectric mirror is formed by laminating layers having different refractive indices, and includes a silicon oxide layer (SiO 2). ₂ ) And a titanium oxide layer (TiO 2) ₂ ) Can be preferably used. For example, TiO ₂ (Refractive index n = 2.40) and SiO ₂ (Refractive index n = 1.46) A stack mirror of three alternate layers can be used. In this case, a reflectance of about 60% can be obtained near a wavelength of 550 nm. The reflection wavelength range (stop band width) can be freely designed by setting the film thickness to satisfy the condition of λ / 4.
[0119]
In addition, the above oxides (SiO ₂ , TiO ₂ If necessary, in order to further improve the gas barrier properties, nitrogen may be added at the time of film formation and partially nitrided. _x N _y , TiO _x N _y Oxynitride represented by the following composition: Increasing the proportion of nitrogen enhances the gas barrier properties, but conversely decreases the transmittance. Therefore, x and y preferably satisfy 0.4 ≦ x / (x + y) ≦ 0.8.
[0120]
Examples of the transparent substrate include glass, quartz, and a transparent resin film. In the present invention, as the transparent substrate, a transparent resin film can be preferably used. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyether imide, polyether ether ketone, polyphenylene sulfide , Polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), and the like.
[0121]
The transparent substrate having the dielectric mirror structure of the present invention is not particularly limited as long as it has a structure in which layers having different refractive indices are stacked, but those having the dielectric mirror layer above the transparent base as described above are preferred. preferable.
[0122]
The transparent substrate having the dielectric mirror structure of the present invention can of course be used for the organic EL device of the present invention, but other uses include a transflective liquid crystal display device, a spatial light modulator, and the like. Electro-optical device applications are conceivable.
[0123]
When the transparent substrate having the dielectric mirror structure of the present invention is applied to the organic EL device of the present invention, a color conversion section described later may be provided between the transparent substrate and the dielectric mirror layer in some cases. A protective layer may be further provided on the dielectric mirror layer.
[0124]
In the transparent substrate having the dielectric mirror structure of the present invention, as a method of providing a dielectric mirror layer on the transparent substrate, an evaporation method, a sputtering method, or the like can be applied.
[0125]
The color conversion section is preferably a color conversion layer. The color conversion section contains a fluorescent dye that absorbs light emitted from the organic EL section, converts the wavelength, and emits visible light fluorescence.
[0126]
In the present invention, an inorganic phosphor is used as the fluorescent dye. The inorganic phosphor that can be used in the present invention is preferably synthesized by a liquid phase synthesis method.
[0127]
The liquid phase synthesis method in the present invention is to synthesize an inorganic phosphor and an inorganic phosphor precursor in the presence or in the presence of a liquid, and includes any crystallization method including cooling crystallization and coprecipitation method. However, the reaction crystallization method is preferred.
[0128]
The reaction crystallization method is a method of synthesizing an inorganic phosphor or an inorganic phosphor precursor by mixing a raw material solution or a raw material gas in a liquid phase or a gas phase. The reaction crystallization method of the present application is preferably a reaction in a liquid phase, and more preferably a reaction of a raw material solution in a liquid phase.
[0129]
The inorganic phosphor precursor crystal is an intermediate product of the inorganic phosphor, and the inorganic phosphor is obtained by firing the inorganic phosphor precursor crystal at a predetermined temperature.
[0130]
After synthesizing the precursor by a liquid phase method, if necessary, filtration, evaporation to dryness, and preferably after washing by a method such as centrifugation, washing, and further drying, may be subjected to various steps such as baking, You may classify.
[0131]
In the method for producing an inorganic phosphor of the present invention, it is preferable to remove impurities such as secondary salts from the precursor by performing a desalting step prior to the firing step. The electric conductivity after the desalting of the precursor is preferably in the range of 0.01 to 20 mS / cm, more preferably 0.01 to 10 mS / cm, and particularly preferably 0.01 to 5 mS / cm. . Even if the electric conductivity is less than 0.01 mS / cm, the effect is not particularly increased, but the productivity is lowered. On the other hand, if it exceeds 20 mS / cm, since the secondary salts and impurities cannot be sufficiently removed, the particles become coarse and the particle size distribution becomes wide, and the light emission intensity deteriorates.
[0132]
In the present invention, any of the above-described methods for measuring electric conductivity can be used, but a commercially available electric conductivity measuring device may be used.
