JP4218328B2 - Nitride phosphor and light emitting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device which emits white light of a reddish warm color type with good luminous efficiency, a phosphor which has an emission spectrum in the yellow to red region and is used in combination with a blue light-emitting device or the like. <P>SOLUTION: The nitride phosphor is represented by the formula: L<SB>X</SB>M<SB>Y</SB>N<SB>((2/3)X+(4/3)Y)</SB>:R or L<SB>X</SB>M<SB>Y</SB>O<SB>Z</SB>N<SB>((2/3)X+(4/3)Y-(2/3)Z)</SB>:R (wherein L is a group II element to be selected from the group consisting of Ca, Sr, Ba and the like; M is a group IV element to be selected from the group consisting of Si, Ge and the like; R is a rare earth element to be selected from the group consisting of Eu and the like; and X, Y, and Z are 0.5&le;X&le;3, 1.5&le;Y&le;8, and 0&lt;Z&le;3, respectively) and contains 1 ppm to 10,000 ppm B. The light-emitting equipment is constituted of the above nitride phosphor which converts the wavelength of part of the light from a blue light-emitting device 10 to have a peak wavelength in the yellow to red region. <P>COPYRIGHT: (C)2004,JPO&amp;NCIPI

Description

【００６８】
ただし、各原料の配合比率を変更することにより、目的とする蛍光体の組成を変更することができる。
【００６９】
焼成は、管状炉、小型炉、高周波炉、メタル炉などを使用することができる。焼成温度は、１２００から２０００℃の範囲で焼成を行うことができるが、１４００から１８００℃の焼成温度が好ましい。焼成は、徐々に昇温を行い１２００から１５００℃で数時間焼成を行う一段階焼成を使用することが好ましいが、８００から１０００℃で一段階目の焼成を行い、徐々に加熱して１２００から１５００℃で二段階目の焼成を行う二段階焼成（多段階焼成）を使用することもできる。蛍光体１１の原料は、窒化ホウ素（ＢＮ）材質の坩堝、ボートを用いて焼成を行うことが好ましい。窒化ホウ素材質の坩堝の他に、アルミナ（Ａｌ_２Ｏ_３）材質の坩堝を使用することもできる。これらＢ、Ａｌ等は、Ｍｏよりも、輝度の向上を図ることができ、高い発光効率を有する蛍光体を提供することができるからである。
【００７０】
また、還元雰囲気は、窒素、水素、アルゴン、二酸化炭素、一酸化炭素、アンモニアの少なくとも１種以上を含む雰囲気とする。ただし、これら以外の還元雰囲気下でも焼成を行うことができる。
【００７１】
以上の製造方法を使用することにより、目的とする窒化物蛍光体を得ることが可能である。
【００７２】
（蛍光体）
発光装置に使用される蛍光体は、本発明に係る窒化物蛍光体の他に、青色に発光する蛍光体、緑色に発光する蛍光体、黄色に発光する蛍光体の少なくともいずれか１以上の蛍光体を混合して、使用することができる。
【００７３】
青色に発光する蛍光体、緑色に発光する蛍光体、黄色に発光する蛍光体には、種々の蛍光体があるが、特に、少なくともセリウムで賦活されたイットリウム・アルミニウム酸化物蛍光体、少なくともセリウムで賦活されたイットリウム・ガドリニウム・アルミニウム酸化物蛍光体、及び少なくともセリウムで賦活されたイットリウム・ガリウム・アルミニウム酸化物蛍光体の少なくともいずれか１以上であることが好ましい。これにより、所望の発光色を有する発光装置を提供することができる。本発明に係る蛍光体と、セリウムで賦活されたイットリウム・アルミニウム酸化物蛍光体等とを用いた場合、これら蛍光体における自己吸収が少ないため、効率よく発光を取り出すことができる。具体的には、Ｌｎ_３Ｍ_５Ｏ_１２：Ｒ（Ｌｎは、Ｙ、Ｇｄ、Ｌａから選ばれる少なくとも１以上である。Ｍは、Ａｌ、Ｃａの少なくともいずれか一方を含む。Ｒは、ランタノイド系である。）、（Ｙ_１−ｘＧａ_ｘ）_３（Ａｌ_１−ｙＧａ_ｙ）_５Ｏ_１２：Ｒ（Ｒは、Ｃｅ、Ｔｂ、Ｐｒ、Ｓｍ、Ｅｕ、Ｄｙ、Ｈｏから選ばれる少なくとも１以上である。０＜Ｒ＜０．５である。）を使用することができる。該蛍光体は、近紫外から可視光の短波長側、２７０〜５００ｎｍの波長域の光により励起され、５００〜６００ｎｍにピーク波長を有する。但し、前記第３の発光スペクトルを有する蛍光体は、上記の蛍光体に限定されず、種々の蛍光体が使用できる。
【００７４】
前記イットリウム・アルミニウム酸化物蛍光体等を含有することにより、所望の色度に調節することができるからである。セリウムで賦活されたイットリウム・アルミニウム酸化物蛍光体等は、発光素子１０により発光された青色光の一部を吸収して黄色領域の光を発光する。ここで、発光素子１０により発光された青色光と、イットリウム・アルミニウム酸化物蛍光体の黄色光とが混色により青白い白色に発光する。従って、このイットリウム・アルミニウム酸化物蛍光体と前記窒化物蛍光体とを透光性を有するコーティング部材と一緒に混合した蛍光体１１と、発光素子１０により発光された青色光とを組み合わせることにより暖色系の白色の発光装置を提供することができる。この暖色系の白色の発光装置は、平均演色評価数Ｒａが７５乃至９５であり色温度が２０００乃至８０００Ｋである。特に好ましいのは、平均演色評価数Ｒａ及び色温度が色度図における黒体放射の軌跡上に位置する白色の発光装置である。但し、所望の色温度及び平均演色評価数の発光装置を提供するため、イットリウム・アルミニウム酸化物蛍光体及び本発明に係る蛍光体の配合量を、適宜変更することもできる。この暖色系の白色の発光装置は、特殊演色評価数Ｒ９の改善を図っている。従来の青色発光素子とセリウムで賦活されたイットリウム・アルミニウム酸化物蛍光体との組合せの白色に発光する発光装置は、特殊演色評価数Ｒ９がほぼ０に近く、赤み成分が不足していた。そのため特殊演色評価数Ｒ９を高めることが解決課題となっていたが、本発明に係る蛍光体をイットリウム・アルミニウム酸化物蛍光体中に含有することにより、特殊演色評価数Ｒ９を６０乃至７０まで高めることができる。ここで、特殊演色評価数Ｒ９は、平均演色評価数とは別の７種類の色票の個々の色ズレを基礎として求めるもので、７種類の平均ではない。７種類の色票としては、比較的彩度の高い赤、黄、緑、青、人の皮膚（白人）、木の葉の緑、人の皮膚（日本人）を代表するものが選ばれている。それぞれ順に、Ｒ９、Ｒ１０、Ｒ１１、Ｒ１２、Ｒ１３、Ｒ１４、Ｒ１５と呼ばれる。このうち、Ｒ９は、赤を示す色票である。
【００７５】
また、本発明の窒化物蛍光体と組み合わせて用いられる蛍光体は、イットリウム・アルミニウム酸化物蛍光体等に限定されるものではなく、該蛍光体と同様の目的を有する青色領域から、緑色領域、黄色領域、赤色領域までに第２の発光スペクトルを少なくとも１以上有する蛍光体も、前記窒化物蛍光体と組み合わせて使用することができる。これにより、光の混色の原理による白色に発光する発光装置を提供することができる。窒化物蛍光体と組み合わせて用いられる蛍光体は、緑色系発光蛍光体ＳｒＡｌ_２Ｏ_４：Ｅｕ、Ｙ_２ＳｉＯ_５：Ｃｅ，Ｔｂ、ＭｇＡｌ_１１Ｏ_１９：Ｃｅ，Ｔｂ、Ｓｒ_７Ａｌ_１２Ｏ_２５：Ｅｕ、（Ｍｇ、Ｃａ、Ｓｒ、Ｂａのうち少なくとも１以上）Ｇａ_２Ｓ_４：Ｅｕ、青色系発光蛍光体Ｓｒ_５（ＰＯ_４）_３Ｃｌ：Ｅｕ、（ＳｒＣａＢａ）_５（ＰＯ_４）_３Ｃｌ：Ｅｕ、（ＢａＣａ）_５（ＰＯ_４）_３Ｃｌ：Ｅｕ、（Ｍｇ、Ｃａ、Ｓｒ、Ｂａのうち少なくとも１以上）_２Ｂ_５Ｏ_９Ｃｌ：Ｅｕ，Ｍｎ、（Ｍｇ、Ｃａ、Ｓｒ、Ｂａのうち少なくとも１以上）（ＰＯ_４）_６Ｃｌ_２：Ｅｕ，Ｍｎ、赤色系発光蛍光体Ｙ_２Ｏ_２Ｓ：Ｅｕ、Ｌａ_２Ｏ_２Ｓ：Ｅｕ、Ｙ_２Ｏ_３：Ｅｕ、Ｇｄ_２Ｏ_２Ｓ：Ｅｕなどをドープすることにより、所望の発光スペクトルを得ることができる。但し、緑色、青色、赤色等の発光蛍光体は、上記の蛍光体に限定されず、種々の蛍光体を使用することができる。
【００７６】
（励起光源）
励起光源は、半導体発光素子、レーザーダイオード、アーク放電の陽光柱において発生する紫外放射、グロー放電の陽光柱において発生する紫外放射などがある。特に、近紫外領域の光を放射する半導体発光素子及びレーザーダイオード、青色に発光する半導体発光素子及びレーザーダイオード、青緑色に発光する半導体発光素子及びレーザーダイオードが好ましい。
【００７７】
近紫外から可視光の短波長領域の光は、２７０ｎｍから５００ｎｍ付近までの波長領域をいう。
【００７８】
（発光素子）
本発明において発光素子は、蛍光体を効率よく励起可能な発光波長を発光できる発光層を有する半導体発光素子が好ましい。このような半導体発光素子の材料として、ＢＮ、ＳｉＣ、ＺｎＳｅやＧａＮ、ＩｎＧａＮ、ＩｎＡｌＧａＮ、ＡｌＧａＮ、ＢＡｌＧａＮ、ＢＩｎＡｌＧａＮなど種々の半導体を挙げることができる。同様に、これらの元素に不純物元素としてＳｉやＺｎなどを含有させ発光中心とすることもできる。蛍光体を効率良く励起できる紫外領域から可視光の短波長を効率よく発光可能な発光層の材料として特に、窒化物半導体（例えば、ＡｌやＧａを含む窒化物半導体、ＩｎやＧａを含む窒化物半導体としてＩｎ_ＸＡｌ_ＹＧａ_{１−Ｘ−Ｙ}Ｎ、０＜Ｘ＜１、０＜Ｙ＜１、Ｘ＋Ｙ≦１）がより好適に挙げられる。
【００７９】
また、半導体の構造としては、ＭＩＳ接合、ＰＩＮ接合やｐｎ接合などを有するホモ構造、ヘテロ構造あるいはダブルへテロ構成のものが好適に挙げられる。半導体層の材料やその混晶比によって発光波長を種々選択することができる。また、半導体活性層を量子効果が生ずる薄膜に形成させた単一量子井戸構造や多重量子井戸構造とすることでより出力を向上させることもできる。
【００８０】
窒化物半導体を使用した場合、半導体用基板にはサファイア、スピネル、ＳｉＣ、Ｓｉ、ＺｎＯ、ＧａＡｓ、ＧａＮ等の材料が好適に用いられる。結晶性の良い窒化物半導体を量産性よく形成させるためにはサファイア基板を利用することが好ましい。このサファイア基板上にＨＶＰＥ法やＭＯＣＶＤ法などを用いて窒化物半導体を形成させることができる。サファイア基板上にＧａＮ、ＡｌＮ、ＧａＡＩＮ等の低温で成長させ非単結晶となるバッファ層を形成しその上にｐｎ接合を有する窒化物半導体を形成させる。
【００８１】
窒化物半導体を使用したｐｎ接合を有する紫外領域を効率よく発光可能な発光素子例として、バッファ層上に、サファイア基板のオリフラ面と略垂直にＳｉＯ_２をストライプ状に形成する。ストライプ上にＨＶＰＥ法を用いてＧａＮをＥＬＯＧ（Epitaxial Lateral Over Grows GaN）成長させる。続いて、ＭＯＣＶＤ法により、ｎ型窒化ガリウムで形成した第１のコンタクト層、ｎ型窒化アルミニウム・ガリウムで形成させた第１のクラッド層、窒化インジウム・アルミニウム・ガリウムの井戸層と窒化アルミニウム・ガリウムの障壁層を複数積層させた多重量子井戸構造とされる活性層、ｐ型窒化アルミニウム・ガリウムで形成した第２のクラッド層、ｐ型窒化ガリウムで形成した第２のコンタクト層を順に積層させたダブルへテロ構成などの構成が挙げられる。活性層をリッジストライプ形状としガイド層で挟むと共に共振器端面を設け本発明に利用可能な半導体レーザー素子とすることもできる。
【００８２】
窒化物半導体は、不純物をドープしない状態でｎ型導電性を示す。発光効率を向上させるなど所望のｎ型窒化物半導体を形成させる場合は、ｎ型ドーパントとしてＳｉ、Ｇｅ、Ｓｅ、Ｔｅ、Ｃ等を適宜導入することが好ましい。一方、ｐ型窒化物半導体を形成させる場合は、ｐ型ドーパントであるＺｎ、Ｍｇ、Ｂｅ、Ｃａ、Ｓｒ、Ｂａ等をドープさせることが好ましい。窒化物半導体は、ｐ型ドーパントをドープしただけではｐ型化しにくいためｐ型ドーパント導入後に、炉による加熱やプラズマ照射等により低抵抗化させることが好ましい。サファイア基板をとらない場合は、第１のコンタクト層の表面までｐ型側からエンチングさせ各コンタクト層を露出させる。各コンタクト層上にそれぞれ電極形成後、半導体ウエハーからチップ状にカットさせることで窒化物半導体からなる発光素子を形成させることができる。
【００８３】
発光装置において、量産性よく形成させるためには透光性封止部材を利用して形成させることが好ましい。特に、蛍光体１１を混合して封止することため、透光性の樹脂が好ましい。この場合蛍光体からの発光波長と透光性樹脂の劣化等を考慮して、発光素子は紫外域に発光スペクトルを有し、その主発光波長は３６０ｎｍ以上４２０ｎｍ以下のものや、４５０ｎｍ以上４７０ｎｍ以下のものも使用することができる。
【００８４】
ここで、半導体発光素子は、不純物濃度１０^１７〜１０^２０／ｃｍ^３で形成されるｎ型コンタクト層のシート抵抗と、透光性ｐ電極のシート抵抗とが、Ｒｐ≧Ｒｎの関係となるように調節されていることが好ましい。ｎ型コンタクト層は、例えば膜厚３〜１０μｍ、より好ましくは４〜６μｍに形成されると好ましく、そのシート抵抗は１０〜１５Ω／□と見積もられることから、このときのＲｐは前記シート抵抗値以上のシート抵抗値を有するように薄膜に形成するとよい。また、透光性ｐ電極は、膜厚が１５０μｍ以下の薄膜で形成されていてもよい。また、ｐ電極は金属以外のＩＴＯ、ＺｎＯも使用することができる。ここで透光性ｐ電極の代わりに、メッシュ状電極などの複数の光取り出しよ用開口部を備えた電極も使用することができる。
【００８５】
また、透光性ｐ電極が、金および白金族元素の群から選択された１種と、少なくとも１種の他の元素とから成る多層膜または合金で形成される場合には、含有されている金または白金族元素の含有量により透光性ｐ電極のシート抵抗の調整をすると安定性および再現性が向上される。金または金属元素は、本発明に使用する半導体発光素子の波長領域における吸収係数が高いので、透光性ｐ電極に含まれる金又は白金族元素の量は少ないほど透過性がよくなる。従来の半導体発光素子はシート抵抗の関係がＲｐ≦Ｒｎであったが、本発明ではＲｐ≧Ｒｎであるので、透光性ｐ電極は従来のものと比較して薄膜に形成されることとなるが、このとき金または白金族元素の含有量を減らすことで薄膜化が容易に行える。
【００８６】
上述のように、本発明で用いられる半導体発光素子は、ｎ型コンタクト層のシート抵抗ＲｎΩ／□と、透光性ｐ電極のシート抵抗ＲｐΩ／□とが、Ｒｐ≧Ｒｎの関係を成していることが好ましい。半導体発光素子として形成した後にＲｎを測定するのは難しく、ＲｐとＲｎとの関係を知るのは実質上不可能であるが、発光時の光強度分布の状態からどのようなＲｐとＲｎとの関係になっているのかを知ることができる。
【００８７】
透光性ｐ電極とｎ型コンタクト層とがＲｐ≧Ｒｎの関係であるとき、前記透光性ｐ電極上に接して延長伝導部を有するｐ側台座電極を設けると、さらなる外部量子効率の向上を図ることができる。延長伝導部の形状及び方向に制限はなく、延長伝導部が衛線上である場合、光を遮る面積が減るので好ましいが、メッシュ状でもよい。また形状は、直線状以外に、曲線状、格子状、枝状、鉤状でもよい。このときｐ側台座電極の総面積に比例して遮光効果が増大するため、遮光効果が発光増強効果を上回らないように延長導電部の線幅及び長さを設計するのがよい。
【００８８】
（発光素子）
上述の紫外光励起の発光素子と異なる青色光励起の発光素子を使用することもできる。青色光励起の発光素子１０は、ＩＩＩ属窒化物系化合物発光素子であることが好ましい。発光素子１０は、例えばサファイア基板１上にＧａＮバッファ層を介して、Ｓｉがアンドープのｎ型ＧａＮ層、Ｓｉがドープされたｎ型ＧａＮからなるｎ型コンタクト層、アンドープＧａＮ層、多重量子井戸構造の発光層（ＧａＮ障壁層／ＩｎＧａＮ井戸層の量子井戸構造）、Ｍｇがドープされたｐ型ＧａＮからなるｐ型ＧａＮからなるｐクラッド層、Ｍｇがドープされたｐ型ＧａＮからなるｐ型コンタクト層が順次積層された積層構造を有し、以下のように電極が形成されている。但し、この構成と異なる発光素子１０も使用できる。
【００８９】
ｐオーミック電極は、ｐ型コンタクト層上のほぼ全面に形成され、そのｐオーミック電極上の一部にｐパッド電極３が形成される。
【００９０】
また、ｎ電極は、エッチングによりｐ型コンタクト層からアンドープＧａＮ層を除去してｎ型コンタクト層の一部を露出させ、その露出された部分に形成される。
【００９１】
なお、本実施の形態では、多重量子井戸構造の発光層を用いたが、本発明は、これに限定されるものではなく、例えば、ＩｎＧａＮを利用した単一量子井戸構造としても良いし、Ｓｉ、Ｚｎ等のｎ型、ｐ型不純物がドープされたＧａＮを利用しても良い。
【００９２】
また、発光素子１０の発光層は、Ｉｎの含有量を変化させることにより、４２０ｎｍから４９０ｎｍの範囲において主発光ピークを変更することができる。また、発光波長は、上記範囲に限定されるものではなく、３６０〜５５０ｎｍに発光波長を有しているものを使用することができる。
【００９３】
（コーティング部材）
コーティング部材１２（光透光性材料）は、リードフレーム１３のカップ内に設けられるものであり発光素子１０の発光を変換する蛍光体１１と混合して用いられる。コーティング部材１２の具体的材料としては、エポキシ樹脂、ユリア樹脂、シリコーン樹脂などの温度特性、耐候性に優れた透明樹脂、シリカゾル、ガラス、無機バインダーなどが用いられる。また、蛍光体１１と共に拡散剤、チタン酸バリウム、酸化チタン、酸化アルミニウムなどを含有させても良い。また、光安定化剤や着色剤を含有させても良い。
【００９４】
（リードフレーム）
リードフレーム１３は、マウントリード１３ａとインナーリード１３ｂとから構成される。
【００９５】
マウントリード１３ａは、発光素子１０を配置させるものである。マウントリード１３ａの上部は、カップ形状になっており、カップ内に発光素子１０をダイボンドし、該発光素子１０の外周面を、カップ内を前記蛍光体１１と前記コーティング部材１２とで覆っている。カップ内に発光素子１０を複数配置しマウントリード１３ａを発光素子１０の共通電極として利用することもできる。この場合、十分な電気伝導性と導電性ワイヤ１４との接続性が求められる。発光素子１０とマウントリード１３ａのカップとのダイボンド（接着）は、熱硬化性樹脂などによって行うことができる。熱硬化性樹脂としては、エポキシ樹脂、アクリル樹脂、イミド樹脂などが挙げられる。また、フェースダウン発光素子１０などによりマウントリード１３ａとダイボンドすると共に電気的接続を行うには、Ａｇ―エースと、カーボンペースト、金属バンプなどを用いることができる。また、無機バインダーを用いることもできる。
【００９６】
インナーリード１３ｂは、マウントリード１３ａ上に配置された発光素子１０の電極３から延びる導電性ワイヤ１４との電気的接続を図るものである。インナーリード１３ｂは、マウントリード１３ａとの電気的接触によるショートを避けるため、マウントリード１３ａから離れた位置に配置することが好ましい。マウントリード１３ａ上に複数の発光素子１０を設けた場合は、各導電性ワイヤ同士が接触しないように配置できる構成にする必要がある。インナーリード１３ｂは、マウントリード１３ａと同様の材質を用いることが好ましく、鉄、銅、鉄入り銅、金、白金、銀などを用いることができる。
【００９７】
（導電性ワイヤ）
導電性ワイヤ１４は、発光素子１０の電極３とリードフレーム１３とを電気的に接続するものである。導電性ワイヤ１４は、電極３とオーミック性、機械的接続性、電気導電性及び熱伝導性が良いものが好ましい。導電性ワイヤ１４の具体的材料としては、金、銅、白金、アルミニウムなどの金属及びそれらの合金などが好ましい。
【００９８】
（モールド部材）
モールド部材１５は、発光素子１０、蛍光体１１、コーティング部材１２、リードフレーム１３及び導電性ワイヤ１４などを外部から保護するために設けられている。モールド部材１５は、外部からの保護目的の他に、視野角を広げたり、発光素子１０からの指向性を緩和したり、発光を収束、拡散させたりする目的も併せ持っている。これらの目的を達成するためモールド部材は、所望の形状にすることができる。また、モールド部材１５は、凸レンズ形状、凹レンズ形状の他、複数積層する構造であっても良い。モールド部材１５の具体的材料としては、エポキシ樹脂、ユリア樹脂、シリコーン樹脂、シリカゾル、ガラスなどの透光性、耐候性、温度特性に優れた材料を使用することができる。モールド部材１５には、拡散剤、着色剤、紫外線吸収剤や蛍光体を含有させることもできる。拡散剤としては、チタン酸バリウム、酸化チタン、酸化アルミニウム等が好ましい。コーティング部材１２との材質の反発性を少なくするため、屈折率を考慮するため、同材質を用いることが好ましい。
【００９９】
以下、本発明に係る蛍光体、発光装置について実施例を挙げて説明するが、この実施例に限定されるものではない。
【０１００】
なお、温度特性は、２５℃の発光輝度を１００％とする相対輝度で示す。粒径は、Ｆ．Ｓ．Ｓ．Ｓ．Ｎｏ．（Fisher Sub Sieve Sizer's No.）という空気透過法による値である。
【０１０１】
【実施例】
（実施例１乃至４）
表１は、実施例１乃至４の窒化物蛍光体の特性を示す。
【０１０２】
また、図３は、実施例３の窒化物蛍光体をＥｘ＝４６０ｎｍで励起したときの発光スペクトルを示す図である。図４は、実施例３の窒化物蛍光体の励起スペクトルを示す図である。図５は、実施例３の窒化物蛍光体の反射スペクトルを示す図である。図６は、実施例３の窒化物蛍光体を撮影したＳＥＭ写真である。図６（ａ）は、１０００倍で撮影している。図６（ｂ）は、５０００倍で撮影している。
【０１０３】
【表１】

