JP4292794B2 - Light emitting device, method for manufacturing light emitting device, and method for adjusting chromaticity of light emitting device - Google Patents

Description

【００４０】
以上の表１及び図３に示すように、分割数が多いほど（グループ数が多いほど）標準偏差σの改善率が大きいことがわかる。
【００４１】
また、本発明者は、作製したサンプルの樹脂の表面を一旦全て研磨して、樹脂の厚さ（サンプルの高さ）を揃えた後、その色度によって５分割（５グループに分類）し、グループごとに決められた量だけ研磨することにより色度補正をした。その結果を、図４に示す。初期サンプル数は、１５８個であり、サンプルの高さ）を揃えた後及び調整後のサンプル数は、１４８個である。
【００４２】
図４から明らかなように、サンプルの樹脂の表面を研磨して、樹脂の厚さ（サンプルの高さ）を揃えただけでは、色度バラツキはほとんど改善されないこと、及び５分割（５グループに分類）し、グループごとに決められた量だけ研磨することにより色度補正することにより、色度バラツキが大幅に改善されることがわかった。
【００４３】
また、本発明に係る研磨により色度を調整する方法によれば、発光装置の発光光度及び発光出力がいずれも高くなることが確認された。
光度については、図６（ａ）に示すように、研磨前（色度調整前）に３５６ｍｃｄであったものが、研磨後（色度調整後）には４１２ｍｃｄとなった。
また、光出力については、図６（ｂ）に示すように、研磨前（色度調整前）に３０６７μＷであったものが、研磨後（色度調整後）には３２６０μＷとなった。
尚、図５には、発光光度及び発光出力の測定に用いたサンプルの研磨前後の色度を示した。
【００４４】
また、図６に示したリファレンスとして示したサンプルは、発光光度及び発光出力の測定に用いたサンプルと同一製造ロットに属するものであって研磨前の色度ｘ値、及び色度ｙ値が最も大きいものの研磨前のデータをリファレンスとして示したものである。
このリファレンスとして示したサンプルの研磨前の色度は、図５に示すように、発光光度及び発光出力の測定に用いたサンプルの研磨前後の色度とほぼ等しいものである。
すなわち、研磨後のサンプルは、リファレンスとして示したサンプルの光度及び発光出力に比較しても高いことから、研磨後のサンプルによる発光光度及び発光出力の向上は、色度の変化によってもたらされたものではなく、研磨による発光面の粗面化および光の樹脂通過距離の短縮によるものであると考えられる。
【００４５】
また、研磨によって、光の配光特性や半値角が変化することはないか確認したが、研磨による変化は確認されなかった。
以上説明したように、本発明によれば、透光性樹脂を硬化させた後に、蛍光体粒子を実質的に含んでいない透光性樹脂を研磨又は塗布しているので、製造工程の最終段階の工程において容易に色度を調整することができる。
すなわち、透光性樹脂を硬化させる前に、色度を調整してその色度に基づいて透光性樹脂をさらに充填する方法も考えられるが、樹脂の硬化前は色度に影響を及ぼす要因が不安定であるために、色度を微調整することが困難であった。
しかしながら、本発明に係る色度調整方法ではこのような困難はない。
【００４６】
また、特許文献１に示された方法では、樹脂の研磨量に対して色度の変化が大きいために、色度を微調整することは困難であるが、本発明に係る色度調整方法ではこのような困難はない。
【００４７】
実施の形態２．
上述の実施の形態１では、主として、発光面全体を研磨することにより、色度を調整する方法及びその方法によって作製された発光装置について説明したが、このような方法では発光装置ごと（又は、研磨グループごと）に高さが変わり、高さが不揃いなものとなる。
そこで、本発明に係る実施の形態２では、製品の高さそのものは変化させることなく、色度を調整する方法とその方法を適用して作製された発光装置について説明する。
【００４８】
まず、具体的な調整方法を説明する前に、実施の形態２の発光装置の構成について説明する。
本実施の形態２の発光装置（発光ダイオード）は、図９に示すように、パッケージの中に発光ダイオードチップ（ＬＥＤチップ）５が透光性樹脂８によって封止されてなる表面実装型（ＳＭＤ型）の発光ダイオードである。本実施の形態２の発光ダイオードにおいて、パッケージは金属ベース２２と側壁部２１とからなり、側壁部２１は収納部を構成するために金属ベース２２の一方の面の周囲に接合されている。尚、金属ベース２２と側壁部２１とからなるパッケージについては、後述の実施の形態３において詳述する。
そして、ＬＥＤチップ５はパッケージの収納部にダイボンディングされてワイヤーボンディングにより所定の配線がされた後、透光性樹脂８により封止されている。
【００４９】
詳細に説明すると、本実施の形態２において、パッケージの金属ベース２２は正の端子を構成する金属薄板２２ａと負の端子を構成する金属薄板２２ｂとが絶縁性樹脂４により接合されることにより構成され、それぞれＬＥＤチップ５の正電極５ａと負電極５ｂにワイヤー７により接続される。また、実施の形態２の発光装置においては、後述の色度調整を考慮して、収納部を構成するための側壁部２１の内周壁が２段になっている。
尚、図９では、ＬＥＤチップ５が一方の金属薄板２２ｂ上にダイボンディング樹脂６によりダイボンディングされている例について示したが、本発明では、ＬＥＤチップ５は他方の金属薄板２２ａ上にダイボンディングされていても良いし、金属薄板２２ａと金属薄板２２ｂとに跨ってダイボンディングされていてもよい。
【００５０】
実施の形態２において、ＬＥＤチップ５は、サファイア基板上に以下の層を順に積層することにより構成する。
（１）バッファ層、（２）アンドープ又はＳｉの含有量の比較的少ないＧａＮ下地層、（３）ＧａＮ下地層よりＳｉの含有量の多いｎ側ＧａＮコンタクト層、（４）ｎ側ＧａＮコンタクト層よりＳｉ含有量が少ないＧａＮ層、（５）順方向電圧Ｖｆを下げるために形成される層である、ＩｎＧａＮ層とＧａＮ層のｎ側多層膜、（６）ＧａＮ層とＩｎＧａＮ層の５ペアからなる量子井戸構造の活性層、（７）ＭｇがドープされたＡｌＧａＮ層とＩｎＧａＮ層からなるｐ側多層膜、（８）Ｍｇがドープされたｐ側ＡｌＧａＮ層、（９）Ｍｇがドープされたｐ側ＧａＮコンタクト層。
また、ｐ側電極はｐ側ＧａＮコンタクト層上に形成され、ｎ側電極は、上層をエッチングすることによりｎ側ＧａＮコンタクト層の一部の表面を露出させて、その露出させた表面に形成している。
以上のように構成された実施の形態２の窒化物半導体発光素子（ＬＥＤチップ）は、ｐ側の層とｎ側の層の間に活性層が形成されたダブルへテロ構造である。
【００５１】
このように構成したＬＥＤチップ５をパッケージの収納部にダイボンディングしてワイヤーボンディングした後、所定量の透光性樹脂を収納部に充填して硬化させる。この透光性樹脂は、例えば、エポキシ樹脂中に無機蛍光体としてＧｄが含有されたＹＡＧ：Ｃｅが含有されてなり、充填時における温度や粘度を調整することによって、透光性樹脂８内において硬化後に波長変換層８ａと非波長変換層８ｂが形成されるようにする。
【００５２】
以上のようにして作製した発光装置の色度を測定して、目標の色度より青みがかったものを例えば、自動選別器によって選別した後、研磨装置上に複数個配列して、目標色度になるように研磨する。
実施の形態２では、研磨するための工具は、図９に示すように、回転軸５１の先に、例えば、円盤形状の砥石（収納部の外周より小さい外形を有する砥石）を設けたものを用い、パッケージの側壁を削ることなく透光性樹脂の非波長変換層のみを、目標色度と測定色度との差に対応した量だけ研磨する。
【００５３】
この研磨の際、研磨装置上に配列した複数の発光装置の各々に対して砥石を設けることにより、複数の発光装置を一度に調整することができる。
また、この際、実施の形態１で説明したように、削り量に応じてグルーピングして一括して削るようにもできるし、１つ１つ光センサーにより色度を測定しながら目標色度になるまで削るようにしてもよい（この場合でも、光センサーと砥石をそれぞれの発光装置に設けて各発光素子ごとに削り量を制御するようにすれば、複数の発光素子を同時に並列処理できることはいうまでもない。）。
【００５４】
以上説明した実施の形態２の色度調整方法（工程）を用いれば、発光装置全体の高さを変えることなく、色度ｘ値及びｙ値を大きくすることができ、所望の色度（例えば、所望の白色）に精度よく調整できる。
【００５５】
以上の実施の形態２の色度調整方法では、透光性樹脂の非波長変換層のみを、目標色度と測定色度との差に対応した量だけ研磨するようにしたが、本発明では、収納部に蛍光体粒子を含んでいない透光性樹脂を追加することにより、非波長変換層の厚さを目標色度と測定色度との差に対応した量だけ増加させて色度を調整するようにしてもよい。この場合において、色度を調整した後の透光性樹脂の表面がパッケージの側壁の高さを超えないように設定すれば、発光装置全体の高さを変えることなく、色度ｘ値及びｙ値を小さくすることができ、所望の色度（例えば、所望の白色）に精度よく調整できる。
【００５６】
実施の形態３．
次に、本発明に係る実施の形態３の発光装置（発光ダイオード）の製造方法について説明する。
本製造方法は、表面実装型の発光ダイオードを安定した品質でかつ量産性良くしかも色度バラツキを小さく製造する方法である。
本製造方法において、透光性樹脂でＬＥＤチップ５を覆う工程までは、複数のパッケージを一括して処理するために、複数のパッケージが集合してなるパッケージアッセンブリが用いられる。このパッケージアッセンブリは、各パッケージの収納部１ａに対応する複数貫通孔１０１ａが形成された絶縁性基板１０１と金属ベース板１０２とが接合されて作製されている（図１３参照）。
【００５７】
ここで、絶縁性基板１０１は、例えば厚さが０．０６ｍｍ〜２．０ｍｍの樹脂積層品等からなり、厚さ方向に貫通する複数の貫通孔１０１ａが形成されている（図１３参照）。貫通孔１０１ａの横断面形状は楕円であってもよいし、円形又は方形でもよい。すなわち、本発明は貫通孔１０１ａの横断面形状によって限定されるものではなく、種々の形状の中から任意に選定することができる。また、貫通孔１０１ａにおいては、貫通孔１０１ａの開口径が絶縁基板の一方の面（金属薄板と接合される面）から他方の面に向かって大きくなるように貫通孔の側面を傾斜させることが好ましい。このように貫通孔１０１ａの側面を傾斜させると、ＬＥＤチップから貫通孔の側面に向かって出射された光を側面で反射させて上方に出力することができるので、ＬＥＤチップ５から出射された光を効率良く発光ダイオードから取り出すことができる。
【００５８】
また、金属ベース板１０２は個々のパッケージごとに切断されたときに、各パッケージにおいて金属薄板２２ａと金属薄板２２ｂとが絶縁性樹脂４により電気的に分離されるように、各貫通孔にそれぞれ対応して分離溝が形成されてその分離溝の中に絶縁性樹脂４が充填されている（図１０参照）。
【００５９】
各パッケージ部分において、貫通孔１０１ａ内で金属薄板２２ａの一部、絶縁性樹脂４、及び金属薄板２２ｂの一部が露出されている。
さらに、パッケージアッセンブリにおいてはさらに、後述のマスク１１２の１つの開口部１１３に対して複数のパッケージがグループ化されて配置されている（図１１、図１２参照）。
【００６０】
＜ＬＥＤチップの実装＞
上述のように構成されたパッケージアッセンブリの各貫通孔（収納部）の所定の位置にダイボンド樹脂を用いてＬＥＤチップ５をダイボンディングして、ワイヤーボンディングにより所定の配線をする（図５）。
各貫通孔の内側には金属薄板２２ａと金属薄板２２ｂが露出され、ＬＥＤチップ５は負電極である金属薄板２２ｂ上に接着され、そのＬＥＤチップ５のｐ側電極５ａ及びｎ側電極５ｂはそれぞれ、ワイヤ７によって金属薄板２２ａ及び金属薄板２２ｂに接続される（図１１、図１３参照）。
【００６１】
＜第１の工程：孔版印刷＞
次に、封止部材である透光性樹脂（本発明のエポキシ樹脂組成物）８は、チャンバー内にて孔版印刷により塗布される。図１１（ａ）は本実施の形態３に係る製造方法の孔版印刷に用いられるマスク１１２の平面図である。マスク１１２には、図１１（ａ）に示すように、複数の開口部１１３が形成されており、各開口部１１３の位置及び大きさは、１つの開口部１１３に対して、１つのグループにまとめられた複数のパッケージが対応するようにが設定される（図１１（ｂ））。このように本発明で用いられるマスクは、各貫通孔内だけに透光性樹脂を設けるのではなく、周囲の絶縁性基板１０１上にも樹脂層が形成されるように設計されている。本実施の形態の製造方法では、このようなマスク１１２を用いて孔版印刷を行うことで、絶縁基板の貫通孔１０１ａ内及び絶縁性基板１０１上に硬化後も表面が平滑面となるように透光性樹脂を形成することができる。