[0133]
As the desalting step in the present invention, it is preferable to apply various membrane separation methods, coagulation sedimentation methods, electrodialysis methods, methods using ion exchange resins, Nudel washing methods, and the like. Further, one or more or all of the raw material solutions may be mixed with a protective colloid. The protective colloid used in the present invention functions to prevent agglomeration of particles, and clearly has a different function from the organic polymer used for controlling the crystal habit disclosed in JP-A-2001-329262. As the protective colloid of the present application, various polymer compounds can be used regardless of whether they are natural or artificial. In this case, the average molecular weight of the protective colloid is preferably 10,000 or more, more preferably 10,000 or more and 300,000 or less, and particularly preferably 10,000 or more and 30,000 or less. The protective colloid of the present application is preferably a protein, and particularly preferably gelatin. Further, it is not necessary to have a single composition, and various binders may be mixed.
[0134]
The term “average particle size” as used herein refers to the length of a ridge of a particle when the particle is a cubic or octahedral so-called normal crystal. In the case of non-normal crystals, for example, in the case of spherical, rod-like or tabular grains, it refers to the diameter of a sphere equivalent to the volume of the grains.
[0135]
Further, the particles are preferably monodispersed. The term “monodispersion” as used herein means a case where the degree of monodispersion determined by the following equation is 40% or less. In the present invention, the monodispersity is more preferably 30% or less, and particularly preferably 0.1 to 20%.
[0136]
Monodispersity = (standard deviation of particle size / average value of particle size) × 100
In the present invention, the method for drying the inorganic phosphor precursor is not particularly limited, and any method such as vacuum drying, flash drying, fluidized bed drying, and spray drying may be used.
[0137]
In the present invention, the firing temperature and time of the inorganic phosphor precursor are not particularly limited, and can be appropriately selected according to the type of the inorganic phosphor. Furthermore, the gas atmosphere during firing may be any of an oxidizing atmosphere, a reducing atmosphere, or an inert atmosphere, and can be appropriately selected depending on the purpose. The firing device is not particularly limited, and any device can be used. For example, a box furnace, a crucible furnace, a rotary kiln and the like are preferably used.
[0138]
A sintering inhibitor may or may not be added during firing. When it is added, it may be added as a slurry at the time of forming the precursor, or a method in which a powdery material is mixed with a dried precursor and fired is preferably used. Furthermore, the sintering inhibitor is not particularly limited, and is appropriately selected depending on the type of the inorganic phosphor and the firing conditions. For example, for firing at 800 ° C. or less depending on the firing temperature range of the inorganic phosphor, TiO 2 ₂ Metal oxide such as SiO. ₂ However, firing at 1700 ° C or lower requires Al ₂ O ₃ Are each preferably used.
[0139]
The average particle diameter of the inorganic phosphor used in the present invention is 0.05 to 1.0 μm, but is preferably 0.8 μm or less. Here, the particle size of the inorganic phosphor means a sphere-converted particle size. The sphere-equivalent particle size is a particle size represented by the particle size of a sphere assuming a sphere having the same volume as the volume of the particle.
[0140]
Further, it is advantageous that the particle size distribution is narrower in advance for the same reason as described above. Specifically, the coefficient of variation of the particle size distribution is preferably 100% or less, and more preferably 70% or less. . Here, the variation coefficient of the particle size distribution (the width of the particle distribution) is a value defined by the following equation.
[0141]
Area of particle size distribution (coefficient of variation) [%]
= (Standard deviation of particle size distribution / average value of particle size) x 100
The above-mentioned inorganic phosphor may be subjected to a surface modification treatment as necessary, and may be subjected to a chemical treatment such as a silane coupling agent or a physical treatment by adding submicron-order fine particles or the like. And the combination thereof.
[0142]
Examples of the rare earth complex-based phosphor include those having rare earth metals such as Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. The ligand may be either aromatic or non-aromatic, and is preferably a compound represented by the following formula (B).
[0143]
General formula (B) Xa- (L _x )-(L _y ) _n − (L _z ) -Ya
[Where L _x , L _y , L _z Each independently represents an atom having two or more bonds, n represents 0 or 1, and Xa represents L _x Represents a substituent having a coordinable atom at the adjacent position of _z Represents a substituent having a coordinable atom at the adjacent position. Furthermore, any part of Xa and L _x May be condensed with each other to form a ring, and any part of Ya and L _z May be fused to each other to form a ring; _x And L _z May be condensed with each other to form a ring, and at least one aromatic hydrocarbon ring or aromatic heterocyclic ring is present in the molecule. However, Xa- (L _x )-(L _y ) _n − (L _z ) -Ya is a β-diketone derivative, a β-ketoester derivative, a β-ketoamide derivative or an oxygen atom of the ketone is a sulfur atom or ₂₀₁ )-, Crown oxygen, azacrown ether, thiacrown ether or crown ether in which oxygen atoms are any number of sulfur atoms or -N (R ₂₀₁ In the case where the crown ether is replaced by-), the aromatic hydrocarbon ring or the aromatic heterocyclic ring may not be present. −N (R ₂₀₁ )- ₂₀₁ Represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. ]
In the general formula (B), the coordinable atoms represented by Xa and Ya are specifically an oxygen atom, a nitrogen atom, a sulfur atom, a selenium atom, a tellurium atom, and particularly an oxygen atom, a nitrogen atom, It is preferably a sulfur atom.