【０１０４】
実施例１乃至４は、（Ｃａ_０．９７Ｅｕ_０．０３）_２Ｓｉ_５Ｎ_８で表される窒化物蛍光体であって、Ｂを所定量含有している。実施例１の窒化物蛍光体を基準に、発光輝度、量子効率を相対値で示す。
【０１０５】
実施例１乃至４において、Ｅｕ濃度は０．０３である。Ｅｕ濃度は、Ｃａのモル濃度に対してのモル比である。
【０１０６】
まず、原料のＣａを１〜１５μｍに粉砕し、窒素雰囲気中で窒化した。その後、Ｃａの窒化物を０．１〜１０μｍに粉砕した。原料のＣａを２０ｇ秤量し、窒化を行った。
【０１０７】
同様に、原料のＳｉを１〜１５μｍに粉砕し、窒素雰囲気中で窒化した。その後、Ｓｉの窒化物を０．１〜１０μｍに粉砕した。原料のＳｉを２０ｇ秤量し、窒化を行った。
【０１０８】
次に、Ｅｕの化合物Ｅｕ_２Ｏ_３に、Ｂの化合物Ｈ_３ＢＯ_３を湿式混合した。Ｅｕの化合物Ｅｕ_２Ｏ_３を２０ｇ、Ｈ_３ＢＯ_３を所定量秤量した。Ｈ_３ＢＯ_３を溶液とした後、Ｅｕ_２Ｏ_３に混合し、乾燥した。乾燥後、７００℃〜８００℃で約５時間、酸化雰囲気中で焼成を行った。これによりＢが添加された酸化ユウロピウムが製造された。この焼成後、ＥｕとＢとの混合物を０．１〜１０μｍに粉砕した。
【０１０９】
Ｃａの窒化物、Ｓｉの窒化物、ＥｕとＢの混合物を、窒素雰囲気中で混合した。実施例１乃至４において、原料である窒化カルシウムＣａ_３Ｎ_２：窒化ケイ素Ｓｉ_３Ｎ_４：酸化ユウロピウムＥｕ_２Ｏ_３の各元素の混合比率（モル比）は、Ｃａ：Ｓｉ：Ｅｕ＝１．９４：５：０．０６となるように調整する。この混合比率になるように、Ｃａ_３Ｎ_２（分子量１４８．２６）、Ｓｉ_３Ｎ_４（分子量１４０．３１）を、ＥｕとＢの混合物を秤量し、混合を行った。Ｂの添加量は、最終組成の分子量に対して１０ｐｐｍ、２００ｐｐｍ、５００ｐｐｍ、１０００ｐｐｍである。
【０１１０】
上記化合物を混合し、焼成を行った。焼成条件は、アンモニア雰囲気中、上記化合物を坩堝に投入し、室温から徐々に昇温して、約１６００℃で約５時間、焼成を行い、ゆっくりと室温まで冷却した。一般に、添加していたＢは、焼成を行っても組成中に残留しているが、焼成によりＢの一部が飛散して、最終生成物中に、当初の添加量よりも少ない量が残存している場合がある。
【０１１１】
実施例１乃至４の窒化物蛍光体の発光輝度及び量子効率は、実施例１を１００％とし、これを基準に相対値で表す。
【０１１２】
表１よりＢを１００００ｐｐｍ以下添加したとき、特に１ｐｐｍ以上１０００ｐｐｍ以下添加したとき、発光輝度、量子効率とも高い値を示した。
【０１１３】
実施例１乃至４の窒化物蛍光体の平均粒径は、６．３乃至７．８μｍであった。また、実施例中の蛍光体には、酸素が、０．５〜１．２重量％含有されていた。
【０１１４】
実施例に係る窒化物蛍光体は、窒化ホウ素材質の坩堝を用い、アンモニア雰囲気中で焼成を行っている。
【０１１５】
実施例に係る窒化物蛍光体は、温度特性が極めて良好である。実施例３の窒化物蛍光体の温度特性は、１００℃のとき９７％、２００℃のとき７０％であった。
【０１１６】
実施例１乃至４の窒化物蛍光体は、４６０ｎｍの励起光源により励起させたとき６０９ｎｍ近傍にピーク波長を有する。
【０１１７】
（実施例５乃至９）
表２は、実施例５乃至９の窒化物蛍光体の特性を示す。
【０１１８】
【表２】

【０１１９】
実施例５乃至９は、（Ｃａ_０．９７Ｅｕ_０．０３）_２Ｓｉ_５Ｎ_８で表される窒化物蛍光体であって、Ｂを所定量含有している。実施例５の窒化物蛍光体を基準に、発光輝度、量子効率を相対値で示す。
【０１２０】
実施例５乃至９において、Ｅｕ濃度は０．０３である。Ｅｕ濃度は、Ｃａのモル濃度に対してのモル比である。
【０１２１】
実施例５乃至９は、実施例１乃至４と製造方法が異なる。
【０１２２】
まず、原料のＣａを１〜１５μｍに粉砕し、窒素雰囲気中で窒化した。その後、Ｃａの窒化物を０．１〜１０μｍに粉砕した。原料のＣａを２０ｇ秤量し、窒化を行った。
【０１２３】
同様に、原料のＳｉを１〜１５μｍに粉砕し、窒素雰囲気中で窒化した。その後、Ｓｉの窒化物を０．１〜１０μｍに粉砕した。原料のＳｉを２０ｇ秤量し、窒化を行った。
【０１２４】
Ｃａの窒化物、Ｓｉの窒化物、Ｅｕの化合物Ｅｕ_２Ｏ_３、Ｂの化合物Ｈ_３ＢＯ_３を乾式で混合を行った。Ｅｕの化合物Ｅｕ_２Ｏ_３を２０ｇ、Ｈ_３ＢＯ_３を所定量秤量したものを使用した。実施例５乃至９において、原料である窒化カルシウムＣａ_３Ｎ_２：窒化ケイ素Ｓｉ_３Ｎ_４：酸化ユウロピウムＥｕ_２Ｏ_３の各元素の混合比率（モル比）は、Ｃａ：Ｓｉ：Ｅｕ＝１．９４：５：０．０６となるように調整する。Ｂの添加量は、最終組成の分子量に対して１０ｐｐｍ、２００ｐｐｍ、５００ｐｐｍ、１０００ｐｐｍ、１００００ｐｐｍである。
【０１２５】
上記化合物を混合し、焼成を行った。焼成条件は、アンモニア雰囲気中、上記化合物を坩堝に投入し、室温から徐々に昇温して、約１６００℃で約５時間、焼成を行い、ゆっくりと室温まで冷却した。
【０１２６】
実施例５乃至９の窒化物蛍光体の発光輝度及び量子効率は、実施例５を１００％とし、これを基準に相対値で表す。
【０１２７】
表２よりＢを１００００ｐｐｍ以下添加したとき、発光輝度、量子効率とも高い値を示した。
【０１２８】
実施例５乃至９の窒化物蛍光体の平均粒径は、６．０乃至７．２μｍであった。酸素濃度は、０．７〜１．０重量％であった。
【０１２９】
（実施例１０乃至１５）
表３は、実施例１０乃至１５の窒化物蛍光体の特性を示す。
【０１３０】
【表３】