【００６２】
すなわち、本製造方法では、図１３に示すように開口部１１３の周辺部分の透光性樹脂を平坦に形成するのが難しい部分を除いて、グルーピングされた複数のパッケージを配置して、複数のパッケージが配置された部分に透光性樹脂を一定の厚さでかつ表面が平坦になるように形成することにより、パッケージ間における透光性樹脂層の厚さのバラツキを抑えかつ各パッケージの透光性樹脂の表面の平坦化を図っている。
【００６３】
このように、複数の発光ダイオードに対して一度に透光性樹脂を形成した後、図１３に示す点線の部分で切断して分離して個々の発光ダイオードとしている。これにより、均一な膜厚を有する発光ダイオードを発光ダイオード間にサイズや色バラツキが生じないように歩留まり良く形成することができる。また、マスクの板厚を調整することで前記絶縁性基板上に形成する透光性樹脂の膜厚を任意に変更することができる。
【００６４】
次に、各開口部１１３において、複数のパッケージが配置された部分に透光性樹脂を一定の厚さでかつ表面が平坦になるように形成する方法の一例を具体的に説明する。
【００６５】
（ステップ１）
まず、貫通孔１０１ａをマスク１１２側に向けたパッケージアッセンブリ１００を昇降ステージ１１７上に吸引して（図１２（ａ））、ステージ１１７を上昇させてパッケージアッセンブリ１００とマスク１１２とを位置合わせして、マスク１１２の下面に接触させる（図１２（ｂ））。これによりパッケージアッセンブリの反りを矯正した状態でパッケージアッセンブリ１００をマスク１１２に接触させることができる。このように、パッケージアッセンブリ１００の反りを矯正することにより、パッケージアッセンブリ１００上の一面に均一な膜厚の透光性樹脂を形成することが可能になる。すなわち、パッケージ基板に反ったまま封止部材を形成すると、形成された個々の発光ダイオード間に厚さのバラツキが生じ歩留まりが悪化する。
【００６６】
蛍光物質を含有させた透光性樹脂は、図１２（ａ）に示すように、大気圧下でマスク１１２の開口部外の端に配置させる。この状態で減圧して脱泡を行う。減圧は１００Ｐａ〜４００Ｐａの範囲に設定することが好ましく、この範囲であると樹脂内部に含まれる気泡を効果的に取り出すことができる。上述のパッケージアッセンブリ１００とマスク１１２を用いた本実施の形態では、透光性樹脂として比較的高い粘度のものを用いることができる。
【００６７】
透光性樹脂中に気泡が混合されたまま封止されると、気泡がＬＥＤチップからの光や蛍光物質の発光を反射屈折させるため、色ムラや輝度ムラが顕著に観測される。そのため蛍光物質を含有した透光性樹脂を形成する際、本実施の形態のように減圧及び加圧を繰り返すことは極めて効果的であり、色ムラや輝度ムラを抑える賢著な効果がある。また、透光性樹脂中に気泡が含まれると、それが原因となって透光性樹脂の剥離やワイヤの接着部分の剥離、ワイヤ切れ等が生じる場合があり、信頼性が低下してしまう。したがって、本方法により気泡を防止することは信頼性を向上させる上でも極めて有効である。
【００６８】
＜ステップ２＞
次に減圧下において、１往復目の往スキージ走査が行われる（図１２（ｃ））。この際に用いられる往スキージ用ヘラ１１４は、図１２（ｃ）に示すように、マスク１１２の垂直ラインに対して動作方向に傾いており、エアー圧によりヘラ１１４をマスク１１２に押し当てて動作させ樹脂８をマスク１１２の開口部１１３に流し込む。往スキージ走査は減圧下で行われるため昇降ステージ１１７の吸引作用は意味をなさないが、物理的に昇降ステージ１１７をマスク１１２に押し当てているためパッケージアッセンブリ１００とマスク１１２とのズレは生じない。
【００６９】
＜ステップ３＞
次に大気圧まで加圧し、加圧完了後、１往復目の復スキージ走査が往スキージ走査と逆方向に行われる（図１２（ｄ））。復スキージ用ヘラ１１５は、マスク１１２の垂直ラインに対して動作方向に往スキージ用ヘラ１１４よりも大きく傾け且つ往スキージ走査のときよりも強いエアー圧により作動させる。このように、強い圧力により復スキージ用ヘラ１１５とマスク１１２との接触面積を大きくして再び透光性樹脂を充填させることにより、開口部１１３内に充填された樹脂の表面に現れた気泡を効率よく除くことができ封止部材の表面を平滑な面に仕上げることができる。
【００７０】
＜ステップ４＞
ステップ２及びステップ３と同様にして、減圧及び加圧を繰り返して脱泡させながら往復スキージを数回行い、開口部１１３内に均一な膜厚で樹脂を充填させる。
【００７１】
＜ステップ５＞
この状態（マスク１１２をパッケージアッセンブリ１００に接触させた状態）で透光性樹脂を硬化して、硬化した後にマスクを除去することによってＬＥＤチップが配置された貫通孔内及び絶縁性基板上面に一体成形された透光性樹脂の上面をパッケージ底面とほぼ平行で且つ平滑な面にすることができる。
【００７２】
次に、ダイシング工程について詳細に説明する。上述のようにして透光性樹脂を形成（硬化）した後、以下のようにダイシングして個々の発光ダイオードに分割される。
【００７３】
＜第２の工程：ダイシング工程＞
（ダイシングステップ１）
まず、樹脂を硬化させた後、パッケージアッセンブリ１００の透光性樹脂側をダイシングシートに接着する。上述したように、パッケージアッセンブリ１００のダイシングシートとの接着面は実質的に同一材料からなり且つ平滑な平面であるので接着強度を強くできる。これにより、ダイシング時におけるチップの飛びやダイシングズレが防止でき、歩留まり良く個々の発光ダイオードに切断することができる。
【００７４】
これに対して、パッケージアッセンブリの個々の貫通孔に対応した開口部を有するマスクを用いて樹脂の充填及び硬化を行った場合、充填された樹脂は熱収縮して貫通孔分部で陥没してしまいダイシングシートと接する面は貫通孔上を除く絶縁性基板上面のみとなり密着性が低下する。また、個々の貫通孔に対応した開口部を有するマスクマスクを用いて樹脂量を多めに充填して硬化させると、ダイシングされる部分である絶縁性基板上面よりも樹脂の上面が高くなり、ダイシングシートとの接着面が樹脂上面のみとなり、この場合もパッケージアッセンブリとダイシングシートとの接着強度が極端に弱くなりダイシングズレが生じる。このようにパッケージアッセンブリとダイシングシートとの固定が不安定なままダイシングを行うと、チップの飛びやダイシングズレが生じる。また、得られた発光ダイオードの切り口にはバリが生じる等の不都合もある。バリは後工程の実装過程等で割れる恐れがあり、前記バリ部分が深く割れてしまうと、外部から封止部材内に湿気が混入され、発光ダイオードの信頼性が低下したり内部の金属部分が酸化されて変色してしまうなどの不良の原因となる。
【００７５】
（ダイシングステップ２）
ステップ１にて密着性良くダイシングシートに固定されたパッケージアッセンブリを、パッケージアッセンブリ底面側からダイシングブレードにより個々に切断する（図１３の破線に沿って切断する）。ダイシングブレートとはボンドを中心として周囲に粒径の小さいダイヤモンドの粒体を集結させてなるものである。
【００７６】
以上のような製造方法で作製された発光ダイオードでは、透光性樹脂が絶縁基板の上面と絶縁基板の貫通孔内とに一体的に成形されており、透光性樹脂の上面がパッケージ底面とほぼ平行であり、且つ透光性樹脂の外周側面は前記パッケージの外周側面とほぼ同一面上にある。このように発光ダイオードの上面を全て透光性樹脂を形成することで発光面を広くでき出力を向上させることができる。
【００７７】
＜色度調整工程＞
そして、以上のようにして作製された発光ダイオードを実施の形態１で説明した色度調整方法により色度を調整する。
これにより、実施の形態１と同様に色度バラツキを小さくできるとともに、研磨による粗面化により発光出力を向上させることができる。
尚、この場合、色度調整後の発光ダイオードにおいて、パッケージの側壁を構成する絶縁基板の上面に、透光性樹脂が残るようにする（すなわち、絶縁基板の上面の透光性樹脂の厚さを色度調整のために研磨することを見込んで研磨量より厚くしておく）ことが好ましく、これにより上述したように発光ダイオードの上面を全て発光面とでき、より発光出力を向上させることができる。
【００７８】
実施の形態３の変形例．
以上の実施の形態３では、実施の形態１で説明した色度調整方法により色度を調整するようにしたが、実施の形態３において、実施の形態２で説明した色度調整方法を適用できることはいうまでもない。
このようにすると、色度バラツキが少なくかつ高さの揃った発光ダイオードを製造できる。
尚、この場合、個々の発光ダイオードに分割する前に（すなわち、図１３に示す集合状態の段階で）、各発光ダイオードの色度を測定して又は色度を測定しながら色度を調整するようにすることもできる。
【００７９】
また、本実施の形態３では、実施の形態２で示したような収納部の内周側面を２段（多段）にしたパッケージを用いてもよい。
このようなパッケージは、実施の形態３の単層の絶縁基板に代えて、互いに異なる大きさの貫通孔を有する２つの（複数）の基板を貼り合わせた積層基板を用いることにより容易に作製することができる。
【００８０】
その他の変形例．
以上の実施の形態１〜３の発光装置では、ＬＥＤチップ５として電極側から光を出射するものを用い、ＬＥＤチップ５の電極とパッケージの電極とをワイヤーボンディングした例について示した。
しかしながら、本発明はこれに限られるものではなく、図１４に示すように、ＬＥＤチップ５をパッケージ内にフリップチップボンディングするようにしてもよい。
具体的には、ＬＥＤチップ５のｐ側の電極５ａとｎ側の電極５ｂとがそれぞれ、パッケージの実装面（収納部の底面）に形成された正負の電極（金属薄板２２ａ，金属薄板２２ｂ）に対向するようにＬＥＤチップを載置して、対向する電極間をそれぞれ半田等の導電性接着部材５２で接合することにより実装する。
【００８１】
尚、フリップチップボンディング用のＬＥＤチップは、基本的にはワイヤーボンディング用のＬＥＤチップと同様に構成される。
例えば、窒化物半導体発光素子（ＬＥＤチップ）の場合では、光透光性の基板の一方の主面上にｎ型およびｐ型窒化物半導体層を含む複数の窒化物半導体層を積層して、最上層のｐ型窒化物半導体層（ｐ型コンタクト層）の上にｐ側の電極を形成し、ｐ型窒化物半導体層の一部を除去することにより露出させたｎ型窒化物半導体層上にｎ側の電極を形成することにより構成し、光透光性基板の他方の主面を主光取り出し面とすればよい。
【００８２】
また、実施の形態１で説明した製造方法及び実施の形態３では、透光性樹脂の表面を色度調整のために研磨する前に、図１５に示すように、１又は２以上の溝を形成し、その後研磨するようにしてもよい。
この場合、溝の形状及び研磨条件等を調整することにより、図１６に示すように、凹凸（うねり）を形成することができる。
【００８３】
以下、現在、最も需要の多い白色の発光装置を構成するために適したＬＥＤチップ及び蛍光体粒子の材料について説明する。
ＬＥＤチップ５．
本発明において、白色の発光装置を構成するために適したＬＥＤチップとして、窒化物半導体（Ｉｎ_ＸＡｌ_ＹＧａ_{１−Ｘ−Ｙ}Ｎ、０≦Ｘ、０≦Ｙ、Ｘ＋Ｙ≦１）を用いたＬＥＤチップを用いることができる。このＬＥＤチップは、Ｉｎ_ｘＧａ_{1- ｘ}Ｎ（０＜ｘ＜１）を発光層として有しており、その混晶度によって発光波長を約３６５ｎｍから６５０ｎｍで任意に変えることができる。
【００８４】
本発明に係る発光装置において、白色系の光を発光させる場合は、蛍光体粒子から出射される光との補色関係を考慮するとＬＥＤチップ５の発光波長は４００ｎｍ以上５３０ｎｍ以下に設定することが好ましく、４２０ｎｍ以上４９０ｎｍ以下に設定することがより好ましい。なお、蛍光体の種類を選択することにより、４００ｎｍより短い紫外域の波長の光を発光するＬＥＤチップを適用することもできる。
【００８５】
蛍光体粒子．
本発明の発光ダイオードにおいては、蛍光物質として、窒化物系半導体を発光層とする半導体ＬＥＤチップから発光された光を励起させて発光できるセリウムで付活されたイットリウム・アルミニウム酸化物系蛍光物質をベースとしたもの、窒化物系蛍光体及びＣａ−Ａｌ−Ｓｉ−Ｏ−Ｎ系オキシ窒化物ガラス蛍光体等の種々の蛍光物質を用いることができる。
【００８６】
＜イットリウム・アルミニウム酸化物系蛍光物質＞
具体的なイットリウム・アルミニウム酸化物系蛍光物質としては、ＹＡｌＯ_３：Ｃｅ、Ｙ_３Ａｌ_５Ｏ_１２：Ｃｅ（ＹＡＧ：Ｃｅ）やＹ_４Ａｌ_２Ｏ_９：Ｃｅ、更にはこれらの混合物などが挙げられる。イットリウム・アルミニウム酸化物系蛍光物質にＢａ、Ｓｒ、Ｍｇ、Ｃａ、Ｚｎの少なくとも一種が含有されていてもよい。また、Ｓｉを含有させることによって、結晶成長の反応を抑制し蛍光物質の粒子を揃えることができる。