[0144]
In the general formula (B), L _x , L _y , L _z The atom having two or more bonds represented by is not particularly limited, but typically includes a carbon atom, an oxygen atom, a nitrogen atom, a silicon atom, a titanium atom, and the like. Is a carbon atom.
[0145]
Hereinafter, specific examples of the rare earth complex-based phosphor represented by the general formula (B) will be shown, but the present invention is not limited thereto.
[0146]
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[0147]
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[0148]
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[0149]
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[0150]
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[0151]
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[0152]
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[0153]
The place where the color conversion part is provided is not particularly limited as long as it can absorb the light emitted from the organic EL part having the optical microresonator structure, but it is between the transparent electrode and the transparent base or the transparent base. It is preferable to provide it on the side opposite to the transparent electrode (before extracting light emission).
[0154]
The color conversion section may be in any form, such as a film formed by vapor deposition or sputtering of the inorganic phosphor or a coating film in which an appropriate resin is dispersed as a binder. The film thickness is suitably about 100 nm to 5 mm. Here, when the coating film is formed by dispersing an appropriate resin as a binder in the coating film, the dispersion concentration of the inorganic phosphor does not cause the quenching of the concentration of the fluorescent light and the light emission from the organic EL portion is sufficiently reduced. What is necessary is just a range which can be absorbed. Depending on the type of inorganic phosphor, 10 g / g of resin used ^-7 -10 ^-3 Molar amounts are appropriate. In the case of an inorganic phosphor, since concentration quenching hardly causes a problem, about 0.1 to 10 g can be used per 1 g of the resin.
[0155]
The organic EL element of the present invention may be used as a kind of lamp for illumination or an exposure light source, or as a projection device for projecting an image or a display device (display) for directly recognizing an image. May be used. When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method.
[0156]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto.
[0157]
<Preparation of inorganic phosphor>
Inorganic phosphor 1 (red inorganic phosphor solid phase method)
The red inorganic phosphor is made of potassium chloride (KCl) and europium oxide (Eu) as raw materials. ₂ O ₃ ) And sodium tungstate (Na ₃ (WO ₄ )) Were mixed in a molar ratio of 0.6: 0.3: 0.1: 1.0, mixed with a suitable amount of flux in a ball mill, and calcined at 1,400 ° C. for 2 hours. Inorganic phosphor 1 (K ₅ Eu _2.5 (WO ₄ ) _6.25 ) Got.
[0158]
Inorganic phosphor 2 (red inorganic phosphor liquid phase method)
1000 ml of water was used as solution [A]. Potassium chloride and europium nitrate hexahydrate were dissolved in 500 ml of water so that the ion concentration of potassium was 0.4659 mol / l and the ion concentration of europium was 0.0388 mol / l, to obtain a solution [B]. Sodium tungstate was dissolved in 500 ml of water such that the ion concentration of tungstic acid was 0.7763 mol / l to obtain a solution [C].
[0159]
The solution [A] (21) was placed in the reaction vessel of FIG. 1, the temperature was kept at 40 ° C., and stirring was performed using a stirring blade. In this state, the solution [B] (22) and the solution [C] (23) also kept at 40 ° C. were added at a constant rate of 100 ml / min from the lower nozzle of the reaction vessel containing the solution [A] (21). went. After the addition, the mixture was aged for 10 minutes to obtain a precursor 2. Thereafter, the precursor 2 was filtered and dried to obtain a dried precursor 2. Further, the dried precursor 2 was calcined at 1,400 ° C. under oxidizing conditions for 2 hours to obtain an inorganic phosphor 2.
[0160]
Inorganic phosphor 3 (green inorganic phosphor solid phase method)
The green inorganic phosphor is made of barium oxide (BaO), silicon oxide (SiO ₂ ) Is mixed in a molar ratio of 2: 1. Next, a predetermined amount of europium oxide (Eu) was added to the mixture. ₂ O ₃ ) Was added and mixed with a ball mill, and then 1,000 ° C., 5% H ₂ -95% N ₂ It was calcined for 2 hours under atmospheric conditions to obtain inorganic phosphor 3.