【０１３１】
実施例１０乃至１５は、（Ｓｒ_０．９７Ｅｕ_０．０３）_２Ｓｉ_５Ｎ_８で表される窒化物蛍光体であって、Ｂを所定量含有している。実施例１０の窒化物蛍光体を基準に、発光輝度、量子効率を相対値で示す。
【０１３２】
実施例１０乃至１５において、Ｅｕ濃度は０．０３である。Ｅｕ濃度は、Ｓｒのモル濃度に対してのモル比である。
【０１３３】
実施例１０乃至１５は、実施例１乃至４と、ほぼ同じ製造方法により製造を行った。実施例１乃至４で使用したＣａに代えて、実施例１０乃至１５は、Ｓｒを使用した。実施例１乃至４は約１６００℃で焼成を行ったが、実施例１０乃至１５は約１３５０℃で焼成を行った。
【０１３４】
表３よりＢを１００００ｐｐｍ以下添加したとき、特に１０ｐｐｍ以上５０００ｐｐｍ以下添加したとき、発光輝度、量子効率とも高い値を示した。
【０１３５】
実施例１０乃至１５の窒化物蛍光体の平均粒径は、２．１乃至４．７μｍであった。酸素濃度は、０．３〜１．１重量％であった。
【０１３６】
（実施例１６乃至２０）
表４は、実施例１６乃至２０の窒化物蛍光体の特性を示す。
【０１３７】
【表４】

【０１３８】
実施例１６乃至２０は、（Ｓｒ_０．９７Ｅｕ_０．０３）_２Ｓｉ_５Ｎ_８で表される窒化物蛍光体であって、Ｂを所定量含有している。実施例１６の窒化物蛍光体を基準に、発光輝度、量子効率を相対値で示す。
【０１３９】
実施例１６乃至２０において、Ｅｕ濃度は０．０３である。Ｅｕ濃度は、Ｓｒのモル濃度に対してのモル比である。
【０１４０】
実施例１６乃至２０は、実施例１乃至４と、ほぼ同じ製造方法により製造を行った。実施例１乃至４で使用したＣａに代えて、実施例１６乃至２０は、Ｓｒを使用した。
【０１４１】
表４よりＢを１０００ｐｐｍ以下添加したとき、特に１０ｐｐｍ以上５００ｐｐｍ以下添加したとき、発光輝度、量子効率とも高い値を示した。
【０１４２】
実施例１６乃至２０の窒化物蛍光体の平均粒径は、３．２乃至３．９μｍであった。
【０１４３】
（実施例２１乃至２６）
表５は、実施例２１乃至２６の窒化物蛍光体の特性を示す。
【０１４４】
【表５】

【０１４５】
実施例２１乃至２６は、（Ｃａ_{０．２８５}Ｓｒ_{０．６８５}Ｅｕ_０．０３）_２Ｓｉ_５Ｎ_８で表される窒化物蛍光体であって、Ｂを所定量含有している。実施例２１の窒化物蛍光体を基準に、発光輝度、量子効率を相対値で示す。
【０１４６】
実施例２１乃至２６において、Ｅｕ濃度は０．０３である。Ｅｕ濃度は、ＣａとＳｒとの混合物のモル濃度に対してのモル比である。
【０１４７】
実施例２１乃至２６は、実施例１乃至４と、ほぼ同じ製造方法により製造を行った。実施例１乃至４で使用したＣａに代えて、実施例２１乃至２６は、ＣａとＳｒの混合物を用い、ＣａとＳｒのモル比は、３：７である。
【０１４８】
表５よりＢを５０００ｐｐｍ以下添加したとき、特に１０ｐｐｍ以上１０００ｐｐｍ以下添加したとき、発光輝度、量子効率とも高い値を示した。
【０１４９】
実施例２１乃至２６の窒化物蛍光体の平均粒径は、１．６乃至２．０μｍであった。
【０１５０】
＜発光装置１＞
発光装置１は、赤味成分を付加した白色発光装置に関する。図１は、本発明に係る発光装置１を示す図である。図７は、本発明に係る発光装置１の色度座標を示す図である。
【０１５１】
発光装置１は、サファイア基板１上にｎ型及びｐ型のＧａＮ層の半導体層２が形成され、該ｎ型及びｐ型の半導体層２に電極３が設けられ、該電極３は、導電性ワイヤ１４によりリードフレーム１３と導電接続されている。発光素子１０の上部は、蛍光体１１及びコーティング部材１２で覆われ、リードフレーム１３、蛍光体１１及びコーティング部材１２等の外周をモールド部材１５で覆っている。半導体層２は、サファイア基板１上にｎ^＋ＧａＮ：Ｓｉ、ｎ−ＡｌＧａＮ：Ｓｉ、ｎ−ＧａＮ、ＧａＩｎＮ ＱＷｓ、ｐ−ＧａＮ：Ｍｇ、ｐ−ＡｌＧａＮ：Ｍｇ、ｐ−ＧａＮ：Ｍｇの順に積層されている。該ｎ^＋ＧａＮ：Ｓｉ層の一部はエッチングされてｎ型電極が形成されている。該ｐ−ＧａＮ：Ｍｇ層上には、ｐ型電極が形成されている。リードフレーム１３は、鉄入り銅を用いる。マウントリード１３ａの上部には、発光素子１０を積載するためのカップが設けられており、該カップのほぼ中央部の底面に該発光素子１０がダイボンドされている。導電性ワイヤ１４には、金を用い、電極３と導電性ワイヤ１４を導電接続するためのバンプ４には、Ｎｉメッキを施す。蛍光体１１には、実施例４９の蛍光体とＹＡＧ系蛍光体とを混合する。コーティング部材１２には、エポキシ樹脂と拡散剤、チタン酸バリウム、酸化チタン及び前記蛍光体１１を所定の割合で混合したものを用いる。モールド部材１５は、エポキシ樹脂を用いる。この砲弾型の発光装置１は、モールド部材１５の半径２〜４ｍｍ、高さ約７〜１０ｍｍの上部が半球の円筒型である。
【０１５２】
発光装置１に電流を流すと、ほぼ４６０ｎｍで励起する第１の発光スペクトルを有する青色発光素子１０が発光し、この第１の発光スペクトルを、半導体層２を覆う蛍光体１１が色調変換を行い、前記第１の発光スペクトルと異なる第２の発光スペクトルを有する。また、蛍光体１１中に含有されているＹＡＧ系蛍光体は、第１の発光スペクトルにより、第３の発光スペクトルを示す。この第１、第２及び第３の発光スペクトルが互いに混色となり赤みを帯びた白色に発光する発光装置１を提供することができる。
【０１５３】
本発明に係る発光装置１の蛍光体１１は、実施例１５の蛍光体と、コーティング部材１２と、セリウムで賦活されたイットリウム・ガドリニウム・アルミニウム酸化物蛍光体（Ｙ−Ｇｄ−Ａｌ−Ｏ：Ｃｅ）とを混合した蛍光体を用いる。実施例１５は、Ｂを添加したＣａ_２Ｓｉ_５Ｎ_７：Ｅｕの窒化物蛍光体である。一方、比較となる発光装置は、実施例１５の蛍光体を含有しておらず、セリウムで賦活されたイットリウム・ガドリニウム・アルミニウム酸化物蛍光体のみの蛍光体を用いる。本発明に係る発光装置１及び比較となる発光装置は、（Ｙ_０．８Ｇｄ_０．２）_３Ａｌ_５Ｏ_１２：Ｃｅの蛍光体を使用する。比較となる発光装置は、青色発光素子と（Ｙ−Ｇｄ−Ａｌ−Ｏ：Ｃｅ）の蛍光体との組合せで発光を行っている。セリウムで賦活されたイットリウム・ガドリニウム・アルミニウム酸化物蛍光体の代わりに、セリウムで賦活されたイットリウム・ガリウム・アルミニウム酸化物蛍光体Ｙ_３（Ａｌ_０．８Ｇａ_０．２）_５Ｏ_１２：Ｃｅを使用することが好ましい。
【０１５４】
発光装置１の蛍光体１１の重量比は、コーティング部材：（Ｙ−Ｇｄ−Ａｌ−Ｏ：Ｃｅ）の蛍光体：実施例１５の蛍光体＝１０：３．８：０．６である。一方、発光装置２の蛍光体の重量比は、コーティング部材：（Ｙ−Ｇｄ−Ａｌ−Ｏ：Ｃｅ）の蛍光体＝１０：３．６の重量比で混合している。
【０１５５】
本発明に係る発光装置１と、青色発光素子及びＹ−Ｇｄ−Ａｌ−Ｏ：Ｃｅの蛍光体とを用いた発光装置とを比較する。表６は、発光装置１と比較となる発光装置の測定結果を示す。
【０１５６】
【表６】

