JP2004210921A - Oxynitride fluorophor and method for producing the same and light-emitting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorophor subject to excitation by an excitation light source with ultraviolet to visible ray region and having luminescent color in a bluish green-color to green-color region subject to wavelength conversion. <P>SOLUTION: The oxynitride fluorophor is such that at least one rare earth element with Eu as the essential element is used as an activator R, essentially containing at least one groupII element with Ba as the essential element selected from the group consisting of Ca, Sr, Ba and Zn, and at least one groupIV element with at least Si as the essential element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr and Hf. In this fluorophor, the molar ratio: the groupII element to R is (1:0.005) to (1:0.15). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

ただし、この組成は、配合比率より推定される代表組成であり、その比率の近傍では、実用に耐える十分な特性を有する。また、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。
【００８４】
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、特に限定されないが、１２００から１７００℃の範囲で焼成を行うことが好ましく、１４００から１７００℃の焼成温度が、さらに好ましい。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。
【００８５】
また、焼成は、還元雰囲気中で行うことが好ましい。還元雰囲気は、窒素雰囲気、窒素−水素雰囲気、アンモニア雰囲気、アルゴン等の不活性ガス雰囲気等である。
【００８６】
以上の製造方法を使用することにより、目的とするオキシ窒化物蛍光体を得ることが可能である。
【００８７】
なお、Ｂａ_ＸＳｉ_ＹＢ_ＴＯ_ＺＮ_{（（２／３）Ｘ＋Ｙ＋Ｔ−（２／３）Ｚ−α）}：Ｅｕで表されるオキシ窒化物蛍光体は、以下のようにして製造することができる。
【００８８】
あらかじめ、Ｅｕの酸化物に、Ｂの化合物Ｈ_３ＢＯ_３を乾式混合する。Ｅｕの化合物として、酸化ユウロピウムを使用するが、前述の他の構成元素と同様、金属ユウロピウム、窒化ユウロピウムなども使用可能である。このほか、原料のＥｕは、イミド化合物、アミド化合物を用いることもできる。酸化ユウロピウムは、高純度のものが好ましいが、市販のものも使用することができる。Ｂの化合物を乾式混合するが、湿式混合することもできる。これらの混合物は、酸化されやすいものもあるため、Ａｒ雰囲気中、又は、窒素雰囲気中、グローブボックス内で、混合を行う。
【００８９】
Ｂの化合物Ｈ_３ＢＯ_３を例にとって、オキシ窒化物蛍光体の製造方法を説明するが、Ｂ以外の成分構成元素には、Ｌｉ、Ｎａ、Ｋ等があり、これらの化合物、例えば、ＬｉＯＨ・Ｈ_２Ｏ、Ｎａ_２ＣＯ_３、Ｋ_２ＣＯ_３、ＲｂＣｌ、ＣｓＣｌ、Ｍｇ（ＮＯ_３）_２、ＣａＣｌ_２・６Ｈ_２Ｏ、ＳｒＣｌ_２・６Ｈ_２Ｏ、ＢａＣｌ_２・２Ｈ_２Ｏ、ＴｉＯＳＯ_４・Ｈ_２Ｏ、ＺｒＯ（ＮＯ_３）_２、ＨｆＣｌ_４、ＭｎＯ_２、ＲｅＣｌ_５、Ｃｕ（ＣＨ_３ＣＯＯ）_２・Ｈ_２Ｏ、ＡｇＮＯ_３、ＨＡｕＣｌ_４・４Ｈ_２Ｏ、Ｚｎ（ＮＯ_３）_２・６Ｈ_２Ｏ、ＧｅＯ_２、Ｓｎ（ＣＨ_３ＣＯＯ）_２等を使用することができる。
【００９０】
ＥｕとＢの混合物を粉砕する。粉砕後のＥｕとＢの混合物の平均粒径は、約０．１μｍから１５μｍであることが好ましい。
【００９１】
上記粉砕を行った後、前述のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕの製造工程とほぼ同様に、Ｂａの窒化物、Ｓｉの窒化物、Ｓｉの酸化物、Ｂを含有するＥｕの酸化物、を混合する。該混合後、焼成を行い、目的のオキシ窒化物蛍光体を得ることができる。
【００９２】
（第２の蛍光体１１、１０８）
蛍光体１１、１０８中には、オキシ窒化物蛍光体と共に、第２の蛍光体が含まれている。第２の蛍光体としては、Ｅｕ等のランタノイド系、Ｍｎ等の遷移金属系の元素により主に付活されるアルカリ土類ハロゲンアパタイト蛍光体、アルカリ土類金属ホウ酸ハロゲン蛍光体、アルカリ土類金属アルミン酸塩蛍光体、アルカリ土類ケイ酸塩、アルカリ土類硫化物、アルカリ土類チオガレート、アルカリ土類窒化ケイ素、ゲルマン酸塩、又は、Ｃｅ等のランタノイド系元素で主に付活される希土類アルミン酸塩、希土類ケイ酸塩、又は、Ｅｕ等のランタノイド系元素で主に賦活される有機及び有機錯体等から選ばれる少なくともいずれか１以上であることが好ましい。具体例として、下記の蛍光体を使用することができるが、これに限定されない。
【００９３】
Ｅｕ等のランタノイド系、Ｍｎ等の遷移金属系の元素により主に付活されるアルカリ土類ハロゲンアパタイト蛍光体には、Ｍ_５（ＰＯ_４）_３Ｘ：Ｒ（Ｍは、Ｓｒ、Ｃａ、Ｂａ、Ｍｇ、Ｚｎから選ばれる少なくとも１種以上である。Ｘは、Ｆ、Ｃｌ、Ｂｒ、Ｉから選ばれる少なくとも１種以上である。Ｒは、Ｅｕ、Ｍｎ、ＥｕとＭｎ、のいずれか１以上である。）などがある。
【００９４】
アルカリ土類金属ホウ酸ハロゲン蛍光体には、Ｍ_２Ｂ_５Ｏ_９Ｘ：Ｒ（Ｍは、Ｓｒ、Ｃａ、Ｂａ、Ｍｇ、Ｚｎから選ばれる少なくとも１種以上である。Ｘは、Ｆ、Ｃｌ、Ｂｒ、Ｉから選ばれる少なくとも１種以上である。Ｒは、Ｅｕ、Ｍｎ、ＥｕとＭｎ、のいずれか１以上である。）などがある。
【００９５】
アルカリ土類金属アルミン酸塩蛍光体には、ＳｒＡｌ_２Ｏ_４：Ｒ、Ｓｒ_４Ａｌ_１４Ｏ_２５：Ｒ、ＣａＡｌ_２Ｏ_４：Ｒ、ＢａＭｇ_２Ａｌ_１６Ｏ_２７：Ｒ、ＢａＭｇ_２Ａｌ_１６Ｏ_１２：Ｒ、ＢａＭｇＡｌ_１０Ｏ_１７：Ｒ（Ｒは、Ｅｕ、Ｍｎ、ＥｕとＭｎ、のいずれか１以上である。）などがある。
【００９６】
アルカリ土類硫化物蛍光体には、Ｌａ_２Ｏ_２Ｓ：Ｅｕ、Ｙ_２Ｏ_２Ｓ：Ｅｕ、Ｇｄ_２Ｏ_２Ｓ：Ｅｕなどがある。
【００９７】
Ｃｅ等のランタノイド系元素で主に賦活される希土類アルミン酸塩蛍光体には、Ｙ_３Ａｌ_５Ｏ_１２：Ｃｅ、（Ｙ_０．８Ｇｄ_０．２）_３Ａｌ_５Ｏ_１２：Ｃｅ、Ｙ_３（Ａｌ_０．８Ｇａ_０．２）_５Ｏ_１２：Ｃｅ、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２の組成式で表されるＹＡＧ系蛍光体などがある。
【００９８】
その他の蛍光体には、ＺｎＳ：Ｅｕ、Ｚｎ_２ＧｅＯ_４：Ｍｎ、ＭＧａ_２Ｓ_４：Ｅｕ（Ｍは、Ｓｒ、Ｃａ、Ｂａ、Ｍｇ、Ｚｎから選ばれる少なくとも１種以上である。Ｘは、Ｆ、Ｃｌ、Ｂｒ、Ｉから選ばれる少なくとも１種以上である。）などがある。また、Ｍ_２Ｓｉ_５Ｎ_８：Ｅｕ、ＭＳｉ_７Ｎ_１０：Ｅｕ、Ｍ_１．８Ｓｉ_５Ｏ_０．２Ｎ_８：Ｅｕ、Ｍ_０．９Ｓｉ_７Ｏ_０．１Ｎ_１０：Ｅｕ（Ｍは、Ｓｒ、Ｃａ、Ｂａ、Ｍｇ、Ｚｎから選ばれる少なくとも１種以上である。）などもある。
【００９９】
上述の第２の蛍光体は、所望に応じてＥｕに代えて、又は、Ｅｕに加えてＴｂ、Ｃｕ、Ａｇ、Ａｕ、Ｃｒ、Ｎｄ、Ｄｙ、Ｃｏ、Ｎｉ、Ｔｉから選択される１種以上を含有させることもできる。
【０１００】
また、上記蛍光体以外の蛍光体であって、同様の性能、効果を有する蛍光体も使用することができる。
【０１０１】
これらの第２の蛍光体は、発光素子１０、１０１の励起光により、黄色、赤色、緑色、青色に発光スペクトルを有する蛍光体を使用することができるほか、これらの中間色である黄色、青緑色、橙色などに発光スペクトルを有する蛍光体も使用することができる。これらの第２の蛍光体を第１の蛍光体と組み合わせて使用することにより、種々の発光色を有する発光装置を製造することができる。
【０１０２】
例えば、第１の蛍光体である緑色から黄色に発光するＣａＳｉ_２Ｏ_２Ｎ_２：Ｅｕ、又はＳｒＳｉ_２Ｏ_２Ｎ_２：Ｅｕと、第２の蛍光体である青色に発光する（Ｓｒ，Ｃａ）_５（ＰＯ_４）_３Ｃｌ：Ｅｕ、赤色に発光する（Ｃａ，Ｓｒ）_２Ｓｉ_５Ｎ_８：Ｅｕと、からなる蛍光体１１、１０８を使用することによって、演色性の良好な白色に発光する発光装置を提供することができる。これは、色の三源色である赤・青・緑を使用しているため、第１の蛍光体及び第２の蛍光体の配合比を変えることのみで、所望の白色光を実現することができる。特に、励起光源に４６０ｎｍ近傍の光を用いて、オキシ窒化物蛍光体と第２の蛍光体に照射させたとき、オキシ窒化物蛍光体が５００ｎｍ近傍の光を発光する。これにより、演色性に優れた白色系発光装置を提供することができる。
【０１０３】
上記蛍光体１１、１０８の粒径は、１μｍ〜２０μｍの範囲が好ましく、より好ましくは２μｍ〜８μｍである。特に、５μｍ〜８μｍが好ましい。２μｍより小さい粒径を有する蛍光体は、凝集体を形成しやすい傾向にある。一方、５μｍ〜８μｍの粒径範囲の蛍光体は、光の吸収率及び変換効率が高い。このように、光学的に優れた特徴を有する粒径の大きな蛍光体を含有させることにより、発光装置の量産性が向上する。
【０１０４】
ここで粒径は、空気透過法で得られる平均粒径を指す。具体的には、気温２５℃、湿度７０％の環境下において、１ｃｍ^３分の試料を計り取り、専用の管状容器にパッキングした後、一定圧力の乾燥空気を流し、差圧から比表面積を読みとり、平均粒径に換算した値である。本発明で用いられる蛍光体の平均粒径は２μｍ〜８μｍの範囲であることが好ましい。また、この平均粒径値を有する蛍光体が、頻度高く含有されていることが好ましい。また、粒度分布も狭い範囲に分布しているものが好ましく、特に、微粒子２μｍ以下の少ないものが好ましい。このように粒径、及び粒度分布のバラツキが小さい蛍光体を用いることにより、より色ムラが抑制され、良好な色調を有する発光装置が得られる。
【０１０５】
発光装置２における蛍光体１０８の配置場所は発光素子１０１との位置関係において種々の場所に配置することができる。例えば、発光素子１０１を被覆するモールド材料中に、蛍光体１０８を含有させることができる。また、発光素子１０１と蛍光体１０８とを、間隙をおいて配置しても良いし、発光素子１０１の上部に蛍光体１０８を、直接載置しても良い。
【０１０６】
（コーティング部材１２、１０９）
蛍光体１１、１０８は、有機材料である樹脂や無機材料であるガラスなど種々のコーティング部材（バインダー）を用いて、付着させることができる。コーティング部材１２、１０９は、蛍光体１１、１０８を発光素子１０、１０１や窓部１０７等に固着させるためのバインダーとしての役割を有することもある。コーティング部材（バインダー）として有機物を使用する場合、具体的材料として、エポキシ樹脂、アクリル樹脂、シリコーンなどの耐候性に優れた透明樹脂が好適に用いられる。特に、シリコーンを用いると、信頼性に優れ、且つ蛍光体１１、１０８の分散性を向上させることができ好ましい。
【０１０７】
また、コーティング部材（バインダー）１２、１０９として、窓部１０７の熱膨張率と近似である無機物を使用すると、蛍光体１０８を良好に前記窓部１０７に密着させることができ好ましい。具体的方法として、沈降法やゾル−ゲル法、スプレー法等を用いることができる。例えば、蛍光体１１、１０８に、シラノール（Ｓｉ（ＯＥｔ）_３ＯＨ）、及びエタノールを混合してスラリーを形成し、該スラリーをノズルから吐出させた後、３００℃にて３時間加熱してシラノールをＳｉＯ_２とし、蛍光体を所望の場所に固着させることができる。
【０１０８】
また、無機物である結着剤をコーティング部材（バインダー）１２、１０９として用いることもできる。結着剤とは、いわゆる低融点ガラスであり、微細な粒子であり、且つ紫外から可視領域の輻射線に対して吸収が少なく、コーティング部材（バインダー）１２、１０９中にて極めて安定であることが好ましい。
【０１０９】
また、粒径の大きな蛍光体をコーティング部材（バインダー）１２、１０９に付着させる場合、融点が高くても粒子が超微粉体である結着剤、例えば、シリカ、アルミナ、あるいは沈殿法で得られる細かい粒度のアルカリ土類金属のピロリン酸塩、正りん酸塩などを使用することが好ましい。これらの結着剤は、単独、若しくは互いに混合して用いることができる。
【０１１０】
ここで、上記結着剤の塗布方法について述べる。結着剤は、結着効果を十分に高めるため、ビヒクル中に湿式粉砕して、スラリー状にして、結着剤スラリーとして用いることが好ましい。前記ビヒクルとは、有機溶媒あるいは脱イオン水に少量の粘結剤を溶解して得られる高粘度溶液である。例えば、有機溶媒である酢酸ブチルに対して粘結剤であるニトロセルロースを１ｗｔ％含有させることにより、有機系ビヒクルが得られる。
【０１１１】
このようにして得られた結着剤スラリーに、蛍光体１１、１０８を含有させて塗布液を作製する。塗布液中のスラリーの添加量は、塗布液中の蛍光体量に対してスラリー中の結着剤の総量が、１〜３％ｗｔ程度とすることができる。光束維持率の低下を抑制するため、結着剤の添加量が少ない方が好ましい。
【０１１２】
前記塗布液を前記窓部１０７の背面に塗布する。その後、温風あるいは熱風を吹き込み乾燥させる。最後に４００℃〜７００℃の温度でベーキングを行い、前記ビヒクルを飛散させる。これにより所望の場所に蛍光体層が結着剤にて付着される。
【０１１３】
（発光素子１０、１０１）
本発明において発光素子１０、１０１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１１、１０８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、０≦Ｙ、Ｘ＋Ｙ≦１）がより好適に挙げられる。
【０１１４】
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。
【０１１５】
発光素子１０、１０１に、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。
【０１１６】
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。
【０１１７】
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。
【０１１８】
本発明の発光装置において、量産性よく形成させるためには、蛍光体１１、１０８を発光素子１０、１０１に固着する際に、樹脂を利用して形成することが好ましい。この場合、蛍光体１１、１０８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１０、１０１は紫外域に発光スペクトルを有し、その発光ピーク波長は、３６０ｎｍ以上４２０ｎｍ以下のものや、４５０ｎｍ以上４７０ｎｍ以下のものを使用することが好ましい。
【０１１９】
ここで、本発明で用いられる半導体発光素子１０、１０１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。
【０１２０】
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。
【０１２１】
上述のように、本発明で用いられる半導体発光素子１０、１０１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１０、１０１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。
【０１２２】
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。
【０１２３】
（発光素子１０、１０１）
発光素子１０、１０１は、上述の紫外発光の発光素子と異なる青色系に発光する発光素子を使用することもできる。青色系に発光する発光素子１０、１０１は、ＩＩＩ族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、１０１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も使用できる。
【０１２４】
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パッド電極が形成される。
【０１２５】
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。
【０１２６】
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がドープされたＧａＮを利用しても良い。
【０１２７】
また、発光素子１０、１０１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波長を変更することができる。また、発光ピーク波長は、上記範囲に限定されるものではなく、３６０〜５５０ｎｍに発光ピーク波長を有しているものを使用することができる。
【０１２８】
（コーティング部材１２、１０９）
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。
【０１２９】
（リードフレーム１３）
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。
【０１３０】
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。
【０１３１】
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。
【０１３２】
（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。
【０１３３】
（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。
【０１３４】
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。
【０１３５】
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、前述の平均粒径を示し、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。
【０１３６】
【実施例】
以下、本発明の実施例について詳述する。
【０１３７】
（蛍光体）
図４は、実施例１乃至５のオキシ窒化物蛍光体をＥｘ＝４００ｎｍで励起したときの発光スペクトルを示す図である。図５は、実施例１乃至５のオキシ窒化物蛍光体を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６は、実施例１乃至５のオキシ窒化物蛍光体の励起スペクトルを示す図である。図７は、実施例１乃至５のオキシ窒化物蛍光体の反射スペクトルを示す図である。図８は、実施例１のオキシ窒化物蛍光体を撮影したＳＥＭ写真である。図８（ａ）は、１０００倍で撮影したものであり、図８（ｂ）は、５０００倍で撮影したのものである。
【０１３８】
実施例１乃至５は、Ｂａの一部をＥｕで置換しており、該Ｅｕ濃度を変えている。実施例１は、Ｂａ_０．９７Ｅｕ_０．０３Ｓｉ_２Ｏ_２Ｎ_２である。実施例２は、Ｂａ_０．９５Ｅｕ_０．０５Ｓｉ_２Ｏ_２Ｎ_２である。実施例３は、Ｂａ_０．９０Ｅｕ_０．１０Ｓｉ_２Ｏ_２Ｎ_２である。実施例４は、Ｂａ_０．８５Ｅｕ_０．１５Ｓｉ_２Ｏ_２Ｎ_２である。実施例５は、Ｂａ_０．８０Ｅｕ_０．２０Ｓｉ_２Ｏ_２Ｎ_２である。
【０１３９】
まず、原料は、Ｂａ_３Ｎ_２、Ｓｉ_３Ｎ_４、ＳｉＯ_２、Ｅｕ_２Ｏ_３を使用した。該原料を、それぞれ０．１〜３．０μｍに粉砕した。粉砕後、実施例１は、上記組成となるように、下記の数量の原料を使用した。ここで、Ｂａに対してＥｕのモル比は、Ｂａ：Ｅｕ＝０．９７：０．０３である。
Ｂａ_３Ｎ_２：５．６０ｇ
Ｓｉ_３Ｎ_４：１．８８ｇ
ＳｉＯ_２：２．３１ｇ
Ｅｕ_２Ｏ_３：０．２１ｇ
上記数量を秤量した後、Ｂａ_３Ｎ_２、Ｓｉ_３Ｎ_４、ＳｉＯ_２、Ｅｕ_２Ｏ_３を、均一になるまで混合した。
【０１４０】
上記化合物を混合し、アンモニア雰囲気中で、窒化ホウ素坩堝に投入し、約１５００℃で約５時間、焼成を行った。
【０１４１】
これにより、目的とするオキシ窒化物蛍光体を得た。得られたオキシ窒化物蛍光体の理論組成は、ＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕである。
【０１４２】
実施例１のオキシ窒化物蛍光体のＯとＮとの重量％を測定すると、全量中にＯが１２．１重量％、Ｎが８．９重量％含まれていた。ＯとＮの重量比は、Ｏ：Ｎ＝１：０．７４である。
【０１４３】
実施例に係るオキシ窒化物蛍光体は、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。坩堝に、金属製の坩堝を使用することはあまり好ましいとはいえない。金属製の坩堝を使用した場合、坩堝が浸食され、発光特性の低下を引き起こすことが考えられるからである。従って、アルミナなどのセラミックス製の坩堝を使用することが好ましい。
【０１４４】
実施例２は、Ｅｕの配合比を変化させたものである。Ｂａの一部をＥｕに置換したオキシ窒化物蛍光体である。細かく砕いた粉末を、下記の数量、秤量した。ここで、Ｂａに対してＥｕのモル比は、Ｂａ：Ｅｕ＝０．９５：０．０５である。
Ｂａ_３Ｎ_２：５．４８ｇ
Ｓｉ_３Ｎ_４：１．９１ｇ
ＳｉＯ_２：２．２８ｇ
Ｅｕ_２Ｏ_３：０．３５ｇ
実施例１と同条件で、該原料を混合し、焼成を行った。
【０１４５】
実施例３は、Ｅｕの配合比を変化させたものである。Ｂａの一部をＥｕに置換したオキシ窒化物蛍光体である。細かく砕いた粉末を、下記の数量、秤量した。ここで、Ｂａに対してＥｕのモル比は、Ｂａ：Ｅｕ＝０．９０：０．１０である。
Ｂａ_３Ｎ_２：５．１８ｇ
Ｓｉ_３Ｎ_４：１．９７ｇ
ＳｉＯ_２：２．１８ｇ
Ｅｕ_２Ｏ_３：０．６９ｇ
実施例１と同条件で、該原料を混合し、焼成を行った。
【０１４６】
実施例４は、Ｅｕの配合比を変化させたものである。Ｂａの一部をＥｕに置換したオキシ窒化物蛍光体である。細かく砕いた粉末を、下記の数量、秤量した。ここで、Ｂａに対してＥｕのモル比は、Ｂａ：Ｅｕ＝０．８５：０．１５である。
Ｂａ_３Ｎ_２：４．８７ｇ
Ｓｉ_３Ｎ_４：２．０３ｇ
ＳｉＯ_２：２．０９ｇ
Ｅｕ_２Ｏ_３：１．０３ｇ
実施例１と同条件で、該原料を混合し、焼成を行った。
【０１４７】
実施例５は、Ｅｕの配合比を変化させたものである。Ｂａの一部をＥｕに置換したオキシ窒化物蛍光体である。細かく砕いた粉末を、下記の数量、秤量した。ここで、Ｂａに対してＥｕのモル比は、Ｂａ：Ｅｕ＝０．８０：０．２０である。
Ｂａ_３Ｎ_２：４．５７ｇ
Ｓｉ_３Ｎ_４：２．１０ｇ
ＳｉＯ_２：１．９９ｇ
Ｅｕ_２Ｏ_３：１．３７ｇ
実施例１と同条件で、該原料を混合し、焼成を行った。
【０１４８】
実施例１乃至５の焼成品は、いずれも、結晶性の粉体若しくは粒体である。粒径は、ほぼ１〜５μｍであった。
【０１４９】
表１は、実施例１乃至５のオキシ窒化物蛍光体をＥｘ＝４００ｎｍで励起させたときの発光特性を示す。
【０１５０】
【表１】