[0161]
Inorganic phosphor 4 (green inorganic phosphor liquid phase method)
1000 ml of water was used as solution [A]. Sodium metasilicate was dissolved in 500 ml of water such that the ion concentration of silicon was 0.5000 mol / l, to obtain a solution [B]. Barium nitrate and europium nitrate hexahydrate were dissolved in 500 ml of water so that the barium ion concentration was 0.9500 mol / l and the manganese ion concentration was 0.0500 mol / l to obtain a solution [C].
[0162]
The solution [A] was placed in the reaction vessel of FIG. 1, the temperature was kept at 40 ° C., and stirring was performed using a stirring blade. In this state, solutions [B] and [C] which were also kept at 40 ° C. were added at a constant rate of 100 ml / min from the lower nozzle of the reaction vessel containing the solution [A]. After the addition, the mixture was aged for 10 minutes to obtain a precursor 4. Thereafter, the precursor 4 was filtered and dried to obtain a dried precursor 4.
Further, the dried precursor 4 is subjected to 1,000 ° C., 5% H ₂ -95% N ₂ Calcination was performed for 2 hours under an atmosphere condition to obtain an inorganic phosphor 4.
[0163]
Inorganic phosphor 5 (blue inorganic phosphor solid phase method)
First, a blue inorganic phosphor is prepared by using barium carbonate (BaCO 3) as a raw material. ₃ ), Magnesium carbonate (MgCO ₃ ), Aluminum oxide (α-Al ₂ O ₃ ) Is mixed in a molar ratio of 1: 1: 1: 5. Next, a predetermined amount of europium oxide (Eu) was added to the mixture. ₂ O ₃ ) Is added. Then, an appropriate amount of flux (AlF ₂ , BaCl ₂ ), And calcined under a reducing condition at 1600 ° C. for 2 hours to obtain an inorganic phosphor 5.
[0164]
Inorganic phosphor 6 (blue inorganic phosphor liquid phase method)
1000 ml of water was used as solution [A]. Barium chloride dihydrate and magnesium chloride 6 were added so that the barium ion concentration was 0.0900 mol / l, the magnesium ion concentration was 0.1000 mol / l, and the europium ion concentration was 0.01 mol / l in 500 ml of water. The hydrate and europium chloride hexahydrate were dissolved to obtain a solution [B]. Aluminum chloride hexahydrate was dissolved in 500 ml of water such that the ion concentration of aluminum was 1.000 mol / l, to obtain a solution [C].
[0165]
The solution [A] was placed in the reaction vessel of FIG. 1, the temperature was kept at 40 ° C., and stirring was performed using a stirring blade. In this state, solutions [B] and [C] which were also kept at 40 ° C. were added at a constant rate of 100 ml / min from the lower nozzle of the reaction vessel containing the solution [A]. After the addition, the mixture was aged for 10 minutes to obtain a precursor 6. Thereafter, the precursor 6 was filtered and dried to obtain a dried precursor 6. Further, the dried precursor 6 was calcined under a reducing condition of 1,600 ° C. for 2 hours to obtain an inorganic phosphor 6.
[0166]
The emission intensity at 147 nm excitation was measured using an Otsuka Electronics Co., Ltd. fluorescence spectrometer, and the relative emission intensity of the inorganic phosphor when the emission intensity of the inorganic phosphor as a comparative example was set to 100% is as follows. Became. Further, the particle size of the inorganic phosphor was observed with a scanning electron microscope, and the average particle size of 500 particles was measured.
[0167]
[Table 1]

[0168]
As described above, it has been clarified that the inorganic phosphor particles of the present invention have excellent characteristics. Further, it can be seen that there is an advantage that the relative emission intensity does not decrease even if the average particle size becomes small.
[0169]
Example 1
On a commercially available PES (polyethersulfone) film (Sumilite FS-1300 manufactured by Sumitomo Bakelite Co., Ltd.) having a size of 25 mm × 75 mm and a thickness of 0.1 mm, a silicon oxide layer (SiO 2) was formed by RF magnetron sputtering. ₂ ), Titanium oxide layer (TiO 2) ₂ 3), a dielectric mirror was formed by alternately laminating each three layers such that the titanium oxide layer was formed at the end. At this time, the thicknesses of the silicon oxide layer and the titanium oxide layer were 69 nm and 42 nm, respectively.
[0170]
Note that this dielectric mirror was designed with the wavelength of light emitted from the element being 405 nm.
[0171]
As described above, a transparent substrate having a dielectric mirror structure was produced using the transparent resin film as a constituent material.
[0172]
By providing the dielectric mirror, the moisture-proof property was remarkably improved as compared with the case of using only the PES film.
[0173]
Example 2
In the same manner as in Example 1, except that the silicon oxide layer was changed to a silicon oxynitride layer and the titanium oxide layer was changed to a titanium oxynitride layer, a transparent resin film was used as a constituent material, and a dielectric mirror structure was formed. When a transparent substrate having the same was prepared, the moisture resistance was further improved as compared with the transparent substrate of Example 1.