【０１５７】
比較となる発光装置と比較して色調はほとんど変化していないが、演色性が改善されている。比較となる発光装置では、特殊演色評価数Ｒ９が不足していたが、発光装置１では、Ｒ９の改善が行われている。特殊演色評価数Ｒ９は、比較的彩度の高い赤色の標準色からの色ずれを測定した値である。また、他の特殊演色評価数Ｒ８、Ｒ１０等もより１００％に近い値に改善されている。ランプ効率は、高い数値を示している。
【０１５８】
コーティング部材１２と共に混合する蛍光体１１は、Ｙ−Ｇｄ−Ａｌ−Ｏ：Ｃｅの蛍光体と、窒化物蛍光体と、を混合して用いている。該蛍光体は、密度が異なるため、密度が高く、粒径が小さいものほど、一般には、早く沈降する。そのため、Ｙ−Ｇｄ−Ａｌ−Ｏ：Ｃｅの蛍光体が先に沈降し、窒化物蛍光体が次に沈降する。よって、同じコーティング部材１２と蛍光体１１とを用いていても、発光装置の色調に色むらが生じることとなる。そのため、窒化物蛍光体の粒径を所定の大きさに制御し、Ｙ−Ｇｄ−Ａｌ−Ｏ：Ｃｅの蛍光体と窒化物蛍光体とが、ほぼ同時に沈降することによって、色むらを生じないように改善することができる。
【０１５９】
＜発光装置２＞
図８は、本発明に係る発光装置２を示す図である。発光装置２は、表面実装タイプの発光装置である。該発光装置２に使用する発光素子１０１は、青色光励起の発光素子を使用するが、３８０〜４００ｎｍの紫外光励起の発光素子も使用することができ、発光素子１０１は、これに限定されない。
【０１６０】
発光層としてピーク波長が青色領域にある４６０ｎｍのＩｎＧａＮ系半導体層を有する発光素子１０１を用いる。該発光素子１０１には、ｐ型半導体層とｎ型半導体層とが形成されており（図示しない）、該ｐ型半導体層とｎ型半導体層には、リード電極１０２へ連結される導電性ワイヤ１０４が形成されている。リード電極１０２の外周を覆うように絶縁封止材１０３が形成され、短絡を防止している。発光素子１０１の上方には、パッケージ１０５の上部にあるリッド１０６から延びる透光性の窓部１０７が設けられている。該透光性の窓部１０７の内面には、本発明に係る蛍光体１０８及びコーティング部材１０９の均一混合物がほぼ全面に塗布されている。発光装置１では、実施例１の蛍光体を使用する。パッケージ１０５は、角部がとれた一辺が８ｍｍ〜１２ｍｍの正方形である。
【０１６１】
発光素子１０１で青色に発光した発光スペクトルは、反射板で反射した間接的な発光スペクトルと、発光素子１０１から直接射出された発光スペクトルとが、本発明の蛍光体１０８に照射され、白色に発光する蛍光体となる。
【０１６２】
以上のようにして形成された発光装置を用いて白色ＬＥＤランプを形成すると、歩留まりは９９％である。このように、本発明である発光ダイオードを使用することで、量産性良く発光装置を生産でき、信頼性が高く且つ色調ムラの少ない発光装置を提供することができる。
【０１６３】
＜発光装置３＞
図９は、本発明に係るキャップタイプの発光装置３を示す図である。
【０１６４】
発光装置１における部材と同一の部材には同一の符号を付して、その説明を省略する。
【０１６５】
発光装置３は、発光装置１のモールド部材１５の表面に、蛍光体（図示しない）を分散させた光透過性樹脂からなるキャップ１６を被せることにより構成される。キャップ１６は、蛍光体を光透過性樹脂に均一に分散させている。この蛍光体を含有する光透過性樹脂を、発光装置１のモールド部材１５の形状に嵌合する形状に成形している。または、所定の型枠内に蛍光体を含有する光透過性樹脂を入れた後、発光装置１を該型枠内に押し込み、成型する製造方法も可能である。キャップ１６の光透過性樹脂の具体的材料としては、エポキシ樹脂、ユリア樹脂、シリコーン樹脂などの温度特性、耐候性に優れた透明樹脂、シリカゾル、ガラス、無機バインダーなどが用いられる。上記の他、メラミン樹脂、フェノール樹脂等の熱硬化性樹脂を使用することができる。また、ポリエチレン、ポリプロピレン、ポリ塩化ビニル、ポリスチレン等の熱可塑性樹脂、スチレン−ブタジエンブロック共重合体、セグメント化ポリウレタン等の熱可塑性ゴム等も使用することができる。また、蛍光体と共に拡散剤、チタン酸バリウム、酸化チタン、酸化アルミニウムなどを含有させても良い。また、光安定化剤や着色剤を含有させても良い。キャップ１６に使用される蛍光体は、実施例１５を使用する。マウントリード１３ａのカップ内に用いられる蛍光体１１は、実施例１５を用いる。しかし、キャップ１６に蛍光体を用いるため、マウントリード１３ａのカップ内は、コーティング部材１２のみでもよい。
【０１６６】
このように構成された発光装置は、発光素子１０から放出された光の一部は、キャップ１６を通過する際に、実施例４３の蛍光体により波長変換される。かかる波長変換された光と、蛍光体により波長変換されなかった青色系の光とが混合され、結果として、キャップ１６の表面からは、白色系の光が外部へ放出される。
【０１６７】
【発明の効果】
以上のことから、本発明は、励起光源に、青色に発光する半導体発光素子を用いて、該半導体発光素子により照射された光が波長変換され、黄から赤領域に発光スペクトルを有する窒化物蛍光体を提供することができる。窒化物蛍光体を用いて、発光効率の良好なやや赤みを帯びた暖色系の白色の発光装置を提供することができる。
【０１６８】
また、本発明は、白色系に発光する発光装置であって、該白色系は、平均演色性評価数Ｒａが８０以上であり、特に赤みを示す特殊演色性評価数Ｒ９が７０以上である発光装置を提供することができる。これにより、演色性に優れた白色系に発光する発光装置を提供することができる。
【０１６９】
また、窒化物蛍光体と、青色に発光する蛍光体、緑色に発光する蛍光体、黄色に発光する蛍光体とを１以上混合することにより、パステルカラーなどの多色化が図られた発光装置を提供することができる。
【０１７０】
また、残光、粒径を所定の範囲に制御された窒化物蛍光体を提供することができる。
【０１７１】
さらに、発光特性、耐久性の向上が図られた窒化物蛍光体を提供することができるという極めて重要な技術的意義を有する。
【図面の簡単な説明】
【図１】 本発明に係る発光装置１を示す図である。
【図２】 本発明に係る窒化物蛍光体の製造方法を示す図である。
【図３】 実施例３の窒化物蛍光体をＥｘ＝４６０ｎｍで励起したときの発光スペクトルを示す図である。
【図４】 実施例３の窒化物蛍光体の励起スペクトルを示す図である。
【図５】 実施例３の窒化物蛍光体の反射スペクトルを示す図である。
【図６】 実施例３の窒化物蛍光体を撮影したＳＥＭ写真である。
【図７】 本発明に係る発光装置１の色度座標を示す図である。
【図８】 本発明に係る発光装置２を示す図である。
【図９】 本発明に係るキャップタイプの発光装置３を示す図である。
【符号の説明】
Ｐ１ 原料のＣａを粉砕する。
Ｐ２ 原料のＣａを窒素雰囲気中で窒化する。
Ｐ３ Ｃａの窒化物を粉砕する。
Ｐ４ 原料のＳｉを粉砕する。
Ｐ５ 原料のＳｉを窒素雰囲気中で窒化する。
Ｐ６ Ｓｉの窒化物を粉砕する。
Ｐ７ Ｅｕの化合物Ｅｕ_２Ｏ_３に、Ｂの化合物Ｈ_３ＢＯ_３を湿式混合する。
Ｐ８ Ｅｕの化合物Ｅｕ_２Ｏ_３と、Ｂの化合物Ｈ_３ＢＯ_３との混合物を、酸化雰囲気中で焼成する。
Ｐ９ ＥｕとＢの混合物を粉砕する。
Ｐ１０ Ｃａの窒化物、Ｓｉの窒化物、ＥｕとＢとの混合物を混合する。
Ｐ１１ Ｃａの窒化物、Ｓｉの窒化物、ＥｕとＢとの混合物をアンモニア雰囲気中で、焼成する。
Ｐ１２ Ｂが添加されたＣａ_２Ｓｉ_５Ｎ_８：Ｅｕで表される蛍光体。
１ 基板
２ 半導体層
３ 電極
４ バンプ
１０ 発光素子
１１ 蛍光体
１２ コーティング部材
１３ リードフレーム
１３ａ マウントリード
１３ｂ インナーリード
１４ 導電性ワイヤ
１５ モールド部材
１０１ 発光素子
１０２ リード電極
１０３ 絶縁封止材
１０４ 導電性ワイヤ
１０５ パッケージ
１０６ リッド
１０７ 窓部
１０８ 蛍光体
１０９ コーティング部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light emitting device used for illumination such as a semiconductor light emitting element and a fluorescent lamp, a display, a backlight for liquid crystal, and the like, and particularly to a nitride phosphor used for the light emitting device.
[0002]
[Prior art]
A light-emitting device using a semiconductor element emits light with a small color, high power efficiency, and vivid colors. In addition, since the light-emitting element used for the light-emitting element lamp is a semiconductor element, there is no fear of a broken ball. Further, it has excellent initial driving characteristics and is strong against vibration and repeated on / off lighting. Because of such excellent characteristics, semiconductor light emitting devices are used as various light sources.
[0003]
A part of the light of the semiconductor light-emitting element is wavelength-converted by a phosphor, and the wavelength-converted light and the light of the light-emitting element that is not wavelength-converted are mixed and emitted to emit a light emission color different from that of the light-emitting element. A light emitting device has been developed. In particular, since a light emitting device that emits white light can be used in a wide range of fields such as general illumination, a display, and a backlight for liquid crystal, there is a demand for a phosphor that is particularly used in a white light emitting device. The emission color of the white light emitting device is obtained by the principle of light color mixing. The blue light emitted from the light emitting element enters the phosphor layer, and after being repeatedly absorbed and scattered several times in the layer, is emitted to the outside. On the other hand, blue light absorbed by the phosphor serves as an excitation source and emits yellow fluorescence. The yellow light and the blue light are mixed with each other due to the complementary color, and appear to be white to the human eye. Thus, a white light emitting device using a blue light emitting element is manufactured.
[0004]
Where M_xSi_yN_z: A nitride phosphor of Eu (wherein M is at least one alkaline earth metal selected from the group consisting of Ca, Sr, Ba, and Zn. Z = 2 / 3x + 4 / 3y). It is disclosed. (Patent Document 1)
[Patent Document 1]
International Publication No. 01/40403 Pamphlet
[0005]
[Problems to be solved by the invention]
However, a light-emitting device including a light-emitting element that emits blue light and a phosphor that emits yellow fluorescence is visible as a pale white with less red component and less redness. Therefore, there is a demand for a light emitting device that emits reddish white light.
[0006]
The nitride phosphor of Patent Document 1 has a problem that luminance is low and sufficient light emission cannot be obtained.
[0007]
Accordingly, an object of the present invention is to solve the above problems and to provide a phosphor having high luminous efficiency. It is another object of the present invention to provide a light emitting device using the phosphor.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. Activated, selected from the group consisting of at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn and C, Si, Ge, Sn, Ti, Zr, Hf A nitride phosphor containing at least one group IV element and N, wherein the nitride phosphor contains 1 ppm to 10000 ppm of B About the body. Thereby, it is possible to improve light emission characteristics such as light emission luminance and quantum efficiency. The cause of this effect is not clear, but it is considered that the addition of boron element causes diffusion of the activator and promotes particle growth. Further, it is considered that boron elements enter the crystal lattice to eliminate the distortion of the crystal lattice or participate in the light emission mechanism to improve the light emission characteristics such as light emission luminance and quantum efficiency.
[0009]
The nitride phosphor is a nitride phosphor composed of at least one element of Ca and Sr, Si, and N, activated by Eu. A part of Eu can be replaced by at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Lu. A part of at least one of Ca and Sr can be substituted with at least one Group II element selected from the group consisting of Be, Mg, Ba, and Zn. A part of Si can be replaced by at least one group IV element selected from the group consisting of C, Ge, Sn, Ti, Zr, and Hf.
[0010]
The present invention relates to a nitride phosphor characterized in that O is contained in the composition of the nitride phosphor. Thereby, since the raw material containing oxygen can be used, it can be made easy to manufacture.
[0011]
The present invention provides a general formula L_XM_YN_{((2/3) X + (4/3) Y)}: R or L_XM_YO_ZN_{((2/3) X + (4/3) Y- (2/3) Z)}: R (L is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn. M is C, Si, Ge, Sn, Ti, Zr, At least one group IV element selected from the group consisting of Hf, R is a group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Lu And at least one rare earth element selected from the group consisting of X, Y, and Z: 0.5 ≦ X ≦ 3, 1.5 ≦ Y ≦ 8, and 0 <Z ≦ 3. A nitride phosphor, wherein the nitride phosphor includes B in an amount of 1 ppm to 10000 ppm. The nitride phosphor can be expressed by the above general formula, and B is included in the general formula. Thereby, it is possible to improve light emission efficiency such as light emission luminance and quantum efficiency.
[0012]
The present invention is a nitride phosphor that wavelength-converts at least part of a first emission spectrum and has at least one second emission spectrum in a region different from the first emission spectrum, wherein the nitride fluorescence The present invention relates to a nitride phosphor characterized in that B added to the raw material of the body so that the amount added can be controlled is included. Thereby, the light emission characteristics such as light emission luminance, quantum efficiency, and afterglow can be adjusted. When boron is not added, light emission characteristics such as light emission luminance and quantum efficiency are constant, but by adding boron, light emission luminance can be improved and afterglow can be shortened. This is because adjustment of the light emission characteristics requires different characteristics depending on applications such as lighting and display, and therefore, it is required to change the light emission characteristics with the same color tone.
[0013]
Note that the first emission spectrum is excited by an external device.
[0014]
The crystal structure of the nitride phosphor is a nitride phosphor that is monoclinic or orthorhombic. The nitride phosphor has a crystal structure, and the crystal structure is monoclinic or orthorhombic. By having the crystal structure, it is possible to provide a nitride phosphor with good luminous efficiency.
[0015]
It is preferable that the rare earth element is at least one element that essentially requires Eu. This is because by using Eu as an activator, a phosphor that emits light from orange to red can be provided. By replacing a part of Eu with another rare earth element, a nitride phosphor having different color tone and afterglow characteristics can be provided.
[0016]
The nitride phosphor preferably further contains 0.1 to 500 ppm of at least one group I element selected from the group consisting of Li, Na, K, Rb, and Cs. Thereby, it is possible to improve light emission characteristics such as light emission luminance and quantum efficiency. This is because the Group I element acts as a flux during synthesis and then. This is because the Group I element that worked as a flux is present between the phosphor particles, or the Group I element is scattered during the manufacturing process, so that it is considered that the phosphor itself hardly inhibits light emission. . Moreover, the particle size of the nitride phosphor can be controlled by containing the Group I element in the nitride phosphor.
[0017]
The nitride phosphor further includes a group I element composed of Cu, Ag, Au, a group III element composed of Al, Ga, In, a group IV element composed of Ti, Zr, Hf, Sn, Pb, P It is preferable that at least one element selected from Group V elements composed of Sb, Bi, and Group VI elements composed of S is contained in an amount of 0.1 to 500 ppm. Thereby, the brightness | luminance of nitride fluorescent substance can be adjusted.
[0018]
The nitride phosphor preferably further contains 1 or more and 500 ppm or less of any element of Ni and Cr. Thereby, the afterglow of the nitride phosphor can be shortened. In addition to Ni and Cr, Mg and Al have the same effect. Afterglow can be controlled by controlling the amount of Mg, Al, Ni and Cr added.
[0019]
The nitride phosphor preferably has an average particle size of 2 to 15 μm. In particular, the average particle size is preferably 3 or more and 12 μm or less. More preferably, the average particle size is 5 or more and 10 μm or less. By controlling the particle size within a predetermined range, a light emitting device with extremely little color unevenness can be provided. Thereby, a light-emitting device with high luminance can be provided. The larger the average particle size of the nitride phosphor, the higher the emission luminance. However, when it is 15 μm or more, it is difficult to apply and handle when used in a light emitting device. On the other hand, the smaller the average particle size of the nitride phosphor, the more uniformly light is emitted when it is applied to the phosphor screen of the light emitting device, but the problem is that the luminance is low and the handling is difficult during application and manufacturing. is there. Therefore, an average particle size in the above range is preferable.
[0020]
The present invention provides an excitation light source that emits light in the short wavelength region from near ultraviolet to visible light, and wavelength-converts at least part of the light from the excitation light source, and emits light in a longer wavelength region than the light from the excitation light source. A light-emitting device comprising: a phosphor having at least one of the nitride phosphors according to claim 1. . As a result, a light emitting device having good light emission efficiency such as light emission luminance and quantum efficiency can be provided. The excitation light source emits light in a short wavelength region from near ultraviolet to visible light. The emitted light illuminates the phosphor. The phosphor absorbs part of the light by the irradiated light and performs wavelength conversion. The wavelength-converted light emits light having a longer wavelength than the light from the excitation light source. Thereby, the light-emitting device which shows the light emission color from an excitation light source, and the light emission color of a different color can be provided. Specifically, the nitride phosphor according to the present invention is irradiated with the light using an excitation light source emitting blue light near 460 nm. The nitride phosphor has an emission color from yellow to red around 580 nm to 650 nm. However, a light-emitting device having a desired emission color can be provided by variously changing the nitride phosphor.
[0021]
The phosphor preferably further includes at least one of a phosphor emitting blue light, a phosphor emitting green light, and a phosphor emitting yellow light. By using a phosphor that emits light of various colors in combination with the nitride phosphor according to the present invention, it is possible to provide a light-emitting device having a desired emission color such as pastel color as well as white. Even if it is white, it can be finely adjusted to (yellowish) white, (greenish) white, (blueish) white, or the like. Furthermore, an excitation light source that emits near-ultraviolet light and at least one of a nitride phosphor, a phosphor that emits blue light, a phosphor that emits green light, and a phosphor that emits yellow light, By using it, a light emitting device having a desired emission color such as white or pastel color can be provided.
[0022]
The excitation light source is preferably a semiconductor light emitting element. By using a semiconductor light emitting element, a light emitting device that makes use of the characteristics of the semiconductor light emitting element can be provided. The features of semiconductor light emitting devices are small size, power efficiency and bright color emission, excellent initial drive characteristics, strong vibration and repeated on / off lighting, and semiconductor light emitting devices used for light emitting device lamps Because it is a semiconductor element, there is no worry of running out of a ball.
[0023]
The light emitting device includes a part of the light from the excitation light source that transmits between the particles of the phosphor, a part of the light emitted from the phosphor that is wavelength-converted by the light from the excitation light source, The present invention relates to a light emitting device that emits white light by being mixed and emitted. Thereby, it is possible to provide a light emitting device that emits white light having high luminous efficiency. For example, a blue phosphor that has passed through between the nitride phosphor and the phosphor by exciting the nitride phosphor to emit yellow-red light and emitting the yellow light by exciting the phosphor by a light emitting element having blue light. The light, yellow-red light of the nitride phosphor, and yellow light of the phosphor appear as white to the human eye by the principle of light color mixing. Here, the light emitting device is a light emitting device having an excellent average color rendering index (Ra). The average color rendering index (Ra) is 80 or more. In particular, the light emitting device is excellent in the special color rendering index (R9) that is an index indicating a red component. The special color rendering index (R9) is 70 or more.
[0024]
The relationship between the color name and the chromaticity coordinate in the specification is based on the JIS standard (JISZ8110).
[0025]
As described above, the nitride phosphor according to the present invention is a phosphor having extremely good light emission characteristics such as luminance and quantum efficiency. The light emitting device according to the present invention can provide a slightly reddish warm white light emitting device with high luminous efficiency. The light emitting device is a light emitting device excellent in average color rendering index (Ra) and special color rendering index (R9). Further, a light emitting device combining a semiconductor light emitting element emitting blue light and the nitride phosphor according to the present invention, a semiconductor light emitting element emitting near-ultraviolet light, the nitride phosphor according to the present invention, and a fluorescence emitting green light By providing a light-emitting device that combines a body and a phosphor that emits yellow light, a light-emitting device that emits white light or pastel color can be provided. Therefore, the present invention has technical significance that a nitride phosphor and a light emitting device using the same can be provided.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the phosphor and the method for producing the same according to the present invention will be described using embodiments and examples. However, the present invention is not limited to this embodiment and example.
[0027]
A light-emitting device according to the present invention includes at least a light-emitting element having a first emission spectrum and a phosphor having a second emission spectrum obtained by wavelength-converting at least a part of the first emission spectrum. It is. An example of a specific light-emitting device will be described with reference to FIG. FIG. 1 is a diagram showing a light emitting device according to the present invention.
[0028]
(Light-emitting device 1)
The light emitting device 1 includes a semiconductor layer 2 stacked on the sapphire substrate 1, a lead frame 13 conductively connected by conductive wires 14 extending from positive and negative electrodes 3 formed on the semiconductor layer 2, and the sapphire substrate 1 and the phosphor 11 provided in the cup of the lead frame 13a so as to cover the outer periphery of the light emitting element 10 composed of the semiconductor layer 2 and the outer periphery of the phosphor 11 and the lead frame 13. And a mold member 15 covering the surface.
[0029]
A semiconductor layer 2 is formed on the sapphire substrate 1, and positive and negative electrodes 3 are formed on the same plane side of the semiconductor layer 2. The semiconductor layer 2 is provided with a light emitting layer (not shown), and the peak wavelength output from the light emitting layer has an emission spectrum in the vicinity of 500 nm or less from the ultraviolet to the blue region.
[0030]
The light-emitting element 10 is set on a die bonder, face-up to a lead frame 13a provided with a cup, and die-bonded (adhered). After die bonding, the lead frame 13 is transferred to a wire bonder, the negative electrode 3 of the light emitting element is wire bonded to the lead frame 13a provided with a cup with a gold wire, and the positive electrode 3 is wire bonded to the other lead frame 13b. .
[0031]
Next, it transfers to a molding apparatus and inject | pours the fluorescent substance 11 and the coating member 12 in the cup of the lead frame 13 with the dispenser of a molding apparatus. The phosphor 11 and the coating member 12 are uniformly mixed in a desired ratio in advance.
[0032]
After the phosphor 11 is injected, the lead frame 13 is immersed in a mold mold in which a mold member 15 is previously injected, and then the mold is removed to cure the resin, and a bullet-type light emitting device 1 as shown in FIG. And
[0033]
For example, only a nitride phosphor is used for the phosphor 11. The phosphor 11 absorbs part of light in the ultraviolet to blue region emitted by the light emitting element 10 and emits light in the yellow to red region. By using the phosphor 11 in the light emitting device having the above-described configuration, a light emitting device that emits warm white light by mixing the blue light emitted from the light emitting element 10 and the red light of the phosphor is provided. The light-emitting device manufactures a light-emitting device that emits light of a light bulb color so as to comply with JIS standards.
[0034]
The light bulb color is a white color based on the JIS standard (JIS Z8110), centering on the point of 2700-2800K on the locus of black body radiation, and having a color from yellow to red. Say. Specifically, it has a light emission color in a (light) yellow-red, (orange) pink, pink, (light) pink, (yellow) white region in the chromaticity locus of FIG.
[0035]
(Light emitting device 2)
A specific configuration of the light emitting device 2 different from the light emitting device 1 will be described in detail. FIG. 8 is a diagram showing the light emitting device 2 according to the present invention. The light emitting device 2 forms a surface mount type light emitting device. As the light-emitting element 101, an ultraviolet-excited nitride semiconductor light-emitting element can be used. The light-emitting element 101 can also be a blue-light-excited nitride semiconductor light-emitting element. Here, the light emitting element 101 excited by ultraviolet light will be described as an example. As the light emitting element 101, the LED chip 101 uses a nitride semiconductor light emitting element having an InGaN semiconductor having a peak wavelength of about 370 nm as a light emitting layer. As a more specific LED element structure, an n-type GaN layer that is an undoped nitride semiconductor on a sapphire substrate, a GaN layer that is formed with an Si-doped n-type electrode and becomes an n-type contact layer, and an undoped nitride semiconductor A single quantum well structure includes an n-type GaN layer, an n-type AlGaN layer that is a nitride semiconductor, and then an InGaN layer that constitutes a light-emitting layer. On the light emitting layer, an AlGaN layer as a p-type cladding layer doped with Mg and a GaN layer as a p-type contact layer doped with Mg are sequentially laminated. (Note that a GaN layer is formed on the sapphire substrate at a low temperature to serve as a buffer layer. In addition, the p-type semiconductor is annealed at 400 ° C. or higher after film formation). Etching exposes the surface of each pn contact layer on the same side as the nitride semiconductor on the sapphire substrate. An n-electrode is formed in a strip shape on the exposed n-type contact layer, and a translucent p-electrode made of a metal thin film is formed on almost the entire surface of the p-type contact layer that remains without being cut. A pedestal electrode is formed on the p-electrode in parallel with the n-electrode using a sputtering method.
[0036]
Next, a Kovar package 105 having a concave portion at the central portion and a base portion having Kovar lead electrodes 102 inserted and fixed in an airtight manner on both sides of the concave portion is used. A Ni / Ag layer is provided on the surface of the package 105 and the lead electrode 102. In the recess of the package 105, the above-described LED chip 101 is die-bonded with an Ag—Sn alloy. With this configuration, all the constituent members of the light emitting device can be made of an inorganic substance, and the light emission emitted from the LED chip 101 can be remarkably reliable even if the light emitted from the LED chip 101 is in the ultraviolet region or the short wavelength region of visible light. A light emitting device with high brightness can be obtained.
[0037]
Next, each electrode of the die-bonded LED chip 101 is electrically connected to each lead electrode 102 exposed from the bottom of the package recess by an Ag wire 104. After sufficiently removing moisture in the recess of the package, sealing is performed with a Kovar lid 106 having a glass window 107 at the center, and seam welding is performed. In the glass window portion, Ca is added in advance to a slurry of 90 wt% nitrocellulose and 10 wt% γ-alumina.₂Si₅N₈: Eu, (Y_0.8Gd_0.2)₃Al₅O₁₂: A phosphor 108 such as Ce is contained, applied to the back surface of the translucent window 107 of the lid 106, and heat-cured at 220 ° C. for 30 minutes to constitute a color conversion member. When the light-emitting device thus formed emits light, a light-emitting diode capable of emitting white light with high luminance can be obtained. As a result, it is possible to obtain a light emitting device that is extremely easy to adjust the chromaticity and has excellent mass productivity and reliability. Hereafter, each structure of this invention is explained in full detail.
[0038]
Hereinafter, constituent members of the light emitting device according to the present invention will be described in detail.
[0039]
(Phosphor)
The phosphor according to the present invention is activated by at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. And at least one selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, and at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn. A nitride phosphor containing at least a group IV element and N, wherein the nitride phosphor contains B in an amount of 1 ppm to 10000 ppm. . Or it is the nitride fluorescent substance in which O is contained in the composition of this nitride fluorescent substance. Among the nitride phosphor combinations, a nitride phosphor composed of at least one element of Ca and Sr, Si, and N, activated by Eu, and containing B in a range of 1 ppm to 10000 ppm Nitride phosphors that are characterized by the above are preferable. A part of Eu can be replaced by at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Lu. A part of at least one of Ca and Sr can be substituted with at least one Group II element selected from the group consisting of Be, Mg, Ba, and Zn. A part of Si can be replaced by at least one group IV element selected from the group consisting of C, Ge, Sn, Ti, Zr, and Hf.
[0040]
Specifically, the phosphor according to the present invention has the general formula L_XM_YN_{((2/3) X + (4/3) Y)}: R or L_XM_YO_ZN_{((2/3) X + (4/3) Y- (2/3) Z)}: R (L is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn. M is C, Si, Ge, Sn, Ti, Zr, At least one group IV element selected from the group consisting of Hf, where R is a group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. And at least one rare earth element selected from the group consisting of X, Y, and Z: 0.5 ≦ X ≦ 3, 1.5 ≦ Y ≦ 8, and 0 <Z ≦ 3. The nitride phosphor is characterized in that B is contained in an amount of 1 ppm to 10,000 ppm. Specific examples of the general formula include (Sr_TCa_1-T)₂Si₅N₈: Eu, Ca₂Si₅N₈: Eu, Sr_TCa_1-TSi₇N₁₀: Eu, SrSi₇N₁₀: Eu, CaSi₇N₁₀: Eu, Sr₂Si₅N₈: Eu, Ba₂Si₅N₈: Eu, Mg₂Si₅N₈: Eu, Zn₂Si₅N₈: Eu, SrSi₇N₁₀: Eu, BaSi₇N₁₀: Eu, MgSi₇N₁₀: Eu, ZnSi₇N₁₀: Eu, Sr₂Ge₅N₈: Eu, Ba₂Ge₅N₈: Eu, Mg₂Ge₅N₈: Eu, Zn₂Ge₅N₈: Eu, SrGe₇N₁₀: Eu, BaGe₇N₁₀: Eu, MgGe₇N₁₀: Eu, ZnGe₇N₁₀: Eu, Sr_1.8Ca_0.2Si₅N₈: Eu, Ba_1.8Ca_0.2Si₅N₈: Eu, Mg_1.8Ca_0.2Si₅N₈: Eu, Zn_1.8Ca_0.2Si₅N₈: Eu, Sr_0.8Ca_0.2Si₇N₁₀: Eu, Ba_0.8Ca_0.2Si₇N₁₀: Eu, Mg_0.8Ca_0.2Si₇N₁₀: Eu, Zn_0.8Ca_0.2Si₇N₁₀: Eu, Sr_0.8Ca_0.2Ge₇N₁₀: Eu, Ba_0.8Ca_0.2Ge₇N₁₀: Eu, Mg_0.8Ca_0.2Ge₇N₁₀: Eu, Zn_0.8Ca_0.2Ge₇N₁₀: Eu, Sr_0.8Ca_0.2Si₆GeN₁₀: Eu, Ba_0.8Ca_0.2Si₆GeN₁₀: Eu, Mg_0.8Ca_0.2Si₆GeN₁₀: Eu, Zn_0.8Ca_0.2Si₆GeN₁₀: Eu, Sr₂Si₅N₈: Pr, Ba₂Si₅N₈: Pr, Sr₂Si₅N₈: Tb, BaGe₇N₁₀: It is preferable to use a nitride phosphor represented by Ce (0 <T <1) or the like.
[0041]
This nitride phosphor has the general formula L_XM_YN_{((2/3) X + (4/3) Y)}: R or L_XM_YO_ZN_{((2/3) X + (4/3) Y- (2/3) Z)}: B contains 1 ppm or more and 10,000 ppm or less with respect to R. The mixing method is wet or dry, and a boron compound can be added to various raw materials. Or Ca₃N₂, Si₃N₄It can also be previously contained in the raw material composition. For example, wet mixing and H₃BO₃Is preferably 1 ppm or more and 1000 ppm or less. In particular, 100 ppm or more and 1000 ppm or less are preferable. When dry-mixing and adding boron, 1 ppm or more and 10000 ppm or less are preferable. 100 ppm or more and 10,000 ppm or less are particularly preferable. The boron acts as a flux. Boron, boride, boron nitride, boron oxide, borate, etc. can be used as boron added to the raw material. Specifically, BN, H₃BO₃, B₂O₆, B₂O₃, BCl₃, SiB₆, CaB₆Etc. A predetermined amount of these boron compounds is weighed and added to the raw material. The amount of boron added to the raw material does not necessarily match the boron content after firing. Since boron partially scatters at the firing stage in the manufacturing process, the boron content after firing is less than when added to the raw material.
[0042]
L is at least one Group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn. Therefore, Mg, Ca, Sr, etc. can be used alone, but combinations of Ca and Sr, Ca and Mg, Ca and Ba, Ca and Sr and Ba, etc. are also possible. In particular, by using at least one of Ca and Sr in the composition of the nitride phosphor, it is possible to provide a phosphor excellent in emission luminance, quantum efficiency, and the like. It has at least one element of Ca and Sr, and a part of Ca and Sr may be substituted with Be, Mg, Ba, and Zn. When using 2 or more types of mixtures, a compounding ratio can be changed as desired. Here, the peak wavelength shifts to the longer wavelength side when Sr and Ca are mixed than when only Sr or Ca is used. When the molar ratio of Sr and Ca is 7: 3 or 3: 7, the peak wavelength is shifted to the long wavelength side compared to the case where only Ca and Sr are used. Furthermore, when the molar ratio of Sr and Ca is approximately 5: 5, the peak wavelength is shifted to the longest wavelength side.
[0043]
M is at least one group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. Therefore, C, Si, Ge, etc. can be used alone, but combinations of C and Si, Ge and Si, Ti and Si, Zr and Si, Ge and Ti and Si, etc. are also possible. In particular, by using Si for the composition of the nitride phosphor, an inexpensive and good crystallinity nitride phosphor can be provided. A part of Si may be substituted with C, Ge, Sn, Ti, Zr, and Hf. When using the mixture which makes Si essential, a compounding ratio can be changed as desired. For example, 95% by weight of Si and 5% by weight of Ge can be used.
[0044]
R is at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. Eu, Pr, Ce, etc. can be used alone, but combinations of Ce and Eu, Pr and Eu, La and Eu, etc. are also possible. In particular, by using Eu as an activator, it is possible to provide a nitride phosphor having excellent emission characteristics having a peak wavelength in the yellow to red region. A part of Eu may be replaced with Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Lu. By substituting a part of Eu with another element, the other element acts as a co-activation. By co-activation, the color tone can be changed, and the light emission characteristics can be adjusted. When using a mixture that requires Eu, the mixing ratio can be changed as desired. In the following examples, europium Eu, which is a rare earth element, is used for the emission center. Europium mainly has bivalent and trivalent energy levels. The phosphor of the present invention has Eu as a base material for alkaline earth metal silicon nitride.²⁺Is used as an activator. Eu²⁺Is easily oxidized and trivalent Eu₂O₃It is marketed with the composition. However, commercially available Eu₂O₃Then, the involvement of O is large, and it is difficult to obtain a good phosphor. Therefore, Eu₂O₃It is preferable to use a product obtained by removing O from the system. For example, it is preferable to use europium alone or europium nitride.
[0045]
The effect of adding boron is Eu²⁺Can be promoted to improve light emission characteristics such as light emission luminance, energy efficiency, and quantum efficiency. In addition, it is possible to increase the particle size and improve the light emission characteristics.
[0046]
The nitride phosphor may further include 1 to 500 ppm of at least one group I element selected from the group consisting of Li, Na, K, Rb, and Cs. Since Group I elements are scattered during firing in the production process, the amount added after firing is smaller than the amount added to the raw material. Therefore, it is preferable to adjust the amount added to the raw material to 1000 ppm or less. This is because light emission efficiency such as light emission luminance can be adjusted. By adding the Group I element, it is possible to improve the light emission luminance and the quantum efficiency as described above.
[0047]
The nitride phosphor further includes a group I element composed of Cu, Ag, Au, a group III element composed of Al, Ga, In, a group IV element composed of Ti, Zr, Hf, Sn, Pb, P 1 to 500 ppm of at least one element selected from Group V elements consisting of Sb, Bi, and Group VI elements consisting of S can also be included. These elements, like the Group I elements, are scattered during firing in the production process, so that the amount added after firing is less than the amount initially added to the raw material. Therefore, it is preferable to adjust the amount added to the raw material to 1000 ppm or less. The luminous efficiency can be adjusted by adding these elements.
[0048]
The nitride phosphor may further contain 1 or more and 500 ppm or less of any element of Ni and Cr. This is to adjust the afterglow. Therefore, it is preferable to adjust the amount added to the raw material to 1000 ppm or less.
[0049]
The elements to be added to the above-described nitride phosphor are usually added as oxides or oxide hydroxides, but are not limited thereto, and are not limited to metals, nitrides, imides, amides, or other inorganic substances. A salt may be sufficient and the state previously contained in the other raw material may be sufficient.
[0050]
Oxygen is contained in the composition of the nitride phosphor. It is conceivable that oxygen is introduced from various oxides as raw materials, or oxygen is mixed during firing. This oxygen is considered to promote the effects of Eu diffusion, grain growth, and crystallinity improvement. That is, even if one compound used as a raw material is replaced with metal, nitride, or oxide, the same effect can be obtained, but rather the effect when using an oxide may be great. The crystal structure of the nitride phosphor may be monoclinic or orthorhombic, but may be non-single crystal or hexagonal.
[0051]
(Phosphor production method)
Next, referring to FIG. 2, the phosphor according to the present invention, B containing B₂Si₅N₈: Although the manufacturing method of Eu is demonstrated, it is not limited to this manufacturing method. The phosphor contains Li, Na, K, B, etc. and O.
[0052]
The raw material Ca is pulverized (P1). The raw material Ca is preferably a simple substance, but compounds such as an imide compound and an amide compound can also be used. The raw material Ca may contain Li, Na, K, B, Al, or the like. The raw material is preferably purified. Thereby, since a purification process is not required, the manufacturing process of the phosphor can be simplified, and an inexpensive nitride phosphor can be provided. The raw material Ca is pulverized in a glove box in an argon atmosphere. As a guide for Ca grinding, the average particle size is preferably in the range of about 0.1 μm or more and 15 μm or less from the viewpoint of reactivity with other raw materials, particle size control during and after firing, etc., It is not limited to this range. The purity of Ca is preferably 2N or higher, but is not limited thereto.
[0053]
The raw material Ca is nitrided in a nitrogen atmosphere (P2). This reaction formula is shown in Chemical Formula 1.
[0054]
[Chemical 1]
3Ca + N₂  → Ca₃N₂
Ca can be nitrided in a nitrogen atmosphere at 600 to 900 ° C. for about 5 hours to obtain a nitride of Ca. The Ca nitride is preferably of high purity.
[0055]
The nitride of Ca is pulverized (P3). Ca nitride is pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere.
[0056]
The raw material Si is pulverized (P4). The raw material Si is preferably a simple substance, but a nitride compound, an imide compound, an amide compound, or the like can also be used. For example, Si₃N₄, Si (NH₂)₂, Mg₂Si and the like. The purity of the raw material Si is preferably 3N or more, but may contain different elements such as Li, Na, K, B, Al and Cu. Si is also pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere in the same manner as the raw material Ca. The average particle size of the Si compound is preferably in the range of about 0.1 μm or more and 15 μm or less from the viewpoints of reactivity with other raw materials, particle size control during and after firing, and the like.
[0057]
The raw material Si is nitrided in a nitrogen atmosphere (P5). This reaction formula is shown in Chemical Formula 2.
[0058]
[Chemical formula 2]
3Si + 2N₂  → Si₃N₄
Silicon Si is also nitrided in a nitrogen atmosphere at 800 to 1200 ° C. for about 5 hours to obtain silicon nitride. The silicon nitride used in the present invention is preferably highly pure.
[0059]
Similarly, Si nitride is pulverized (P6).
[0060]
Next, Eu compound Eu₂O₃And B compound H₃BO₃Is wet-mixed (P7). Europium oxide is used as the Eu compound, but metal europium, europium nitride, and the like can also be used. In addition, an imide compound or an amide compound can also be used as the raw material Eu. Europium oxide is preferably highly pure. Different elements such as the compound of B are wet mixed, but may be dry mixed. Since some of these mixtures are easily oxidized, they are mixed in a glove box in an Ar atmosphere or a nitrogen atmosphere.
[0061]
Compound H of B₃BO₃In addition, Group I elements, Group IV elements and the like can be wet mixed with Eu. Compounds such as Group I elements and Group IV elements include, for example, H₂MoO₄, LiOH · H₂O, Na₂CO₃, K₂CO₃, RbCl, CsCl, Mg (NO₃)₂, CaCl₂・ 6H₂O, SrCl₂・ 6H₂O, BaCl₂・ 2H₂O, TiOSO₄・ H₂O, ZrO (NO₃)₂, HfCl₄, VCl₃, Nb₂O₅, TaCl₅, Cr (NO₃)₃・ 9H₂O, H₂WO₄, ReCl₅, FeCl₃・ 3H₂O, RuCl₃・ 2H₂O, Co (NO₃)₃・ 6H₂O, NiCl₂・ H₂O, IrCl₃, PdCl₂, H₂PtCl₆・ 6H₂O, Cu (CH₃COO)₂・ H₂O, AgNO₃, HAuCl₄・ 4H₂O, Zn (NO₃)₂・ 6H₂O, H₃BO₃, Al (NO₃)₃・ 9H₂O, GaCl₃, InCl₃, GeO₂, Sn (CH₃COO)₂, Pb (NO₃)₂, (NH₄)₂HPO₄, Sb₂O₃, Bi (NO₃)₃・ 5H₂O, (NH₄)₂SO₄Etc. can be used. These compounds are added separately from Ca nitride, Si nitride, Eu compound, etc., but different elements are contained in the raw material composition of Ca nitride, Si nitride, Eu compound, etc. It may be.
[0062]
Eu compounds Eu₂O₃And the compound H of B₃BO₃The mixture is fired in an oxidizing atmosphere (P8).
[0063]
The mixture of Eu and B is pulverized (P9). The average particle size of the mixture of Eu and B after pulverization is preferably about 0.1 μm to 15 μm.
[0064]
After the pulverization, Ca nitride, Si nitride, and a mixture of Eu and B are mixed (P10).
[0065]
Steps P7 to P9 are omitted, and in step P10, Ca nitride, Si nitride, Eu compound Eu₂O₃, B Compound H₃BO₃Can also be mixed dry.
[0066]
Ca nitride, Si nitride, and a mixture of Eu and B are fired in an ammonia atmosphere (P11). Ca to which B is added by firing₂Si₅N₈: A phosphor represented by Eu can be obtained (P12). The reaction formula of the nitride phosphor by this firing is shown in Chemical Formula 3.
[0067]
[Chemical 3]