【００８７】
本明細書において、Ｃｅで付活されたイットリウム・アルミニウム酸化物系蛍光物質は特に広義に解釈するものとし、以下の蛍光物質を含むものである。
（１）イットリウム・アルミニウム酸化物系蛍光物質において、イットリウムの一部あるいは全体がＬｕ、Ｓｃ、Ｌａ、Ｇｄ及びＳｍからなる群から選ばれる少なくとも１つの元素に置換された蛍光物質。
（２）イットリウム・アルミニウム酸化物系蛍光物質において、アルミニウムの一部あるいは全体がＢａ、Ｔｌ、Ｇａ、Ｉｎからなる群から選ばれる少なくとも１つの元素に置換された蛍光物質。
（３）イットリウム・アルミニウム酸化物系蛍光物質において、イットリウムの一部あるいは全体がＬｕ、Ｓｃ、Ｌａ、Ｇｄ及びＳｍからなる群から選ばれる少なくとも１つの元素に置換され、アルミニウムの一部あるいは全体がアルミニウムの一部あるいは全体をＢａ、Ｔｌ、Ｇａ、Ｉｎからなる群から選ばれる少なくとも１つの元素に置換された蛍光物質。
【００８８】
更に詳しくは、一般式（Ｙ_zＧｄ_1-z）₃Ａｌ₅Ｏ₁₂：Ｃｅ（但し、０＜ｚ≦１）で示されるフォトルミネッセンス蛍光体や一般式（Ｒｅ_1-aＳｍ_a）₃Ｒｅ‘₅Ｏ₁₂：Ｃｅ（但し、０≦ａ＜１、０≦ｂ≦１、Ｒｅは、Ｙ、Ｇｄ、Ｌａ、Ｓｃから選択される少なくとも一種、Ｒｅ’は、Ａｌ、Ｇａ、Ｉｎから選択される少なくとも一種である。）で示されるフォトルミネッセンス蛍光体である。
【００８９】
この蛍光物質は、ガーネット構造のため、熱、光及び水分に強く、励起スペクトルのピークを４５０ｎｍ付近にさせることができ、発光ピークも、５８０ｎｍ付近にあり７００ｎｍまですそを引くブロードな発光スペクトルを持つ。
【００９０】
またフォトルミネセンス蛍光体は、結晶中にＧｄ（ガドリニウム）を含有することにより、４６０ｎｍ以上の長波長域の励起発光効率を高くすることができる。Ｇｄの含有量の増加により、発光ピーク波長が長波長に移動し全体の発光波長も長波長側にシフトする。すなわち、赤みの強い発光色が必要な場合、Ｇｄの置換量を多くすることで達成できる。一方、Ｇｄが増加すると共に、青色光によるフォトルミネセンスの発光輝度は低下する傾向にある。さらに、所望に応じてＣｅに加えＴｂ、Ｃｕ、Ａｇ、Ａｕ、Ｆｅ、Ｃｒ、Ｎｄ、Ｄｙ、Ｃｏ、Ｎｉ、Ｔｉ、Ｅｕ、Ｐｔらを含有させることもできる。
【００９１】
しかも、ガーネット構造を持ったイットリウム・アルミニウム・ガーネット系蛍光体の組成のうち、Ａｌの一部をＧａで置換することで発光波長が短波長側にシフトする。また、組成のＹの一部をＧｄで置換することで、発光波長が長波長側にシフトする。
【００９２】
Ｙの一部をＧｄで置換する場合、Ｇｄへの置換を１割未満にし、且つＣｅの含有（置換）を０．０３から１．０にすることが好ましい。Ｇｄへの置換が２割未満では緑色成分が大きく赤色成分が少なくなるが、Ｃｅの含有量を増やすことで赤色成分を補え、輝度を低下させることなく所望の色調を得ることができる。このような組成にすると温度特性が良好となり、発光ダイオードの信頼性を向上させることができる。また、赤色成分を多く有するように調整されたフォトルミネセンス蛍光体を使用すると、ピンク等の中間色を発光することが可能な発光ダイオードを製作することができる。
【００９３】
このようなフォトルミネセンス蛍光体は以下のようにして作製することができる。まず、Ｙ、Ｇｄ、Ａｌ、及びＣｅの原料として酸化物、又は高温で容易に酸化物になる化合物を使用し、それらを化学量論比で十分に混合して原料を得る。又は、Ｙ、Ｇｄ、Ｃｅの希土類元素を化学量論比で酸に溶解した溶解液を蓚酸で共沈したものを焼成して得られる共沈酸化物と、酸化アルミニウムとを混合して混合原料を得る。これにフラックスとしてフッ化バリウムやフッ化アンモニウム等のフッ化物を適量混合して坩堝に詰め、空気中１３５０〜１４５０°Ｃの温度範囲で２〜５時間焼成して焼成品を得、つぎに焼成品を水中でボールミルして、洗浄、分離、乾燥、最後に篩を通すことで得ることができる。
【００９４】
本願発明の発光ダイオードにおいて、このようなフォトルミネセンス蛍光体は、２種類以上のセリウムで付活されたイットリウム・アルミニウム・ガーネット系蛍光体や他の蛍光体を混合させてもよい。
ＹからＧｄへの置換量が異なる２種類のイットリウム・アルミニウム・ガーネット系蛍光体を混合することにより、容易に所望とする色調の光を容易に実現することができる。特に、前記置換量の多い蛍光物質を上記大粒径蛍光物質とし、前記置換量の少なく又はゼロである蛍光物質を上記中粒径蛍光物質とすると、演色性および輝度の向上を同時に実現することができる。
【００９５】
＜窒化物系蛍光体：赤色蛍光体＞
本窒化物系蛍光体は、第１の発光スペクトルの少なくとも一部を波長変換し、前記第１の発光スペクトルと異なる領域に第２の発光スペクトルを少なくとも１以上有する蛍光体であって、前記蛍光体は、Ｍｎが添加されたＳｒ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドであることを特徴とする蛍光体に関する。製造工程においてＳｒ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドにＭｎを添加することにより、Ｍｎが添加されていないときよりも、発光効率の向上を図ることができる。ＭｎがＳｒ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドに及ぼす効果は上述と同様で、Ｍｎが付活剤であるＥｕ２＋の拡散を促進させ、粒径を大きくし、結晶性の向上が図られたためであると考えられる。Ｅｕ２＋を付活剤とする蛍光体において、Ｍｎが増感剤として働き、付活剤Ｅｕ２＋の発光強度の増大を図ったためと考えられる。本発明に係るＳｒ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体は、上述のＳｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体と異なる組成及び発光スペクトルを有し、６１０〜６３０近傍にピーク波長を有する。
【００９６】
本窒化物系蛍光体は、第１の発光スペクトルの少なくとも一部を波長変換し、前記第１の発光スペクトルと異なる領域に第２の発光スペクトルを少なくとも１以上有する蛍光体であって、前記蛍光体は、Ｍｎが添加されたＣａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドであることを特徴とする蛍光体に関する。Ｍｎを添加したときの効果は上述と同様である。ただし、Ｍｎが添加されたＣａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドは、６００〜６２０近傍にピーク波長を有する。
【００９７】
上述のシリコンナイトライドの蛍光体に添加するＭｎは、通常、ＭｎＯ_２、Ｍｎ_２Ｏ_３、Ｍｎ_３Ｏ_４、ＭｎＯＯＨ等の酸化物、若しくは酸化水酸化物で加えられるが、これに限定されるものではなく、Ｍｎメタル、Ｍｎ窒化物、イミド、アミド、若しくはその他の無機塩類でも良く、また、予め他の原料に含まれている状態でも良い。前記シリコンナイトライドは、その組成中にＯが含有されている。Ｏは、原料となる各種Ｍｎ酸化物から導入されるか、本窒化物系蛍光体のＭｎによるＥｕ拡散、粒成長、結晶性向上の効果を促進すると考えられる。すなわち、Ｍｎ添加の効果は、Ｍｎ化合物をメタル、窒化物、酸化物と変えても同様の効果が得られ、むしろ酸化物を用いた場合の効果が大きい。結果としてシリコンナイトライドの組成中に微量のＯが含有されたものが製造される。従って、基本構成元素は、Ｓｒ−Ｃａ−Ｓｉ−Ｏ−Ｎ：Ｅｕ、Ｓｒ−Ｓｉ−Ｏ−Ｎ：Ｅｕ、Ｃａ−Ｓｉ−Ｏ−Ｎ：Ｅｕになる。これにより、Ｍｎ化合物に酸素を含有していないものを用いる場合でも、Ｅｕ２Ｏ３等のその他原料、雰囲気等によりＯが導入され、Ｏが含有している化合物を使わなくても上記課題を解決できる。
前記Ｏの含有量は、全組成量に対して３重量％以下であることが好ましい。これにより発光効率の向上を図ることができるからである。
【００９８】
前記シリコンナイトライドは、Ｍｇ、Ｓｒ、Ｃａ、Ｂａ、Ｚｎ、Ｂ、Ａｌ、Ｃｕ、Ｍｎ、Ｃｒ及びＮｉからなる群より選ばれる少なくとも１種以上が含有されていることが好ましい。前記シリコンナイトライドにＭｎ、Ｍｇ、Ｂ等の成分構成元素を少なくとも含有することにより、発光輝度、量子効率等の発光効率の向上を図ることができる。この理由は定かではないが、上記基本構成元素にＭｎ、Ｂ等の成分構成元素を含有させることにより粉体の粒径が均一かつ大きくなり、結晶性が著しく良くなるためであると考えられる。結晶性を良くすることにより、第１の発光スペクトルを高効率に波長変換し、発光効率の良好な第２の発光スペクトルを有する蛍光体にすることができる。また、蛍光体の残光特性を任意に調整することができる。ディスプレイ、ＰＤＰ等のように表示が連続して繰り返し行われるような表示装置では、残光特性が問題となる。そのため、蛍光体の基本構成元素に、Ｂ、Ｍｇ、Ｃｒ、Ｎｉ、Ａｌなどを微量に含有させることにより、残光を抑えることができる。これにより、ディスプレイ等の表示装置に本発明に係る蛍光体を使用することができる。
【００９９】
また、Ｍｎ、Ｂ等の添加剤は、ＭｎＯ_２、Ｍｎ_２Ｏ_３、Ｍｎ_３Ｏ_４や、Ｈ_３ＢＯ_３のような酸化物を加えても、発光特性を低下させることとならず、前述したようにＯもまた、拡散過程において、重要な役割を示すと考えられる。このように、前記シリコンナイトライドにＭｎ、Ｍｇ、Ｂ等の成分構成元素を含有することにより、蛍光体の粒径、結晶性、エネルギー伝達経路が変わり、吸収、反射、散乱が変化し、発光及び光の取り出し、残光などの発光装置における発光特性に大きく影響を及ぼすからである。
【０１００】
Ｓｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドは、ＳｒとＣａとのモル比が、Ｓｒ：Ｃａ＝１〜９：９〜１であることが好ましい。特に、Ｓｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドは、ＳｒとＣａとのモル比が、Ｓｒ：Ｃａ＝１：１であることが好ましい。ＳｒとＣａとのモル比を変えることにより、第２の発光スペクトルを長波長側にシフトすることができる。後述する表１において、Ｓｒ：Ｃａ＝９：１、Ｓｒ：Ｃａ＝１：９の組成を有する蛍光体では、ピーク波長が６２４ｎｍ、６０９ｎｍであるのに対し、Ｓｒ：Ｃａ＝７：３、Ｓｒ：Ｃａ＝６：４及びＳｒ：Ｃａ＝３：７、Ｓｒ：Ｃａ＝４：６と徐々にＳｒとＣａのモル比を変えていくと、ピーク波長が６３９ｎｍ、６４３ｎｍ及び６３６ｎｍ、６４２ｎｍと長波長側にピーク波長をシフトすることができる。このように、より長波長側にピーク波長を有する蛍光体を製造することができる。さらに、ＳｒとＣａのモル比を変えていくと、Ｓｒ：Ｃａ＝１：１の時に、ピーク波長が６４４ｎｍと最も長波長側にピーク波長を有する蛍光体を製造することができる。また、ＳｒとＣａとのモル比を変えることにより、発光輝度の向上を図ることができる。
【０１０１】
Ｓｒに対してＣａのモル量を増やしていくと、Ｓｒ：Ｃａ＝１：９のとき１７０．３％と７０．３％もの発光輝度の向上が図られている。また、ＳｒとＣａとのモル比を変えることにより、量子効率の向上を図ることができる。表１では、Ｓｒ：Ｃａ＝９：１のとき１００％であった量子効率が、Ｓｒ：Ｃａ＝５：５のとき１６７．７％と量子効率の向上が図られている。このようにＳｒとＣａとのモル比を変えることにより、発光効率の向上を図ることができる。
【０１０２】
前記蛍光体のＥｕの配合量は、対応するＳｒ−Ｃａ、Ｓｒ、Ｃａに対して０．００３〜０．５モルであることが好ましい。特に、前記蛍光体のＥｕの配合量は、対応するＳｒ−Ｃａ、Ｓｒ、Ｃａに対して０．００５〜０．１モルであることが好ましい。Ｅｕの配合量を変えることによりピーク波長を長波長側にシフトすることができる。また、発光輝度、量子効率等の発光効率の向上を図ることができる。後述する表２乃至４では、Ｓｒ−Ｃａ−Ｓｉ−Ｎ：ＥｕのシリコンナイトライドにおけるＥｕの配合量を変えた試験結果を示す。表２では、例えばＳｒ：Ｃａ＝７：３において、Ｓｒ−Ｃａに対してＥｕが０．００５モルであるときピーク波長が６２４ｎｍ、発光輝度が１００％、量子効率が１００％であるのに対して、Ｅｕが０．０３モルであるときピーク波長が６３７ｎｍ、発光輝度が１３９．５％、量子効率が１９９．２％と、発光効率が極めて良好になっている。
【０１０３】