[0174]
Example 3
A transparent conductive layer (ITO) having a thickness of 50 nm was formed as a transparent electrode (anode) by RF magnetron sputtering on the dielectric mirror on the transparent substrate manufactured in Example 1. This was sufficiently washed with an organic solvent, and then fixed in a vacuum evaporation apparatus. First, 20 nm of m-MTDATXA was deposited as a hole transport layer, 20 nm of DMPhen was deposited as a light emitting layer, and 20 nm of bathocuproine (BC) was deposited as an electron transport layer. Thereby, the total of the transparent conductive layer and the organic compound thin film became 110 nm. DMPhen is BP-13 described above. The structural formulas of m-MTDATXA and BC are shown below.
[0175]
Embedded image

[0176]
The optical length of the optical micro-resonator in this element is determined by the above-mentioned equation (Equation 1) from the thickness and refractive index of the transparent conductive layer and the organic compound thin film and the amount of penetration into the dielectric mirror. 1.5 times of 405 nm.
[0177]
A 180 nm MgAg alloy (10: 1) was deposited as a cathode.
<Preparation of color conversion filter using inorganic phosphor>
15 g of ethanol and 0.22 g of γ-glycidoxypropyltriethoxysilane were added to 0.16 g of aerosil having an average particle size of 5 nm, and the mixture was stirred for 1 hour at room temperature in an open system. This mixture and 20 g of the inorganic phosphor 1 were transferred to a mortar, mixed well, and heated in an oven at 70 ° C. for 2 hours and further in an oven at 120 ° C. for 2 hours to obtain a surface-modified inorganic phosphor 1. .
[0178]
Similarly, the surface modification of the inorganic phosphors 2 to 6 was also performed.
To 10 g of the surface-modified inorganic phosphor 1, 30 g of butyral (BX-1) dissolved in a mixed solution (300 g) of toluene / ethanol = 1/1 was added, and the mixture was stirred. Coated on glass at 200 μm. The obtained coated glass was dried by heating in an oven at 100 ° C. for 4 hours to produce a red conversion filter (F-1) as a color conversion portion of the present invention.
[0179]
Further, a green conversion filter (F-3) coated with the inorganic phosphor 3 and a blue conversion filter (F-5) coated with the inorganic phosphor 5 were produced in the same manner. Similarly, filters F-2, F-4, and F-6 coated with the inorganic phosphors 2, 4, and 6 were produced.
[0180]
Subsequently, a blue color conversion filter (F-5) as a color conversion portion was stuck on the lower side of the transparent base of the transparent resin film in a stripe shape. The organic EL device of this embodiment has the following configuration.
[0181]
Color converter / transparent substrate / dielectric mirror / transparent electrode / organic compound thin film / metal electrode
As described above, an organic electroluminescence device having an optical microresonator structure was manufactured.
[0182]
When a voltage of 8 V was applied to this device, clear blue light emission was obtained. The maximum emission wavelength of the emission spectrum was 448 nm, and was (0.15, 0.06) on the CIE chromaticity coordinates.
[0183]
Further, an organic EL device was produced in which the blue conversion filter (F-5) of the color conversion section was replaced with a green conversion filter (F-3) or a red conversion filter (F-1). As a result, from the organic EL device provided with the green conversion filter (F-3), green light having a maximum emission wavelength of 532 nm and a CIE chromaticity coordinate of (0.24, 0.63) is converted to a red conversion filter (F-3). Red light having a maximum emission wavelength of 615 nm and CIE chromaticity coordinates (0.63, 0.33) was obtained from the organic EL device provided with 1).
[0184]
Further, an organic EL device having the following layer configuration in which the position of the following color conversion portion was changed to the upper side of the transparent substrate was produced.
[0185]
Transparent substrate / color converter / derivative mirror / transparent electrode / organic compound thin film / metal electrode
Also in this case, the emission spectrum having the maximum emission wavelength and the CIE chromaticity coordinates almost similar to those of the blue, green and red colors was obtained.
[0186]
Incidentally, even when the used transparent substrate was changed to the one produced in Example 2, the same result could be obtained.
[0187]
Comparative Example 1
In the dielectric mirror manufactured in Example 1, SiO 2 ₂ Layer, TiO ₂ A transparent substrate having a dielectric mirror structure was manufactured in exactly the same manner as in Example 1 except that the thicknesses of the layers were 79 nm and 48 nm, respectively.