[0068]
However, the composition of the target phosphor can be changed by changing the blending ratio of each raw material.
[0069]
For firing, a tubular furnace, a small furnace, a high-frequency furnace, a metal furnace, or the like can be used. The firing temperature can be in the range of 1200 to 2000 ° C., but the firing temperature of 1400 to 1800 ° C. is preferred. It is preferable to use a one-step baking in which the temperature is gradually raised and the baking is performed at 1200 to 1500 ° C. for several hours, but the first baking is performed at 800 to 1000 ° C. and the heating is gradually started from 1200. Two-stage firing (multi-stage firing) in which the second stage firing is performed at 1500 ° C. can also be used. The raw material of the phosphor 11 is preferably fired using a crucible or boat made of boron nitride (BN). In addition to crucible made of boron nitride, alumina (Al₂O₃) Material crucibles can also be used. This is because these B, Al, and the like can improve the luminance more than Mo and can provide a phosphor having high luminous efficiency.
[0070]
The reducing atmosphere is an atmosphere containing at least one of nitrogen, hydrogen, argon, carbon dioxide, carbon monoxide, and ammonia. However, firing can be performed in a reducing atmosphere other than these.
[0071]
By using the above manufacturing method, it is possible to obtain a target nitride phosphor.
[0072]
(Phosphor)
In addition to the nitride phosphor according to the present invention, the phosphor used in the light emitting device includes at least one of a phosphor that emits blue light, a phosphor that emits green light, and a phosphor that emits yellow light. The body can be mixed and used.
[0073]
There are various types of phosphors that emit blue light, phosphors that emit green light, and phosphors that emit yellow light. In particular, at least cerium activated yttrium / aluminum oxide phosphors, at least cerium. It is preferable that at least one of activated yttrium / gadolinium / aluminum oxide phosphor and at least one of yttrium / gallium / aluminum oxide phosphor activated by cerium. Thereby, a light emitting device having a desired emission color can be provided. When the phosphor according to the present invention and the yttrium / aluminum oxide phosphor activated with cerium are used, the self-absorption in these phosphors is small, so that light emission can be efficiently extracted. Specifically, Ln₃M₅O₁₂: R (Ln is at least one selected from Y, Gd and La. M includes at least one of Al and Ca. R is a lanthanoid type), (Y_1-xGa_x)₃(Al_1-yGa_y)₅O₁₂: R (R is at least one or more selected from Ce, Tb, Pr, Sm, Eu, Dy, and Ho. 0 <R <0.5) can be used. The phosphor is excited by light in the wavelength range of 270 to 500 nm on the short wavelength side of visible light from near ultraviolet, and has a peak wavelength at 500 to 600 nm. However, the phosphor having the third emission spectrum is not limited to the above phosphor, and various phosphors can be used.
[0074]
This is because it can be adjusted to a desired chromaticity by containing the yttrium aluminum oxide phosphor. The yttrium / aluminum oxide phosphor activated with cerium absorbs part of the blue light emitted by the light emitting element 10 and emits light in the yellow region. Here, the blue light emitted from the light emitting element 10 and the yellow light of the yttrium / aluminum oxide phosphor emit light in pale white color. Therefore, a warm color can be obtained by combining the phosphor 11 obtained by mixing the yttrium aluminum oxide phosphor and the nitride phosphor together with a translucent coating member and the blue light emitted from the light emitting element 10. System white light emitting device can be provided. This warm white light emitting device has an average color rendering index Ra of 75 to 95 and a color temperature of 2000 to 8000K. Particularly preferred is a white light emitting device in which the average color rendering index Ra and the color temperature are located on the locus of black body radiation in the chromaticity diagram. However, in order to provide a light emitting device having a desired color temperature and average color rendering index, the blending amount of the yttrium / aluminum oxide phosphor and the phosphor according to the present invention can be appropriately changed. This warm white light-emitting device aims to improve the special color rendering index R9. A conventional light emitting device that emits white light in combination with a blue light emitting element and a cerium-activated yttrium aluminum oxide phosphor has a special color rendering index R9 of almost 0 and lacks a red component. Therefore, increasing the special color rendering index R9 has been a problem to be solved, but the special color rendering index R9 is increased to 60 to 70 by including the phosphor according to the present invention in the yttrium aluminum oxide phosphor. be able to. Here, the special color rendering index R9 is obtained on the basis of individual color shifts of seven types of color charts different from the average color rendering index, and is not an average of the seven types. As the seven types of color charts, those representing red, yellow, green, blue, human skin (white), green leaves, and human skin (Japanese) with relatively high saturation are selected. These are called R9, R10, R11, R12, R13, R14, and R15, respectively. Among these, R9 is a color chart indicating red.
[0075]
Further, the phosphor used in combination with the nitride phosphor of the present invention is not limited to the yttrium aluminum oxide phosphor and the like, from the blue region having the same purpose as the phosphor, the green region, A phosphor having at least one second emission spectrum in the yellow region and the red region can also be used in combination with the nitride phosphor. Thereby, it is possible to provide a light emitting device that emits white light based on the principle of light color mixing. The phosphor used in combination with the nitride phosphor is a green light emitting phosphor SrAl.₂O₄: Eu, Y₂SiO₅: Ce, Tb, MgAl₁₁O₁₉: Ce, Tb, Sr₇Al₁₂O₂₅: Eu, (at least one of Mg, Ca, Sr, Ba) Ga₂S₄: Eu, blue light emitting phosphor Sr₅(PO₄)₃Cl: Eu, (SrCaBa)₅(PO₄)₃Cl: Eu, (BaCa)₅(PO₄)₃Cl: Eu, (at least one of Mg, Ca, Sr, Ba)₂B₅O₉Cl: Eu, Mn, (at least one of Mg, Ca, Sr, Ba) (PO₄)₆Cl₂: Eu, Mn, red light emitting phosphor Y₂O₂S: Eu, La₂O₂S: Eu, Y₂O₃: Eu, Gd₂O₂A desired emission spectrum can be obtained by doping with S: Eu or the like. However, the light emitting phosphors such as green, blue, and red are not limited to the above phosphors, and various phosphors can be used.
[0076]
(Excitation light source)
Examples of the excitation light source include semiconductor light emitting devices, laser diodes, ultraviolet radiation generated in the positive column of arc discharge, and ultraviolet radiation generated in the positive column of glow discharge. In particular, semiconductor light emitting devices and laser diodes that emit light in the near ultraviolet region, semiconductor light emitting devices and laser diodes that emit blue light, and semiconductor light emitting devices and laser diodes that emit blue green light are preferable.
[0077]
Light in the short wavelength region from near ultraviolet to visible light refers to a wavelength region from 270 nm to around 500 nm.
[0078]
(Light emitting element)
In the present invention, the light-emitting element is preferably a semiconductor light-emitting element having a light-emitting layer capable of emitting a light emission wavelength capable of efficiently exciting the phosphor. Examples of the material of such a semiconductor light emitting device include various semiconductors such as BN, SiC, ZnSe, GaN, InGaN, InAlGaN, AlGaN, BAlGaN, and BInAlGaN. Similarly, these elements may contain Si, Zn, or the like as an impurity element to serve as a light emission center. In particular, nitride semiconductors (eg, nitride semiconductors containing Al and Ga, nitrides containing In and Ga, etc.) as materials for the light emitting layer capable of efficiently emitting short wavelengths of visible light from the ultraviolet region that can excite phosphors efficiently In as a semiconductor_XAl_YGa_1-XYN, 0 <X <1, 0 <Y <1, X + Y ≦ 1) are more preferable.
[0079]
Further, as a semiconductor structure, a homostructure having a MIS junction, a PIN junction, a pn junction, or the like, a heterostructure, or a double hetero configuration is preferably exemplified. Various emission wavelengths can be selected depending on the semiconductor layer material and the mixed crystal ratio. Further, the output can be further improved by adopting a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film that produces a quantum effect.
[0080]
When a nitride semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO, GaAs, or GaN is preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate by HVPE method, MOCVD method or the like. A buffer layer made of GaN, AlN, GaAIN or the like is grown at a low temperature on the sapphire substrate to form a non-single crystal, and a nitride semiconductor having a pn junction is formed thereon.
[0081]
As an example of a light emitting device capable of efficiently emitting light in the ultraviolet region having a pn junction using a nitride semiconductor, a SiO 2 layer is formed on the buffer layer substantially perpendicularly to the orientation flat surface of the sapphire substrate.₂Are formed in stripes. GaN is grown on the stripes using EHV (Epitaxial Lateral Over Grows GaN) using the HVPE method. Subsequently, by MOCVD, a first contact layer formed of n-type gallium nitride, a first cladding layer formed of n-type aluminum nitride / gallium, a well layer of indium nitride / aluminum / gallium, and aluminum nitride / gallium An active layer having a multiple quantum well structure in which a plurality of barrier layers are stacked, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked. Examples include a double hetero configuration. The active layer may be formed into a ridge stripe shape and sandwiched between guide layers, and a resonator end face may be provided to provide a semiconductor laser device usable in the present invention.
[0082]
Nitride semiconductors exhibit n-type conductivity without being doped with impurities. When forming a desired n-type nitride semiconductor, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, it is preferable to dope p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to reduce resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant. When the sapphire substrate is not used, the contact layer is exposed by etching from the p-type side to the surface of the first contact layer. A light emitting element made of a nitride semiconductor can be formed by cutting the semiconductor wafer into chips after forming electrodes on each contact layer.
[0083]
In order to form the light emitting device with high productivity, it is preferable to use a light-transmitting sealing member. In particular, a translucent resin is preferable because the phosphor 11 is mixed and sealed. In this case, considering the emission wavelength from the phosphor and the deterioration of the translucent resin, the light-emitting element has an emission spectrum in the ultraviolet region, and the main emission wavelength is from 360 nm to 420 nm, or from 450 nm to 470 nm. Can also be used.
[0084]
Here, the semiconductor light emitting device has an impurity concentration of 10¹⁷-10²⁰/ Cm³It is preferable that the sheet resistance of the n-type contact layer and the sheet resistance of the light-transmitting p electrode are adjusted so as to satisfy the relationship of Rp ≧ Rn. The n-type contact layer is preferably formed to a film thickness of, for example, 3 to 10 μm, more preferably 4 to 6 μm, and the sheet resistance is estimated to be 10 to 15Ω / □, so that Rp at this time is the sheet resistance value. It is good to form in a thin film so that it may have the above sheet resistance values. The translucent p-electrode may be formed of a thin film having a thickness of 150 μm or less. Moreover, ITO other than a metal and ZnO can also be used for a p electrode. Here, instead of the translucent p-electrode, an electrode having a plurality of light extraction openings such as a mesh electrode can also be used.
[0085]
Further, when the translucent p-electrode is formed of a multilayer film or alloy composed of one kind selected from the group of gold and platinum group elements and at least one other element, it is contained. When the sheet resistance of the translucent p-electrode is adjusted by the content of the gold or platinum group element, stability and reproducibility are improved. Since gold or a metal element has a high absorption coefficient in the wavelength region of the semiconductor light emitting device used in the present invention, the smaller the amount of gold or platinum group element contained in the translucent p-electrode, the better the transparency. In the conventional semiconductor light emitting device, the relationship of sheet resistance is Rp ≦ Rn. However, in the present invention, Rp ≧ Rn, and therefore the translucent p-electrode is formed in a thin film as compared with the conventional one. However, thinning can be easily performed by reducing the content of gold or platinum group elements.
[0086]
As described above, in the semiconductor light emitting device used in the present invention, the sheet resistance RnΩ / □ of the n-type contact layer and the sheet resistance RpΩ / □ of the translucent p-electrode form a relationship of Rp ≧ Rn. Preferably it is. It is difficult to measure Rn after it is formed as a semiconductor light emitting device, and it is practically impossible to know the relationship between Rp and Rn, but what is the relationship between Rp and Rn from the state of the light intensity distribution during light emission? You can know if they are in a relationship.
[0087]
When the translucent p-electrode and the n-type contact layer have a relationship of Rp ≧ Rn, providing a p-side pedestal electrode in contact with the translucent p-electrode and having an extended conductive portion further improves external quantum efficiency. Can be achieved. There is no limitation on the shape and direction of the extended conductive portion, and when the extended conductive portion is on the satellite, it is preferable because the area for blocking light is reduced, but a mesh shape may be used. Further, the shape may be a curved shape, a lattice shape, a branch shape, or a hook shape in addition to the straight shape. At this time, since the light shielding effect increases in proportion to the total area of the p-side pedestal electrode, it is preferable to design the line width and length of the extended conductive portion so that the light shielding effect does not exceed the light emission enhancing effect.
[0088]
(Light emitting element)
A blue-light-excited light-emitting element different from the above-described ultraviolet-light-excited light-emitting element can also be used. The blue light-excited light emitting device 10 is preferably a Group III nitride compound light emitting device. The light emitting element 10 includes, for example, an n-type GaN layer in which Si is undoped, an n-type contact layer made of n-type GaN doped with Si, an undoped GaN layer, and a multiple quantum well structure on a sapphire substrate 1 via a GaN buffer layer. Light emitting layer (GaN barrier layer / InGaN well layer quantum well structure), p-clad layer made of p-type GaN made of Mg-doped p-type GaN, p-type contact layer made of p-type GaN doped with Mg Are sequentially stacked, and electrodes are formed as follows. However, a light emitting element 10 different from this configuration can also be used.
[0089]
The p ohmic electrode is formed on almost the entire surface of the p-type contact layer, and the p pad electrode 3 is formed on a part of the p ohmic electrode.
[0090]
The n-electrode is formed in the exposed portion by removing the undoped GaN layer from the p-type contact layer by etching to expose a part of the n-type contact layer.
[0091]
In the present embodiment, the light emitting layer having a multiple quantum well structure is used. However, the present invention is not limited to this, and for example, a single quantum well structure using InGaN may be used. Alternatively, GaN doped with n-type and p-type impurities such as Zn may be used.
[0092]
The light emitting layer of the light emitting element 10 can change the main light emission peak in the range of 420 nm to 490 nm by changing the In content. The emission wavelength is not limited to the above range, and those having an emission wavelength of 360 to 550 nm can be used.
[0093]
(Coating material)
The coating member 12 (light transmissive material) is provided in the cup of the lead frame 13 and is used by mixing with the phosphor 11 that converts the light emission of the light emitting element 10. Specific materials for the coating member 12 include transparent resins, silica sol, glass, inorganic binders, and the like that are excellent in temperature characteristics and weather resistance, such as epoxy resins, urea resins, and silicone resins. In addition to the phosphor 11, a diffusing agent, barium titanate, titanium oxide, aluminum oxide, or the like may be included. Moreover, you may contain a light stabilizer and a coloring agent.
[0094]
(Lead frame)
The lead frame 13 includes a mount lead 13a and an inner lead 13b.
[0095]
The mount lead 13a is for placing the light emitting element 10 thereon. The upper portion of the mount lead 13a has a cup shape, and the light emitting element 10 is die-bonded in the cup, and the outer peripheral surface of the light emitting element 10 is covered with the phosphor 11 and the coating member 12 inside the cup. . A plurality of light emitting elements 10 can be arranged in the cup, and the mount lead 13 a can be used as a common electrode of the light emitting elements 10. In this case, sufficient electrical conductivity and connectivity with the conductive wire 14 are required. Die bonding (adhesion) between the light emitting element 10 and the cup of the mount lead 13a can be performed with a thermosetting resin or the like. Examples of the thermosetting resin include an epoxy resin, an acrylic resin, and an imide resin. In addition, Ag-ace, carbon paste, metal bumps, or the like can be used for die-bonding and electrical connection with the mount lead 13a by the face-down light emitting element 10 or the like. An inorganic binder can also be used.
[0096]
The inner lead 13b is intended to be electrically connected to the conductive wire 14 extending from the electrode 3 of the light emitting element 10 disposed on the mount lead 13a. The inner lead 13b is preferably disposed at a position away from the mount lead 13a in order to avoid a short circuit due to electrical contact with the mount lead 13a. In the case where the plurality of light emitting elements 10 are provided on the mount lead 13a, it is necessary that the conductive wires be arranged so as not to contact each other. The inner lead 13b is preferably made of the same material as the mount lead 13a, and iron, copper, iron-containing copper, gold, platinum, silver, or the like can be used.
[0097]
(Conductive wire)
The conductive wire 14 is for electrically connecting the electrode 3 of the light emitting element 10 and the lead frame 13. The conductive wire 14 preferably has good ohmic properties, mechanical connectivity, electrical conductivity, and thermal conductivity with the electrode 3. Specific materials for the conductive wire 14 are preferably metals such as gold, copper, platinum, and aluminum, and alloys thereof.
[0098]
(Mold member)
The mold member 15 is provided to protect the light emitting element 10, the phosphor 11, the coating member 12, the lead frame 13, the conductive wire 14, and the like from the outside. In addition to the purpose of protection from the outside, the mold member 15 also has the purposes of widening the viewing angle, relaxing the directivity from the light emitting element 10, and converging and diffusing the emitted light. In order to achieve these objects, the mold member can have a desired shape. Further, the mold member 15 may have a structure in which a plurality of layers are stacked in addition to the convex lens shape and the concave lens shape. As a specific material of the mold member 15, a material excellent in translucency, weather resistance, and temperature characteristics such as epoxy resin, urea resin, silicone resin, silica sol, and glass can be used. The mold member 15 can contain a diffusing agent, a colorant, an ultraviolet absorber, and a phosphor. As the diffusing agent, barium titanate, titanium oxide, aluminum oxide or the like is preferable. In order to reduce the resilience of the material with the coating member 12, it is preferable to use the same material in consideration of the refractive index.
[0099]
Hereinafter, the phosphor and the light emitting device according to the present invention will be described with reference to examples, but the present invention is not limited to these examples.
[0100]
The temperature characteristics are shown as relative luminance with the emission luminance at 25 ° C. being 100%. The particle size is F. S. S. S. No. (Fisher Sub Sieve Sizer's No.) Value by air permeation method.
[0101]
【Example】
(Examples 1 to 4)
Table 1 shows the characteristics of the nitride phosphors of Examples 1 to 4.
[0102]
FIG. 3 is a diagram showing an emission spectrum when the nitride phosphor of Example 3 is excited at Ex = 460 nm. FIG. 4 is a diagram showing an excitation spectrum of the nitride phosphor of Example 3. FIG. 5 is a graph showing the reflection spectrum of the nitride phosphor of Example 3. FIG. 6 is an SEM photograph of the nitride phosphor of Example 3. FIG. 6A is taken at 1000 times. FIG. 6B is taken at 5000 times.
[0103]
[Table 1]