前記蛍光体のＭｎの添加量は、対応するＳｒ−Ｃａ、Ｓｒ、Ｃａに対して０．００１〜０．３モルであることが好ましい。特に、前記蛍光体のＭｎの添加量は、対応するＳｒ−Ｃａ、Ｓｒ、Ｃａに対して０．００２５〜０．０３モルであることが好ましい。原料中若しくは製造工程中、シリコンナイトライドの蛍光体にＭｎを添加することにより、発光輝度、エネルギー効率、量子効率等の発光効率の向上を図ることができる。後述する表５乃至９では、Ｃａ−Ｓｉ−Ｎ：ＥｕのシリコンナイトライドにおけるＭｎの添加量を変えた試験結果を示す。表５乃至９では、例えばＭｎが無添加のシリコンナイトライドの蛍光体を基準として、発光輝度が１００％、量子効率が１００％とすると、Ｃａに対してＭｎを０．０１５モル添加したシリコンナイトライドの蛍光体は、発光輝度が１１５．３％、量子効率が１１７．４％である。このように、発光輝度、量子効率等の発光効率の向上を図ることができる。
【０１０４】
前記蛍光体は、Ｓｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体とＳｒ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体とを混合した蛍光体をいう。例えばＳｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体では、６５０ｎｍ近傍に発光スペクトルを有するのに対し、Ｓｒ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体は、６２０ｎｍ近傍に発光スペクトルを有する。これを所望量混合することにより６２０〜６５０ｎｍの波長範囲の所望の位置にピーク波長を有する蛍光体を製造することができるからである。ここで上記組合せに限られず、Ｓｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体とＣａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体とを混合した蛍光体、Ｓｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体とＳｒ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体とＣａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体とを混合した蛍光体も製造することができる。これらの組合せでも、６００〜６８０ｎｍの波長範囲の所望の位置にピーク波長を有する蛍光体を製造することができる。
【０１０５】
前記蛍光体は、平均粒径が３μｍ以上であることを特徴とする蛍光体であることが好ましい。Ｍｎが添加されていないＳｒ−Ｃａ−Ｓｉ−Ｎ：Ｅｕ系、Ｓｒ−Ｓｉ−Ｎ：Ｅｕ系、Ｃａ−Ｓｉ−Ｎ：Ｅｕ系シリコンナイトライドの蛍光体は、平均粒径が１〜２μｍ程度であるが、Ｍｎを添加する上記シリコンナイトライドは、平均粒径が３μｍ以上である。この粒径の違いにより、粒径が大きいと発光輝度が向上し、光取り出し効率が上昇するなどの利点がある。
【０１０６】
前記蛍光体は、Ｍｎの残留量が１０００ｐｐｍ以下であることが好ましい。前記蛍光体に、Ｍｎを添加することにより上記効果が得られるからである。
上記蛍光体において、Ｍｎの少なくとも一部をＢに置換することも可能であり、Ｂの添加はＭｎの添加と同様の効果を得ることができる。
【０１０７】
＜Ｃａ−Ａｌ−Ｓｉ−Ｏ−Ｎ系オキシ窒化物ガラス蛍光体＞
Ｃａ−Ａｌ−Ｓｉ−Ｏ−Ｎ系オキシ窒化物ガラス蛍光体とは、モル％表示で、ＣａＣＯ_３ をＣａＯに換算して：２０〜５０モル％、Ａｌ_２Ｏ_３ ：０〜３０モル％、ＳｉＯ：２５〜６０モル％、ＡｌＮ：５〜５０モル％、希土類酸化物または遷移金属酸化物：０．１〜２０モル％で、５成分の合計が１００モル％となるオキシ窒化物ガラスを母体材料とした蛍光体である。
尚、オキシ窒化物ガラスを母体材料とした蛍光体では、窒素含有量が１５ｗｔ％以下であることが好ましく、希土類酸化物イオンの他に増感剤となる他の希土類元素イオンを希土類酸化物として蛍光ガラス中に０．１〜１０モル％の範囲の含有量で共賦活剤として含むことが好ましい。
【０１０８】
本蛍光体の成分のＣａＣＯ_３ は、ＣａＯの原料であり、ガラス化範囲を広げるだけでなく、蛍光ガラス中に発光中心となる希土類イオンまたは遷移金属イオンを多量に、かつ、安定に含有させることができるものであり、２０〜３０モル％の範囲がより好ましい。なお、Ｃａ2+サイトにあるＣａ2+イオンをＳｒ2+やＢａ2+イオンに容易に置き換えることによって発光中心イオンとなる希土類酸化物または遷移金属酸化物の含有量を上記のとおり０．１〜２０モル％の範囲内で自在に制御することが可能になる。
【０１０９】
ＡｌＮとＡｌ_２Ｏ_３は、窒素含有量を変化させるために用いる。ＡｌＮが４０〜１０モル％、Ａｌ_２Ｏ_３が０〜２０モル％の範囲がより好ましい。ＳｉＯ_２は、ガラス形成成分の一つであり、ＣａＯ と組み合わせることによりガラス融液の溶融温度を低下させるものであり、３０〜４０モル％の範囲がより好ましい。
【０１１０】
希土類酸化物または遷移金属酸化物は、Ｅｕ2+、Ｅｕ3+、Ｃｅ3+、Ｔｂ3+などの希土類イオンまたはＣｒ3+、Ｍｎ2+などの遷移金属イオンをガラス中にドープする原料であり、ガラス組成限界である２０モル％以下の範囲において賦活し、発光中心の濃度消光が認められない０．５〜１０モル％の賦活量において強い発光強度を有する。
【０１１１】
オキシ窒化物ガラスは、酸素の一部を窒素に置換したものであり、窒素の導入によってガラス網目構造の化学結合が強化され、ガラス転移温度、軟化温度などの熱的性質の他、機械的な性質や化学的な性質が著しく向上する（例えば、特公平７−３７３３３号公報）ことが知られている。
【０１１２】
本蛍光体は、ガラス中の窒素含有量は、１５ｗｔ％以下のガラス組成範囲において窒素含有量を制御して発光スペクトルのピーク位置を移動させることができ、さらにオキシ窒化物ガラス蛍光体の励起スペクトル中のピーク波長を紫外から緑の範囲で調整できる。この発光ピーク波長の移動はゆるやかに黄から赤に変化するため、窒素含有量を変化させることにより蛍光体の多色化が容易に図れる。より好ましい窒素含有量は、４〜７ｗｔ％である。
【０１１３】
オキシ窒化物ガラスを製造する代表的な方法としては二つの方法があり、一つは窒素源に窒化物を用いて溶融する方法であり、他の方法としてはゾル−ゲル法などで作製した多孔質ガラスをアンモニアガスで窒化させる方法がある。
【０１１４】
前者の方法は溶融時の高温で窒化物が分解するので、窒素含有量を１０ｗｔ％以上にすることは非常に難しいが、例えば、１０気圧の窒素加圧下でこれらのガラスを合成することにより、比較的多量の窒素を含むオキシ窒化物ガラスが得られる。このようなオキシ窒化物ガラスは、機械的強度や化学的安定性にさらに優れる
【０１１５】
蛍光ガラス中には、基本的に一種類の発光中心しか含まない。ただし、二種類の希土類元素が蛍光ガラス中に含まれる場合は有り得る。この二種類を同時に蛍光ガラスにドープする効果として二つ挙げることができる。一つは、増感作用、もう一つは、キャリアーのトラップ準位を新たに形成し、長残光性の発現および改善やサーモルミネッセンスを改善させるというものである。増感作用が観察される組み合わせとして、一般的に、Ｅｕ3+イオンに対してＴｂ3+イオン、Ｔｂ3+イオンに対してＣｅ3+イオンが挙げられる。
【０１１６】
Ｅｕ2+（あるいはＣｅ3+）イオンのほかに他の希土類元素イオン（Ｇｄ3+、Ｔｂ3+、Ｄｙ3+、またはＳｍ3+イオンなど）を増感剤とするために、これら希土類酸化物を蛍光ガラス中に０．１〜１０モル％の含有量で共賦活剤として含ませることができる。
【０１１７】
このＣａ−Ａｌ−Ｓｉ−Ｏ−Ｎ系オキシ窒化物ガラスの窒素含有量は、約５．５ｗｔ％と報告されており、本発明の蛍光体の母材ガラスとしてこのオキシ窒化物ガラスの組成を用いることができる。
【０１１８】
Ｃａ−Ａｌ−Ｓｉ−Ｏ−Ｎ系オキシ窒化物ガラス蛍光体の製造方法は上述の従来公知の方法を用いることができるが、その場合、希土類酸化物を原料として用い、他の原料と混合し、これを出発原料として窒素雰囲気において加熱溶融して蛍光ガラスを合成する。
【０１１９】
例えば、希土類酸化物、金属酸化物ＣａＯ（←ＣａＣＯ_３、Ａｌ_２ Ｏ_３ 、ＳｉＯ_２ ）にＡｌＮを加え、高温、例えば１７００℃程度で融解して合成することができる。この際に、Ａｌ_２ Ｏ_３ とＡｌＮの割合を変えることによって、ガラスにおける窒素含有量を変化させることができる。
【０１２０】
＜蛍光体を組み合わせて用いる場合の例＞
尚、以下の各例は、白色発光装置を構成する１つの例であって、白色発光装置を構成するＬＥＤチップと蛍光体との組み合わせは種々存在し、本発明は以下のものに限定されるものではないことを念のために言っておく。
（１）実施の形態１〜３の発光装置において、
（ｉ）青色発光ＬＥＤチップ、
（ｉｉ）黄緑色発光蛍光体（Ｙ_３Ａｌ_５Ｏ_１２：Ｃｅ）と赤色発光蛍光体（Ｓｒ_{０．６７９}Ｃａ_０．２９１Ｅｕ_{０．０１５}）_２Ｓｉ_５Ｎ_８）とからなる蛍光体粒子を用いる。
本発明に係る発光装置では、このような組み合わせにより、白色発光装置を構成でき、かつ複数の蛍光体を用いることによる色むらを改善できる。
【０１２１】
（２）実施の形態１〜３の発光装置において、
（ｉ）青色発光ＬＥＤチップ、
（ｉｉ）緑色発光蛍光体（Ｙ_{２．９６５}Ａｌ_３．００Ｇａ_２Ｏ_１２：Ｃｅ_{０．０３５}）と黄色発光蛍光体（Ｃａ−Ａｌ−Ｓｉ−Ｏ−Ｎ系オキシ窒化物ガラス蛍光体）と赤色発光蛍光体（Ｓｒ_{０．６７９}Ｃａ_{０．２９１}Ｅｕ_{０．０１５}）_２Ｓｉ_５Ｎ_８）とからなる蛍光体粒子を用いる。
本発明に係る発光装置では、このような組み合わせによっても、白色発光装置を構成でき、かつ複数の蛍光体を用いることによる色むらを改善できる。
【０１２２】
【発明の効果】
以上詳細に説明したように、本発明に係る発光装置の色度調整方法は、前記透光性樹脂を硬化させた後に、前記透光性樹脂の量を変化させることによって前記透光性樹脂に対する前記蛍光体粒子の比率を変化させて色度を調整する工程を含むので、色度の微調整を容易にできる。
また、本発明に係る発光装置の製造方法によれば、色度バラツキの小さい発光装置を製造できる。
さらに、本発明に係る発光装置によれば、色度バラツキが小さくかつ発光強度の高い発光装置を提供できる。
【図面の簡単な説明】
【図１】 本発明に係る実施の形態の発光装置の断面図である。
【図２】 本実施の形態における樹脂研磨量に対する色度ｘ値のシフト量を示すグラフである。
【図３】 本実施の形態の色度調整方法におけるサンプルの色度調整前と色度調整後のバラツキ分布を示すグラフである。
【図４】 本実施の形態の色度調整方法におけるサンプルの色度調整前、高さ統一後および色度調整後のバラツキ分布を示すグラフである。
【図５】 本実施の形態において、光度測定及び光出力特性の測定に用いたサンプルの色度調整前後の色度を示すグラフである。
【図６】 本実施の形態において、色度調整のために研磨した前後のサンプルの光度（ａ）と光出力（ｂ）の測定結果を示すグラフである。
【図７】 本発明に係る変形例（その１）の発光装置の断面図である。
【図８】 本発明の原理を説明するための模式図である。
【図９】 本発明に係る実施の形態２の発光装置の構成と色度調整の様子をを示す断面図である。
【図１０】 本発明に係る実施の形態３の発光装置の断面図である。
【図１１】 実施の形態３の製造工程において、透光性樹脂の形成に使用するマスクの平面図（ａ）とその一部の拡大図（ｂ）である。
【図１２】 実施の形態３の製造工程において、透光性樹脂の形成工程の流れを示す図である。
【図１３】 実施の形態３の製造工程において、透光性樹脂を形成した後の断面図である。
【図１４】 本発明に係る変形例（その２）の発光装置の断面図である。
【図１５】 本発明に係る製造方法の変形例であって、研磨前に表面に溝を形成した後の断面図である。
【図１６】 図１５の溝を形成してから研磨した場合の断面図である。
【符号の説明】
１ａ…収納部、
２…パッケージ、
２ａ，２ｂ…電極リード、
５…発光ダイオードチップ（ＬＥＤチップ）、
８…透光性樹脂、
８ａ…波長変換層、
８ｂ…非波長変換層、
２２…金属ベース、
２２ａ，２２ｂ…金属薄板、
８１…蛍光体粒子、
１００…パッケージアッセンブリー、
１０１…絶縁性基板、
１０１ａ…貫通孔、
１１２…マスク、
１１３…開口部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light emitting device including a translucent resin containing a phosphor and a chromaticity adjustment method for the light emitting device.