実施例１乃至５のオキシ窒化物蛍光体の励起スペクトルを測定した。測定の結果、実施例１乃至４は、３５０ｎｍ近傍よりも３７０ｎｍから４７０ｎｍの方が強く励起される。
【０１５１】
実施例１乃至５のオキシ窒化物蛍光体の反射スペクトルを測定した。測定の結果、実施例１乃至５は、２９０ｎｍから４７０ｎｍまで、高い吸収率を示す。そのため、２９０ｎｍから４７０ｎｍまでの励起光源からの光を効率よく吸収し、波長変換を行うことができる。
【０１５２】
励起光源として、Ｅｘ＝４００ｎｍ近傍の光を実施例１乃至５のオキシ窒化物蛍光体に照射して励起させた。実施例１のオキシ窒化物蛍光体は、色調ｘ＝０．１０６、色調ｙ＝０．４７１、発光ピーク波長λｐ＝４９６ｎｍの緑色領域に発光色を有する。実施例２は、色調ｘ＝０．１２１、色調ｙ＝０．４８１、λｐ＝４９８ｎｍの緑色領域に発光色を有する。実施例３は、色調ｘ＝０．２４７、色調ｙ＝０．４７７、λｐ＝５００ｎｍの緑色領域に発光色を有する。実施例１乃至３のオキシ窒化物蛍光体のいずれも、従来の蛍光体よりも、高い発光効率を示した。特に、実施例１乃至４のオキシ窒化物蛍光体は、実施例５よりも高い発光効率を示した。なお、実施例２乃至５は、実施例１の発光輝度及び量子効率を１００％として、その相対値で表す。
【０１５３】
表２は、実施例１のオキシ窒化物蛍光体の温度特性を示す。温度特性は、２５℃の発光輝度を１００％とする相対輝度で示す。励起光源は、Ｅｘ＝４００ｎｍ近傍の光である。
【０１５４】
【表２】

この結果より、オキシ窒化物蛍光体を１００℃まで昇温したとき、８８．８％と、極めて高い発光輝度を維持しており、さらに２００℃まで昇温しても６４．７％と、高い発光輝度を維持している。これより、オキシ窒化物蛍光体は、極めて良好な温度特性を示す。
【０１５５】
これら上記オキシ窒化物蛍光体のＸ線回折像を測定したところ、いずれもシャープな回折ピークを示し、得られた蛍光体が、規則性を有する結晶性の化合物であることが明らかとなった。
【０１５６】
＜発光装置＞
上述のオキシ窒化物蛍光体を用いて、実施例１の発光装置を製造した。励起光源として、４００ｎｍの発光スペクトルを有する発光素子を使用する。蛍光体は、実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕと、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅと、ＳｒＣａＳｉ_５Ｎ_８：Ｅｕと、（Ｃａ_０．９３，Ｅｕ_０．０５，Ｍｎ_０．０２）_１０（ＰＯ_４）_６Ｃｌ_２を使用する。図１は、本発明に係る発光装置を示す。図９は、本発明に係る発光素子を示す平面図である。図１０は、本発明に係る発光素子のＡ−Ａ‘を示す断面図である。図１１は、実施例１の発光装置の発光スペクトル（シミュレーション）を示す図である。図１２は、実施例１乃至３の発光装置の色度座標（シミュレーション）を示す図である。該実施例１の発光装置は、色温度を４０００〜５０００Ｋに合わせている。
【０１５７】
（発光素子）
サファイア（Ｃ面）よりなる基板２０１をＭＯＶＰＥの反応容器内にセットし、水素を流しながら、基板２０１の温度を約１０５０℃まで上昇させ、基板２０１のクリーニングを行う。
【０１５８】
ここで、本実施例では、基板２０１に、サファイア基板を用いているが、基板２０１として窒化物半導体と異なる異種基板、ＡｌＮ、ＡｌＧａＮ、ＧａＮ等の窒化物半導体基板を用いてもよい。異種基板としては、例えば、Ｃ面、Ｒ面及びＡ面のいずれかを主面とするサファイア、スピネル（ＭｇＡｌ_２Ｏ_４のような絶縁性基板、ＳｉＣ（６Ｈ、４Ｈ、３Ｃを含む）、ＺｎＳ、ＺｎＯ、ＧａＡｓ、Ｓｉ及び窒化物半導体と格子整合する酸化物基板等、窒化物半導体を成長させることが可能であり、窒化物半導体と異なる基板材料を用いることができる。好ましい異種基板としては、サファイア、スピネルが挙げられる。また、異種基板は、オフアングルしていてもよく、この場合、ステップ状にオフアングルしたものを用いると窒化ガリウムからなる下地層２０２の成長が結晶性よく成長するため好ましい。更に、異種基板を用いる場合には、異種基板上に素子構造形成前の下地層２０２となる窒化物半導体を成長させた後、異種基板を研磨などの方法により除去して、窒化物半導体の単体基板として素子構造を形成してもよく、また、素子構造形成後に、異種基板を除去する方法でも良い。ＧａＮ基板の他に、ＡｌＮ等の窒化物半導体の基板を用いても良い。
【０１５９】
（バッファ層）
続いて、基板２０１の温度を５１０℃まで下げ、キャリアガスに水素、原料ガスにアンモニアとＴＭＧ（トリメチルガリウム）とを用い、基板２０１上にＧａＮよりなるバッファ層（図示しない）を約１００オングストロームの膜厚で成長させる。
【０１６０】
（下地層）
バッファ層成長後、ＴＭＧのみ止めて、基板２０１の温度を１０５０℃まで上昇させる。１０５０℃になったら、同じく原料ガスにＴＭＧ、アンモニアガスを用い、アンドープＧａＮ層を２μｍの膜厚で成長させる。
【０１６１】
（ｎ型層）
続いて１０５０℃で、同じく原料ガスにＴＭＧ、アンモニアガス、不純物ガスにシランガスを用い、Ｓｉを４．５×１０^１８／ｃｍ^３ドープしたＧａＮよりなるｎ型層２０３を、ｎ型層としてｎ側電極２１１ａを形成するｎ側コンタクト層として、厚さ３μｍで成長させる。
【０１６２】
（活性層）
ＳｉドープＧａＮよりなる障壁層を５０オングストロームの膜厚で成長させ、続いて温度を８００℃にして、ＴＭＧ、ＴＭＩ、アンモニアを用いアンドープＩｎ_０．１Ｇａ_０．７Ｎよりなる井戸層を５０オングストロームの膜厚で成長させる。そして障壁＋井戸＋障壁＋井戸・・・＋障壁の順で障壁層を４層、井戸を３層、交互に積層して、総膜厚３５０オングストロームの多重量子井戸構造よりなる活性層２０４を成長させる。
【０１６３】
（ｐ側キャリア閉込め層）
次に、ＴＭＧ、ＴＭＡ、アンモニア、Ｃｐ_２Ｍｇ（シクロペンタジエニルマグネシウム）を用い、Ｍｇを５×１０^１９／ｃｍ^３ドープしたＡｌ_０．３Ｇａ_０．７Ｎよりなるｐ側キャリア閉込め層２０５を、膜厚１００オングストロームで成長させる。
【０１６４】
（第１ｐ型層）
続いて、ＴＭＧ、アンモニア、Ｃｐ_２Ｍｇを用い、ｐ型不純物をドープしたＧａＮよりなる第１ｐ型層２０６を、膜厚０．１μｍで成長させる。
【０１６５】
（第２ｐ型層）
第２ｐ型層として、表面にｐ側電極２１０を形成するｐ側コンタクト層２０８を形成する。ｐ側コンタクト層２０８は、電流拡散層２０７の上に、Ｍｇを１×１０^２０／ｃｍ^３ドープしたｐ型ＧａＮを１５０オングストロームの膜厚で成長させる。ｐ側コンタクト層２０８は、ｐ側電極２１０を形成する層であるので、１×１０^１７／ｃｍ^３以上の高キャリア濃度とすることが望ましい。１×１０^１７／ｃｍ^３よりも低いと電極と好ましいオーミックを得るのが難しくなる傾向にある。さらにコンタクト層の組成をＧａＮとすると、電極材料と好ましいオーミックが得られやすくなる。
【０１６６】
以上の素子構造を形成する反応を終了した後、温度を室温まで下げ、さらに窒素雰囲気中、ウェハーを反応容器内において、７００℃でアニーリングを行い、ｐ型層をさらに低抵抗化する。素子構造を形成したウェハーを装置から取り出し、以下に説明する電極形成工程を実施する。
【０１６７】
アニーリング後、ウェハーを反応容器から取り出し、最上層のｐ側コンタクト層２０８の表面に所定のマスクを形成し、ＲＩＥ（反応性イオンエッチング）装置でｐ側コンタクト層２０８側からエッチングを行い、ｎ側コンタクト層の表面を露出させて、電極形成面を形成する。
【０１６８】
ｐ側電極２１０として、Ｎｉ、Ａｕを順に積層して、Ｎｉ／Ａｕよりなるｐ側電極２１０を形成する。また、このｐ側電極２１０は、第２ｐ型層、ｐ側コンタクト層２０８にオーミック接触させたオーミック電極となる。このとき、形成された電極枝２１０ａは、ストライプ状の発光部２０９の幅を約５μｍ、ストライプ状の電極枝２１０ａの幅を約３μｍとし、ストライプ状の発光部２０９と電極枝２１０ａを交互に形成する。また、ｐ側パット電極が形成される領域には、ｐ側電極２１０を一部だけ形成し、ｐ側パット電極の上にわたって形成して、電気的に導通させる。このとき、ｐ側パット電極が形成される領域には、ｐ側電極２１０を一部だけ形成し、ｐ側パット電極２１０ｂを、ｐ側コンタクト層２０８の表面上に形成して、一部をｐ側電極２１０の上にわたって形成して、電気的に導通させる。このとき、ｐ側パット電極２１０ｂが設けられるｐ側コンタクト層２０８の表面は、ｐ側電極２１０とｐ側コンタクト層２０８とはオーミック接触させずに、ショットキー障壁が両者の間に形成されて、ｐ側パット電極２１０ｂの形成部からは、直接素子内部に電流が流れずに、電気的に接続された電極枝２１０ａを通って、電流を素子内部に注入する構造となる。
【０１６９】
続いて、ｎ型層２０３を露出させた露出面２０３ａに、ｎ側電極２１１ａを形成する。ｎ側電極２１１ａは、Ｔｉ、Ａｌを積層して形成する。
【０１７０】
ここで、ｎ側電極２１１ａは、ｎ型層２０３の露出面２０３ａにオーミック接触させたオーミック電極となる。オーミック用のｐ側電極２１０、ｎ側電極２１１ａを形成した後、熱処理でアニールして、各電極をオーミック接触させる。この時得られるｐ側のオーミック電極は、活性層２０４の発光をほぼ透過しない不透光性膜となる。
【０１７１】
続いて、上記ｐ側電極２１０、ｎ側電極２１１ａの一部、若しくは全部を除く表面全体に、すなわち、ｎ型層２０３の露出面２０３ａ及び該露出面２０３ａの側面などの素子表面全体に、ＳｉＯ_２よりなる絶縁膜を形成する。絶縁膜形成後、絶縁膜から露出したｐ側電極２１０、ｎ側電極２１１ａの表面に、それぞれボンディング用のパット電極を形成して、各オーミック用の電極に電気的に導通させる。ｐ側パット電極２１０ｂ、ｎ側パット電極２１１ｂは、各オーミック用の電極の上に、Ｎｉ、Ｔｉ、Ａｕを積層してそれぞれ形成する。
【０１７２】
最後に、基板２０１を分割して、一辺の長さが３００μｍの発光素子を得る。
【０１７３】
得られた発光素子は、発光ピーク波長が約４００ｎｍである。
【０１７４】
（蛍光体）
実施例１の発光装置には、実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕと、（Ｃａ_０．９３，Ｅｕ_０．０５，Ｍｎ_０．０２）_１０（ＰＯ_４）_６Ｃｌ_２と、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅと、ＳｒＣａＳｉ_５Ｎ_８：Ｅｕとを使用する。この配合比は、適宜変更することができる。Ｅｘ＝４００ｎｍの励起光源を用いて、これらの蛍光体に照射する。これらの蛍光体は、該励起光源からの光を吸収し、波長変換を行い、所定の発光波長を有する。実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは、４７０ｎｍ〜５３０ｎｍに発光ピーク波長を有する。（Ｃａ_０．９３，Ｅｕ_０．０５，Ｍｎ_０．０２）_１０（ＰＯ_４）_６Ｃｌ_２は、４４０〜５００ｎｍに発光ピーク波長を有する。（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは、５００〜６５０ｎｍに発光ピーク波長を有する。ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは、５８０ｎｍ〜７３０ｎｍに発光ピーク波長を有する。
【０１７５】
（実施例１の発光装置の特性）
表３は、実施例１の発光装置の特性及び演色性を示す。但し、この実施例１の発光装置の特性及び演色性は、シミュレーションであり、実際に製造した場合は、自己吸収が起こり、波長のズレが生ずると思われる。比較例１の発光装置として、Ｅｘ＝４００ｎｍの励起光源を用いて、（Ｃａ_０．９３，Ｅｕ_０．０５，Ｍｎ_０．０２）_１０（ＰＯ_４）_６Ｃｌ_２と、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅとを用いる。
【０１７６】
【表３】

４００ｎｍ励起の発光素子により励起された蛍光体は、実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは青緑色から緑色系領域に、（Ｃａ_０．９３，Ｅｕ_０．０５，Ｍｎ_０．０２）_１０（ＰＯ_４）_６Ｃｌ_２は青紫色から青色系領域に、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは緑色から黄赤色系領域に、ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは黄赤色から赤色系領域に、それぞれ発光ピーク波長を有する。これらの蛍光体の光の混色により、白色系領域に発光色を示す。これより、実施例１の発光装置は、白色域に発光色を示す。また、視感度特性の低い４００ｎｍ近傍の励起光源を用いていることから、蛍光体の配合比を変えることにより、容易に色調を変えることができる。特に、比較例１に示す白色系発光装置では、平均演色評価数（Ｒａ）が７６．０であったが、実施例１に係る白色系発光装置は、平均演色評価数（Ｒａ）が８８．１と、極めて良好であった。これより演色性が改善されている。また、特殊演色評価数（Ｒ１〜Ｒ１５）は、ほぼ全ての色票で演色性が改善されている。更に、比較例１に示す白色系発光装置は、特殊演色評価数（Ｒ９）が−１．９であるのに対し、実施例１に係る白色系発光装置は、特殊演色評価数（Ｒ９）が９６．１と、極めて良好であった。この特殊演色評価数（Ｒ９）は、比較的彩度の高い赤色の色票である。視感度効率は、比較例１の発光装置を１００％としたときの相対値で表す。
【０１７７】
＜発光装置＞
実施例２及び３の発光装置は、励起光源に発光ピーク波長が４６０ｎｍの発光素子を用いた白色系発光装置に関する。図１は、本発明に係る発光装置を示す図である。図１３は、実施例２及び３の発光装置の発光スペクトル（シミュレーション）を示す図である。
【０１７８】
（発光素子）
実施例２及び３の発光装置は、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。この砲弾型の実施例１の発光装置は、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。
【０１７９】
実施例２及び３の発光装置に電流を流すと、ほぼ４６０ｎｍに発光ピーク波長がある青色系発光素子１０が発光する。この青色光を、半導体層２を覆う蛍光体１１が色調変換を行う。その結果、白色に発光する実施例２及び３の発光装置を提供することができる。
【０１８０】
（蛍光体）
本発明に係る実施例２及び３の発光装置に用いる蛍光体１１は、実施例１のオキシ窒化物蛍光体と、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅで表されるＹＡＧ蛍光体と、ＣａＳｒＳｉ_５Ｎ_８：Ｅｕで表される窒化物蛍光体と、を混合した蛍光体１１を用いる。該蛍光体１１は、コーティング部材１２と一緒に混合されている。この配合比は、適宜変更することができる。Ｅｘ＝４６０ｎｍの励起光源を用いて、これらの蛍光体１１に照射する。これらの蛍光体１１は、該励起光源からの光を吸収し、波長変換を行い、所定の発光波長を有する。実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは、４７０ｎｍ〜５３０ｎｍに発光ピーク波長を有する。（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは、５００〜６５０ｎｍに発光ピーク波長を有する。ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは、５８０ｎｍ〜７３０ｎｍに発光ピーク波長を有する。
【０１８１】
実施例２及び３の発光装置は、発光素子１０の光の一部が透過する。また、発光素子１０の光の一部が蛍光体１１を励起し、波長変換を行い、該蛍光体１１は所定の発光波長を有する。これらの発光素子１０からの青色光と、蛍光体１１からの光の混色により、白色に発光する発光装置を提供することができる。
【０１８２】
（実施例２及び３の発光装置の特性）
表４は、実施例２及び３の発光装置の特性及び演色性を示す。但し、この実施例２及び３の発光装置の特性及び演色性は、シミュレーションであり、実際に製造した場合は、自己吸収が起こり、波長のズレが生ずると思われる。比較例２の発光装置として、Ｅｘ＝４６０ｎｍの励起光源を用いて、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅとを用いる。また、実施例２及び３は、ピーク値が同一の場合の発光スペクトルである。
【０１８３】
【表４】