[0188]
A 50 nm transparent conductive layer (ITO) was formed on the transparent substrate having the dielectric mirror structure by RF magnetron sputtering. After sufficiently washing these substrates with an organic solvent, they were fixed in a vacuum evaporation apparatus. First, 40 nm of m-MTDATA was deposited as a hole transport layer, 25 nm of DPVBi was deposited as a light emitting layer, and Alq was deposited as an electron transport layer. ₃ Was deposited to a thickness of 10 nm. Thereby, the total of the transparent conductive layer and the organic compound layer became 125 nm.
[0189]
Below, m-MTDATA, DPVBi, Alq ₃ Shows the structural formula of
[0190]
Embedded image

[0191]
The optical length of the optical micro-resonator in this element is determined by the above-mentioned equation (Equation 1) from the thickness and refractive index of the transparent conductive layer and the organic compound thin film and the amount of penetration into the dielectric mirror. 1.5 times of 460 nm. Finally, a 180 nm MgAg alloy (10: 1) was deposited as a cathode.
[0192]
<Preparation of color conversion unit using organic phosphor>
The color converter using an organic phosphor was prepared in the same manner as in JP-A-3-152897. Specifically, the green converter is a coumarin 153 described in the above publication as a polymethyl methacrylate (PMMA) dispersed film, and the red converter is a phenoxazine 9 and pyridine 1 described in the above publication as a PMMA dispersed film. Using.
[0193]
On the lower side of the transparent substrate of the transparent resin film, a green color conversion portion was stuck in a stripe shape as a color conversion portion. When a voltage of 8 V was applied to this element, green light was emitted. The maximum emission wavelength of the emission spectrum was 532 nm, and was (0.24, 0.63) on the CIE chromaticity coordinates.
[0194]
Further, an organic EL device in which the above-mentioned green conversion part was replaced with a red conversion part was produced. When a voltage of 8 V was applied to this device, red light emission was obtained. The maximum emission wavelength of the emission spectrum was 615 nm, and was (0.63, 0.32) on the CIE chromaticity coordinates.
[0195]
As described above, an organic electroluminescence element having an optical microresonator structure was manufactured. Compared with Example 2 in which the light from the light emitting layer was blue-violet, both the green and red emission luminances were higher. It was a low value. Further, in this case, since the light from the light emitting layer is blue, a color conversion unit is not required, and an organic electroluminescence element having a blue optical micro-resonator structure is difficult to manufacture because a viewing angle cannot be obtained. There is a disadvantage.
[0196]
Comparative Example 2
In Example 3 above, ₂ , TiO ₂ Was manufactured in the same manner as in Example 3, except that the step of forming a dielectric mirror in which three layers were laminated was omitted. At this time, the layer configuration of the organic EL element of this comparative example is as follows:
Color conversion part / transparent substrate / transparent electrode / organic compound thin film / metal electrode
It is.
[0197]
The intensities of blue light, green light and red light were 0.27 times, 0.33 times and 0.24 times of Example 3, respectively.
[0198]
Comparative Example 3
In Comparative Example 1 described above, ₂ , TiO ₂ Was manufactured in the same manner as in Comparative Example 1 except that the step of forming a dielectric mirror in which each of the three layers was laminated was omitted. At this time, the layer configuration of the organic EL element of this comparative example is as follows:
Color conversion part / transparent substrate / transparent electrode / organic compound thin film / metal electrode
It is.
[0199]
The intensities of green light and red light were 0.40 times and 0.33 times that of Comparative Example 1, respectively. When the blue light emission from the organic EL unit is color-converted, the effect of increasing the light emission intensity by introducing the optical microresonator structure is smaller than when the blue-violet light emission from the organic EL unit is color-converted. I understand.
[0200]
Comparative Example 4
An organic electroluminescence device was manufactured in the same manner as in Example 3 except that the process of manufacturing the color conversion unit was omitted in Example 3 described above. In the emission spectrum of this comparative example, blue-violet emission having a maximum emission wavelength of 405 nm, a half width of 12 nm, and CIE chromaticity coordinates (x = 0.16, y = 0.036) was able to be obtained. However, it was found that the emission pattern of light emission was not suitable for a display device because a viewing angle could not be obtained.
[0201]
Example 4
Hereinafter, an example of the display device of the present invention composed of the organic EL element of the present invention manufactured in Example 3 will be described below with reference to the drawings.
[0202]
FIG. 2 is a schematic diagram of a display such as a mobile phone for displaying image information by light emission of an organic EL element.
[0203]
The display 1 includes a display unit A having a plurality of pixels 3, a control unit B that performs image scanning of the display unit A based on image information, and the like.
[0204]
The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels 3 based on image information from the outside. Light emission is performed sequentially in accordance with the signal, and image scanning is performed to display image information on the display unit A.