[0104]
Examples 1 to 4 are (Ca_0.97Eu_0.03)₂Si₅N₈And a predetermined amount of B. The light emission luminance and quantum efficiency are shown as relative values based on the nitride phosphor of Example 1.
[0105]
In Examples 1 to 4, the Eu concentration is 0.03. Eu concentration is a molar ratio with respect to the molar concentration of Ca.
[0106]
First, the raw material Ca was pulverized to 1 to 15 μm and nitrided in a nitrogen atmosphere. Thereafter, the Ca nitride was pulverized to 0.1 to 10 μm. 20 g of raw material Ca was weighed and nitrided.
[0107]
Similarly, raw material Si was pulverized to 1 to 15 μm and nitrided in a nitrogen atmosphere. Thereafter, the Si nitride was pulverized to 0.1 to 10 μm. 20 g of raw material Si was weighed and nitrided.
[0108]
Next, Eu compound Eu₂O₃And B compound H₃BO₃Were wet mixed. Eu compounds Eu₂O₃20g, H₃BO₃Was weighed a predetermined amount. H₃BO₃After making into a solution, Eu₂O₃And dried. After drying, baking was performed at 700 ° C. to 800 ° C. for about 5 hours in an oxidizing atmosphere. As a result, europium oxide to which B was added was produced. After this calcination, the mixture of Eu and B was pulverized to 0.1 to 10 μm.
[0109]
Ca nitride, Si nitride, and a mixture of Eu and B were mixed in a nitrogen atmosphere. In Examples 1 to 4, calcium nitride Ca as a raw material₃N₂: Silicon nitride Si₃N₄: Europium oxide Eu₂O₃The mixing ratio (molar ratio) of each element is adjusted so that Ca: Si: Eu = 1.94: 5: 0.06. To achieve this mixing ratio, Ca₃N₂(Molecular weight 148.26), Si₃N₄(Molecular weight 140.31) was weighed and mixed with a mixture of Eu and B. The addition amount of B is 10 ppm, 200 ppm, 500 ppm, and 1000 ppm with respect to the molecular weight of the final composition.
[0110]
The above compounds were mixed and fired. As the firing conditions, the above compound was put into a crucible in an ammonia atmosphere, gradually heated from room temperature, fired at about 1600 ° C. for about 5 hours, and slowly cooled to room temperature. In general, the added B remains in the composition even after firing, but a part of B is scattered by firing, and an amount smaller than the initial addition amount remains in the final product. May have.
[0111]
The light emission luminance and quantum efficiency of the nitride phosphors of Examples 1 to 4 are expressed as relative values with Example 1 as 100%.
[0112]
From Table 1, when B was added in an amount of 10,000 ppm or less, particularly when 1 ppm or more and 1000 ppm or less were added, both the luminance and quantum efficiency were high.
[0113]
The average particle diameters of the nitride phosphors of Examples 1 to 4 were 6.3 to 7.8 μm. The phosphors in the examples contained 0.5 to 1.2% by weight of oxygen.
[0114]
The nitride phosphor according to the example is fired in an ammonia atmosphere using a crucible made of boron nitride.
[0115]
The nitride phosphor according to the example has very good temperature characteristics. The temperature characteristics of the nitride phosphor of Example 3 were 97% at 100 ° C. and 70% at 200 ° C.
[0116]
The nitride phosphors of Examples 1 to 4 have a peak wavelength near 609 nm when excited by a 460 nm excitation light source.
[0117]
(Examples 5 to 9)
Table 2 shows the characteristics of the nitride phosphors of Examples 5 to 9.
[0118]
[Table 2]