４６０ｎｍ励起の発光素子により励起された蛍光体は、実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは青緑色から緑色系領域に、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは緑色から黄赤色系領域に、ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは黄赤色から赤色系領域に、それぞれ発光ピーク波長を有する。これらの蛍光体の光の混色により、白色系領域に発光色を示す。これより、実施例２及び３の発光装置は、白色域に発光色を示す。また、励起光源に４６０ｎｍ近傍の可視光を用い、青色に発光する蛍光体を用いていないことから、波長変換に伴う発光効率のロスが少ない。さらに、蛍光体の配合比を変えることにより、容易に色調を変えることができる。特に、比較例２に示す白色系発光装置では、平均演色評価数（Ｒａ）が７６．０であったが、実施例２及び３に係る白色系発光装置は、平均演色評価数（Ｒａ）が８４．５及び８３．１と、極めて良好であった。これより演色性が改善されている。また、特殊演色評価数（Ｒ１〜Ｒ１５）は、ほぼ全ての色票で演色性が改善されている。更に、比較例２に示す白色系発光装置は、特殊演色評価数（Ｒ９）が−１．９であるのに対し、実施例２及び３に係る白色系発光装置は、特殊演色評価数（Ｒ９）が７０．７と９４．１と、極めて良好であった。この特殊演色評価数（Ｒ９）は、比較的彩度の高い赤色の色票である。視感度効率は、比較例の発光装置を１００％としたときの相対値で表す。
【０１８４】
＜発光装置＞
実施例４の発光装置は、励起光源に発光ピーク波長が４５７ｎｍの発光素子を用いた白色系発光装置に関する。図１は、本発明に係る発光装置を示す図である。図１４は、実施例４及び実施例５の発光装置の発光スペクトルを示す図である。
【０１８５】
（発光素子）
実施例４の発光装置に電流を流すと、ほぼ４５７ｎｍに発光ピーク波長がある青色系発光素子１０が発光する。この青色光を、半導体層２を覆う蛍光体１１が色調変換を行う。その結果、白色に発光する実施例４の発光装置を提供することができる。
【０１８６】
（蛍光体）
本発明に係る実施例４の発光装置に用いる蛍光体１１は、実施例１のオキシ窒化物蛍光体と、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅで表されるＹＡＧ蛍光体と、ＣａＳｒＳｉ_５Ｎ_８：Ｅｕで表される窒化物蛍光体と、を混合した蛍光体１１を用いる。該蛍光体１１は、コーティング部材１２と一緒に混合されている。この配合比は、適宜変更することができる。Ｅｘ＝４５７ｎｍの励起光源を用いて、これらの蛍光体１１に照射する。これらの蛍光体１１は、該励起光源からの光を吸収し、波長変換を行い、所定の発光波長を有する。実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは、４７０ｎｍ〜５３０ｎｍに発光ピーク波長を有する。（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは、５００〜６５０ｎｍに発光ピーク波長を有する。ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは、５８０ｎｍ〜７３０ｎｍに発光ピーク波長を有する。
【０１８７】
実施例４の発光装置は、発光素子１０の光の一部が透過する。また、発光素子１０の光の一部が蛍光体１１を励起し、波長変換を行い、該蛍光体１１は所定の発光波長を有する。これらの発光素子１０からの青色光と、蛍光体１１からの光の混色により、白色に発光する発光装置を提供することができる。
【０１８８】
（実施例４の発光装置の特性）
表５は、実施例４の発光装置の特性及び演色性を示す。
【０１８９】
【表５】

４５７ｎｍ励起の発光素子により励起された蛍光体は、実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは青緑色から緑色系領域に、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは緑色から黄赤色系領域に、ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは黄赤色から赤色系領域に、それぞれ発光ピーク波長を有する。これらの蛍光体の光の混色により、白色系領域に発光色を示す。これより、実施例４の発光装置は、白色域に発光色を示す。また、励起光源に４５７ｎｍ近傍の可視光を用い、青色に発光する蛍光体を用いていないことから、波長変換に伴う発光効率のロスが少ない。さらに、蛍光体の配合比を変えることにより、容易に色調を変えることができる。実施例４の白色系発光装置は、ランプ効率が２５．０ｌｍ／Ｗと極めて高い発光特性を示す。実施例４に係る白色系発光装置は、平均演色評価数（Ｒａ）が９２．７と、極めて良好であった。これより演色性が改善されている。また、特殊演色評価数（Ｒ１〜Ｒ１５）は、ほぼ全ての色票で演色性が改善されている。更に、実施例４に係る白色系発光装置は、特殊演色評価数（Ｒ９）が８３．０と、極めて良好であった。
【０１９０】
以上より、実施例４の白色系発光装置は、演色性に優れた発光装置を提供することができる。
【０１９１】
＜発光装置＞
実施例５の発光装置は、励起光源に発光ピーク波長が４６３ｎｍの発光素子を用いた白色系発光装置に関する。図１は、本発明に係る発光装置を示す図である。図１４は、実施例４及び実施例５の発光装置の発光スペクトルを示す図である。
【０１９２】
（発光素子）
実施例５の発光装置に電流を流すと、ほぼ４６３ｎｍに発光ピーク波長がある青色系発光素子１０が発光する。この青色光を、半導体層２を覆う蛍光体１１が色調変換を行う。その結果、白色に発光する実施例５の発光装置を提供することができる。
【０１９３】
（蛍光体）
本発明に係る実施例５の発光装置に用いる蛍光体１１は、実施例１のオキシ窒化物蛍光体と、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅで表されるＹＡＧ蛍光体と、ＣａＳｒＳｉ_５Ｎ_８：Ｅｕで表される窒化物蛍光体と、を混合した蛍光体１１を用いる。該蛍光体１１は、コーティング部材１２と一緒に混合されている。この配合比は、適宜変更することができる。Ｅｘ＝４６３ｎｍの励起光源を用いて、これらの蛍光体１１に照射する。これらの蛍光体１１は、該励起光源からの光を吸収し、波長変換を行い、所定の発光波長を有する。実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは、４７０ｎｍ〜５３０ｎｍに発光ピーク波長を有する。（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは、５００〜６５０ｎｍに発光ピーク波長を有する。ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは、５８０ｎｍ〜７３０ｎｍに発光ピーク波長を有する。
【０１９４】
実施例５の発光装置は、発光素子１０の光の一部が透過する。また、発光素子１０の光の一部が蛍光体１１を励起し、波長変換を行い、該蛍光体１１は所定の発光波長を有する。これらの発光素子１０からの青色光と、蛍光体１１からの光の混色により、白色に発光する発光装置を提供することができる。
【０１９５】
（実施例５の発光装置の特性）
表６は、実施例５の発光装置の特性及び演色性を示す。
【０１９６】
【表６】