[0002]
[Prior art]
In recent years, blue light-emitting diodes using nitride semiconductors have been developed. By combining with phosphors that absorb part of the light output from the light-emitting diode and output light of different wavelengths, various color tones can be obtained. It became possible to produce a light-emitting device having the emission color.
Generally, a light-emitting device in which a light-emitting diode and a phosphor are combined is configured by covering the light-emitting diode with a light-transmitting resin containing the phosphor.
However, the light emitting device combined with the light emitting diode and the phosphor has a problem that the color tone varies due to the variation in the phosphor content.
Therefore, in the conventional light emitting device, for example, the variation in color tone is suppressed by making the thickness of the wavelength conversion layer uniform.
[0003]
[Patent Document 1]
JP 2001-177158 A
[0004]
[Problems to be solved by the invention]
However, the conventional chromaticity adjustment method has a problem that fine adjustment of chromaticity is difficult.
[0005]
Accordingly, an object of the present invention is to provide a chromaticity adjustment method for a light emitting device in which fine adjustment of chromaticity is easy.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, a method for adjusting chromaticity of a light-emitting device according to the present invention includes a light-emitting element and a translucent resin that includes phosphor particles and is formed and cured so as to cover the light-emitting element. A method for adjusting the chromaticity of a light emitting device provided,
  The translucent resin comprises a wavelength conversion layer containing the phosphor particles and a non-wavelength conversion layer substantially not containing the phosphor particles,
  After curing the translucent resin,In non-wavelength conversion layerChanging the ratio of the phosphor particles to the translucent resin by changing the amount of the translucent resin, and adjusting the chromaticity.See
The step of adjusting the chromaticity is a step of adjusting the chromaticity by changing the thickness of the non-wavelength conversion layer that does not substantially contain the phosphor particles in the translucent resin.It is characterized by that.
  According to this method, since the chromaticity is adjusted after the translucent resin is cured, the chromaticity can be adjusted with high accuracy.
[0007]
  In the chromaticity adjustment method according to the present invention, the step of adjusting the chromaticity includes:in frontThe chromaticity may be adjusted by polishing the non-wavelength conversion layer, or the chromaticity may be adjusted by further applying a translucent resin on the translucent resin.
[0008]
  Further, the chromaticity adjustment method for a light emitting device according to the present invention includes a plurality of light emitting devices each including a light emitting element and a translucent resin that includes phosphor particles and is formed so as to cover the light emitting element and cured. A method for adjusting chromaticity,
  The translucent resin comprises a wavelength conversion layer containing the phosphor particles and a non-wavelength conversion layer substantially not containing the phosphor particles,
  An initial chromaticity measuring step of measuring the chromaticity of the plurality of light emitting devices after curing the translucent resin;
  Based on the measured chromaticity, a plurality of the plurality of light emitting devices are provided by grouping each of which has a difference between the measured chromaticity and the target chromaticity within a preset range. Grouping process to divide into groups,
  The upper layer portion of the translucent resin by an amount set based on the difference from the target chromaticity for each groupNon-wavelength conversion layerAnd a polishing step of polishing the substrate.
[0015]
  In a first method for manufacturing a light emitting device according to the present invention, a light emitting element is mounted in a housing part of a package, and a light transmissive resin containing phosphor particles is filled in the housing part so as to cover the light emitting element. A method of manufacturing a light emitting device including curing,
  The viscosity of the translucent resin is adjusted so that more phosphor particles settle around the light emitting element than the surface layer portion before being cured.And after curing the translucent resin, the translucent resin comprises a wavelength conversion layer containing the phosphor particles and a non-wavelength conversion layer substantially free of phosphor particles, and
After curing the translucent resin, the phosphor for the translucent resin is polished by polishing the surface of the non-wavelength conversion layer that does not substantially contain the phosphor particles of the translucent resin. Adjust the chromaticity by changing the proportion of particlesIt is characterized by that.
  In the first manufacturing method according to the present invention configured as described above, after the translucent resin is cured,Non-wavelength conversion layerSince the content of the phosphor particles with respect to the translucent resin can be changed by polishing, the chromaticity can be adjusted.
[0016]
  In the first manufacturing method of the light emitting device according to the present invention, grooves may be formed on the surface of the cured translucent resin before the surface of the translucent resin is polished.
[0017]
  The second manufacturing method of the light emitting device according to the present invention is:
A pair of thin metal plates constituting the positive and negative electrodes are joined to the periphery of one surface of the metal base to form a storage portion and a metal base joined so as to be electrically separated by an insulating resin. A method of manufacturing a light emitting device including a package including a side wall portion and an LED chip provided in the storage portion,
  By joining an insulating substrate in which a plurality of through-holes corresponding to the storage portions are formed in groups and a metal base plate having portions separated by the insulating resin corresponding to the through-holes, A first step of producing a package assembly comprising an assembly of a plurality of packages;
  A second step of mounting the LED chip in the housing part of each package formed by the through hole;
  Applying the translucent resin to the upper surface of the insulating substrate and the through holes by stencil printing using a mask having one opening corresponding to each group, and curingA third step of forming a translucent resin comprising a wavelength conversion layer containing the phosphor particles and a non-wavelength conversion layer substantially not containing the phosphor particles;
After curing the translucent resin, the chromaticity is adjusted by changing the ratio of the phosphor particles to the translucent resin by changing the amount of the translucent resin in the non-wavelength conversion layer. 4 processes,
The step of adjusting the chromaticity is a step of adjusting the chromaticity by changing the thickness of the non-wavelength conversion layer that does not substantially contain the phosphor particles in the translucent resin.It is characterized by that.
[0018]
  The second manufacturing method of the light emitting device according to the present invention is:in frontA plurality of grooves may be formed on the surface of the translucent resin between the third step and the fourth step.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a light emitting device and a chromaticity adjustment method of the light emitting device according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the light-emitting diode (light-emitting device) of the present embodiment is a surface-mounted type (SMD) in which a light-emitting diode chip (LED chip) 5 is sealed in a package 2 with a translucent resin 8. Type) light emitting diode. In the light emitting diode of the present embodiment, the package 2 is made of a resin molded body in which a base portion and a side wall portion are integrally molded, and electrode leads 2a and 2b are insert-molded in the base portion of the resin molded body.
The LED chip 5 is die-bonded with a die-bonding resin 6 on the electrode lead 2b exposed on the bottom surface of the housing portion of the package 2, and the positive and negative electrodes are connected to the electrode leads 2a and 2b by wires 7. After that, it is sealed with a translucent resin 8.
[0020]
Here, in the light emitting diode according to the present embodiment, the phosphor particles of the LED chip 5 are formed on the translucent resin 8 by converting the light emitted from the light emitting diode (LED) chip 5 into light having different wavelengths and outputting the light. The translucent resin 8 is dispersed around the wavelength conversion layer 8a around the LED chip 5 in which the phosphor particles 81 are dispersed and the non-wavelength conversion layer 8b substantially not including the phosphor particles 81. ing.
And in the light-emitting device of this Embodiment, the surface of the non-wavelength conversion layer 8b is roughened by grinding | polishing.
Here, in the present specification, “substantially free of phosphor particles” and “substantially free of phosphor particles” mean that the phosphor does not contain phosphor particles at all, Even if it contains particles, it means that the absorption of light emitted by the LED chip 5 is not confirmed.
[0021]
Further, in the present invention, the translucent resin 8 is composed of the wavelength conversion layer 8a around the LED chip 5 in which the phosphor particles 81 are dispersed and the non-wavelength conversion layer 8b substantially not including the phosphor particles 81. However, the wavelength conversion layer 8a and the non-wavelength conversion layer 8b do not need to have a clear boundary, and as the distance from the LED chip 5, the phosphor content gradually decreases, and at least the chromaticity is adjusted. It is sufficient that the non-wavelength conversion layer 8b having a necessary thickness is formed.
In such a layer, the phosphor particles dispersed in the translucent resin usually have a specific gravity greater than that of the translucent resin, and the thermosetting resin has a greatly reduced viscosity during heat curing. Therefore, it can be easily formed by utilizing these things.
That is, the viscosity of the translucent resin may be adjusted so that more phosphor particles settle around the light emitting element than the surface layer portion before being cured.
Moreover, in order to form the non-wavelength conversion layer 8b having a controlled thickness, the particle diameter of the phosphor particles and the viscosity of the translucent resin in the manufacturing process may be controlled within a certain range.
[0022]
Hereinafter, a method for adjusting the chromaticity of the light emitting device according to the present embodiment will be described.
The chromaticity adjustment method according to the present invention is based on the knowledge found by the present inventor that “the chromaticity can be adjusted by polishing the non-wavelength conversion layer 8b substantially not including the phosphor particles 81”. .
That is, according to the present invention, as shown in FIG. 2, by polishing the non-wavelength conversion layer 8b not including the phosphor particles 81, the resin polishing amount and chromaticity (the chromaticity x shown in FIG. This is based on the experimental fact that the shift amount of the value is approximately proportional.