[0119]
Examples 5 to 9 are (Ca_0.97Eu_0.03)₂Si₅N₈And a predetermined amount of B. The light emission luminance and quantum efficiency are shown as relative values based on the nitride phosphor of Example 5.
[0120]
In Examples 5 to 9, the Eu concentration is 0.03. Eu concentration is a molar ratio with respect to the molar concentration of Ca.
[0121]
Examples 5 to 9 differ from Examples 1 to 4 in the manufacturing method.
[0122]
First, the raw material Ca was pulverized to 1 to 15 μm and nitrided in a nitrogen atmosphere. Thereafter, the Ca nitride was pulverized to 0.1 to 10 μm. 20 g of raw material Ca was weighed and nitrided.
[0123]
Similarly, raw material Si was pulverized to 1 to 15 μm and nitrided in a nitrogen atmosphere. Thereafter, the Si nitride was pulverized to 0.1 to 10 μm. 20 g of raw material Si was weighed and nitrided.
[0124]
Ca nitride, Si nitride, Eu compound Eu₂O₃, B Compound H₃BO₃Were mixed dry. Eu compounds Eu₂O₃20g, H₃BO₃What weighed a predetermined amount was used. In Examples 5 to 9, calcium nitride Ca as a raw material₃N₂: Silicon nitride Si₃N₄: Europium oxide Eu₂O₃The mixing ratio (molar ratio) of each element is adjusted so that Ca: Si: Eu = 1.94: 5: 0.06. The addition amount of B is 10 ppm, 200 ppm, 500 ppm, 1000 ppm, or 10,000 ppm with respect to the molecular weight of the final composition.
[0125]
The above compounds were mixed and fired. As the firing conditions, the above compound was put into a crucible in an ammonia atmosphere, gradually heated from room temperature, fired at about 1600 ° C. for about 5 hours, and slowly cooled to room temperature.
[0126]
The light emission luminance and quantum efficiency of the nitride phosphors of Examples 5 to 9 are represented by relative values with Example 5 as 100%.
[0127]
From Table 2, when B was added in an amount of 10,000 ppm or less, both the luminance and quantum efficiency were high.
[0128]
The average particle diameters of the nitride phosphors of Examples 5 to 9 were 6.0 to 7.2 μm. The oxygen concentration was 0.7 to 1.0% by weight.
[0129]
(Examples 10 to 15)
Table 3 shows the characteristics of the nitride phosphors of Examples 10 to 15.
[0130]
[Table 3]

[0131]
In Examples 10 to 15, (Sr_0.97Eu_0.03)₂Si₅N₈And a predetermined amount of B. The light emission luminance and quantum efficiency are shown as relative values based on the nitride phosphor of Example 10.
[0132]
In Examples 10 to 15, the Eu concentration is 0.03. Eu concentration is a molar ratio with respect to the molar concentration of Sr.
[0133]
Examples 10 to 15 were manufactured by substantially the same manufacturing method as Examples 1 to 4. Instead of Ca used in Examples 1 to 4, Examples 10 to 15 used Sr. Examples 1 to 4 were fired at about 1600 ° C., while Examples 10 to 15 were fired at about 1350 ° C.
[0134]
From Table 3, when B was added in an amount of 10,000 ppm or less, particularly when 10 ppm or more and 5000 ppm or less were added, both the luminance and quantum efficiency were high.
[0135]
The average particle diameters of the nitride phosphors of Examples 10 to 15 were 2.1 to 4.7 μm. The oxygen concentration was 0.3 to 1.1% by weight.
[0136]
(Examples 16 to 20)
Table 4 shows the characteristics of the nitride phosphors of Examples 16 to 20.
[0137]
[Table 4]

[0138]
In Examples 16 to 20, (Sr_0.97Eu_0.03)₂Si₅N₈And a predetermined amount of B. The light emission luminance and quantum efficiency are shown as relative values based on the nitride phosphor of Example 16.
[0139]
In Examples 16 to 20, the Eu concentration is 0.03. Eu concentration is a molar ratio with respect to the molar concentration of Sr.
[0140]
Examples 16 to 20 were manufactured by substantially the same manufacturing method as Examples 1 to 4. Instead of Ca used in Examples 1 to 4, Examples 16 to 20 used Sr.
[0141]
From Table 4, when B was added at 1000 ppm or less, particularly when 10 ppm or more and 500 ppm or less were added, both the luminance and quantum efficiency were high.
[0142]
The average particle diameters of the nitride phosphors of Examples 16 to 20 were 3.2 to 3.9 μm.
[0143]
(Examples 21 to 26)
Table 5 shows the characteristics of the nitride phosphors of Examples 21 to 26.
[0144]
[Table 5]