４６３ｎｍ励起の発光素子により励起された蛍光体は、実施例１のＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕは青緑色から緑色系領域に、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅは緑色から黄赤色系領域に、ＳｒＣａＳｉ_５Ｎ_８：Ｅｕは黄赤色から赤色系領域に、それぞれ発光ピーク波長を有する。これらの蛍光体の光の混色により、白色系領域に発光色を示す。これより、実施例５の発光装置は、白色域に発光色を示す。また、励起光源に４６３ｎｍ近傍の可視光を用い、青色に発光する蛍光体を用いていないことから、波長変換に伴う発光効率のロスが少ない。さらに、蛍光体の配合比を変えることにより、容易に色調を変えることができる。実施例５の白色系発光装置は、ランプ効率が２１．３ｌｍ／Ｗと高い発光特性を示す。実施例５に係る白色系発光装置は、平均演色評価数（Ｒａ）が８４．９と、極めて良好であった。これより演色性が改善されている。また、特殊演色評価数（Ｒ１〜Ｒ１５）は、ほぼ全ての色票で演色性が改善されている。更に、実施例５に係る白色系発光装置は、特殊演色評価数（Ｒ９）が９１．０と、極めて良好であった。
【０１９７】
以上より、実施例４の白色系発光装置は、演色性に優れた発光装置を提供することができる。
【０１９８】
＜発光装置＞
図１５は、実施例６のキャップタイプの発光装置を示す図である。
【０１９９】
実施例６の発光装置は、実施例１の発光装置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。発光素子１０は、４００ｎｍに発光ピーク波長を有する発光素子を使用する。
【０２００】
実施例６の発光装置は、実施例１の発光装置のモールド部材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。
【０２０１】
マウントリード１３ａの上部に、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。実施例１の発光装置では、該カップの上部に発光素子１０を覆うように、蛍光体１１が設けられているが、実施例６の発光装置では、特に設けなくてもよい。該発光素子１０の上部に蛍光体１１を設けないことにより、発光素子１０から発生する熱の影響を直接受けないからである。
【０２０２】
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、ＢａＳｉ_２Ｏ_２Ｎ_２：Ｅｕのオキシ窒化物蛍光体と、（Ｙ，Ｇｄ）_３（Ａｌ，Ｇａ）_５Ｏ_１２：Ｃｅの蛍光体と、Ｂａ_２Ｓｉ_５Ｎ_８：Ｅｕの窒化物蛍光体と、（Ｃａ_０．９５，Ｅｕ_０．０５）_１０（ＰＯ_４）_６Ｃｌ_２の蛍光体とを使用する。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６のオキシ窒化物蛍光体を用いる。しかし、キャップ１６に蛍光体を用いるため、オキシ窒化物蛍光体をキャップ１６に含有し、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。
【０２０３】
このように構成された発光装置は、発光素子１０から放出される光の一部は、蛍光体１１のオキシ窒化物蛍光体を励起し、緑色に発光する。また、発光素子１０から放出される光の一部、若しくはオキシ窒化物蛍光体から放出される光の一部がキャップ１６の蛍光体を励起し、青色と黄色から赤色に発光する。これにより、オキシ窒化物蛍光体の緑色光と、キャップ１６の蛍光体の青色と黄色から赤色光とが混合し、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。
【０２０４】
【発明の効果】
以上のことから、本発明は、紫外から可視光の短波長領域に発光波長を有する励起光源からの光を吸収し、波長変換を行い、該励起光源からの発光色と異なる発光色を有するオキシ窒化物蛍光体に関する。該オキシ窒化物蛍光体は、青緑色から緑色系領域に発光ピーク波長を有しており、極めて高い発光効率を有する。また、該オキシ窒化物蛍光体は、温度特性に極めて優れている。特に、賦活剤Ｒが第ＩＩ族元素に対して、モル比で、第ＩＩ族元素：Ｒ＝１：０．００５乃至１：０．１５のとき、最も高い発光効率を示す。
【０２０５】
また、本発明は、簡易で、再現性に優れたオキシ窒化物蛍光体の製造方法を提供することができる。
【０２０６】
また、本発明は、上記オキシ窒化物蛍光体と、発光素子とを有する発光装置に関する。これにより該発光装置は、鮮やかな青から緑色に発光する発光装置を提供することができる。また、該オキシ窒化物蛍光体と第２の蛍光体である青色、緑色、赤色の三波長の蛍光体とを組み合わせた発光装置を製造することができる。これにより、該発光装置は、白色系に発光する演色性に優れた発光装置を提供することができる。さらに、該オキシ窒化物蛍光体と第２の蛍光体であるＹＡＧ系蛍光体と、青色系発光素子とを組み合わせた発光装置を製造することができる。これにより、白色系に発光する演色性に優れた、発光効率の極めて高い発光装置を提供することができる。該演色性は、特に赤色を示す特殊演色評価数（Ｒ９）の改善が行われている。従って、本発明は、上述のような発光装置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】本発明に係る砲弾型の発光装置を示す図である。
【図２】（ａ）本発明に係る表面実装型の発光装置を示す平面図である。（ｂ）本発明に係る表面実装型の発光装置の断面図である。
【図３】オキシ窒化物蛍光体の製造方法を示す工程図である。
【図４】実施例１乃至５のオキシ窒化物蛍光体をＥｘ＝４００ｎｍで励起したときの発光スペクトルを示す図である。
【図５】実施例１乃至５のオキシ窒化物蛍光体を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６】実施例１乃至５のオキシ窒化物蛍光体の励起スペクトルを示す図である。
【図７】実施例１乃至５のオキシ窒化物蛍光体の反射スペクトルを示す図である。
【図８】実施例１のオキシ窒化物蛍光体を撮影したＳＥＭ写真である。
【図９】本発明に係る発光素子を示す平面図である。
【図１０】本発明に係る発光素子のＡ−Ａ‘を示す断面図である。
【図１１】実施例１の発光装置の発光スペクトル（シミュレーション）を示す図である。
【図１２】実施例１乃至３の発光装置の色度座標（シミュレーション）を示す図である。
【図１３】実施例２及び３の発光装置の発光スペクトル（シミュレーション）を示す図である。
【図１４】実施例４及び実施例５の発光装置の発光スペクトルを示す図である。
【図１５】実施例６のキャップタイプの発光装置を示す図である。
【符号の説明】
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
２０１ 基板
２０２ 下地層
２０３ ｎ型層
２０３ａ 露出面
２０４ 活性層
２０５ ｐ側キャリア閉込め層
２０６ 第１ｐ型層
２０７ 電流拡散層
２０８ ｐ側コンタクト層
２０９ 発光部
２１０ ｐ側電極
２１０ａ 電極枝
２１０ｂ ｐ側パット電極
２１１ａ ｎ側電極
２１１ｂ ｎ側パット電極[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a phosphor that emits light when excited by heat, such as electromagnetic waves such as light, electron beams, and X-rays. In particular, general lighting such as a fluorescent lamp, on-vehicle lighting, a backlight for a liquid crystal, a light emitting device such as a display, And a phosphor used in the light emitting device. In particular, the present invention relates to white and multicolor light emitting devices using semiconductor light emitting elements.
[0002]
[Prior art]
A light-emitting device using a light-emitting element emits bright colors with small size, high power efficiency, and low power consumption. In addition, since the light emitting element is a semiconductor element, there is no fear of a broken ball or the like. Furthermore, it has a feature that it has excellent initial drive characteristics and is resistant to vibration and repeated on / off lighting. Because of these excellent characteristics, light-emitting devices using semiconductor light-emitting elements such as LEDs (Light Emitting Diodes) and LDs (Laser Diodes) are used as various light sources.
[0003]
A part or all of the light of the light emitting element is wavelength-converted by the phosphor, and the wavelength-converted light and the light of the light-emitting element that is not wavelength-converted are mixed and emitted, so that a light emission color different from that of the light-emitting element is emitted. Light emitting devices that emit light have been developed.
[0004]
Among these light-emitting devices, light-emitting devices that emit white light (hereinafter, referred to as "white light-emitting devices") are required in a wide range of fields such as lighting such as fluorescent lamps, vehicle-mounted lighting, displays, and liquid crystal backlights. I have. Further, there is a demand for a light emitting device having a tint such as a pastel color by combining a semiconductor light emitting element and a phosphor.
[0005]
The light emission color of a light emitting device using a white semiconductor light emitting element is obtained by the principle of light mixing. The blue light emitted from the light emitting element is emitted into the phosphor layer after being repeatedly absorbed and scattered several times in the layer, and then emitted outside. On the other hand, the blue light absorbed by the phosphor functions as an excitation light source and emits yellow fluorescence. The yellow light and the blue light are mixed and appear to human eyes as white.
[0006]
For example, a light emitting element that emits blue light (hereinafter, referred to as a “blue light emitting element”) is used as the light emitting element, and a thin phosphor is coded on the surface of the blue light emitting element. The light emitting device is a blue light emitting device using an InGaN-based material. The phosphor is (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : YAG-based phosphor represented by the composition formula of Ce is used.
[0007]
In recent years, a white light emitting device has been reported using a light emitting element in a short wavelength region of visible light and combining a phosphor that emits blue light and a YAG phosphor that emits yellow light. In this case, the YAG-based phosphor that emits yellow light is hardly excited by light in a short wavelength region of visible light, and does not emit light. Therefore, the light emitting element excites the blue phosphor to emit blue light. Next, the YAG phosphor is excited by the blue light to emit yellow light. Thus, white light is emitted by mixing the blue light of the blue phosphor and the yellow-green to yellow light of the YAG phosphor.
[0008]
Various phosphors have been developed for the light emitting device.
[0009]
For example, oxide-based phosphors using a rare-earth element as a luminescent center have been widely known, and some of them have been put to practical use. However, nitride phosphors and oxynitride phosphors have not been studied much, and only a few research reports have been made compared to oxide-based phosphors. For example, there is an oxynitride glass phosphor represented by Si-ON, Mg-Si-ON, Ca-Al-Si-ON, or the like (see Patent Document 1). Further, there is a phosphor of oxynitride glass represented by Ca-Al-Si-ON activated with Eu (see Patent Document 2).
[0010]
[Patent Document 1]
JP 2001-214162 A
[Patent Document 2]
JP-A-2002-76434
[0011]
[Problems to be solved by the invention]
However, conventional phosphors have low light emission luminance and are insufficient for use in light emitting devices. In a light-emitting device using a light-emitting element in the ultraviolet region as an excitation light source, a two-stage excitation in which a blue phosphor is excited by the light-emitting element and a YAG-based phosphor is excited by the excitation light, so that highly efficient white light is emitted. Difficult to get. Therefore, a phosphor that emits blue-green to yellow light after being directly wavelength-converted by light in a short wavelength region of visible light is required.
[0012]
Further, for a white light emitting device using a light emitting element in a short wavelength region of visible light and a phosphor, an appropriate phosphor has not been manufactured, and a light emitting device that can withstand practical use is not commercially available. Therefore, a phosphor that efficiently emits light in a short wavelength region of visible light is required.
[0013]
A white light emitting device including a blue light emitting element and a YAG phosphor emits white light in a mixed color of blue light near 460 nm and yellow-green light near 565 nm. The emission intensity is insufficient.
[0014]
Further, the oxynitride phosphors and the like of Patent Documents 1 and 2 have low light emission luminance and are insufficient for use in light emitting devices. In addition, since the phosphor of oxynitride glass is a glass body, it is generally difficult to process.
[0015]
Accordingly, an object of the present invention is to provide a light emitting device using a phosphor having a luminescent color from blue-green to green, which is excited by an excitation light source in the ultraviolet to visible light region and whose wavelength is converted. It is another object of the present invention to provide a light emitting device with high luminous efficiency and excellent reproducibility.
[0016]
[Means for Solving the Problems]
In order to solve the above problems, the present invention uses at least one or more rare earth elements that require Eu as the activator R, and requires Ba selected from the group consisting of Ca, Sr, Ba, and Zn. At least one group II element, and at least one group IV element essentially including at least Si selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. An oxynitride phosphor containing at least, wherein R is a group II element: the R = 1: 0.005 to 1: 0.15 in a molar ratio to the group II element. The present invention relates to an oxynitride phosphor. This makes it possible to provide a phosphor with high luminance. Further, it is possible to provide a phosphor that absorbs a part of light from an excitation light source having an emission wavelength in a short wavelength region from ultraviolet to visible light, is wavelength-converted, and emits light in a bluish green to greenish color. .
[0017]
When light from an excitation light source having an emission wavelength in the short wavelength region of ultraviolet to visible light is applied to the oxynitride phosphor containing the above element, the oxynitride phosphor is excited, and the light from the excitation light source is excited. Absorb some. The oxynitride phosphor that has absorbed part of the light from the excitation light source performs wavelength conversion. The wavelength-converted light has an emission peak wavelength in a blue-green to greenish region. Thus, a light emitting device that emits light of a predetermined color can be provided. The oxynitride phosphor absorbs a part of light from the light emitting element and has an emission spectrum having an emission peak wavelength in a blue-green to green region. In addition, the oxynitride phosphor has high luminous efficiency, and can emit light from the light-emitting element very efficiently.
[0018]
The oxynitride phosphor contains O and N in a composition, and a weight ratio of the O and the N is 1 to O and N is 0.2 to 2.1. The present invention relates to a nitride phosphor. This makes it possible to provide a phosphor that is excited by light from the excitation light source and emits light in a green to yellowish region.
[0019]
The oxynitride phosphor is L _X M _Y O _Z N _{((2/3) X + (4/3) Y- (2/3) Z)} : R or L _X M _Y Q _T O _Z N _{((2/3) X + (4/3) Y + T- (2/3) Z)} : R (L is a group II element which is at least one or more kinds of which Ba is selected from the group consisting of Ca, Sr, Ba and Zn. M is C, Si, Ge, Sn, Ti, Q is an at least one element selected from the group consisting of B, Al, Ga, and In which is at least one element selected from the group consisting of B, Al, Ga, and In. A group III element, O is an oxygen element, N is a nitrogen element, R is at least one or more rare earth elements containing Eu as an essential element, and 0.5 <X <1.5. , 1.5 <Y <2.5, 0 <T <0.5, and 1.5 <Z <2.5). The oxynitride phosphor is excited by excitation light in a short wavelength region from ultraviolet to visible light, and has an emission peak wavelength in a green to yellow region. Further, the oxynitride phosphor has the same or higher stability than the YAG phosphor. Further, the oxynitride phosphor is not a glass body (amorphous), and the light-emitting part is a powder or granule having crystallinity, so that it is easy to manufacture and process. By setting X, Y, and Z in the above ranges, it is possible to provide a phosphor with good luminous efficiency. That is, within the above range, a crystal layer having substantially light emitting properties is formed. On the other hand, when the ratio is out of the above range, the luminous efficiency decreases.
[0020]
The composition is L _X M _Y O _Z N _{((2/3) X + (4/3) Y- (2/3) Z-α)} : R or L _X M _Y Q _T O _Z N _{((2/3) X + (4/3) Y + T- (2/3) Z-α)} : R (0 ≦ α <1) in some cases. This is because the oxynitride phosphor sometimes lacks nitrogen. However, the closer the α is to 0, the better the crystallinity and the higher the emission luminance.
[0021]
It is preferable that X, Y, and Z are X = 1, Y = 2, and Z = 2. This is because, when the composition is used, the crystallinity is improved and the luminous efficiency is increased.
[0022]
It is preferable that 70% or more of R is Eu. The rare earth element R is preferably Eu because it has high luminous efficiency. This is because high luminous efficiency can be obtained by using the Eu amount in this range.
[0023]
The oxynitride fluorescent material is excited by light from an excitation light source having an emission peak wavelength of 360 to 480 nm, and has an emission peak wavelength longer than the emission peak wavelength. About the body. By using an excitation light source in this range, a phosphor with high luminous efficiency can be provided. An excitation light source having an emission peak wavelength at 240 to 480 nm can be used. Among them, it is preferable to use an excitation light source having an emission peak wavelength at 360 to 470 nm. In particular, it is preferable to use an excitation light source of 380 to 420 nm or 450 to 470 nm used in a semiconductor light emitting device.
[0024]
The oxynitride phosphor has an emission peak wavelength in a blue-green to green region. In the case of a YAG-based phosphor having an emission peak wavelength from yellowish green to yellowish, even if it emits light using excitation light near 400 nm, it hardly emits light. Light shows high luminous efficiency. In addition, high luminous efficiency is exhibited also when blue light is used as the excitation light source.
[0025]
Here, the relationship between the wavelength range of light and the color name of monochromatic light conforms to JIS Z8110. Specifically, 380 to 455 nm is blue-violet, 455 to 485 nm is blue, 485 to 495 nm is blue-green, 495 to 548 nm is green, 548 to 573 nm is yellow-green, 573 to 584 nm is yellow, and 584 to 610 nm is yellow-red. , 610-780 nm are red.
[0026]
The oxynitride phosphor relates to an oxynitride phosphor characterized in that 50% by weight or more has a crystal structure. The oxynitride phosphor has a crystal structure of at least 50% by weight or more, preferably 80% by weight or more. This indicates the proportion of a crystal phase having a light-emitting property. When the crystal phase has a content of 50% by weight or more, light emission that can withstand practical use is obtained. The more crystal layers, the better. Thereby, the emission luminance can be increased, and the production and processing of the oxynitride phosphor can be facilitated.
[0027]
The oxynitride phosphor has a higher intensity excitation spectrum near 460 nm than near 350 nm. As a result, higher luminous efficiency is obtained when the excitation light source near 460 nm is used than when near 350 nm.
[0028]
The present invention provides a nitride of L (L is at least one element selected from the group consisting of Ca, Sr, Ba, and Zn and a Group II element that is at least one element of Ba) and a nitride of M. (M is at least one element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, which is at least one element of Group IV.) And an oxide of M; A first step of mixing an oxide of R (R is at least one or more rare earth elements which essentially include Eu); and a second step of firing the mixture obtained in the first step. Wherein the R is a molar ratio of the L to the L in a ratio of L: R = 1: 0.005 to 1: 0.15. The present invention also relates to a method for producing an oxynitride phosphor. This makes it possible to provide a phosphor that is easy to manufacture and process. In addition, an extremely stable phosphor can be provided. Further, by controlling the amount of R, a phosphor having higher luminous efficiency can be provided. Here, the base of the oxynitride phosphor may contain Li, Na, K, Rb, Cs, Mn, Re, Cu, Ag, Au, and the like. The reason is that Li, Na, K, and the like can improve the light emission characteristics in some cases, such as increasing the particle size or increasing the light emission luminance. On the other hand, these Li, Na, K and the like may be contained in the raw material composition. This is because Li, Na, K, and the like are scattered during the firing step in the production process of the oxynitride phosphor, and are hardly contained in the composition. However, Li, Na, K and the like are preferably 1000 ppm or less based on the weight of the oxynitride phosphor. More preferably, it is preferably 100 ppm or less. This is because high luminous efficiency can be maintained in this range. Further, other elements may be included to such an extent that the characteristics are not impaired.
[0029]
It is preferable that a nitride of R is used instead of the oxide of R or together with the oxide of R. This makes it possible to provide an oxynitride phosphor having high emission luminance.
[0030]
In the first step, it is preferable to further mix Q (Q is at least one group III element selected from the group consisting of B, Al, Ga, and In). Thereby, the particle size can be increased and the emission luminance can be improved.
[0031]
The nitride of L, the nitride of M, and the oxide of M are 0.5 <L nitride <1.5, 0.25 <M nitride <1.75, 2.25 <M The present invention relates to a method for producing an oxynitride phosphor represented by a molar ratio of oxide <3.75. Thus, L _X M _Y O _Z N _{((2/3) X + (4/3) Y- (2/3) Z)} : R or L _X M _Y Q _T O _Z N _{((2/3) X + (4/3) Y + T- (2/3) Z)} : R can be provided.
[0032]
It is preferable that at least a part of the nitride of L is substituted with at least one of an oxide of R and a nitride of R. Thereby, an oxynitride phosphor having high luminous efficiency can be provided.
[0033]
The present invention relates to an oxynitride phosphor produced by the method for producing an oxynitride phosphor according to at least one of claims 11 to 15.
[0034]
The present invention provides an excitation light source having an emission wavelength in a short wavelength region from ultraviolet to visible light, absorbing at least a part of light from the excitation light source, performing wavelength conversion, and emitting light different from the emission color of the excitation light source. And a phosphor having: wherein the phosphor contains an oxynitride phosphor essentially containing Ba having an emission peak wavelength in a blue-green to green region. Light emitting device. Thus, a light emitting device having high luminous efficiency and excellent color rendering can be provided. Also, part of the light from the excitation light source having an emission wavelength in the short wavelength region from ultraviolet to visible light, and part of the light from the oxynitride phosphor having the emission peak wavelength in the blue-green to green region. Thus, it is possible to provide a light emitting device that becomes mixed color light and emits light in a blue-violet to green region.
[0035]
Here, the short wavelength region from ultraviolet to visible light is not particularly limited, but refers to a region of 240 to 480 nm.
[0036]
Preferably, the excitation light source is a light emitting device. The light emitting element is small in size, has high power efficiency, and emits bright colors. In addition, since the light emitting element is a semiconductor element, there is no fear of a broken ball or the like. Furthermore, it has a feature that it has excellent initial drive characteristics and is resistant to vibration and repeated on / off lighting. Therefore, a light emitting device in which a light emitting element and an oxynitride phosphor are combined is preferable.
[0037]
The light emitting layer of the light emitting element preferably includes a nitride semiconductor containing In. As a result, the light emitting element emits light having an emission peak wavelength around 360 to 410 nm, and the light from the light emitting element excites the oxynitride phosphor to exhibit a predetermined emission color. This is because the oxynitride phosphor strongly emits light in the vicinity of 360 to 410 nm, and thus a light-emitting element in the wavelength range is required. Further, since the emission spectrum width can be narrowed, the oxynitride phosphor can be efficiently excited, and the emission spectrum that does not substantially affect the color tone change can be obtained from the light emitting device. Can be released.
[0038]
The oxynitride phosphor preferably uses the oxynitride phosphor according to at least one of claims 1 to 10 and 16.
[0039]
The phosphor includes a second phosphor used together with the oxynitride phosphor, and the second phosphor includes light from the excitation light source and light from the oxynitride phosphor. , At least a part of which has a light emission peak wavelength in a visible light region. Accordingly, it is possible to provide a light emitting device having a light emission color in a visible light region by mixing colors of light from the excitation light source, light of the oxynitride phosphor, and light of the second phosphor. The light emitting device can emit a desired emission color within a wavelength range from the emission color of the excitation light source to the emission color of the oxynitride phosphor or the emission color of the second phosphor.
[0040]
The second phosphor relates to a light emitting device having at least one emission peak wavelength from a blue region to a green, yellow, and red region. Thereby, the light emitting device can show a desired light emitting color. In particular, combining the blue-green to green of the oxynitride phosphor excited by an excitation light source having an emission peak wavelength in a short wavelength region from ultraviolet to visible light, the blue of the second phosphor, and the three primary colors of red Thereby, various emission colors can be realized. A light in a blue-violet to blue range from a blue light-emitting element; a light in a blue-green to green range emitted from an oxynitride phosphor wavelength-converted by the light from the light-emitting element; By mixing yellow-green to red-based light of the phosphor, it is possible to provide a light-emitting device having various luminescent colors. However, a light emitting device having a combination of two kinds of colors, such as green and red, and green and yellow, may be used.
[0041]
The second phosphor is an alkaline earth halogen apatite phosphor activated mainly by a transition metal based element such as Eu, a transition metal based element such as Mn, an alkaline earth metal borate halogen phosphor, an alkaline earth Mainly activated by lanthanoid elements such as metal aluminate phosphor, alkaline earth silicate, alkaline earth sulfide, alkaline earth thiogallate, alkaline earth silicon nitride, germanate, or Ce It is preferably at least one selected from the group consisting of rare earth aluminates, rare earth silicates, and organic and organic complexes mainly activated by lanthanoid elements such as Eu. Thereby, it is possible to provide a light emitting device with high light emission efficiency such as light emission luminance and quantum efficiency. Further, a light-emitting device having good color rendering properties can be provided. However, the second phosphor is not limited to the above, and phosphors emitting light of various colors can be used.
[0042]
The light emitting device emits a mixture of at least two or more of a part of light from the excitation light source, light from the oxynitride phosphor, and light from the second phosphor. Preferably. Thereby, the emission color of the light emitting device can be adjusted and a desired emission color can be emitted. In particular, when a light emitting element that emits light in the ultraviolet region is used, human eyes can hardly see the emission color in the ultraviolet region. Therefore, the emission color is obtained by mixing light from the oxynitride phosphor and light from the second phosphor. Since the emission color is determined only by the phosphor, it is extremely easy to adjust the emission color. Here, the second phosphor is described, but the second phosphor is not limited to one kind, and may include several kinds of phosphors. This is because by including several types of phosphors, finer chromaticity adjustment is possible. In particular, when a light-emitting element in the ultraviolet region is used, light from the light-emitting element is less likely to be perceived by human eyes, so that chromaticity deviation due to manufacturing variations is small.
[0043]
The light emitting device may have an intermediate emission color from the emission peak wavelength of the excitation light source to the emission peak wavelength of the oxynitride phosphor or the emission peak wavelength of the second phosphor. The emission spectrum of the excitation light source has a shorter wavelength and higher energy than the oxynitride phosphor or the second phosphor. Emission colors from the high energy region to the low energy regions of the oxynitride phosphor and the second phosphor can be emitted. In particular, it shows the emission color from the emission peak wavelength of the light emitting element to the first emission peak wavelength of the oxynitride phosphor or the second emission peak wavelength of the second phosphor. For example, when the emission peak wavelength of the light emitting element is in the blue region, the emission peak wavelength of the excited first phosphor is green, and the emission peak wavelength of the excited second phosphor is red, It is possible to show a white emission color by mixing colors. As a different example, the emission peak wavelength of the light emitting element is in the ultraviolet region, the emission peak wavelength of the excited first phosphor is green, and the emission peak wavelength of the excited second phosphor is yellow and red. In some cases, it is possible to exhibit a slightly yellowish white or polychromatic emission color. By changing the compounding amount of the oxynitride phosphor and the second phosphor, light emission from a color close to the emission color of the oxynitride phosphor to a color close to the emission color of the second phosphor is obtained. Color can be shown. Furthermore, when the second phosphor has two or more emission peak wavelengths, the emission peak wavelength of the excitation light source, the emission peak wavelength of the oxynitride phosphor, and the two or more emission peak wavelengths of the second phosphor are provided. This is a light emitting device that shows a light emission color between the light emission peak wavelengths. The second phosphor can be used not only in one kind but also in combination of two or more kinds. In addition to a light-emitting device that emits white light, a light-emitting device that emits light of various colors such as pastel colors is also required. By variously combining the oxynitride phosphor that emits green light, the phosphor that emits red light, and the phosphor that emits blue light, a light emitting device having a desired color can be provided. Light emitting devices with different colors are not only changed by changing the type of phosphor, but also by changing the mixing ratio of the phosphors to be combined, by changing the application method of applying the phosphor to the excitation light source, or by changing the excitation light source. There is a method of adjusting the lighting time.
[0044]
The intermediate emission color preferably emits white light. In particular, white light emission near the locus of black body radiation is preferable. Thereby, it can be used for various purposes such as lighting, a liquid crystal backlight, and a display.
[0045]
The light emitting device is preferably a light emitting device having an emission spectrum having at least one emission peak wavelength at 360 to 485 nm, 485 to 548 nm, and 548 to 730 nm. By combining the three primary colors of blue light, green light, red light, and the like, a light-emitting device that emits light of a desired color can be provided. In addition, by combining some phosphors, the color rendering can be improved. This is because, even with the same white light emission, some yellowish white and some bluish white exist.
[0046]
The light emitting device is preferably a light emitting device having an emission spectrum having one or more emission peak wavelengths at 360 to 485 nm and 485 to 584 nm. For example, a light emitting device that emits white light can be obtained by combining a blue light emitting element and a YAG phosphor, but light near 500 nm is insufficient. Therefore, a light-emitting device having excellent color rendering properties can be provided by further including an oxynitride phosphor that emits light near 500 nm in the light-emitting device.
[0047]
The light emitting device preferably has an average color rendering index (Ra) of 80 or more. Thereby, a light emitting device having excellent color rendering properties can be provided. In particular, it is possible to provide a light-emitting device with improved special color rendering (R9).
[0048]
As described above, the oxynitride phosphor according to the present invention provides a phosphor with extremely good luminous efficiency, which is excited by light in a short wavelength region from ultraviolet to visible light and emits light in a blue-green to green region. be able to. In addition, a crystalline oxynitride phosphor that can be easily manufactured and processed can be provided. Further, an oxynitride phosphor excellent in stability and reproducibility can be provided. Further, a novel method for producing an oxynitride phosphor can be provided. Further, there is a technical significance that a light emitting device having a desired emission color can be provided by combining the light emitting element, the oxynitride phosphor, and the second phosphor.
[0049]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a light emitting device according to the present invention, an oxynitride phosphor used for the light emitting device, and a method for manufacturing the same will be described with reference to embodiments and examples. However, the present invention is not limited to this embodiment and Examples.
[0050]
A light emitting device according to the present invention is a light emitting device having at least a light emitting element and a first phosphor and / or a second phosphor that converts at least a part of light from the light emitting element into a wavelength. 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. Here, the relationship between the color name and the chromaticity coordinates is based on JIS Z8110.
[0051]
(Excitation light source)
An excitation light source having an emission peak wavelength on the short wavelength side from ultraviolet to visible light is used. It is not particularly limited as long as it is an excitation light source having an emission peak wavelength in the range. Although there are a lamp, a semiconductor light emitting element, and the like as the excitation light source, it is preferable to use a semiconductor light emitting element.
[0052]
(Light emitting device)
The light emitting device according to the first embodiment includes a semiconductor layer 2 stacked on a sapphire substrate 1 and a lead frame 13 conductively connected by conductive wires 14 extending from positive and negative electrodes 3 formed on the semiconductor layer 2. A phosphor 11 and a coating member 12 provided in a cup of a lead frame 13a so as to cover an outer periphery of a light emitting element 10 composed of the sapphire substrate 1 and the semiconductor layer 2; And a mold member 15 that covers the outer peripheral surface of the frame 13.
[0053]
A semiconductor layer 2 is formed on a 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 light-emitting layer has a light emission peak wavelength having a light emission spectrum near 500 nm or less in the ultraviolet to blue region.
[0054]
The light emitting element 10 is set on a die bonder, and is face-up to a lead frame 13a provided with a cup and die-bonded (bonded). After die bonding, the lead frame 13 is transferred to a wire bonder, and the negative electrode 3 of the light emitting element is wire-bonded to a 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. .
[0055]
Next, the phosphor 11 and the coating member 12 are transferred into a mold device and injected into the cup of the lead frame 13 by a dispenser of the mold device. The phosphor 11 and the coating member 12 are previously uniformly mixed at a desired ratio.
[0056]
After the phosphor 11 is injected, the lead frame 13 is immersed in a mold mold in which the mold member 15 has been injected in advance, and then the mold is removed to cure the resin. I do.
[0057]
(Light emitting device)
The specific configuration of the light emitting device according to the second embodiment, which is different from the light emitting device according to the first embodiment, will be described in detail. FIG. 2 is a diagram showing a light emitting device according to the present invention. The light-emitting device of Embodiment 2 forms a surface-mounted light-emitting device. As the light emitting element 101, a nitride semiconductor light emitting element excited by ultraviolet light can be used. Further, as the light emitting element 101, a nitride semiconductor light emitting element excited by blue light can also be used. Here, the light-emitting element 101 excited by ultraviolet light will be described as an example. As the light emitting element 101, a nitride semiconductor light emitting element having an InGaN semiconductor having a light emission peak wavelength of about 370 nm as a light emitting layer is used. As a more specific LED device structure, an undoped nitride semiconductor n-type GaN layer on a sapphire substrate, a GaN layer on which a Si-doped n-type electrode is formed to serve as an n-type contact layer, and an undoped nitride semiconductor It has a single quantum well structure of a certain n-type GaN layer, an n-type AlGaN layer which is a nitride semiconductor, and then an InGaN layer constituting a light emitting layer. On the light emitting layer, an AlGaN layer as a Mg-doped p-type cladding layer and a GaN layer as a Mg-doped p-type contact layer are sequentially laminated. (Note that a GaN layer is formed at a low temperature on a sapphire substrate to serve as a buffer layer. The p-type semiconductor is annealed at 400 ° C. or higher after film formation.) The surface of each pn contact layer is exposed on the same side of the nitride semiconductor on the sapphire substrate by etching. An n-electrode is formed in a strip shape on the exposed n-type contact layer, and a light-transmitting p-electrode made of a metal thin film is formed on almost the entire surface of the uncut p-type contact layer. A pedestal electrode is formed on the p electrode in parallel with the n electrode using a sputtering method.
[0058]
Next, a Kovar package 105 having a concave portion in the center and a base portion having Kovar lead electrodes 102 inserted and fixed on both sides of the concave portion in an airtight and insulating manner is used. On the surfaces of the package 105 and the lead electrode 102, a Ni / Ag layer is provided. The above-described light emitting element 101 is die-bonded with an Ag-Sn alloy in the recess of the package 105. With such a configuration, all the components of the light emitting device can be made inorganic, and the reliability of the light emitting device 101 can be greatly improved even if the light emitted from the light emitting element 101 is in an ultraviolet region or a short wavelength region of visible light. A light emitting device with a high level can be obtained.
[0059]
Next, each electrode of the light-emitting element 101 die-bonded and each lead electrode 102 exposed from the bottom surface of the concave portion of the package are electrically connected to each other by the Ag wire 104. After the moisture in the concave portion of the package is sufficiently removed, the package is sealed with a Kovar lid 106 having a glass window 107 at the center, and seam welding is performed. In the glass window, a slurry composed of 90 wt% of nitrocellulose and 10 wt% of γ-alumina ₂ O ₂ N ₂ : Eu, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ A phosphor 108 such as Ce is contained, applied to the rear surface of the light-transmitting window 107 of the lid 106, and heated and 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. This makes it possible to provide a light-emitting device with extremely simple chromaticity adjustment and excellent mass productivity and reliability. Hereinafter, each configuration of the present invention will be described in detail.
[0060]
Hereinafter, components of the light emitting device according to the present invention will be described in detail.
[0061]
(Phosphors 11, 108)
Phosphors 11 and 108 include oxynitride phosphors. Also, as the phosphors 11 and 108, a combination of an oxynitride phosphor and a second phosphor can be used. The oxynitride phosphor according to the present invention uses at least one or more rare earth elements that require Eu as an activator, and requires Ba selected from the group consisting of Ca, Sr, Ba, and Zn. At least one group II element, and at least one group IV element essentially containing Si selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf; contains. The combination of the elements is arbitrary, but it is preferable to use one having the following composition. The oxynitride phosphor is L _X M _Y O _Z N _{((2/3) X + (4/3) Y- (2/3) Z)} : R or L _X M _Y Q _T O _Z N _{((2/3) X + (4/3) Y + T- (2/3) Z)} : R (L is a group II element which is at least one or more kinds of which Ba is selected from the group consisting of Ca, Sr, Ba and Zn. M is C, Si, Ge, Sn, Ti, Q is an at least one element selected from the group consisting of B, Al, Ga, and In which is at least one element selected from the group consisting of B, Al, Ga, and In. A group III element, O is an oxygen element, N is a nitrogen element, R is at least one or more rare earth elements containing Eu as an essential element, and 0.5 <X <1.5. , 1.5 <Y <2.5, 0 <T <0.5, and 1.5 <Z <2.5). The X, the Y, and the Z indicate high luminance in the range. In the general formula, X, Y, and Z are 0.8 <X <1.2, 1.8 <Y <2.2, 0 <T <0.5, 1.7 <Z <2. The oxynitride phosphor, in which X, Y, and Z are represented by X = 1, Y = 2, and Z = 2, is particularly preferable because of its high luminance. However, the present invention is not limited to the above range, and any one can be used. Specifically, BaSi _1.8 Ge _0.2 O ₂ N ₂ : Eu, BaSi _1.9 Ge _0.1 O ₂ N ₂ : Eu, BaSi _1.8 C _0.2 O ₂ N ₂ : Eu, BaSi _1.9 C _0.1 O ₂ N ₂ : Eu, BaSi _1.8 Ti _0.2 O ₂ N ₂ : Eu, BaSi _1.9 Ti _0.1 O ₂ N ₂ : Eu, BaSi _1.8 Sn _0.2 O ₂ N ₂ : Eu, BaSi _1.9 Sn _0.1 O ₂ N ₂ : Eu, Ba _0.9 Ca _0.1 Si ₂ O ₂ N ₂ : Eu, Ba _0.9 Sr _0.1 Si ₂ O ₂ N ₂ : Eu, Ba _0.9 Zn _0.1 Si ₂ O ₂ N ₂ : Eu, Ba _0.9 Ca _0.1 Si _1.8 Ge _0.2 O ₂ N ₂ : Eu, Ba _0.9 Sr _0.1 Si _1.8 Ge _0.2 O ₂ N ₂ : Oxynitride phosphor represented by Eu, etc. can be used. Further, as shown here, the present oxynitride phosphor can adjust the color tone and the luminance by changing the ratio of O to N. It is also possible to finely adjust the emission spectrum and intensity by changing the molar ratio of the cation to the anion represented by (L + M) / (O + N). This can be performed, for example, by performing a process such as vacuum and desorbing N and O, but is not limited to this method. The composition of the oxynitride phosphor may contain at least one of Li, Na, K, Rb, Cs, Mn, Re, Cu, Ag, and Au. It is because the luminous efficiency such as luminance and quantum efficiency can be adjusted by adding these. Further, other elements may be included to such an extent that the characteristics are not impaired. However, the present invention is not limited to this embodiment and Examples.
[0062]
L is a Group II element that is at least one or more elements selected from the group consisting of Ca, Sr, Ba and Zn. That is, Ba may be used alone, but various combinations such as Ba and Ca, Ba and Sr, and Ba and Ca and Sr may be used. The mixture ratio of the mixture of these Group II elements can be changed as desired.
[0063]
M is a Group IV element that is at least one or more elements that essentially includes Si selected from the group consisting of C, Si, Ge, Sn, Ti, and Hf. For M, Si may be used alone, but various combinations such as Si and Ge, Si and C, etc. may be used. This is because the use of Si makes it possible to provide an inexpensive phosphor having good crystallinity.
[0064]
R is a rare earth element that is at least one or more of which Eu is essential. Specifically, rare earth elements are La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lr. Of these rare earth elements, Eu may be used alone, but an element containing Eu and at least one element selected from rare earth elements may also be used. Elements other than Eu act as a co-activator. It is preferable that R contains 70% or more of Eu. In particular, R is a Group II element: R = 1: 0.005 to 1: 0.15 in a molar ratio to the Group II element.
[0065]
Europium Eu, which is a rare earth element, is used for the emission center. In the present invention, description will be made using only Eu, but the present invention is not limited to this, and one co-activated with Eu can also be used. Europium has mainly divalent and trivalent energy levels. The phosphor of the present invention is based on the alkaline earth metal-based silicon nitride as a base material. ²⁺ Is used as an activator. Eu ²⁺ Is easily oxidized, and generally trivalent Eu ₂ O ₃ It is commercially available in the composition of
[0066]
As the base material, the respective compounds can also be used for the main components L and M. As the main components L and M, metals, oxides, imides, amides, nitrides, various salts, and the like can be used. Further, the main components L and M may be mixed and used in advance.
[0067]
Q is at least one group III element selected from the group consisting of B, Al, Ga, and In. As Q, metals, oxides, imides, amides, nitrides and various salts can be used. For example, B ₂ O ₆ , H ₃ BO ₃ , Al ₂ O ₃ , Al (NO ₃ ) ₃ ・ 9H ₂ O, AlN, GaCl ₃ , InCl ₃ And so on.
[0068]
The nitride of L, the nitride of M, and the oxide of M are mixed as a base material. An Eu oxide is mixed into the base material as an activator. These are weighed and mixed until desired. In particular, the nitride of L, the nitride of M, and the oxide of M of the base material are 0.5 <L nitride <1.5, 0.25 <M nitride <1.75, 2.N. Preferably, they are mixed in a molar ratio of 25 <M oxide <3.75. These base materials are referred to as L _X M _Y O _Z N _{((2/3) X + Y- (2/3) Z-α)} : R or L _X M _Y Q _T O _Z N _{((2/3) X + Y + T- (2/3) Z-α)} : A predetermined amount is weighed and mixed so as to have a composition ratio of R.
[0069]
(Production method of oxynitride phosphor)
Next, the oxynitride phosphor according to the present invention, BaSi ₂ O ₂ N ₂ : A method for producing Eu will be described, but the present invention is not limited to this method. FIG. 3 is a process chart showing a method for producing an oxynitride phosphor.
[0070]
First, a nitride of Ba, a nitride of Si, an oxide of Si, and an oxide of Eu are mixed so as to have a predetermined compounding ratio.
[0071]
A nitride of Ba, a nitride of Si, an oxide of Si, and an oxide of Eu are prepared in advance. As these raw materials, it is preferable to use purified ones, but commercially available ones may also be used. Specifically, an oxynitride phosphor is manufactured by the following method.
[0072]
Ba nitride Ba as raw material ₃ N ₂ Use As the raw material, it is preferable to use a simple substance of Ba, but it is also possible to use a compound such as an imide compound, an amide compound, or BaO. The raw material Ba may contain B, Ga, or the like.
[0073]
Ba nitride Ba ₃ N ₂ Is ground (P1). Ba nitride is pulverized in an argon atmosphere or a nitrogen atmosphere in a glove box.
[0074]
Raw material Si nitride Si ₃ N ₄ Use As the raw material, it is preferable to use a simple substance of Si, but it is also possible to use a nitride compound, an imide compound, an amide compound, or the like. For example, Si ₃ N ₄ , Si (NH ₂ ) ₂ , Mg ₂ Si, Ca ₂ Si, SiC and the like. The raw material Si preferably has a purity of 3N or more, but may contain B, Ga, or the like.
[0075]
Si nitride Si ₃ N ₄ Is ground (P2). The Si nitride is pulverized in an argon atmosphere or a nitrogen atmosphere in a glove box.
[0076]
Raw material Si oxide SiO ₂ Use Here, a commercially available product (Silicon Dioxide 99.9%, 190-09072, manufactured by Wako Pure Chemical Industries, Ltd.) is used.
[0077]
Si oxide SiO ₂ Is ground (P3).
[0078]
Eu oxide Eu as raw material ₂ O ₂ Use As a raw material, it is preferable to use a simple substance of Eu, but it is also possible to use a nitride compound, an imide compound, an amide compound, or the like. In particular, it is preferable to use europium nitride in addition to europium oxide. This is because the product contains oxygen or nitrogen.
[0079]
Eu oxide Eu ₂ O ₂ Is ground (P4).
[0080]
Nitride Ba of the above raw material Ba ₃ N ₂ , Si nitride Si ₃ N ₄ , Si oxide SiO ₂ , Eu oxide Eu ₂ O ₂ Are weighed and mixed (P5). A predetermined molar amount of the raw material is weighed so as to have a predetermined mixing ratio.
[0081]
Next, a mixture of Ba nitride, Si nitride, Si oxide, and Eu oxide is fired (P6). The mixture is put into a crucible and fired.
[0082]
By mixing and firing, BaSi ₂ O ₂ N ₂ : An oxynitride phosphor represented by Eu can be obtained (P7). The reaction formula of the basic constituent elements by this firing is shown in Chemical formula 1.
[0083]
Embedded image