[0205]
FIG. 3 is a schematic diagram of the display unit A.
The display section A has a wiring section including a plurality of scanning lines 5 and data lines 6 and a plurality of pixels 3 on a base. The main members of the display unit A will be described below.
[0206]
The figure shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).
[0207]
The scanning lines 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at orthogonal positions (not shown in detail). ).
[0208]
When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data. By appropriately arranging pixels in a red region, pixels in a green region, and pixels in a blue region on the same substrate, a full-color display is possible.
[0209]
Next, a light emitting process of the pixel 3 will be described.
FIG. 4 is a schematic diagram of the pixel 3.
[0210]
The pixel 3 includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like.
[0211]
In the figure, an image data signal is applied from the control unit B to the drain of the switching transistor 11 via the data line 6. When a scanning signal is applied to the gate of the switching transistor 11 from the control unit B via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is transferred to the capacitor 13 and the driving transistor 12. Transmitted to the gate.
[0212]
By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the driving of the drive transistor 12 is turned on. The driving transistor 12 has a drain connected to the power supply line 7, a source connected to the electrode of the organic EL element 10, and from the power supply line 7 to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.
[0213]
When the scanning signal is transferred to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even when the driving of the switching transistor 11 is turned off, the capacitor 13 holds the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. The light emission of the organic EL element 10 continues until this. When the next scanning signal is applied by the sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.
[0214]
That is, the organic EL element 10 emits light by providing a switching transistor 11 and a driving transistor 12 that are active elements to the organic EL elements 10 of the plurality of pixels 3, respectively. It is emitting light. Such a light emitting method is called an active matrix method.
[0215]
Here, the light emission of the organic EL element 10 may be a light emission of a plurality of gradations by a multi-valued image data signal having a plurality of gradation potentials, or a predetermined light emission amount on / off by a binary image data signal. But it's fine.
[0216]
Further, the holding of the potential of the capacitor 13 may be continued until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.
[0219]
The present invention is not limited to the active matrix method described above, but may be a passive matrix light emission drive in which an organic EL element emits light in accordance with a data signal only when a scanning signal is scanned.
[0218]
FIG. 5 is a cross-sectional view of only the organic EL element 10 of the pixel 3 taken out and viewed from the thickness direction.
[0219]
FIGS. 5A and 5B show different arrangements of the color conversion units. In FIG. 5A, the organic EL element 10 is an embodiment in which an organic EL section Y is laminated on a transparent resin film 10e as a transparent substrate, and a color conversion section X is laminated on a lower side. The EL element 10 has a mode in which a color conversion section X and an organic EL section Y are stacked in this order on a transparent resin film 10e.
[0220]
In the figure, reference numeral 10a is a metal electrode, 10b is an organic compound thin film including a light emitting layer, 10c is a transparent electrode, 10d is a dielectric mirror, 10e is a transparent resin film, and 10f is a color conversion layer.
[0221]
When a current is supplied to the organic compound thin film 10b via the metal electrode 10a and the transparent electrode 10c, light is emitted according to the amount of current. The emission color at this time is preferably a color in the blue-violet region in the present invention. The light emission of the color in the blue-violet region is amplified between the dielectric mirror 10d and the metal electrode 10a as the light reflecting portion, and is extracted as light having high directivity in the downward direction in the drawing. . Then, it is absorbed by the color conversion layer 10f with or without the transparent resin film 10e, and is in the red region when the color conversion layer has red conversion capability, and in the green region when it has green conversion capability. However, in the case of having blue conversion capability, light emission in the blue region can be extracted in the direction indicated by the white arrow in the figure.
[0222]
FIG. 6 is a schematic diagram of a display A using a passive matrix method.
In the figure, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a grid pattern facing each other with the pixel 3 interposed therebetween.
[0223]
When the scanning signal of the scanning line 5 is applied by the sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.
[0224]
In the passive matrix system, there is no active element in the pixel 3, and the manufacturing cost can be reduced.
[0225]
【The invention's effect】
An organic EL element having high luminous efficiency, a wide viewing angle, and having no color change depending on the angle, a light emitting method thereof, a display device using the organic EL element and a display method thereof, and a portable, transparent It was possible to provide a transparent substrate having low wettability and applicable to an organic EL device.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of an apparatus for producing a precursor of an inorganic phosphor.
FIG. 2 is a schematic diagram illustrating an example of a display device including an organic EL element.
FIG. 3 is a schematic diagram of a display unit.
FIG. 4 is a schematic diagram of a pixel.
FIG. 5 is a cross-sectional view of the organic EL element viewed from a thickness direction.
FIG. 6 is a schematic diagram of a display device using a passive matrix method.