When the shift amount of the chromaticity x value is A and the resin polishing amount is B (mm), the proportional relationship indicated by a straight line in the graph of FIG. 2 is expressed by A = 0.034B (Equation 1). .
[0023]
Hereinafter, experimental facts (hereinafter referred to as “Fact 1” of the present application) serving as the basis of the present invention will be described in detail in comparison with matters described in Patent Document 1 cited in the description of the prior art.
(1) First, in fact 1 in the present application, as shown in FIG. 2, the chromaticity x value is increased by polishing the resin to reduce the thickness of the translucent resin layer 8. is there.
On the other hand, according to FIG. 3 of the conventional patent document 1, it is shown that the chromaticity x value decreases by reducing the thickness of the resin, which is the reverse tendency to the fact 1 of the present application. Yes.
[0024]
(2) Second, in the fact 1 of the present application, as shown in the graph of FIG. 2, the change in the chromaticity x value is about 0 with respect to the change in the resin thickness of 0.1 mm (1000 μm). .0035.
On the other hand, according to FIG. 3 of the conventional patent document 1, the change of the chromaticity x value is about 0.03 to 0.04 with respect to the change of the resin thickness of 10 μm.
That is, the change amount of the chromaticity x value with respect to the change in the thickness of the resin in the fact 1 of the present application is compared with the change amount of the chromaticity x value with respect to the change in the thickness of the resin described in FIG. 2 digits smaller, suitable for fine adjustment of chromaticity.
[0025]
The difference between the phenomenon described in FIG. 3 of the present application fact 1 and the patent document 1 described above is that the present application fact 1 is for polishing the non-wavelength conversion layer 8b that does not include the phosphor particles 81. 3 of 1 is presumed to be based on the premise that a resin layer containing a phosphor is polished, and the basic mechanism is different.
[0026]
Moreover, in order to confirm the said difference from another surface, this inventor produced the light-emitting device of the structure shown in FIG. 1 (after hardening a translucent resin), and then changed the surface of the translucent resin. It was confirmed that the chromaticity x value was decreased by applying a light-transmitting resin containing no phosphor particles to the surface without being polished and curing (Fact 2 of the present application).
[0027]
The experimental facts that serve as the basis of the present invention have been described above. This fact can be explained as follows.
FIG. 8 is a diagram schematically showing a path of light emitted from the side surface of the light emitting element 5 in the translucent resin, before and after polishing a part (polishing portion) 8bk of the non-wavelength conversion layer 8b. It shows the path of light.
[0028]
Before the part 8bk of the non-wavelength conversion layer 8b is polished, the light emitted from the side surface of the light emitting element 5 is reflected by the side surface of the package and then passes through the point A as shown in FIG. After reaching the surface 8s2, the light is reflected at one point B and further reflected at one point C on the side surface of the package, and then reaches the wavelength conversion resin layer 8a.
On the other hand, after the part 8bk of the non-wavelength conversion layer 8b is polished, the light emitted from the side surface of the light emitting element 5 is reflected on the side surface of the package as shown in FIG. After being reflected at point A of 8s1 and directed downward (in the direction where the wavelength conversion layer is present), it reaches the wavelength conversion layer 8a as it is, or after being reflected at one point (for example, point D) on the side of the package, wavelength conversion is performed. Reach layer 8a.
In the example shown in FIG. 8, since the distance between AB and AB ′ is equal, and the distance between BC and B′D is equal, the distance to the wavelength conversion layer is (in other words, fluorescence The distance to the body particles) is shorter by the distance between CE after polishing than before polishing.
[0029]
In the above description, one example has been described. However, at least for light accompanied by reflection on the surfaces 8s1 and 8s2 which are light emitting surfaces, whatever path is taken (that is, what kind of light is emitted from the light emitting element) Even if the light is reflected at an angle, the distance to the wavelength conversion layer 8a (phosphor particles) is shorter after polishing than before polishing.
As a result, after polishing, the distance to the wavelength conversion layer (phosphor particles) becomes shorter, so that attenuation due to absorption of the translucent resin can be reduced, and the phosphor particles are excited with stronger light than before polishing. can do.
In addition, after polishing, since light is confined in a narrower space (translucent resin), more reflections are repeated, and the probability that the light meets the phosphor particles increases, and the wavelength conversion rate is high. Become.
[0030]
For these reasons, the wavelength conversion rate by the phosphor particles for light emitted from the light emitting element (particularly, light emitted from the side surface of the light emitting element) increases, and the chromaticity x value and y value increase by polishing.
As described above, in the present application, in order to increase the chromaticity x value and the y value, (1) the light is reflected on the light emitting surface without substantially changing the amount of the phosphor particles contained in the translucent resin. It is important to shorten the distance of the light to the phosphor particles and (2) to confine the light in a narrower translucent resin.
Conversely, in order to reduce the chromaticity x value and y value, the phosphor of light reflected on the light emitting surface or the like without substantially changing the amount of phosphor particles contained in the translucent resin. What is necessary is just to lengthen the distance to particle | grains, and to confine light in a wider translucent resin.
[0031]
As is clear from the above description, in the present application, at least the distance of the light reflected on the light emitting surface or the like to the phosphor particles can be changed, and the range of the translucent resin space for confining the light can be changed. Any means can be applied.
That is, changing the thickness of the non-wavelength conversion layer 8b by polishing or the like changes the distance of the light reflected from the light emitting surface to the phosphor particles and changes the range of the transparent resin space for confining the light. The present application is not limited to changing the thickness of the non-wavelength conversion layer 8b.
[0032]
For example, if the volume (volume) of the translucent resin is changed without changing the amount of the phosphor particles, the distance of the light reflected on the light emitting surface or the like to the phosphor particles is changed to confine the light. Since the range of the translucent resin space can be changed, the color tone can be changed.
Even if the amount of phosphor particles changes, changing the amount of translucent resin at a rate exceeding that will change the distance of the light emitted from the side surface of the LED chip to the phosphor particles. Since the range of the translucent resin space that confines light can be changed, the color tone can be changed.
[0033]
As described above, the method for adjusting the chromaticity of the light emitting device according to the present invention is based on the ratio of the phosphor particles to the translucent resin after curing the translucent resin 81 (even if the volume ratio is the weight ratio). The chromaticity may be adjusted by changing the above.
Therefore, in the present invention, in the translucent resin 8, it is not essential that the non-wavelength conversion layer 8b substantially not including the phosphor particles is formed, and the translucent resin layer is separated from the light emitting element. You may make it form so that fluorescent substance particle may decrease, and the surface may be grind | polished or a translucent resin may be apply | coated to the surface. Even if it does in this way, the ratio of the fluorescent substance particle with respect to translucent resin can be changed, and chromaticity can be adjusted.
[0034]
Further, as a more specific means, after curing the translucent resin 8, the non-wavelength conversion layer 8b of the translucent resin 8 that does not substantially contain phosphor particles is polished, or non-wavelength conversion is performed. Further, a translucent resin that does not contain phosphor particles is applied on the layer 8b, and various modifications are possible in this case.
For example, when polishing after curing the translucent resin 8, the upper surface 2s of the side wall portion of the package 2 may be polished together with the surface of the translucent resin 8, as shown in FIG. As shown in FIG. 7, a translucent resin may be formed so as to cover the upper surface of the side wall portion of the package 2, and only the surface of the translucent resin may be polished.
[0035]
As described above, after forming the translucent resin layer 8, the color tone can be adjusted by changing the content ratio of the phosphor particles to the resin.
However, it is not practical to adjust the light emitting elements one by one in the actual manufacturing process.
[0036]
Then, next, the adjustment method which applied the chromaticity adjustment method which concerns on this invention in an actual manufacturing process is demonstrated.
That is, the present adjustment method has the chromaticity of a very large number of light-emitting devices each including a light-emitting element and a light-transmitting resin that includes phosphor particles and is formed to cover the light-emitting element and cured. It is a method of adjusting efficiently and includes the following steps.
[0037]
Step 1.
In step 1, the chromaticity of the light emitting device after curing the translucent resin is measured in its entirety (initial chromaticity measurement step).
Step 2.
Then, in step 2, based on the chromaticity measured in step 1, those in which the difference between the measured chromaticity and the target chromaticity is within a preset range are grouped into one group. Sort by chromaticity range (grouping process).
The number of groups to be classified is preferably as large as possible to reduce the chromaticity variation after adjustment, but the number of groups is set to an appropriate number in consideration of the required chromaticity range (standard) and manufacturing efficiency.
[0038]
Step 3.
Finally, in step 3, the upper layer portion of the translucent resin is polished for each group by an amount set based on the difference from the target chromaticity (polishing step).
That is, light emitting elements belonging to the same group are polished by the same polishing amount (value set for each group).
According to the adjustment method as described above, chromaticity can be adjusted collectively for each group, so that chromaticity can be adjusted efficiently and chromaticity variation can be reduced.
[0039]
In addition, in the chromaticity adjustment method including Steps 1 to 3 described above, the inventor evaluated the improvement rate of the standard deviation after the adjustment with respect to the number of divisions by simulation. The results are shown in the following Table 1 and FIG. Table 1 shows chromaticity x values.
Table 1

[0040]
As shown in Table 1 and FIG. 3, it can be seen that the improvement rate of the standard deviation σ increases as the number of divisions increases (the number of groups increases).
[0041]
In addition, the present inventor once polished all the resin surface of the sample and aligned the resin thickness (sample height), then divided into 5 (classified into 5 groups) according to its chromaticity, Chromaticity was corrected by polishing the amount determined for each group. The result is shown in FIG. The initial number of samples is 158, and the number of samples after aligning and adjusting the sample height is 148.
[0042]
As is clear from FIG. 4, the chromaticity variation is hardly improved by polishing the resin surface of the sample and aligning the resin thickness (sample height). It was found that the chromaticity variation was significantly improved by correcting the chromaticity by polishing the amount determined for each group.
[0043]
Further, according to the method of adjusting chromaticity by polishing according to the present invention, it was confirmed that both the luminous intensity and the luminous output of the light emitting device were increased.
As shown in FIG. 6A, the luminous intensity was 356 mcd before polishing (before chromaticity adjustment) and 412 mcd after polishing (after chromaticity adjustment).
Further, as shown in FIG. 6B, the light output was 3067 μW before polishing (before chromaticity adjustment), but was 3260 μW after polishing (after chromaticity adjustment).
FIG. 5 shows the chromaticity before and after polishing of the sample used for measuring the luminous intensity and the luminous output.
[0044]
Further, the sample shown as the reference shown in FIG. 6 belongs to the same production lot as the sample used for the measurement of the luminous intensity and the luminous output, and has the highest chromaticity x value and chromaticity y value before polishing. The large data before polishing is shown as a reference.
As shown in FIG. 5, the chromaticity before polishing of the sample shown as the reference is substantially equal to the chromaticity before and after polishing of the sample used for measuring the luminous intensity and the luminous output.
That is, since the sample after polishing is higher than the luminous intensity and light emission output of the sample shown as a reference, the improvement in light emission intensity and light emission output by the sample after polishing was brought about by a change in chromaticity. It is thought that this is due to the roughening of the light emitting surface by polishing and the shortening of the light passing distance through the resin.
[0045]
Further, it was confirmed whether or not the light distribution characteristics and the half-value angle of light were changed by polishing, but no change due to polishing was confirmed.
As described above, according to the present invention, after the translucent resin is cured, the translucent resin that does not substantially contain the phosphor particles is polished or applied, so that the final stage of the manufacturing process. In this process, the chromaticity can be easily adjusted.
That is, a method of adjusting the chromaticity and further filling the translucent resin based on the chromaticity before curing the translucent resin is conceivable, but the factor that affects the chromaticity before the resin is cured. Is unstable, and it is difficult to finely adjust the chromaticity.
However, there is no such difficulty in the chromaticity adjustment method according to the present invention.
[0046]
Further, in the method disclosed in Patent Document 1, it is difficult to finely adjust the chromaticity because the change in chromaticity is large with respect to the polishing amount of the resin. However, in the chromaticity adjusting method according to the present invention, There is no such difficulty.
[0047]
Embodiment 2. FIG.
In Embodiment 1 described above, the method of adjusting chromaticity by polishing the entire light emitting surface and the light emitting device manufactured by the method have been described. However, in such a method, for each light emitting device (or, The height changes for each polishing group), and the height is uneven.
Therefore, in Embodiment 2 according to the present invention, a method for adjusting chromaticity without changing the height of the product itself and a light-emitting device manufactured by applying the method will be described.
[0048]
First, before describing a specific adjustment method, the configuration of the light-emitting device of Embodiment 2 will be described.