However, this composition is a typical composition estimated from the compounding ratio, and has a sufficient property for practical use in the vicinity of the ratio. Further, by changing the mixing ratio of each raw material, the composition of the target phosphor can be changed.
[0084]
For firing, a tubular furnace, a small furnace, a high-frequency furnace, a metal furnace, or the like can be used. The firing temperature is not particularly limited, but firing is preferably performed in the range of 1200 to 1700 ° C., and a firing temperature of 1400 to 1700 ° C. is more preferable. The raw material of the phosphor 11 is preferably fired using a crucible or boat made of boron nitride (BN). In addition to the crucible made of boron nitride, alumina (Al ₂ O ₃ ) A crucible made of a material can also be used.
[0085]
The firing is preferably performed in a reducing atmosphere. The reducing atmosphere is a nitrogen atmosphere, a nitrogen-hydrogen atmosphere, an ammonia atmosphere, an inert gas atmosphere such as argon, or the like.
[0086]
By using the above manufacturing method, it is possible to obtain a target oxynitride phosphor.
[0087]
In addition, Ba _X Si _Y B _T O _Z N _{((2/3) X + Y + T- (2/3) Z-α)} : The oxynitride phosphor represented by Eu can be manufactured as follows.
[0088]
In advance, the compound of B is added to the oxide of Eu. ₃ BO ₃ Is dry mixed. Europium oxide is used as the Eu compound, but metal europium, europium nitride, and the like can also be used as in the other constituent elements described above. In addition, as the raw material Eu, an imide compound or an amide compound can be used. Europium oxide is preferably of high purity, but a commercially available one can also be used. The compound of B is dry-mixed, but may also be wet-mixed. Since some of these mixtures are easily oxidized, they are mixed in an Ar atmosphere or a nitrogen atmosphere in a glove box.
[0089]
Compound H of B ₃ BO ₃ In the following, a method for producing an oxynitride phosphor will be described by way of example. Examples of component elements other than B include Li, Na, and K, and these compounds, for example, LiOH.H ₂ O, Na ₂ CO ₃ , K ₂ CO ₃ , RbCl, CsCl, Mg (NO ₃ ) ₂ , CaCl ₂ ・ 6H ₂ O, SrCl ₂ ・ 6H ₂ O, BaCl ₂ ・ 2H ₂ O, TiOSO ₄ ・ H ₂ O, ZrO (NO ₃ ) ₂ , HfCl ₄ , MnO ₂ , ReCl ₅ , Cu (CH ₃ COO) ₂ ・ H ₂ O, AgNO ₃ , HAuCl ₄ ・ 4H ₂ O, Zn (NO ₃ ) ₂ ・ 6H ₂ O, GeO ₂ , Sn (CH ₃ COO) ₂ Etc. can be used.
[0090]
Grind the mixture of Eu and B. The average particle size of the mixture of Eu and B after pulverization is preferably about 0.1 μm to 15 μm.
[0091]
After performing the above pulverization, the aforementioned BaSi ₂ O ₂ N ₂ : A nitride of Ba, a nitride of Si, an oxide of Si, and an oxide of Eu containing B are mixed in substantially the same manner as in the production process of Eu. After the mixing, baking is performed to obtain a target oxynitride phosphor.
[0092]
(Second phosphors 11, 108)
The phosphors 11 and 108 include a second phosphor together with the oxynitride phosphor. Examples of the second phosphor include an alkaline earth halogen apatite phosphor activated mainly by a transition metal based element such as Eu, a transition metal based element such as Mn, an alkaline earth metal borate halogen phosphor, and an alkaline earth. Mainly activated by lanthanoid elements such as metal aluminate phosphor, alkaline earth silicate, alkaline earth sulfide, alkaline earth thiogallate, alkaline earth silicon nitride, germanate, or Ce It is preferably at least one selected from rare earth aluminates, rare earth silicates, and organic and organic complexes mainly activated by lanthanoid elements such as Eu. As specific examples, the following phosphors can be used, but are not limited thereto.
[0093]
Alkaline earth halogen apatite phosphors mainly activated by lanthanoid-based elements such as Eu and transition metal-based elements such as Mn include M ₅ (PO ₄ ) ₃ X: R (M is at least one or more selected from Sr, Ca, Ba, Mg, and Zn. X is at least one or more selected from F, Cl, Br, and I. R is Eu. , Mn, or at least one of Eu and Mn.).
[0094]
Alkaline earth metal halogen borate phosphors include M ₂ B ₅ O ₉ X: R (M is at least one or more selected from Sr, Ca, Ba, Mg, and Zn. X is at least one or more selected from F, Cl, Br, and I. R is Eu. , Mn, or at least one of Eu and Mn.).
[0095]
Alkaline earth metal aluminate phosphors include SrAl ₂ O ₄ : R, Sr ₄ Al ₁₄ O ₂₅ : R, CaAl ₂ O ₄ : R, BaMg ₂ Al ₁₆ O ₂₇ : R, BaMg ₂ Al ₁₆ O ₁₂ : R, BaMgAl ₁₀ O ₁₇ : R (R is one or more of Eu and Mn, and Eu and Mn).
[0096]
Alkaline earth sulfide phosphors include La ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, Gd ₂ O ₂ S: Eu and the like.
[0097]
Rare earth aluminate phosphors mainly activated by lanthanoid elements such as Ce include Y ₃ Al ₅ O ₁₂ : Ce, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce, Y ₃ (Al _0.8 Ga _0.2 ) ₅ O ₁₂ : Ce, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ YAG-based phosphor represented by the following composition formula:
[0098]
Other phosphors include ZnS: Eu, Zn ₂ GeO ₄ : Mn, MGa ₂ S ₄ : Eu (M is at least one or more selected from Sr, Ca, Ba, Mg, and Zn. X is at least one or more selected from F, Cl, Br, and I). Also, M ₂ Si ₅ N ₈ : Eu, MSi ₇ N ₁₀ : Eu, M _1.8 Si ₅ O _0.2 N ₈ : Eu, M _0.9 Si ₇ O _0.1 N ₁₀ : Eu (M is at least one selected from Sr, Ca, Ba, Mg, and Zn).
[0099]
The second phosphor described above may be replaced with Eu or one or more selected from Tb, Cu, Ag, Au, Cr, Nd, Dy, Co, Ni, and Ti, if desired. Can also be contained.
[0100]
Further, phosphors other than the above-mentioned phosphors and having the same performance and effect can also be used.
[0101]
As these second phosphors, phosphors having emission spectrums of yellow, red, green, and blue by the excitation light of the light emitting elements 10 and 101 can be used. A phosphor having an emission spectrum in orange or the like can also be used. By using these second phosphors in combination with the first phosphor, light emitting devices having various luminescent colors can be manufactured.
[0102]
For example, the first phosphor, CaSi, which emits light from green to yellow ₂ O ₂ N ₂ : Eu or SrSi ₂ O ₂ N ₂ : Emits blue light as Eu and the second phosphor (Sr, Ca) ₅ (PO ₄ ) ₃ Cl: Eu, emits red light (Ca, Sr) ₂ Si ₅ N ₈ By using the phosphors 11 and 108 composed of: Eu, a light emitting device that emits white light with good color rendering properties can be provided. Since the three primary colors of red, blue and green are used, a desired white light can be realized only by changing the mixing ratio of the first phosphor and the second phosphor. Can be. In particular, when the oxynitride phosphor and the second phosphor are irradiated with light near 460 nm as the excitation light source, the oxynitride phosphor emits light near 500 nm. Thereby, a white light emitting device having excellent color rendering properties can be provided.
[0103]
The particle size of the phosphors 11 and 108 is preferably in the range of 1 μm to 20 μm, and more preferably 2 μm to 8 μm. In particular, 5 μm to 8 μm is preferable. Phosphors having a particle size smaller than 2 μm tend to form aggregates. On the other hand, a phosphor having a particle size range of 5 μm to 8 μm has high light absorption and conversion efficiency. As described above, the mass productivity of the light-emitting device is improved by including a phosphor having a large particle diameter having excellent optical characteristics.
[0104]
Here, the particle size refers to an average particle size obtained by an air permeation method. Specifically, under an environment of a temperature of 25 ° C. and a humidity of 70%, 1 cm ³ After weighing out the sample and packing it in a dedicated tubular container, dry air at a constant pressure is flowed, the specific surface area is read from the differential pressure, and the value is converted to the average particle size. The average particle size of the phosphor used in the present invention is preferably in the range of 2 μm to 8 μm. Further, it is preferable that the phosphor having the average particle size is contained frequently. In addition, the particle size distribution is preferably distributed in a narrow range, and in particular, those having a small particle size of 2 μm or less are preferable. By using a phosphor having a small variation in particle size and particle size distribution, color unevenness is further suppressed, and a light emitting device having a good color tone can be obtained.
[0105]
The location of the phosphor 108 in the light emitting device 2 can be located at various locations depending on the positional relationship with the light emitting element 101. For example, the phosphor 108 can be contained in a molding material for covering the light emitting element 101. Further, the light emitting element 101 and the phosphor 108 may be arranged with a gap therebetween, or the phosphor 108 may be directly mounted on the light emitting element 101.
[0106]
(Coating members 12, 109)
The phosphors 11 and 108 can be attached using various kinds of coating members (binders) such as a resin as an organic material and a glass as an inorganic material. The coating members 12, 109 may have a role as a binder for fixing the phosphors 11, 108 to the light emitting elements 10, 101, the window 107, and the like. When an organic substance is used as the coating member (binder), a transparent resin having excellent weather resistance such as an epoxy resin, an acrylic resin, or silicone is preferably used as a specific material. In particular, it is preferable to use silicone because it is excellent in reliability and can improve the dispersibility of the phosphors 11 and 108.
[0107]
Also, it is preferable to use an inorganic substance having a coefficient of thermal expansion similar to that of the window 107 as the coating members (binders) 12 and 109 because the phosphor 108 can be brought into good contact with the window 107. As a specific method, a sedimentation method, a sol-gel method, a spray method, or the like can be used. For example, the phosphors 11 and 108 are provided with silanol (Si (OEt) ₃ OH) and ethanol were mixed to form a slurry, and the slurry was discharged from a nozzle, and then heated at 300 ° C. for 3 hours to convert the silanol to SiO 2. ₂ Then, the phosphor can be fixed to a desired place.
[0108]
In addition, an inorganic binder can be used as the coating members (binders) 12 and 109. The binder is a so-called low-melting glass, is a fine particle, has little absorption for radiation in the ultraviolet to visible region, and is extremely stable in the coating member (binder) 12, 109. Is preferred.
[0109]
When a phosphor having a large particle diameter is adhered to the coating members (binders) 12 and 109, a binder in which the particles are ultrafine even if the melting point is high, such as silica, alumina, or a precipitation method is used. It is preferable to use alkaline earth metal pyrophosphate, orthophosphate and the like having a fine particle size. These binders can be used alone or as a mixture with one another.
[0110]
Here, a method of applying the binder will be described. In order to sufficiently enhance the binding effect, the binder is preferably wet-pulverized in a vehicle to form a slurry and used as a binder slurry. The vehicle is a high-viscosity solution obtained by dissolving a small amount of a binder in an organic solvent or deionized water. For example, an organic vehicle can be obtained by adding 1% by weight of nitrocellulose as a binder to butyl acetate as an organic solvent.
[0111]
The binder slurry thus obtained contains phosphors 11 and 108 to prepare a coating solution. The addition amount of the slurry in the coating solution may be such that the total amount of the binder in the slurry is about 1 to 3% wt with respect to the amount of the phosphor in the coating solution. In order to suppress a decrease in the luminous flux maintenance rate, it is preferable that the amount of the binder added is small.
[0112]
The coating liquid is applied to the back of the window 107. After that, hot air or hot air is blown to dry. Finally, baking is performed at a temperature of 400 ° C. to 700 ° C. to disperse the vehicle. As a result, the phosphor layer is attached to a desired place with the binder.
[0113]
(Light-emitting elements 10, 101)
In the present invention, the light emitting elements 10 and 101 are preferably semiconductor light emitting elements having a light emitting layer capable of emitting a light emission wavelength capable of efficiently exciting a phosphor. As a material of such a semiconductor light emitting device, various semiconductors such as BN, SiC, ZnSe, GaN, InGaN, InAlGaN, AlGaN, BAlGaN, and BInAlGaN can be given. Similarly, these elements may contain Si, Zn, or the like as an impurity element to serve as a light emission center. In particular, a nitride semiconductor (for example, a nitride semiconductor containing Al or Ga, In or Ga, etc.) may be used as a material of a light emitting layer capable of efficiently emitting a short wavelength of visible light from an ultraviolet region where the phosphors 11 and 108 can be efficiently excited. In as a nitride semiconductor containing _X Al _Y Ga _1-XY N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) are more preferable.
[0114]
Further, as a semiconductor structure, a homo structure, a hetero structure, or a double hetero structure having a MIS junction, a PIN junction, a pn junction, or the like is preferably exemplified. Various emission wavelengths can be selected depending on the material of the semiconductor layer and its mixed crystal ratio. Further, the output can be further improved by using a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed as a thin film in which a quantum effect occurs.
[0115]
When a nitride semiconductor is used for the light emitting elements 10 and 101, 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 having good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate by using the HVPE method, the MOCVD method, or the like. A non-single-crystal buffer layer is formed on a sapphire substrate by growing at a low temperature such as GaN, AlN, or GaAIN, and a nitride semiconductor having a pn junction is formed thereon.
[0116]
As an example of a light-emitting element capable of efficiently emitting light in an ultraviolet region having a pn junction using a nitride semiconductor, a SiO.sub.2 is formed on a buffer layer in a direction substantially perpendicular to the orientation flat surface of a sapphire substrate. ₂ Are formed in a stripe shape. ELOG (Epitaxial Lateral Over Grows GaN) is grown on the stripes using HVPE. Subsequently, a first contact layer formed of n-type gallium nitride, a first cladding layer formed of n-type aluminum gallium nitride, a well layer of indium aluminum gallium nitride and aluminum gallium nitride are formed by MOCVD. 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-gallium nitride, and a second contact layer formed of p-type gallium nitride are sequentially stacked. A configuration such as a double hetero configuration is included. The active layer may be formed in a ridge stripe shape, sandwiched between guide layers, and provided with an end face of a resonator to provide a semiconductor laser device usable in the present invention.
[0117]
A nitride semiconductor shows n-type conductivity without doping impurities. When a desired n-type nitride semiconductor is formed, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, or the like as an n-type dopant. On the other hand, when a p-type nitride semiconductor is formed, it is preferable to dope a p-type dopant such as Zn, Mg, Be, Ca, Sr, or Ba. Since it is difficult to make a nitride semiconductor p-type only by doping it with a p-type dopant, it is preferable to lower the resistance by introducing a p-type dopant and then heating the furnace or irradiating plasma. If a 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. After forming electrodes on each contact layer, the semiconductor wafer is cut into chips to form a light emitting element made of a nitride semiconductor.
[0118]
In the light-emitting device of the present invention, in order to form the phosphors 11 and 108 on the light-emitting elements 10 and 101 in order to form the light-emitting elements 10 and 101 with good mass productivity, it is preferable to use resin to form the phosphors 11 and 108. In this case, the light emitting elements 10 and 101 have an emission spectrum in the ultraviolet region in consideration of the emission wavelength from the phosphors 11 and 108 and the deterioration of the translucent resin, and the emission peak wavelength is 360 nm or more and 420 nm or less. It is preferable to use those having a thickness of 450 nm or more and 470 nm or less.
[0119]
Here, the semiconductor light emitting devices 10 and 101 used in the present invention have an impurity concentration of 10%. ¹⁷ -10 ²⁰ / Cm ³ It is preferable that the sheet resistance of the n-type contact layer and the sheet resistance of the translucent p-electrode are adjusted so that Rp ≧ Rn. The n-type contact layer is preferably formed to have a thickness of, for example, 3 to 10 μm, more preferably 4 to 6 μm, and its sheet resistance is estimated to be 10 to 15 Ω / □. The thin film is preferably formed to have the above sheet resistance. Further, the translucent p-electrode may be formed as a thin film having a thickness of 150 μm or less.
[0120]
Further, when the translucent p-electrode is formed of a multilayer film or an alloy composed of one selected from the group consisting 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 the gold or 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 the gold or platinum group element contained in the translucent p-electrode, the better the transmittance. In the conventional semiconductor light emitting element, the relation of the sheet resistance is Rp ≦ Rn. However, in the present invention, since Rp ≧ Rn, the translucent p-electrode is formed in a thin film as compared with the conventional one. However, at this time, a thin film can be easily formed by reducing the content of the gold or platinum group element.
[0121]
As described above, in the semiconductor light emitting devices 10 and 101 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 have a relationship of Rp ≧ Rn. Preferably. It is difficult to measure Rn after forming the semiconductor light emitting devices 10 and 101, and it is practically impossible to know the relationship between Rp and Rn. It is possible to know whether or not it has a relationship with Rn.
[0122]
When the translucent p-electrode and the n-type contact layer have a relationship of Rp ≧ Rn, providing a p-side pedestal electrode having an extended conduction portion in contact with the translucent p-electrode further improves external quantum efficiency. Can be achieved. There is no limitation on the shape and direction of the extension conducting part. When the extension conducting part is on the satellite, it is preferable because the area that blocks light is reduced. 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, the light-shielding effect increases in proportion to the total area of the p-side pedestal electrode. Therefore, 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.
[0123]
(Light-emitting elements 10, 101)
As the light emitting elements 10 and 101, a light emitting element that emits blue light different from the above-described ultraviolet light emitting element can be used. The light-emitting elements 10 and 101 that emit blue light are preferably group III nitride compound light-emitting elements. The light-emitting elements 10 and 101 include, for example, an undoped n-type GaN layer, an n-type contact layer made of Si-doped n-type GaN, an undoped GaN layer, and a multiple quantum well on a sapphire substrate 1 via a GaN buffer layer. Light emitting layer having a well structure (GaN barrier layer / quantum well structure of InGaN well layer), p-type GaN made of p-type GaN doped with Mg, p-type made of p-type GaN doped with Mg It has a laminated structure in which contact layers are sequentially laminated, and electrodes are formed as follows. However, a light emitting element different from this configuration can be used.
[0124]
The p-ohmic electrode is formed on almost the entire surface of the p-type contact layer, and a p-pad electrode is formed on a part of the p-ohmic electrode.
[0125]
The n-electrode is formed on 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.
[0126]
In the present embodiment, a light emitting layer having a multiple quantum well structure is used. However, the present invention is not limited to this. For example, a single quantum well structure using InGaN may be used. , Zn-doped GaN may be used.
[0127]
In the light emitting layers of the light emitting elements 10 and 101, the main emission peak wavelength can be changed in the range of 420 nm to 490 nm by changing the In content. Further, the emission peak wavelength is not limited to the above range, and those having an emission peak wavelength at 360 to 550 nm can be used.
[0128]
(Coating members 12, 109)
The coating member 12 (light-transmissive material) is provided in the cup of the lead frame 13 and is used by being mixed with the phosphor 11 that converts light emission of the light emitting element 10. As a specific material of the coating member 12, a transparent resin having excellent temperature characteristics and weather resistance, such as an epoxy resin, a urea resin, and a silicone resin, silica sol, glass, and an inorganic binder are used. Further, a diffusing agent, barium titanate, titanium oxide, aluminum oxide, or the like may be contained together with the phosphor. Further, a light stabilizer and a coloring agent may be contained.
[0129]
(Lead frame 13)
The lead frame 13 includes a mount lead 13a and an inner lead 13b.
[0130]
The mount lead 13a is for disposing the light emitting element 10. 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 in the cup. . A plurality of light emitting elements 10 may be arranged in a cup and the mount lead 13a may be used as a common electrode of the light emitting element 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, in order to perform die bonding with the mount lead 13a using the face-down light emitting element 10 and to make electrical connection, an Ag-ace, a carbon paste, a metal bump, or the like can be used. Further, an inorganic binder can be used.
[0131]
The inner lead 13b is for electrically connecting 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 arranged at a position distant from the mount lead 13a in order to avoid a short circuit due to electrical contact with the mount lead 13a. When a plurality of light emitting elements 10 are provided on the mount lead 13a, it is necessary to adopt a configuration in which the conductive wires can 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 may be made of iron, copper, iron-containing copper, gold, platinum, silver, or the like.
[0132]
(Conductive wire)
The conductive wire 14 electrically connects 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. As a specific material of the conductive wire 14, metals such as gold, copper, platinum, and aluminum, and alloys thereof are preferable.
[0133]
(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 has a purpose of widening a viewing angle, relaxing directivity from the light emitting element 10, and converging and diffusing light emission. To achieve these objects, the mold member can have a desired shape. The mold member 15 may have a convex lens shape, a concave lens shape, or a structure in which a plurality of layers are stacked. As a specific material of the mold member 15, a material having excellent light transmission, weather resistance, and temperature characteristics such as an epoxy resin, a urea resin, a silicone resin, a silica sol, and glass can be used. The mold member 15 may contain a diffusing agent, a coloring agent, an ultraviolet absorber, and a phosphor. As the diffusing agent, barium titanate, titanium oxide, aluminum oxide and the like are preferable. In order to reduce the resilience of the material with the coating member 12 and to consider the refractive index, it is preferable to use the same material.
[0134]
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.
[0135]
The temperature characteristics are shown as relative luminance with the emission luminance at 25 ° C. being 100%. The particle size indicates the above-mentioned average particle size, and F.I. S. S. S. No. (Fisher Sub Sieve Sizer's No.) by the air permeation method.
[0136]
【Example】
Hereinafter, examples of the present invention will be described in detail.
[0137]
(Phosphor)
FIG. 4 is a diagram showing an emission spectrum when the oxynitride phosphors of Examples 1 to 5 are excited at Ex = 400 nm. FIG. 5 is a diagram showing an emission spectrum when the oxynitride phosphors of Examples 1 to 5 are excited at Ex = 460 nm. FIG. 6 is a diagram showing excitation spectra of the oxynitride phosphors of Examples 1 to 5. FIG. 7 is a diagram showing reflection spectra of the oxynitride phosphors of Examples 1 to 5. FIG. 8 is an SEM photograph of the oxynitride phosphor of Example 1. FIG. 8A is a photograph taken at a magnification of 1000 times, and FIG. 8B is a photograph taken at a magnification of 5000 times.
[0138]
In Examples 1 to 5, Ba is partially replaced by Eu, and the Eu concentration is changed. In the first embodiment, Ba _0.97 Eu _0.03 Si ₂ O ₂ N ₂ It is. Example 2 is based on Ba _0.95 Eu _0.05 Si ₂ O ₂ N ₂ It is. Example 3 is based on Ba _0.90 Eu _0.10 Si ₂ O ₂ N ₂ It is. In Example 4, Ba was used. _0.85 Eu _0.15 Si ₂ O ₂ N ₂ It is. In Example 5, Ba was used. _0.80 Eu _0.20 Si ₂ O ₂ N ₂ It is.
[0139]
First, the raw material is Ba ₃ N ₂ , Si ₃ N ₄ , SiO ₂ , Eu ₂ O ₃ It was used. The raw materials were each pulverized to 0.1 to 3.0 μm. After pulverization, Example 1 used the following amounts of raw materials so as to have the above composition. Here, the molar ratio of Eu to Ba is Ba: Eu = 0.97: 0.03.
Ba ₃ N ₂ ： 5.60g
Si ₃ N ₄ : 1.88 g
SiO ₂ : 2.31 g
Eu ₂ O ₃ : 0.21g
After weighing the above quantity, Ba ₃ N ₂ , Si ₃ N ₄ , SiO ₂ , Eu ₂ O ₃ Was mixed until uniform.
[0140]
The above compounds were mixed, put into a boron nitride crucible in an ammonia atmosphere, and fired at about 1500 ° C. for about 5 hours.
[0141]
Thus, the desired oxynitride phosphor was obtained. The theoretical composition of the obtained oxynitride phosphor is BaSi ₂ O ₂ N ₂ : Eu.
[0142]
When the weight percentages of O and N in the oxynitride phosphor of Example 1 were measured, it was found that 12.1% by weight of O and 8.9% by weight of N were contained in the total amount. The weight ratio of O and N is O: N = 1: 0.74.
[0143]
The oxynitride phosphor according to the embodiment is fired in an ammonia atmosphere using a crucible made of boron nitride. It is not very preferable to use a metal crucible as the crucible. This is because when a metal crucible is used, the crucible may be eroded, causing a decrease in light emission characteristics. Therefore, it is preferable to use a crucible made of ceramics such as alumina.
[0144]
In Example 2, the mixing ratio of Eu was changed. This is an oxynitride phosphor in which Ba is partially substituted with Eu. The finely ground powder was weighed in the following quantities. Here, the molar ratio of Eu to Ba is Ba: Eu = 0.95: 0.05.
Ba ₃ N ₂ : 5.48 g
Si ₃ N ₄ 1.91 g
SiO ₂ : 2.28 g
Eu ₂ O ₃ ： 0.35g
The raw materials were mixed and fired under the same conditions as in Example 1.
[0145]
In Example 3, the mixing ratio of Eu was changed. This is an oxynitride phosphor in which Ba is partially substituted with Eu. The finely ground powder was weighed in the following quantities. Here, the molar ratio of Eu to Ba is Ba: Eu = 0.90: 0.10.
Ba ₃ N ₂ : 5.18g
Si ₃ N ₄ : 1.97 g
SiO ₂ ： 2.18g
Eu ₂ O ₃ : 0.69 g
The raw materials were mixed and fired under the same conditions as in Example 1.
[0146]
In Example 4, the mixing ratio of Eu was changed. This is an oxynitride phosphor in which Ba is partially substituted with Eu. The finely ground powder was weighed in the following quantities. Here, the molar ratio of Eu to Ba is Ba: Eu = 0.85: 0.15.
Ba ₃ N ₂ : 4.87 g
Si ₃ N ₄ ： 2.03g
SiO ₂ ： 2.09g
Eu ₂ O ₃ ： 1.03g
The raw materials were mixed and fired under the same conditions as in Example 1.
[0147]
In Example 5, the mixing ratio of Eu was changed. This is an oxynitride phosphor in which Ba is partially substituted with Eu. The finely ground powder was weighed in the following quantities. Here, the molar ratio of Eu to Ba is Ba: Eu = 0.80: 0.20.
Ba ₃ N ₂ : 4.57 g
Si ₃ N ₄ ： 2.10g
SiO ₂ : 1.99 g
Eu ₂ O ₃ : 1.37 g
The raw materials were mixed and fired under the same conditions as in Example 1.
[0148]
The fired products of Examples 1 to 5 are all crystalline powders or granules. The particle size was approximately 1-5 μm.
[0149]
Table 1 shows the emission characteristics when the oxynitride phosphors of Examples 1 to 5 were excited at Ex = 400 nm.
[0150]
[Table 1]