[0145]
Examples 21 to 26 are (Ca_0.285Sr_0.685Eu_0.03)₂Si₅N₈And a predetermined amount of B. The light emission luminance and quantum efficiency are shown as relative values based on the nitride phosphor of Example 21.
[0146]
In Examples 21 to 26, the Eu concentration is 0.03. Eu concentration is a molar ratio with respect to the molar concentration of the mixture of Ca and Sr.
[0147]
Examples 21 to 26 were manufactured by substantially the same manufacturing method as Examples 1 to 4. In place of Ca used in Examples 1 to 4, Examples 21 to 26 use a mixture of Ca and Sr, and the molar ratio of Ca and Sr is 3: 7.
[0148]
From Table 5, when B was added in an amount of 5000 ppm or less, particularly when 10 ppm or more and 1000 ppm or less were added, both the luminance and quantum efficiency were high.
[0149]
The average particle diameter of the nitride phosphors of Examples 21 to 26 was 1.6 to 2.0 μm.
[0150]
<Light-emitting device 1>
The light emitting device 1 relates to a white light emitting device to which a reddish component is added. FIG. 1 is a diagram showing a light emitting device 1 according to the present invention. FIG. 7 is a diagram showing chromaticity coordinates of the light emitting device 1 according to the present invention.
[0151]
In the light emitting device 1, a semiconductor layer 2 of n-type and p-type GaN layers is formed on a sapphire substrate 1, and an electrode 3 is provided on the n-type and p-type semiconductor layer 2. The wire 14 is electrically connected to the lead frame 13. The upper part of the light emitting element 10 is covered with the phosphor 11 and the coating member 12, and the outer periphery of the lead frame 13, the phosphor 11, the coating member 12, and the like is covered with the mold member 15. The semiconductor layer 2 is formed on the sapphire substrate 1 with n⁺The layers are stacked in the order of GaN: Si, n-AlGaN: Si, n-GaN, GaInN QWs, p-GaN: Mg, p-AlGaN: Mg, and p-GaN: Mg. The n⁺A part of the GaN: Si layer is etched to form an n-type electrode. A p-type electrode is formed on the p-GaN: Mg layer. The lead frame 13 uses iron-containing copper. A cup for mounting the light-emitting element 10 is provided on the upper portion of the mount lead 13a, and the light-emitting element 10 is die-bonded to the bottom surface of the substantially central portion of the cup. Gold is used for the conductive wire 14, and Ni plating is applied to the bump 4 for conductively connecting the electrode 3 and the conductive wire 14. The phosphor 11 is mixed with the phosphor of Example 49 and the YAG phosphor. As the coating member 12, a material obtained by mixing an epoxy resin, a diffusing agent, barium titanate, titanium oxide, and the phosphor 11 at a predetermined ratio is used. The mold member 15 uses an epoxy resin. This bullet-type light emitting device 1 is a cylindrical shape in which the upper part of the mold member 15 having a radius of 2 to 4 mm and a height of about 7 to 10 mm is a hemisphere.
[0152]
When a current is passed through the light emitting device 1, the blue light emitting element 10 having the first emission spectrum excited at about 460 nm emits light, and the phosphor 11 covering the semiconductor layer 2 performs color tone conversion on the first emission spectrum. , Having a second emission spectrum different from the first emission spectrum. In addition, the YAG phosphor contained in the phosphor 11 exhibits a third emission spectrum by the first emission spectrum. It is possible to provide the light emitting device 1 that emits reddish white light in which the first, second, and third emission spectra are mixed with each other.
[0153]
The phosphor 11 of the light emitting device 1 according to the present invention includes the phosphor of Example 15, the coating member 12, and the yttrium-gadolinium-aluminum oxide phosphor (Y-Gd-Al-O: Ce) activated with cerium. ) Is used. In Example 15, Ca added with B was added.₂Si₅N₇: Eu nitride phosphor. On the other hand, the comparative light-emitting device does not contain the phosphor of Example 15, but uses only a cerium-activated yttrium / gadolinium / aluminum oxide phosphor. The light emitting device 1 according to the present invention and the comparative light emitting device are (Y_0.8Gd_0.2)₃Al₅O₁₂: Ce phosphor is used. The comparative light emitting device emits light with a combination of a blue light emitting element and a phosphor of (Y-Gd-Al-O: Ce). Cerium-activated yttrium / gallium / aluminum oxide phosphor Y instead of cerium-activated yttrium / gadolinium / aluminum oxide phosphor₃(Al_0.8Ga_0.2)₅O₁₂: It is preferable to use Ce.
[0154]
The weight ratio of the phosphor 11 of the light emitting device 1 is: coating member: phosphor of (Y-Gd-Al-O: Ce): phosphor of Example 15 = 10: 3.8: 0.6. On the other hand, the weight ratio of the phosphor of the light emitting device 2 is mixed at a weight ratio of coating member: (Y—Gd—Al—O: Ce) = 10: 3.6.
[0155]
The light emitting device 1 according to the present invention is compared with a light emitting device using a blue light emitting element and a phosphor of Y-Gd-Al-O: Ce. Table 6 shows the measurement results of the light emitting device for comparison with the light emitting device 1.
[0156]
[Table 6]

[0157]
Although the color tone is hardly changed as compared with the comparative light emitting device, the color rendering property is improved. In the comparative light emitting device, the special color rendering index R9 is insufficient, but in the light emitting device 1, R9 is improved. The special color rendering index R9 is a value obtained by measuring a color shift from a red standard color having relatively high saturation. Further, the other special color rendering evaluation numbers R8, R10, etc. are improved to values close to 100%. The lamp efficiency shows a high value.
[0158]
The phosphor 11 to be mixed together with the coating member 12 uses a mixture of Y-Gd-Al-O: Ce phosphor and nitride phosphor. Since the phosphors have different densities, generally, the higher the density and the smaller the particle size, the faster the sediment. Therefore, the phosphor of Y—Gd—Al—O: Ce is first precipitated, and the nitride phosphor is subsequently precipitated. Therefore, even when the same coating member 12 and phosphor 11 are used, color unevenness occurs in the color tone of the light emitting device. For this reason, the particle size of the nitride phosphor is controlled to a predetermined size, and the Y-Gd-Al-O: Ce phosphor and the nitride phosphor settle almost simultaneously, thereby preventing uneven color. Can be improved.
[0159]
<Light-emitting device 2>
FIG. 8 is a diagram showing the light emitting device 2 according to the present invention. The light emitting device 2 is a surface mount type light emitting device. The light emitting element 101 used in the light emitting device 2 uses a blue light excited light emitting element, but an ultraviolet light excited light emitting element with a wavelength of 380 to 400 nm can also be used, and the light emitting element 101 is not limited to this.
[0160]
A light emitting element 101 having an InGaN-based semiconductor layer with a peak wavelength of 460 nm in the blue region is used as the light emitting layer. The light-emitting element 101 includes a p-type semiconductor layer and an n-type semiconductor layer (not shown), and the p-type semiconductor layer and the n-type semiconductor layer have conductive wires connected to the lead electrode 102. 104 is formed. An insulating sealing material 103 is formed so as to cover the outer periphery of the lead electrode 102 to prevent a short circuit. Above the light emitting element 101, a translucent window 107 extending from a lid 106 at the top of the package 105 is provided. A uniform mixture of the phosphor 108 and the coating member 109 according to the present invention is applied to the entire inner surface of the translucent window 107. In the light emitting device 1, the phosphor of Example 1 is used. The package 105 is a square having a side with a corner portion of 8 mm to 12 mm.
[0161]
The emission spectrum of the blue light emitted from the light emitting element 101 is that the indirect emission spectrum reflected by the reflector and the emission spectrum directly emitted from the light emitting element 101 are applied to the phosphor 108 of the present invention to emit white light. It becomes a fluorescent substance.
[0162]
When a white LED lamp is formed using the light emitting device formed as described above, the yield is 99%. Thus, by using the light-emitting diode of the present invention, a light-emitting device can be produced with high productivity, and a light-emitting device with high reliability and less color unevenness can be provided.
[0163]
<Light-emitting device 3>
FIG. 9 is a diagram showing a cap-type light emitting device 3 according to the present invention.
[0164]
The same members as those in the light emitting device 1 are denoted by the same reference numerals, and the description thereof is omitted.
[0165]
The light emitting device 3 is configured by covering the surface of the mold member 15 of the light emitting device 1 with a cap 16 made of a light transmissive resin in which a phosphor (not shown) is dispersed. The cap 16 has the phosphor uniformly dispersed in the light transmissive resin. The light transmissive resin containing the phosphor is molded into a shape that fits into the shape of the mold member 15 of the light emitting device 1. Alternatively, a manufacturing method is also possible in which a light-transmitting resin containing a phosphor is placed in a predetermined mold and then the light-emitting device 1 is pushed into the mold and molded. Specific materials for the light transmissive resin of the cap 16 include transparent resins, silica sol, glass, inorganic binders, etc. that are excellent in temperature characteristics and weather resistance, such as epoxy resins, urea resins, and silicone resins. In addition to the above, thermosetting resins such as melamine resins and phenol resins can be used. In addition, thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, and polystyrene, thermoplastic rubbers such as styrene-butadiene block copolymer, segmented polyurethane, and the like can also be used. Further, a diffusing agent, barium titanate, titanium oxide, aluminum oxide or the like may be contained together with the phosphor. Moreover, you may contain a light stabilizer and a coloring agent. Example 15 is used as the phosphor used for the cap 16. Example 15 is used as the phosphor 11 used in the cup of the mount lead 13a. However, since the phosphor is used for the cap 16, only the coating member 12 may be provided in the cup of the mount lead 13a.
[0166]
In the light emitting device configured as described above, a part of the light emitted from the light emitting element 10 is wavelength-converted by the phosphor of Example 43 when passing through the cap 16. Such wavelength-converted light and blue light that has not been wavelength-converted by the phosphor are mixed. As a result, white light is emitted from the surface of the cap 16 to the outside.
[0167]
【The invention's effect】
As described above, the present invention uses a semiconductor light emitting element that emits blue light as an excitation light source, the wavelength of the light emitted by the semiconductor light emitting element is converted, and the nitride fluorescence having an emission spectrum in the yellow to red region. The body can be provided. A nitride-based phosphor can be used to provide a slightly reddish warm-colored white light-emitting device with good luminous efficiency.
[0168]
Further, the present invention is a light emitting device that emits white light, and the white light emitting has an average color rendering index Ra of 80 or more, and particularly has a special color rendering index R9 showing redness of 70 or more. An apparatus can be provided. Thereby, it is possible to provide a light emitting device that emits white light with excellent color rendering.
[0169]
In addition, a light emitting device in which multiple colors such as a pastel color are achieved by mixing one or more of a nitride phosphor, a phosphor emitting blue light, a phosphor emitting green light, and a phosphor emitting yellow light Can be provided.
[0170]
In addition, it is possible to provide a nitride phosphor whose afterglow and particle size are controlled within a predetermined range.
[0171]
Furthermore, it has a very important technical significance that it is possible to provide a nitride phosphor with improved light emission characteristics and durability.
[Brief description of the drawings]
FIG. 1 shows a light emitting device 1 according to the present invention.
FIG. 2 is a diagram showing a method for producing a nitride phosphor according to the present invention.
3 is a diagram showing an emission spectrum when the nitride phosphor of Example 3 is excited at Ex = 460 nm. FIG.
4 is a diagram showing an excitation spectrum of the nitride phosphor according to Example 3. FIG.
5 is a diagram showing a reflection spectrum of the nitride phosphor of Example 3. FIG.
6 is a SEM photograph of the nitride phosphor of Example 3. FIG.
FIG. 7 is a diagram showing chromaticity coordinates of the light emitting device 1 according to the present invention.
FIG. 8 is a view showing a light emitting device 2 according to the present invention.
FIG. 9 is a diagram showing a cap-type light emitting device 3 according to the present invention.
[Explanation of symbols]
P1 Raw material Ca is pulverized.
P2 Raw material Ca is nitrided in a nitrogen atmosphere.
P3 Ca nitride is pulverized.
P4 Raw material Si is pulverized.
P5 Raw material Si is nitrided in a nitrogen atmosphere.
P6 Si nitride is pulverized.
Compound Eu of P7 Eu₂O₃And B compound H₃BO₃Wet mix.
P8 Eu Compound Eu₂O₃And the compound H of B₃BO₃And the mixture is fired in an oxidizing atmosphere.
Grind the mixture of P9 Eu and B.
P10 Ca nitride, Si nitride, and a mixture of Eu and B are mixed.
P11 Ca nitride, Si nitride, and a mixture of Eu and B are fired in an ammonia atmosphere.
Ca with P12 B added₂Si₅N₈: A phosphor represented by Eu.
1 Substrate
2 Semiconductor layer
3 electrodes
4 Bump
10 Light emitting element
11 Phosphor
12 Coating material
13 Lead frame
13a Mount lead
13b Inner lead
14 Conductive wire
15 Mold member
101 Light emitting device
102 Lead electrode
103 Insulating sealing material
104 conductive wire
105 packages
106 Lid
107 windows
108 Phosphor
109 Coating material

Claims (10)

_{Formula, L X Si Y N ((} 2/3) X + (4/3) Y): Eu or _{L X Si Y O Z N (} (2/3) X + (4/3) Y- (2/3 _{) Z)} : Eu (L is at least one group II element selected from the group consisting of Mg, Ca, Sr, Ba, Zn. X, Y, Z are X = 2 and Y = 5. 0 <Z ≦ 3), and a nitride phosphor represented by
The nitride phosphor has an added amount of B except that BN is contained in a raw material in an amount of 0.25 wt% to 3.00 wt% or H ₃ BO ₃ is contained in an amount of 0.25 wt% to 3.00 wt%. 10 to 10,000 ppm, and B contains 1 ppm to 10,000 ppm after firing .   2. The nitride phosphor according to claim 1, wherein the crystal structure of the nitride phosphor is monoclinic or orthorhombic. 3.   The nitride phosphor further includes at least one group I element selected from the group consisting of Li, Na, K, Rb, and Cs in a range of 0.1 to 500 ppm. Item 3. The nitride phosphor according to Item 1 or 2.   The nitride phosphor further includes a group I element composed of Cu, Ag, Au, a group III element composed of Al, Ga, In, a group IV element composed of Ti, Zr, Hf, Sn, Pb, P At least one element selected from Group V elements composed of Sb, Bi, and Group VI elements composed of S is contained in an amount of 0.1 to 500 ppm. The nitride phosphor according to any one of the above.   The nitride phosphor according to any one of claims 1 to 4, wherein the nitride phosphor further contains one or more elements of Ni and Cr in an amount of 1 to 500 ppm.   6. The nitride phosphor according to claim 1, wherein the nitride phosphor has an average particle diameter of 2 to 15 μm. An excitation light source that emits light in the short wavelength region from near ultraviolet to visible light;
A phosphor that converts the wavelength of at least part of the light from the excitation light source and emits light in a longer wavelength region than the light from the excitation light source;
A light emitting device comprising:
The light emitting device characterized in that the phosphor has at least the nitride phosphor according to any one of claims 1 to 6.   The light emitting device according to claim 7, wherein the phosphor further includes at least one of a phosphor that emits blue light, a phosphor that emits green light, and a phosphor that emits yellow light. .   The light emitting device according to claim 7, wherein the excitation light source is a semiconductor light emitting element. The light emitting device includes a part of the light from the excitation light source that transmits between particles of the phosphor,
A portion of the light emitted from the phosphor, wavelength-converted by light from the excitation light source;
The light emitting device according to claim 7, wherein the light emitting device emits white light by being mixed and emitted.

Images