As shown in FIG. 9, the light-emitting device (light-emitting diode) according to the second embodiment is a surface-mount type (SMD) in which a light-emitting diode chip (LED chip) 5 is sealed with a translucent resin 8 in a package. Type) light emitting diode. In the light emitting diode according to the second embodiment, the package includes a metal base 22 and a side wall portion 21, and the side wall portion 21 is joined around one surface of the metal base 22 to form a storage portion. The package made up of the metal base 22 and the side wall portion 21 will be described in detail in a third embodiment to be described later.
Then, the LED chip 5 is die-bonded to a package housing portion and predetermined wiring is performed by wire bonding, and then sealed with a translucent resin 8.
[0049]
More specifically, in the second embodiment, the metal base 22 of the package is configured by joining the thin metal plate 22a constituting the positive terminal and the thin metal plate 22b constituting the negative terminal by the insulating resin 4. Then, they are connected to the positive electrode 5a and the negative electrode 5b of the LED chip 5 by wires 7, respectively. Further, in the light emitting device of the second embodiment, the inner peripheral wall of the side wall portion 21 for constituting the storage portion has two stages in consideration of the chromaticity adjustment described later.
9 shows an example in which the LED chip 5 is die-bonded on one metal thin plate 22b by the die bonding resin 6. However, in the present invention, the LED chip 5 is die-bonded on the other metal thin plate 22a. Alternatively, they may be die-bonded across the thin metal plate 22a and the thin metal plate 22b.
[0050]
In Embodiment 2, the LED chip 5 is configured by sequentially stacking the following layers on a sapphire substrate.
(1) buffer layer, (2) undoped or GaN underlayer with relatively low Si content, (3) n-side GaN contact layer with more Si content than GaN underlayer, (4) n-side GaN contact layer A GaN layer having a lower Si content, (5) an n-side multilayer film of an InGaN layer and a GaN layer, which is a layer formed to lower the forward voltage Vf, and (6) five pairs of a GaN layer and an InGaN layer An active layer having a quantum well structure, (7) a p-side multilayer film comprising an AlGaN layer doped with Mg and an InGaN layer, (8) a p-side AlGaN layer doped with Mg, and (9) a p doped with Mg. Side GaN contact layer.
The p-side electrode is formed on the p-side GaN contact layer, and the n-side electrode is formed on the exposed surface by exposing a part of the n-side GaN contact layer by etching the upper layer. ing.
The nitride semiconductor light-emitting element (LED chip) of Embodiment 2 configured as described above has a double hetero structure in which an active layer is formed between a p-side layer and an n-side layer.
[0051]
The LED chip 5 configured in this manner is die-bonded and wire-bonded to the package housing portion, and then a predetermined amount of translucent resin is filled into the housing portion and cured. This translucent resin contains, for example, YAG: Ce containing Gd as an inorganic phosphor in an epoxy resin. By adjusting the temperature and viscosity during filling, the translucent resin 8 The wavelength conversion layer 8a and the non-wavelength conversion layer 8b are formed after curing.
[0052]
Measure the chromaticity of the light-emitting device produced as described above, and for example, those that are more bluish than the target chromaticity are sorted by an automatic sorter, then arranged on the polishing apparatus to achieve the target chromaticity Polish to be.
In the second embodiment, as shown in FIG. 9, the tool for polishing is provided with, for example, a disc-shaped grindstone (a grindstone having an outer shape smaller than the outer periphery of the storage portion) at the tip of the rotating shaft 51. Only the non-wavelength conversion layer of the translucent resin is polished by an amount corresponding to the difference between the target chromaticity and the measured chromaticity without using the side walls of the package.
[0053]
During this polishing, a plurality of light emitting devices can be adjusted at a time by providing a grindstone for each of the plurality of light emitting devices arranged on the polishing apparatus.
At this time, as described in the first embodiment, grouping can be performed according to the amount of shaving, and shaving can be performed collectively. (Even in this case, if a light sensor and a grindstone are provided in each light emitting device and the amount of shaving is controlled for each light emitting element, a plurality of light emitting elements can be processed in parallel at the same time. Needless to say.)
[0054]
If the chromaticity adjustment method (process) of the second embodiment described above is used, the chromaticity x value and the y value can be increased without changing the height of the entire light emitting device, and desired chromaticity (for example, , Desired white).
[0055]
In the chromaticity adjustment method of the second embodiment described above, only the non-wavelength conversion layer of the translucent resin is polished by an amount corresponding to the difference between the target chromaticity and the measured chromaticity. By adding a translucent resin that does not contain phosphor particles in the storage unit, the thickness of the non-wavelength conversion layer is increased by an amount corresponding to the difference between the target chromaticity and the measured chromaticity, thereby increasing the chromaticity. You may make it adjust. In this case, if the surface of the translucent resin after adjusting the chromaticity is set so as not to exceed the height of the side wall of the package, the chromaticity x value and the y value are not changed without changing the height of the entire light emitting device. A value can be made small and it can adjust to desired chromaticity (for example, desired white) accurately.
[0056]
Embodiment 3 FIG.
Next, a method for manufacturing the light-emitting device (light-emitting diode) according to Embodiment 3 of the present invention will be described.
This manufacturing method is a method for manufacturing a surface-mount type light emitting diode with stable quality, high mass productivity, and small chromaticity variation.
In the present manufacturing method, a package assembly in which a plurality of packages are collected is used to process the plurality of packages at a time until the step of covering the LED chip 5 with a translucent resin. This package assembly is manufactured by joining an insulating substrate 101 having a plurality of through holes 101a corresponding to the housing portions 1a of each package and a metal base plate 102 (see FIG. 13).
[0057]
Here, the insulating substrate 101 is made of, for example, a resin laminate having a thickness of 0.06 mm to 2.0 mm, and has a plurality of through holes 101a penetrating in the thickness direction (see FIG. 13). The cross-sectional shape of the through hole 101a may be an ellipse, a circle or a rectangle. That is, the present invention is not limited by the cross-sectional shape of the through hole 101a, and can be arbitrarily selected from various shapes. Further, in the through hole 101a, the side surface of the through hole may be inclined so that the opening diameter of the through hole 101a increases from one surface of the insulating substrate (the surface bonded to the metal thin plate) toward the other surface. preferable. When the side surface of the through hole 101a is inclined in this way, the light emitted from the LED chip toward the side surface of the through hole can be reflected by the side surface and output upward, so the light emitted from the LED chip 5 Can be efficiently taken out from the light emitting diode.
[0058]
Further, the metal base plate 102 corresponds to each through hole so that the metal thin plate 22a and the metal thin plate 22b are electrically separated by the insulating resin 4 in each package when cut for each package. Thus, a separation groove is formed, and the insulating resin 4 is filled in the separation groove (see FIG. 10).
[0059]
In each package portion, a part of the metal thin plate 22a, the insulating resin 4, and a part of the metal thin plate 22b are exposed in the through hole 101a.
Further, in the package assembly, a plurality of packages are arranged in a group with respect to one opening 113 of a mask 112 described later (see FIGS. 11 and 12).
[0060]
<Mounting LED chip>
The LED chip 5 is die-bonded using a die-bonding resin at a predetermined position of each through hole (housing portion) of the package assembly configured as described above, and predetermined wiring is performed by wire bonding (FIG. 5).
The metal thin plate 22a and the metal thin plate 22b are exposed inside each through hole, the LED chip 5 is bonded onto the metal thin plate 22b as a negative electrode, and the p-side electrode 5a and the n-side electrode 5b of the LED chip 5 are respectively The metal thin plate 22a and the metal thin plate 22b are connected by the wire 7 (see FIGS. 11 and 13).
[0061]
<First step: Stencil printing>
Next, a translucent resin (an epoxy resin composition of the present invention) 8 as a sealing member is applied by stencil printing in a chamber. FIG. 11A is a plan view of a mask 112 used for stencil printing in the manufacturing method according to the third embodiment. As shown in FIG. 11A, the mask 112 has a plurality of openings 113, and the position and size of each opening 113 are in one group with respect to one opening 113. The plurality of collected packages are set to correspond to each other (FIG. 11B). As described above, the mask used in the present invention is designed so that a resin layer is also formed on the surrounding insulating substrate 101 instead of providing a translucent resin only in each through hole. In the manufacturing method of the present embodiment, stencil printing using such a mask 112 is performed so that the surface becomes smooth even after curing in the through-hole 101a of the insulating substrate and on the insulating substrate 101. A light-sensitive resin can be formed.
[0062]
That is, in this manufacturing method, as shown in FIG. 13, a plurality of grouped packages are arranged except for a portion where it is difficult to form a transparent resin in the periphery of the opening 113, and a plurality of packages are arranged. By forming the light-transmitting resin with a certain thickness and a flat surface on the part where the package is disposed, the variation in the thickness of the light-transmitting resin layer between the packages can be suppressed and the transparency of each package can be reduced. The surface of the photo-resin is flattened.
[0063]
Thus, after forming a translucent resin at once for a plurality of light-emitting diodes, the light-emitting diodes are cut and separated at dotted portions shown in FIG. 13 to form individual light-emitting diodes. Accordingly, light emitting diodes having a uniform film thickness can be formed with high yield so that size and color variations do not occur between the light emitting diodes. Moreover, the film thickness of the translucent resin formed on the said insulating board | substrate can be arbitrarily changed by adjusting the board thickness of a mask.
[0064]
Next, an example of a method for forming the light-transmitting resin with a certain thickness and a flat surface in a portion where a plurality of packages are arranged in each opening 113 will be specifically described.
[0065]
(Step 1)
First, the package assembly 100 with the through-hole 101a facing the mask 112 is sucked onto the lifting stage 117 (FIG. 12A), and the stage 117 is raised to align the package assembly 100 and the mask 112. Then, it is brought into contact with the lower surface of the mask 112 (FIG. 12B). As a result, the package assembly 100 can be brought into contact with the mask 112 in a state where the warpage of the package assembly is corrected. Thus, by correcting the warpage of the package assembly 100, it is possible to form a translucent resin having a uniform film thickness on one surface of the package assembly 100. That is, if the sealing member is formed while warping the package substrate, the thickness varies between the formed light emitting diodes, and the yield deteriorates.
[0066]
As shown in FIG. 12A, the translucent resin containing the fluorescent material is disposed at the end outside the opening of the mask 112 under atmospheric pressure. In this state, decompression is performed by depressurization. The reduced pressure is preferably set in a range of 100 Pa to 400 Pa, and in this range, bubbles contained in the resin can be taken out effectively. In the present embodiment using the above-described package assembly 100 and mask 112, a light-transmitting resin having a relatively high viscosity can be used.
[0067]
When the bubbles are mixed in the translucent resin and sealed, the bubbles reflect and refract the light from the LED chip and the light emitted from the fluorescent material, so that color unevenness and luminance unevenness are remarkably observed. Therefore, when forming a translucent resin containing a fluorescent substance, it is extremely effective to repeat pressure reduction and pressurization as in this embodiment, and there is a wise effect of suppressing color unevenness and luminance unevenness. In addition, if bubbles are included in the translucent resin, the translucent resin may be peeled off, the bonded portion of the wire may be peeled off, the wire may be cut, and the reliability is lowered. . Therefore, prevention of bubbles by this method is extremely effective in improving reliability.
[0068]
<Step 2>
Next, under reduced pressure, the first round-trip forward squeegee scan is performed (FIG. 12C). The forward squeegee spatula 114 used at this time is inclined in the operation direction with respect to the vertical line of the mask 112 as shown in FIG. 12C, and operates by pressing the spatula 114 against the mask 112 by air pressure. Then, the resin 8 is poured into the opening 113 of the mask 112. Since the forward squeegee scan is performed under reduced pressure, the suction action of the lift stage 117 does not make sense, but since the lift stage 117 is physically pressed against the mask 112, there is no deviation between the package assembly 100 and the mask 112. .
[0069]
<Step 3>
Next, the pressure is increased to atmospheric pressure, and after the pressurization is completed, the first reciprocating squeegee scan is performed in the opposite direction to the forward squeegee scan (FIG. 12D). The return squeegee spatula 115 is actuated by an air pressure that is larger than the forward squeegee spatula 114 in the operation direction with respect to the vertical line of the mask 112 and is stronger than that during forward squeegee scanning. In this way, by increasing the contact area between the recovery squeegee spatula 115 and the mask 112 with a strong pressure and filling the translucent resin again, bubbles appearing on the surface of the resin filled in the opening 113 are removed. It can be removed efficiently and the surface of the sealing member can be finished to a smooth surface.
[0070]
<Step 4>
In the same manner as in Step 2 and Step 3, the reciprocating squeegee is performed several times while repeatedly depressurizing and pressurizing to defoam, and the opening 113 is filled with resin with a uniform film thickness.
[0071]
<Step 5>
In this state (a state where the mask 112 is in contact with the package assembly 100), the translucent resin is cured, and after the curing, the mask is removed to integrate the LED chip in the through hole and the upper surface of the insulating substrate. The upper surface of the molded translucent resin can be made to be a surface that is substantially parallel to the bottom surface of the package and smooth.