The excitation spectra of the oxynitride phosphors of Examples 1 to 5 were measured. As a result of the measurement, in Examples 1 to 4, excitation is stronger at 370 nm to 470 nm than at around 350 nm.
[0151]
The reflection spectra of the oxynitride phosphors of Examples 1 to 5 were measured. As a result of the measurement, Examples 1 to 5 show high absorptivity from 290 nm to 470 nm. Therefore, light from the excitation light source from 290 nm to 470 nm can be efficiently absorbed, and wavelength conversion can be performed.
[0152]
As an excitation light source, light near Ex = 400 nm was irradiated to the oxynitride phosphors of Examples 1 to 5 to excite the light. The oxynitride phosphor of Example 1 has a light emission color in a green region having a color tone x = 0.106, a color tone y = 0.471, and an emission peak wavelength λp = 496 nm. Example 2 has a light emission color in a green region where the color tone x = 0.121, the color tone y = 0.481, and λp = 498 nm. The third embodiment has a light emission color in a green region where the color tone x is 0.247, the color tone y is 0.477, and λp is 500 nm. Each of the oxynitride phosphors of Examples 1 to 3 showed higher luminous efficiency than the conventional phosphor. In particular, the oxynitride phosphors of Examples 1 to 4 exhibited higher luminous efficiency than Example 5. In Examples 2 to 5, the emission luminance and the quantum efficiency of Example 1 are set to 100%, and are represented by relative values.
[0153]
Table 2 shows the temperature characteristics of the oxynitride phosphor of Example 1. The temperature characteristics are indicated by relative luminance with the emission luminance at 25 ° C. being 100%. The excitation light source is light near Ex = 400 nm.
[0154]
[Table 2]