[Explanation of symbols]
1 Display
3 pixels
5 scan lines
6 Data line
7 Power line
10 Organic EL device
10a metal electrode
10b Organic compound thin film
10c transparent electrode
10d dielectric mirror
10e transparent resin film
10f color conversion layer
11 Switching transistor
12 Driving transistor
13 Capacitor
A Display (display)
B control unit
X color converter
Y Organic EL section
21 Solution [A]
22 Solution [B]
23 Solution [C]

Claims (27)

An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: An organic electroluminescent device, which is an inorganic phosphor having a diameter of 0.05 to 1.0 μm. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region; and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: An organic electroluminescent device comprising an inorganic phosphor containing Si and Si. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: An organic electroluminescent device comprising an inorganic phosphor containing Ba and Si having a diameter of 0.05 to 1.0 μm. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing the light emitted from the organic electroluminescent portion are formed of particles. the organic electroluminescent device size characterized in that it is a _{Ba 2-a} Eu _a SiO ₄ of 0.05 to 1.0 [mu] m. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region; and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: An organic electroluminescent device, comprising: an inorganic phosphor containing Mg and Mg. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing light emitted from the organic electroluminescent portion, comprising: An organic electroluminescence device comprising an inorganic phosphor containing Ba and Mg having a diameter of 0.05 to 1.0 μm. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing the light emitted from the organic electroluminescent portion are formed of particles. the organic electroluminescent device characterized by size of _{Ba 1-a Eu a MgAl 10} O 17 of 0.05 to 1.0 [mu] m. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion that emits visible light fluorescence by absorbing light emitted from the organic electroluminescent portion is K. And an inorganic phosphor containing W. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing the light emitted from the organic electroluminescent portion are formed of particles. An organic electroluminescent device comprising an inorganic phosphor containing K and W having a diameter of 0.05 to 1.0 μm. An organic electroluminescent portion having an optical microresonator structure and emitting light of a color in the blue-violet region, and a color conversion portion emitting visible light fluorescence by absorbing the light emitted from the organic electroluminescent portion are formed of particles. the organic electroluminescent device characterized by size of _{K 5 Eu 2.5 (WO 4)} 6.25 of 0.05 to 1.0 [mu] m. An organic electroluminescent portion is provided on the upper side of the transparent substrate, and has a half mirror portion, an organic compound thin film including a light emitting layer, and a light reflecting portion in this order from the transparent substrate side. Item 10. The organic electroluminescent device according to any one of Items 1 to 10. The organic electroluminescence device according to claim 1, wherein the half mirror portion has a dielectric mirror and a transparent electrode in this order from the transparent substrate side. The organic electroluminescence device according to any one of claims 1 to 12, wherein the light reflecting portion is a metal electrode. The organic electroluminescence device according to claim 1, wherein the color conversion unit is provided below the dielectric mirror. The organic dielectric according to any one of claims 1 to 14, wherein the dielectric mirror is formed by stacking a plurality of layers each including a layer mainly containing silicon oxide and a layer mainly containing titanium oxide. Electroluminescent element. The organic electroluminescence device according to claim 15, wherein at least one of the layer containing silicon oxide as a main component and the layer containing titanium oxide as a main component contains silicon oxynitride or titanium oxynitride. The organic electroluminescent device according to any one of claims 1 to 16, wherein the transparent substrate is a transparent resin film. A display device comprising the organic electroluminescence device according to claim 1. A light emitting method having an optical microresonator structure, wherein visible light fluorescence is emitted by absorbing light emitted from an organic electroluminescence portion, which emits light in a blue-violet region, into a color conversion portion. The organic electroluminescent portion is provided on the upper side of the transparent substrate, and has a half mirror portion, an organic compound thin film including a light emitting layer, and a light reflecting portion in this order from the transparent substrate side. Item 20. The light emitting method according to Item 19. 21. The light emitting method according to claim 20, wherein the half mirror section has a dielectric mirror and a transparent electrode in this order from the transparent substrate side. 22. The light emitting method according to claim 20, wherein the light reflecting portion is a metal electrode. 23. The light emitting method according to claim 20, wherein the color conversion unit is provided below the dielectric mirror. The light-emitting device according to any one of claims 20 to 23, wherein the dielectric mirror is formed by stacking a plurality of layers including a layer mainly composed of silicon oxide and a layer mainly composed of titanium oxide. Method. The light emitting method according to claim 24, wherein at least one of the layer containing silicon oxide as a main component and the layer containing titanium oxide as a main component contains silicon oxynitride or titanium oxynitride. The light emitting method according to any one of claims 20 to 25, wherein the transparent substrate is a transparent resin film. A display method, wherein display is performed using light emission by the light emission method according to any one of claims 19 to 26.

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