From this result, when the oxynitride phosphor was heated to 100 ° C., it maintained an extremely high emission luminance of 88.8%, and as high as 64.7% even when the temperature was raised to 200 ° C. Light emission brightness is maintained. Thus, the oxynitride phosphor exhibits extremely good temperature characteristics.
[0155]
When the X-ray diffraction images of these oxynitride phosphors were measured, each showed a sharp diffraction peak, and it was revealed that the obtained phosphor was a crystalline compound having regularity.
[0156]
<Light emitting device>
Using the oxynitride phosphor described above, the light emitting device of Example 1 was manufactured. A light-emitting element having an emission spectrum of 400 nm is used as an excitation light source. The phosphor is BaSi of Example 1. ₂ O ₂ N ₂ : Eu and (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce and SrCaSi ₅ N ₈ : Eu and (Ca _0.93 , Eu _0.05 , Mn _0.02 ) ₁₀ (PO ₄ ) ₆ Cl ₂ Use FIG. 1 shows a light emitting device according to the present invention. FIG. 9 is a plan view showing a light emitting device according to the present invention. FIG. 10 is a sectional view showing AA ′ of the light emitting device according to the present invention. FIG. 11 is a diagram illustrating an emission spectrum (simulation) of the light emitting device according to the first embodiment. FIG. 12 is a diagram illustrating chromaticity coordinates (simulation) of the light emitting devices of Examples 1 to 3. The color temperature of the light emitting device of Example 1 is adjusted to 4000 to 5000K.
[0157]
(Light emitting element)
The substrate 201 made of sapphire (C plane) is set in a MOVPE reaction vessel, and the temperature of the substrate 201 is increased to about 1050 ° C. while flowing hydrogen to clean the substrate 201.
[0158]
Here, in this embodiment, a sapphire substrate is used as the substrate 201, but a heterogeneous substrate different from a nitride semiconductor, or a nitride semiconductor substrate such as AlN, AlGaN, or GaN may be used as the substrate 201. Examples of the heterogeneous substrate include sapphire and spinel (MgAl ₂ O ₄ It is possible to grow a nitride semiconductor such as an insulating substrate such as, an SiC (including 6H, 4H, and 3C), an oxide substrate lattice-matched with ZnS, ZnO, GaAs, Si, and a nitride semiconductor. A substrate material different from the nitride semiconductor can be used. Preferred heterosubstrates include sapphire and spinel. Further, the heterogeneous substrate may be off-angled. In this case, it is preferable to use a substrate that is off-angled in a step-like manner because the underlayer 202 made of gallium nitride grows with good crystallinity. Further, when a heterogeneous substrate is used, after growing a nitride semiconductor to be the base layer 202 before forming an element structure on the heterogeneous substrate, the heterogeneous substrate is removed by a method such as polishing, and the nitride semiconductor alone is removed. An element structure may be formed as a substrate, or a method of removing a heterogeneous substrate after forming the element structure may be used. In addition to the GaN substrate, a substrate of a nitride semiconductor such as AlN may be used.
[0159]
(Buffer layer)
Subsequently, the temperature of the substrate 201 was lowered to 510 ° C., and a buffer layer (not shown) made of GaN was formed on the substrate 201 to a thickness of about 100 Å using hydrogen as a carrier gas, ammonia and TMG (trimethylgallium) as source gases. It grows with the film thickness.
[0160]
(Underlayer)
After the growth of the buffer layer, only the TMG is stopped, and the temperature of the substrate 201 is raised to 1050 ° C. When the temperature reaches 1050 ° C., an undoped GaN layer is grown to a thickness of 2 μm using TMG and ammonia gas as source gases.
[0161]
(N-type layer)
Subsequently, at 1050 ° C., TMG and ammonia gas were used as the source gas, and silane gas was used as the impurity gas. ¹⁸ / Cm ³ An n-type layer 203 made of doped GaN is grown to a thickness of 3 μm as an n-side contact layer for forming an n-side electrode 211a as an n-type layer.
[0162]
(Active layer)
A barrier layer made of Si-doped GaN is grown to a thickness of 50 angstroms, then the temperature is set to 800 ° C., and undoped In using TMG, TMI and ammonia. _0.1 Ga _0.7 A well layer made of N is grown to a thickness of 50 angstroms. Four barrier layers and three wells are alternately stacked in the order of barrier + well + barrier + well... + Barrier to grow an active layer 204 having a multiple quantum well structure with a total thickness of 350 Å. Let it.
[0163]
(P-side carrier confinement layer)
Next, TMG, TMA, ammonia, Cp ₂ Using Mg (cyclopentadienyl magnesium), ¹⁹ / Cm ³ Doped Al _0.3 Ga _0.7 A p-side carrier confinement layer 205 made of N is grown to a thickness of 100 Å.
[0164]
(First p-type layer)
Then, TMG, ammonia, Cp ₂ A first p-type layer 206 made of GaN doped with p-type impurities using Mg is grown to a thickness of 0.1 μm.
[0165]
(2nd p-type layer)
As a second p-type layer, a p-side contact layer 208 for forming a p-side electrode 210 on the surface is formed. The p-side contact layer 208 is composed of 1 × 10 Mg on the current diffusion layer 207. ²⁰ / Cm ³ The doped p-type GaN is grown to a thickness of 150 Å. Since the p-side contact layer 208 is a layer for forming the p-side electrode 210, 1 × 10 ¹⁷ / Cm ³ It is desirable that the carrier concentration be as high as described above. 1 × 10 ¹⁷ / Cm ³ If it is lower than this, it tends to be difficult to obtain a preferable ohmic with the electrode. Furthermore, when the composition of the contact layer is GaN, it becomes easy to obtain an electrode material and a preferable ohmic.
[0166]
After the reaction for forming the above element structure is completed, the temperature is lowered to room temperature, and the wafer is annealed at 700 ° C. in a reaction vessel in a nitrogen atmosphere to further reduce the resistance of the p-type layer. The wafer on which the element structure has been formed is taken out of the apparatus, and an electrode forming step described below is performed.
[0167]
After the annealing, the wafer is taken out of the reaction vessel, a predetermined mask is formed on the surface of the uppermost p-side contact layer 208, and the wafer is etched from the p-side contact layer 208 side by an RIE (reactive ion etching) apparatus. An electrode formation surface is formed by exposing the surface of the contact layer.
[0168]
As the p-side electrode 210, Ni and Au are sequentially stacked to form the p-side electrode 210 made of Ni / Au. The p-side electrode 210 is an ohmic electrode that is in ohmic contact with the second p-type layer and the p-side contact layer 208. At this time, the formed electrode branch 210a has a stripe-shaped light-emitting portion 209 having a width of about 5 μm and a stripe-shaped electrode branch 210a having a width of about 3 μm, and the stripe-shaped light-emitting portion 209 and the electrode branch 210a are alternately formed. I do. Further, only a part of the p-side electrode 210 is formed in a region where the p-side pad electrode is formed, and the p-side electrode 210 is formed over the p-side pad electrode to be electrically connected. At this time, only a part of the p-side electrode 210 is formed in the region where the p-side pad electrode is to be formed, and the p-side pad electrode 210b is formed on the surface of the p-side contact layer 208 to partially It is formed over the side electrode 210 to make it electrically conductive. At this time, the surface of the p-side contact layer 208 on which the p-side pad electrode 210b is provided does not make ohmic contact between the p-side electrode 210 and the p-side contact layer 208, and a Schottky barrier is formed between them. From the formation portion of the p-side pad electrode 210b, a current is injected into the element through the electrode branch 210a that is electrically connected without a current flowing directly into the element.
[0169]
Subsequently, an n-side electrode 211a is formed on the exposed surface 203a exposing the n-type layer 203. The n-side electrode 211a is formed by stacking Ti and Al.
[0170]
Here, the n-side electrode 211a is an ohmic electrode in ohmic contact with the exposed surface 203a of the n-type layer 203. After the ohmic p-side electrode 210 and the n-side electrode 211a are formed, they are annealed by heat treatment to bring the respective electrodes into ohmic contact. The p-side ohmic electrode obtained at this time is an opaque film that does not substantially transmit light emitted from the active layer 204.
[0171]
Subsequently, SiO is formed on the entire surface excluding part or all of the p-side electrode 210 and the n-side electrode 211a, that is, on the entire element surface such as the exposed surface 203a of the n-type layer 203 and the side surface of the exposed surface 203a. ₂ An insulating film is formed. After the formation of the insulating film, pad electrodes for bonding are respectively formed on the surfaces of the p-side electrode 210 and the n-side electrode 211a exposed from the insulating film, and are electrically connected to the respective ohmic electrodes. The p-side pad electrode 210b and the n-side pad electrode 211b are formed by laminating Ni, Ti, and Au on the respective ohmic electrodes.
[0172]
Finally, the substrate 201 is divided to obtain a light emitting element having a side length of 300 μm.
[0173]
The obtained light emitting device has an emission peak wavelength of about 400 nm.
[0174]
(Phosphor)
The light emitting device of the first embodiment includes the BaSi of the first embodiment. ₂ O ₂ N ₂ : Eu and (Ca _0.93 , Eu _0.05 , Mn _0.02 ) ₁₀ (PO ₄ ) ₆ Cl ₂ And (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce and SrCaSi ₅ N ₈ : Eu is used. This mixing ratio can be appropriately changed. These phosphors are irradiated with an excitation light source of Ex = 400 nm. These phosphors absorb light from the excitation light source, perform wavelength conversion, and have a predetermined emission wavelength. BaSi of Example 1 ₂ O ₂ N ₂ : Eu has an emission peak wavelength at 470 nm to 530 nm. (Ca _0.93 , Eu _0.05 , Mn _0.02 ) ₁₀ (PO ₄ ) ₆ Cl ₂ Has an emission peak wavelength at 440 to 500 nm. (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce has an emission peak wavelength at 500 to 650 nm. SrCaSi ₅ N ₈ : Eu has an emission peak wavelength at 580 nm to 730 nm.
[0175]
(Characteristics of Light Emitting Device of Example 1)
Table 3 shows the characteristics and color rendering of the light emitting device of Example 1. However, the characteristics and color rendering properties of the light emitting device of Example 1 are simulations, and it is considered that when actually manufactured, self-absorption occurs and a wavelength shift occurs. As the light emitting device of Comparative Example 1, (Ca = Ca) using an excitation light source of Ex = 400 nm _0.93 , Eu _0.05 , Mn _0.02 ) ₁₀ (PO ₄ ) ₆ Cl ₂ And (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce is used.
[0176]
[Table 3]

The phosphor excited by the light emitting element excited at 400 nm is the same as that of BaSi of Example 1. ₂ O ₂ N ₂ : Eu changes from bluish green to greenish region, (Ca _0.93 , Eu _0.05 , Mn _0.02 ) ₁₀ (PO ₄ ) ₆ Cl ₂ Is from blue-violet to blue, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce is SrCaSi in green to yellow-red region ₅ N ₈ : Eu has an emission peak wavelength from yellow-red to red. Due to the color mixture of the light of these phosphors, a light emission color is shown in a white region. Thus, the light emitting device of the first embodiment emits light in a white color region. In addition, since the excitation light source having a low luminosity characteristic near 400 nm is used, the color tone can be easily changed by changing the mixing ratio of the phosphor. In particular, in the white light-emitting device shown in Comparative Example 1, the average color rendering index (Ra) was 76.0, but in the white light-emitting device according to Example 1, the average color rendering index (Ra) was 88. 1, which was extremely good. Thus, the color rendering properties are improved. The color rendering properties of the special color rendering evaluation numbers (R1 to R15) are improved in almost all color charts. Further, the white light emitting device shown in Comparative Example 1 has a special color rendering index (R9) of -1.9, whereas the white light emitting device according to Example 1 has a special color rendering index (R9). 96.1, which was extremely good. The special color rendering index (R9) is a red color chart with relatively high saturation. The luminous efficiency is represented by a relative value when the light emitting device of Comparative Example 1 is set to 100%.
[0177]
<Light emitting device>
The light emitting devices of Examples 2 and 3 relate to a white light emitting device using a light emitting element having an emission peak wavelength of 460 nm as an excitation light source. FIG. 1 is a diagram showing a light emitting device according to the present invention. FIG. 13 is a diagram illustrating an emission spectrum (simulation) of the light emitting devices of Examples 2 and 3.
[0178]
(Light emitting element)
In the light emitting devices of Examples 2 and 3, the n-type and p-type GaN semiconductor layers 2 are formed on the sapphire substrate 1, and the n-type and p-type semiconductor layers 2 are provided with the electrodes 3. 3 is conductively connected to the lead frame 13 by a conductive wire 14. 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 by n ⁺ GaN: Si, n-AlGaN: Si, n-GaN, GaInN QWs, p-GaN: Mg, p-AlGaN: Mg, p-GaN: Mg are stacked in this order. 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 part of the mount lead 13a, and the light emitting element 10 is die-bonded to a bottom surface at a 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. For the phosphor 11, the phosphor of Example 49 and a YAG-based phosphor are mixed. As the coating member 12, a mixture of an epoxy resin, a diffusing agent, barium titanate, titanium oxide, and the phosphor 11 in a predetermined ratio is used. The mold member 15 uses an epoxy resin. The shell type light emitting device of the first embodiment is a cylindrical member having a radius of 2 to 4 mm and a height of about 7 to 10 mm of the mold member 15 and a hemispherical upper portion.
[0179]
When a current is applied to the light emitting devices of Examples 2 and 3, the blue light emitting element 10 having an emission peak wavelength at approximately 460 nm emits light. The phosphor 11 covering the semiconductor layer 2 performs color conversion of the blue light. As a result, the light-emitting devices of Examples 2 and 3 that emit white light can be provided.
[0180]
(Phosphor)
The phosphor 11 used in the light emitting devices of Examples 2 and 3 according to the present invention includes the oxynitride phosphor of Example 1 and (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : YAG phosphor represented by Ce and CaSrSi ₅ N ₈ : A phosphor 11 mixed with a nitride phosphor represented by Eu. The phosphor 11 is mixed together with the coating member 12. This mixing ratio can be appropriately changed. These phosphors 11 are irradiated with an excitation light source of Ex = 460 nm. These phosphors 11 absorb light from the excitation light source, perform wavelength conversion, and have a predetermined emission wavelength. BaSi of Example 1 ₂ O ₂ N ₂ : Eu has an emission peak wavelength at 470 nm to 530 nm. (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce has an emission peak wavelength at 500 to 650 nm. SrCaSi ₅ N ₈ : Eu has an emission peak wavelength at 580 nm to 730 nm.
[0181]
In the light emitting devices of Examples 2 and 3, a part of the light of the light emitting element 10 is transmitted. In addition, part of the light from the light emitting element 10 excites the phosphor 11 to perform wavelength conversion, and the phosphor 11 has a predetermined emission wavelength. A light-emitting device that emits white light can be provided by mixing the blue light from the light-emitting element 10 and the light from the phosphor 11.
[0182]
(Characteristics of Light Emitting Devices of Examples 2 and 3)
Table 4 shows the characteristics and the color rendering properties of the light emitting devices of Examples 2 and 3. However, the characteristics and the color rendering properties of the light emitting devices of Examples 2 and 3 are simulations, and when they are actually manufactured, self-absorption occurs, and it is considered that the wavelength shifts. As the light emitting device of Comparative Example 2, using an excitation light source of Ex = 460 nm, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce is used. Examples 2 and 3 are emission spectra when the peak values are the same.
[0183]
[Table 4]

The phosphor excited by the 460-nm-excited light emitting element is the BaSi of Example 1. ₂ O ₂ N ₂ : Eu changes from bluish green to greenish region, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce is SrCaSi in green to yellow-red region ₅ N ₈ : Eu has an emission peak wavelength from yellow-red to red. Due to the color mixture of the light of these phosphors, a light emission color is shown in a white region. Thus, the light emitting devices of Examples 2 and 3 emit light in the white color region. Further, since visible light of about 460 nm is used as the excitation light source and no phosphor that emits blue light is used, there is little loss in luminous efficiency due to wavelength conversion. Further, the color tone can be easily changed by changing the mixing ratio of the phosphor. In particular, the white light-emitting device shown in Comparative Example 2 had an average color rendering index (Ra) of 76.0, but the white light-emitting devices according to Examples 2 and 3 had an average color rendering index (Ra) of 76.0. Very good, 84.5 and 83.1. Thus, the color rendering properties are improved. In addition, the color rendering properties of the special color rendering evaluation numbers (R1 to R15) are improved in almost all color charts. Further, the white light-emitting device shown in Comparative Example 2 has a special color rendering index (R9) of -1.9, whereas the white light-emitting devices according to Examples 2 and 3 have the special color rendering index (R9). ) Were extremely good, 70.7 and 94.1. The special color rendering index (R9) is a red color chart with relatively high saturation. The luminous efficiency is represented by a relative value when the light emitting device of the comparative example is set to 100%.
[0184]
<Light emitting device>
The light emitting device of Example 4 relates to a white light emitting device using a light emitting element having an emission peak wavelength of 457 nm as an excitation light source. FIG. 1 is a diagram showing a light emitting device according to the present invention. FIG. 14 is a diagram illustrating emission spectra of the light emitting devices of the fourth and fifth embodiments.
[0185]
(Light emitting element)
When a current is applied to the light emitting device of Example 4, the blue light emitting element 10 having an emission peak wavelength at approximately 457 nm emits light. The phosphor 11 covering the semiconductor layer 2 performs color conversion of the blue light. As a result, it is possible to provide the light emitting device of Example 4 that emits white light.
[0186]
(Phosphor)
The phosphor 11 used in the light emitting device of the fourth embodiment according to the present invention includes the oxynitride phosphor of the first embodiment and (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : YAG phosphor represented by Ce and CaSrSi ₅ N ₈ : A phosphor 11 mixed with a nitride phosphor represented by Eu. The phosphor 11 is mixed together with the coating member 12. This mixing ratio can be appropriately changed. These phosphors 11 are irradiated with an excitation light source of Ex = 457 nm. These phosphors 11 absorb light from the excitation light source, perform wavelength conversion, and have a predetermined emission wavelength. BaSi of Example 1 ₂ O ₂ N ₂ : Eu has an emission peak wavelength at 470 nm to 530 nm. (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce has an emission peak wavelength at 500 to 650 nm. SrCaSi ₅ N ₈ : Eu has an emission peak wavelength at 580 nm to 730 nm.
[0187]
In the light emitting device of the fourth embodiment, part of the light of the light emitting element 10 is transmitted. In addition, part of the light from the light emitting element 10 excites the phosphor 11 to perform wavelength conversion, and the phosphor 11 has a predetermined emission wavelength. A light-emitting device that emits white light can be provided by mixing the blue light from the light-emitting element 10 and the light from the phosphor 11.
[0188]
(Characteristics of Light Emitting Device of Example 4)
Table 5 shows the characteristics and the color rendering properties of the light emitting device of Example 4.
[0189]
[Table 5]

The phosphor excited by the light-emitting element excited by 457 nm is the same as that of BaSi of Example 1. ₂ O ₂ N ₂ : Eu changes from bluish green to greenish region, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce is SrCaSi in green to yellow-red region ₅ N ₈ : Eu has an emission peak wavelength from yellow-red to red. Due to the color mixture of the light of these phosphors, a light emission color is shown in a white region. Thus, the light emitting device of the fourth embodiment emits light in a white color region. Further, since visible light having a wavelength of about 457 nm is used as the excitation light source and a phosphor that emits blue light is not used, a loss in luminous efficiency due to wavelength conversion is small. Further, the color tone can be easily changed by changing the mixing ratio of the phosphor. The white light-emitting device of Example 4 exhibits extremely high light emission characteristics with a lamp efficiency of 25.0 lm / W. The white light-emitting device according to Example 4 had an extremely good average color rendering index (Ra) of 92.7. Thus, the color rendering properties are improved. In addition, the color rendering properties of the special color rendering evaluation numbers (R1 to R15) are improved in almost all color charts. Furthermore, the white light emitting device according to Example 4 had a special color rendering index (R9) of 83.0, which was extremely good.
[0190]
As described above, the white light-emitting device of Example 4 can provide a light-emitting device having excellent color rendering properties.
[0191]
<Light emitting device>
The light emitting device of Example 5 relates to a white light emitting device using a light emitting element having an emission peak wavelength of 463 nm as an excitation light source. FIG. 1 is a diagram showing a light emitting device according to the present invention. FIG. 14 is a diagram illustrating emission spectra of the light emitting devices of the fourth and fifth embodiments.
[0192]
(Light emitting element)
When a current is applied to the light emitting device of the fifth embodiment, the blue light emitting element 10 having an emission peak wavelength at approximately 463 nm emits light. The phosphor 11 covering the semiconductor layer 2 performs color conversion of the blue light. As a result, it is possible to provide the light emitting device of Example 5 that emits white light.
[0193]
(Phosphor)
The phosphor 11 used in the light emitting device of the fifth embodiment according to the present invention includes the oxynitride phosphor of the first embodiment and (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : YAG phosphor represented by Ce and CaSrSi ₅ N ₈ : A phosphor 11 mixed with a nitride phosphor represented by Eu. The phosphor 11 is mixed together with the coating member 12. This mixing ratio can be appropriately changed. These phosphors 11 are irradiated with an excitation light source of Ex = 463 nm. These phosphors 11 absorb light from the excitation light source, perform wavelength conversion, and have a predetermined emission wavelength. BaSi of Example 1 ₂ O ₂ N ₂ : Eu has an emission peak wavelength at 470 nm to 530 nm. (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce has an emission peak wavelength at 500 to 650 nm. SrCaSi ₅ N ₈ : Eu has an emission peak wavelength at 580 nm to 730 nm.
[0194]
In the light emitting device of the fifth embodiment, part of the light of the light emitting element 10 is transmitted. In addition, part of the light from the light emitting element 10 excites the phosphor 11 to perform wavelength conversion, and the phosphor 11 has a predetermined emission wavelength. A light-emitting device that emits white light can be provided by mixing the blue light from the light-emitting element 10 and the light from the phosphor 11.
[0195]
(Characteristics of Light Emitting Device of Example 5)
Table 6 shows the characteristics and the color rendering of the light emitting device of Example 5.
[0196]
[Table 6]

The phosphor excited by the light emitting element excited at 463 nm is the same as that of BaSi of Example 1. ₂ O ₂ N ₂ : Eu changes from bluish green to greenish region, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce is SrCaSi in green to yellow-red region ₅ N ₈ : Eu has an emission peak wavelength from yellow-red to red. Due to the color mixture of the light of these phosphors, a light emission color is shown in a white region. Thus, the light emitting device of the fifth embodiment emits light in the white region. Further, since visible light having a wavelength of about 463 nm is used as the excitation light source and a phosphor that emits blue light is not used, a loss in luminous efficiency due to wavelength conversion is small. Further, the color tone can be easily changed by changing the mixing ratio of the phosphor. The white light-emitting device of Example 5 has a high light emission characteristic with a lamp efficiency of 21.3 lm / W. The white light emitting device according to Example 5 had an extremely good average color rendering index (Ra) of 84.9. Thus, the color rendering properties are improved. In addition, the color rendering properties of the special color rendering evaluation numbers (R1 to R15) are improved in almost all color charts. Furthermore, the white light-emitting device according to Example 5 had an extremely good special color rendering index (R9) of 91.0.
[0197]
As described above, the white light-emitting device of Example 4 can provide a light-emitting device having excellent color rendering properties.
[0198]
<Light emitting device>
FIG. 15 is a diagram illustrating a cap-type light emitting device according to a sixth embodiment.
[0199]
In the light emitting device according to the sixth embodiment, the same members as those in the light emitting device according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. As the light emitting element 10, a light emitting element having an emission peak wavelength at 400 nm is used.
[0200]
The light emitting device of the sixth embodiment is configured by covering the surface of the mold member 15 of the light emitting device of the first embodiment with a cap 16 made of a light transmitting resin in which a phosphor (not shown) is dispersed.
[0201]
A cup for mounting the light emitting element 10 is provided on the upper part of the mount lead 13a, and the light emitting element 10 is die-bonded to a bottom surface of a substantially central portion of the cup. In the light emitting device according to the first embodiment, the phosphor 11 is provided so as to cover the light emitting element 10 above the cup. However, in the light emitting device according to the sixth embodiment, the phosphor 11 may not be provided. By not providing the phosphor 11 above the light emitting element 10, the effect of heat generated from the light emitting element 10 is not directly exerted.
[0202]
The cap 16 has the phosphor uniformly dispersed in the light transmitting resin. The light transmitting resin containing the phosphor is molded into a shape that fits into the shape of the mold member 15 of the light emitting device. 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 is pressed into the mold and molded. As a specific material of the light transmitting resin of the cap 16, a transparent resin having excellent temperature characteristics and weather resistance, such as an epoxy resin, a urea resin, and a silicone resin, a silica sol, glass, and an inorganic binder are used. In addition to the above, a thermosetting resin such as a melamine resin and a phenol resin can be used. In addition, thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, and polystyrene, styrene-butadiene block copolymers, and thermoplastic rubbers such as segmented polyurethane can also be used. Further, a diffusing agent, barium titanate, titanium oxide, aluminum oxide, or the like may be contained together with the phosphor. Further, a light stabilizer and a coloring agent may be contained. The phosphor used for the cap 16 is BaSi ₂ O ₂ N ₂ : Eu oxynitride phosphor and (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor and Ba ₂ Si ₅ N ₈ : Eu nitride phosphor and (Ca _0.95 , Eu _0.05 ) ₁₀ (PO ₄ ) ₆ Cl ₂ And phosphor. The oxynitride phosphor of Example 6 is used as the phosphor 11 used in the cup of the mount lead 13a. However, since a phosphor is used for the cap 16, an oxynitride phosphor may be contained in the cap 16 and only the coating member 12 may be provided in the cup of the mount lead 13a.
[0203]
In the light emitting device thus configured, a part of the light emitted from the light emitting element 10 excites the oxynitride phosphor of the phosphor 11 and emits green light. In addition, a part of the light emitted from the light emitting element 10 or a part of the light emitted from the oxynitride phosphor excites the phosphor of the cap 16 and emits light from blue and yellow to red. As a result, the green light of the oxynitride phosphor and the blue and yellow to red light of the phosphor of the cap 16 are mixed, and as a result, white light is emitted from the surface of the cap 16 to the outside. .
[0204]
【The invention's effect】
From the foregoing, the present invention provides a light emitting device that absorbs light from an excitation light source having an emission wavelength in a short wavelength region from ultraviolet to visible light, performs wavelength conversion, and has an emission color different from the emission color from the excitation light source. The present invention relates to a nitride phosphor. The oxynitride phosphor has an emission peak wavelength in a blue-green to green region, and has extremely high luminous efficiency. In addition, the oxynitride phosphor has extremely excellent temperature characteristics. In particular, the highest luminous efficiency is exhibited when the activator R is a Group II element: R = 1: 0.005 to 1: 0.15 in a molar ratio to the Group II element.
[0205]
Further, the present invention can provide a method for producing an oxynitride phosphor which is simple and excellent in reproducibility.
[0206]
The present invention also relates to a light emitting device having the above oxynitride phosphor and a light emitting element. Thus, the light-emitting device can provide a light-emitting device that emits bright blue to green light. Further, it is possible to manufacture a light emitting device in which the oxynitride phosphor is combined with a second phosphor, that is, a phosphor of three wavelengths of blue, green and red. Thereby, the light emitting device can provide a light emitting device that emits white light and has excellent color rendering properties. Further, it is possible to manufacture a light emitting device in which the oxynitride phosphor, a YAG phosphor as a second phosphor, and a blue light emitting element are combined. This makes it possible to provide a light-emitting device that emits white light and has excellent color rendering properties and extremely high luminous efficiency. With regard to the color rendering properties, the special color rendering index (R9) showing a red color is particularly improved. Therefore, the present invention has an extremely important technical meaning that the light emitting device as described above can be provided.
[Brief description of the drawings]
FIG. 1 is a view showing a shell type light emitting device according to the present invention.
FIG. 2A is a plan view showing a surface-mounted light emitting device according to the present invention. (B) It is sectional drawing of the light emitting device of a surface mount type which concerns on this invention.
FIG. 3 is a process chart showing a method for producing an oxynitride phosphor.
FIG. 4 is a diagram showing emission spectra when the oxynitride phosphors of Examples 1 to 5 are excited at Ex = 400 nm.
FIG. 5 is a diagram showing emission spectra when the oxynitride phosphors of Examples 1 to 5 are excited at Ex = 460 nm.
FIG. 6 is a diagram showing an excitation spectrum of the oxynitride phosphors of Examples 1 to 5.
FIG. 7 is a diagram showing reflection spectra of the oxynitride phosphors of Examples 1 to 5.
FIG. 8 is an SEM photograph of the oxynitride phosphor of Example 1.
FIG. 9 is a plan view showing a light emitting device according to the present invention.
FIG. 10 is a sectional view showing AA ′ of the light emitting device according to the present invention.
FIG. 11 is a diagram showing an emission spectrum (simulation) of the light emitting device of Example 1.
FIG. 12 is a diagram showing chromaticity coordinates (simulation) of the light emitting devices of Examples 1 to 3.
FIG. 13 is a diagram showing an emission spectrum (simulation) of the light emitting devices of Examples 2 and 3.
FIG. 14 is a diagram showing emission spectra of the light emitting devices of Example 4 and Example 5.
FIG. 15 is a diagram illustrating a cap type light emitting device according to a sixth embodiment.
[Explanation of symbols]
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 element
102 Lead electrode
103 Insulation sealing material
104 conductive wire
105 packages
106 lid
107 Window
108 phosphor
109 Coating material
201 substrate
202 Underlayer
203 n-type layer
203a exposed surface
204 Active layer
205 p-side carrier confinement layer
206 First p-type layer
207 Current spreading layer
208 p-side contact layer
209 Light emitting unit
210 p-side electrode
210a electrode branch
210b p-side pad electrode
211a n-side electrode
211b n-side pad electrode

Claims (28)

The activator R uses at least one or more rare earth elements that require Eu, and at least one or more group II elements that require Ba selected from the group consisting of Ca, Sr, Ba, and Zn. An oxynitride phosphor containing at least one of a group IV element, which is at least one element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, wherein at least Si is essential. ,
The oxynitride phosphor according to claim 1, wherein R is a molar ratio of the Group II element: R = 1: 0.005 to 1: 0.15 with respect to the Group II element. The oxynitride phosphor contains O and N in the composition, and the weight ratio of O to N is 1 to O and N is 0.2 to 2.1. Item 2. The oxynitride phosphor according to Item 1. The oxynitride phosphor according to claim 1, wherein the oxynitride phosphor is represented by the following general formula.
_{L X M Y O Z N (} (2/3) X + (4/3) Y- (2/3) Z): R
(L is a group II element that is at least one or more of Ba, selected from the group consisting of Ca, Sr, Ba, and Zn. M is C, Si, Ge, Sn, Ti, Zr, H is at least one element selected from the group consisting of Hf, which is at least one group IV element, O is an oxygen element, N is a nitrogen element, and R is at least Eu which is essential. One or more rare earth elements. 0.5 <X <1.5, 1.5 <Y <2.5, 1.5 <Z <2.5.) The oxynitride phosphor according to claim 1, wherein the oxynitride phosphor is represented by the following general formula.
_{L X M Y Q T O Z} N ((2/3) X + (4/3) Y + T- (2/3) Z): R
(L is a group II element which is at least one or more elements selected from the group consisting of Ca, Sr, Ba and Zn. M is C, Si, Ge, Sn, Ti, Zr, Q is a group IV element that is at least one or more selected from the group consisting of Hf, and is a group III element that is at least one or more selected from the group consisting of B, Al, Ga, and In. O is an oxygen element, N is a nitrogen element, R is at least one or more rare earth elements that require Eu.0.5 <X <1.5,1 .5 <Y <2.5, 0 <T <0.5, 1.5 <Z <2.5.) The oxynitride phosphor according to claim 3, wherein the X, the Y, and the Z are X = 1, Y = 2, and Z = 2. 5. The oxynitride phosphor according to claim 1, wherein 70% or more of R is Eu. 6. The oxynitride phosphor is excited by light from an excitation light source having an emission peak wavelength at 360 to 480 nm, and has an emission peak wavelength on a longer wavelength side than the emission peak wavelength. 7. The oxynitride phosphor according to at least one of 6. The oxynitride phosphor according to at least one of claims 1 to 7, wherein the oxynitride phosphor has an emission peak wavelength in a blue-green to green region. 9. The oxynitride phosphor according to claim 1, wherein the oxynitride phosphor has a crystal structure in an amount of 50% by weight or more. The oxynitride according to any one of claims 1 to 9, wherein the oxynitride phosphor has an excitation spectrum having a higher intensity near 460 nm than near 350 nm. Phosphor. A nitride of L (L is at least one or more group II element that essentially includes Ba selected from the group consisting of Ca, Sr, Ba, and Zn) and a nitride of M (M is C, Si, Ge, Sn, Ti, Zr, and Hf are at least one or more group IV elements that essentially include Si selected from the group consisting of), M oxide, and R oxide. (R is at least one or more rare earth elements that essentially contain Eu).
A second step of firing the mixture obtained in the first step;
A method for producing an oxynitride phosphor having
The method of manufacturing an oxynitride phosphor according to claim 1, wherein R is a molar ratio of L to the L, wherein L: R = 1: 0.005 to 1: 0.15. The method for producing an oxynitride phosphor according to claim 11, wherein a nitride of R is used instead of the oxide of R or together with the oxide of R. The first step further comprises mixing Q (Q is at least one group III element selected from the group consisting of B, Al, Ga, and In). 13. The method for producing an oxynitride phosphor according to any one of 11 and 12. The nitride of L, the nitride of M, and the oxide of M are:
0.5 <L nitride <1.5,
0.25 <M nitride <1.75,
2.25 <M oxide <3.75,
The method for producing an oxynitride phosphor according to at least one of claims 11 to 13, wherein the molar ratio is represented by the following formula: The method for producing an oxynitride phosphor according to claim 11, wherein at least one of the oxide of R and the nitride of R is substituted for at least a part of the nitride of L. 15. . An oxynitride phosphor produced by the method for producing an oxynitride phosphor according to at least one of claims 11 to 15. An excitation light source having an emission wavelength in a short wavelength region from ultraviolet to visible light,
Absorbing at least a part of light from the excitation light source, performing wavelength conversion, and a phosphor having an emission color different from the emission color of the excitation light source,
A light emitting device having
The light emitting device according to claim 1, wherein the phosphor includes an oxynitride phosphor that essentially includes Ba and has an emission peak wavelength in a blue-green to green region. The light emitting device according to claim 17, wherein the excitation light source is a light emitting element. The light emitting device according to claim 18, wherein the light emitting layer of the light emitting element includes a nitride semiconductor containing In. The light emitting device according to claim 17, wherein the oxynitride phosphor uses the oxynitride phosphor according to at least one of claims 1 to 10. The phosphor includes a second phosphor used together with the oxynitride phosphor,
The second phosphor converts the wavelength of at least a part of light from the excitation light source and light from the oxynitride phosphor, and has a light emission peak wavelength in a visible light region. The light emitting device according to claim 17, characterized in that: 22. The light emitting device according to claim 21, wherein the second phosphor has at least one emission peak wavelength from a blue region to a green, yellow, and red region. The light emitting device,
Part of the light from the excitation light source,
Light from the oxynitride phosphor;
Light from the second phosphor;
23. The light emitting device according to claim 17, wherein at least two or more lights are mixed and emitted. The light emitting device has an intermediate emission color from the emission peak wavelength of the excitation light source to the emission peak wavelength of the oxynitride phosphor or the emission peak wavelength of the second phosphor. The light emitting device according to at least one of claims 17 to 23. The light emitting device according to claim 24, wherein the intermediate emission color emits white light. The light emitting device according to any one of claims 17 to 25, wherein the light emitting device has an emission spectrum having at least one emission peak wavelength at 360 to 485 nm, 485 to 548 nm, and 548 to 730 nm. The light emitting device according to any one of claims 17 to 25, wherein the light emitting device has an emission spectrum having one or more emission peak wavelengths at 360 to 485 nm and 485 to 584 nm. The light emitting device according to any one of claims 17 to 27, wherein the light emitting device has an average color rendering index (Ra) of 80 or more.

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