[0072]
Next, the dicing process will be described in detail. After the translucent resin is formed (cured) as described above, it is divided into individual light emitting diodes by dicing as follows.
[0073]
<Second step: dicing step>
(Dicing step 1)
First, after the resin is cured, the translucent resin side of the package assembly 100 is bonded to the dicing sheet. As described above, since the bonding surface of the package assembly 100 with the dicing sheet is made of substantially the same material and is a flat surface, the bonding strength can be increased. As a result, chip skipping and dicing displacement during dicing can be prevented, and individual light emitting diodes can be cut with a high yield.
[0074]
On the other hand, when the resin is filled and cured using a mask having openings corresponding to the individual through holes of the package assembly, the filled resin is thermally contracted and depressed at the through hole portion. The surface in contact with the dicing sheet is only the upper surface of the insulating substrate except on the through hole, and the adhesion is reduced. Also, if a mask mask having openings corresponding to individual through holes is used to fill and cure a large amount of resin, the upper surface of the resin becomes higher than the upper surface of the insulating substrate, which is the portion to be diced, and dicing is performed. The adhesive surface with the sheet is only the upper surface of the resin. Also in this case, the adhesive strength between the package assembly and the dicing sheet becomes extremely weak, and dicing deviation occurs. When dicing is performed with the package assembly and the dicing sheet being unstable as described above, chip skipping or dicing displacement occurs. In addition, there is a disadvantage that burrs are generated at the cut end of the obtained light emitting diode. The burr may break in the subsequent mounting process, etc.If the burr part is deeply cracked, moisture is mixed into the sealing member from the outside, and the reliability of the light emitting diode is lowered or the internal metal part is This may cause defects such as oxidation and discoloration.
[0075]
(Dicing step 2)
The package assembly fixed to the dicing sheet with good adhesion in step 1 is individually cut by a dicing blade from the bottom side of the package assembly (cut along the broken line in FIG. 13). The dicing braid is formed by collecting diamond particles having a small particle diameter around the bond.
[0076]
In the light emitting diode manufactured by the manufacturing method as described above, the translucent resin is integrally formed on the upper surface of the insulating substrate and the through hole of the insulating substrate, and the upper surface of the translucent resin is the bottom surface of the package. The outer peripheral side surface of the translucent resin is substantially parallel to the outer peripheral side surface of the package. In this way, by forming a light-transmitting resin on the entire top surface of the light emitting diode, the light emitting surface can be widened and the output can be improved.
[0077]
<Chromaticity adjustment process>
Then, the chromaticity of the light-emitting diode manufactured as described above is adjusted by the chromaticity adjusting method described in the first embodiment.
Thereby, the chromaticity variation can be reduced as in the first embodiment, and the light emission output can be improved by roughening by polishing.
In this case, in the light-emitting diode after adjusting the chromaticity, the translucent resin remains on the upper surface of the insulating substrate constituting the side wall of the package (that is, the thickness of the translucent resin on the upper surface of the insulating substrate). In order to adjust the chromaticity, it is preferable to make it thicker than the polishing amount), and as described above, the entire top surface of the light emitting diode can be made to be a light emitting surface, and the light emission output can be further improved. it can.
[0078]
Modified example of the third embodiment.
In the third embodiment, the chromaticity is adjusted by the chromaticity adjustment method described in the first embodiment. However, in the third embodiment, the chromaticity adjustment method described in the second embodiment can be applied. Needless to say.
In this way, it is possible to manufacture a light emitting diode with little chromaticity variation and uniform height.
In this case, before dividing into individual light emitting diodes (that is, at the stage of the collective state shown in FIG. 13), the chromaticity is adjusted by measuring the chromaticity of each light emitting diode or measuring the chromaticity. It can also be done.
[0079]
Further, in the present third embodiment, a package in which the inner peripheral side surface of the storage portion as shown in the second embodiment has two stages (multistage) may be used.
Such a package is easily manufactured by using a laminated substrate in which two (plural) substrates having through-holes having different sizes are used instead of the single-layer insulating substrate of the third embodiment. be able to.
[0080]
Other variations.
In the light emitting devices of the above first to third embodiments, the LED chip 5 that emits light from the electrode side is used, and an example in which the electrode of the LED chip 5 and the electrode of the package are wire bonded has been described.
However, the present invention is not limited to this, and the LED chip 5 may be flip-chip bonded in the package as shown in FIG.
Specifically, the p-side electrode 5a and the n-side electrode 5b of the LED chip 5 are respectively positive and negative electrodes (metal thin plate 22a, metal thin plate 22b) formed on the package mounting surface (bottom surface of the storage portion). The LED chips are placed so as to face each other, and the electrodes facing each other are mounted by joining them with a conductive adhesive member 52 such as solder.
[0081]
The LED chip for flip chip bonding is basically configured in the same manner as the LED chip for wire bonding.
For example, in the case of a nitride semiconductor light emitting device (LED chip), a plurality of nitride semiconductor layers including n-type and p-type nitride semiconductor layers are stacked on one main surface of a light-transmitting substrate, On the n-type nitride semiconductor layer exposed by forming a p-side electrode on the uppermost p-type nitride semiconductor layer (p-type contact layer) and removing a portion of the p-type nitride semiconductor layer The other main surface of the light-transmitting substrate may be used as a main light extraction surface.
[0082]
Further, in the manufacturing method described in Embodiment 1 and Embodiment 3, before polishing the surface of the translucent resin for chromaticity adjustment, as shown in FIG. 15, one or more grooves are formed. It may be formed and then polished.
In this case, irregularities (swells) can be formed as shown in FIG. 16 by adjusting the groove shape and polishing conditions.
[0083]
Hereinafter, materials for LED chips and phosphor particles suitable for constituting the most demanding white light emitting devices will be described below.
LED chip 5.
In the present invention, as an LED chip suitable for constituting a white light emitting device, a nitride semiconductor (In_XAl_YGa_1-XYN, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) can be used. This LED chip is In_xGa_{1- x}N (0 <x <1) is included as the light emitting layer, and the light emission wavelength can be arbitrarily changed from about 365 nm to 650 nm depending on the degree of mixed crystal.
[0084]
In the light emitting device according to the present invention, when white light is emitted, the emission wavelength of the LED chip 5 is preferably set to 400 nm or more and 530 nm or less in consideration of the complementary color relationship with the light emitted from the phosphor particles. More preferably, it is set to 420 nm or more and 490 nm or less. An LED chip that emits light having a wavelength in the ultraviolet region shorter than 400 nm can also be applied by selecting the type of phosphor.
[0085]
Phosphor particles.
In the light emitting diode of the present invention, a cerium-activated yttrium / aluminum oxide phosphor capable of emitting light by exciting light emitted from a semiconductor LED chip having a nitride semiconductor as a light emitting layer is used as the phosphor. Various fluorescent materials such as a base, a nitride-based phosphor, and a Ca—Al—Si—O—N-based oxynitride glass phosphor can be used.
[0086]
<Yttrium / aluminum oxide phosphor>
As a specific yttrium / aluminum oxide fluorescent material, YAlO₃: Ce, Y₃Al₅O₁₂: Ce (YAG: Ce) or Y₄Al₂O₉: Ce, and also a mixture thereof. The yttrium / aluminum oxide phosphor may contain at least one of Ba, Sr, Mg, Ca, and Zn. Moreover, by containing Si, the reaction of crystal growth can be suppressed and the particles of the fluorescent material can be aligned.
[0087]
In this specification, the yttrium-aluminum oxide fluorescent material activated with Ce is to be interpreted in a broad sense, and includes the following fluorescent materials.
(1) A fluorescent material in which a part or all of yttrium is substituted with at least one element selected from the group consisting of Lu, Sc, La, Gd and Sm in the yttrium / aluminum oxide fluorescent material.
(2) In the yttrium / aluminum oxide phosphor, a part or all of aluminum is substituted with at least one element selected from the group consisting of Ba, Tl, Ga, and In.
(3) In the yttrium / aluminum oxide fluorescent material, a part or the whole of yttrium is substituted with at least one element selected from the group consisting of Lu, Sc, La, Gd and Sm, A fluorescent material in which a part or all of aluminum is substituted with at least one element selected from the group consisting of Ba, Tl, Ga, and In.
[0088]
More specifically, the general formula (Y_zGd_1-z)_ThreeAl_FiveO₁₂: Photoluminescence phosphor represented by Ce (where 0 <z ≦ 1) or a general formula (Re_1-aSm_a)_ThreeRe ’_FiveO₁₂: Ce (where 0 ≦ a <1, 0 ≦ b ≦ 1, Re is at least one selected from Y, Gd, La, Sc, and Re ′ is at least one selected from Al, Ga, In) The photoluminescence phosphor shown in FIG.
[0089]
This fluorescent material has a garnet structure and is resistant to heat, light, and moisture, and can make the peak of the excitation spectrum around 450 nm. The emission peak is also around 580 nm and has a broad emission spectrum that pulls up to 700 nm. .
[0090]
Further, the photoluminescence phosphor can increase the excitation light emission efficiency in a long wavelength region of 460 nm or more by containing Gd (gadolinium) in the crystal. As the Gd content increases, the emission peak wavelength shifts to a longer wavelength, and the entire emission wavelength also shifts to the longer wavelength side. That is, when a strong reddish emission color is required, it can be achieved by increasing the amount of Gd substitution. On the other hand, as Gd increases, the emission luminance of photoluminescence by blue light tends to decrease. Furthermore, in addition to Ce, Tb, Cu, Ag, Au, Fe, Cr, Nd, Dy, Co, Ni, Ti, Eu, Pt, and the like can be contained as desired.
[0091]
Moreover, in the composition of the yttrium / aluminum / garnet phosphor having a garnet structure, the emission wavelength is shifted to the short wavelength side by replacing a part of Al with Ga. Further, by substituting part of Y in the composition with Gd, the emission wavelength is shifted to the longer wavelength side.
[0092]
When substituting a part of Y with Gd, it is preferable that the substitution with Gd is less than 10%, and the Ce content (substitution) is 0.03 to 1.0. If the substitution with Gd is less than 20%, the green component is large and the red component is small. However, by increasing the Ce content, the red component can be supplemented and a desired color tone can be obtained without lowering the luminance. With such a composition, the temperature characteristics are improved and the reliability of the light emitting diode can be improved. In addition, when a photoluminescent phosphor adjusted to have a large amount of red component is used, a light emitting diode capable of emitting an intermediate color such as pink can be manufactured.
[0093]
Such a photoluminescent phosphor can be produced as follows. First, an oxide or a compound that easily becomes an oxide at a high temperature is used as a raw material for Y, Gd, Al, and Ce, and these are sufficiently mixed in a stoichiometric ratio to obtain a raw material. Alternatively, a mixed raw material obtained by mixing a coprecipitation oxide obtained by firing a solution obtained by coprecipitation of a solution obtained by dissolving a rare earth element of Y, Gd, and Ce in an acid in a stoichiometric ratio with oxalic acid and aluminum oxide. Get. A suitable amount of fluoride such as barium fluoride or ammonium fluoride is mixed as a flux and packed in a crucible, and fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a fired product, and then fired. The product can be obtained by ball milling in water, washing, separating, drying and finally passing through a sieve.
[0094]
In the light emitting diode of the present invention, such a photoluminescent phosphor may be a mixture of yttrium / aluminum / garnet phosphors activated by two or more kinds of cerium and other phosphors.
By mixing two types of yttrium / aluminum / garnet phosphors with different amounts of substitution from Y to Gd, light having a desired color tone can be easily realized. In particular, when the fluorescent material with a large amount of substitution is the large particle size fluorescent material and the fluorescent material with the small amount of substitution or zero is the medium particle size fluorescent material, the color rendering property and the luminance can be improved at the same time. Can do.
[0095]
<Nitride-based phosphor: red phosphor>
The nitride-based phosphor is a phosphor that wavelength-converts at least a part of a first emission spectrum and has at least one second emission spectrum in a region different from the first emission spectrum, The body relates to a phosphor that is Sr—Si—N: Eu-based silicon nitride to which Mn is added. By adding Mn to the Sr—Si—N: Eu-based silicon nitride in the manufacturing process, the luminous efficiency can be improved as compared with the case where Mn is not added. The effect of Mn on Sr—Si—N: Eu-based silicon nitride is the same as described above, because Mn promotes the diffusion of Eu2 + as an activator, increases the particle size, and improves the crystallinity. It is thought that. In the phosphor using Eu2 + as an activator, it is considered that Mn worked as a sensitizer and increased the emission intensity of the activator Eu2 +. The phosphor of Sr—Si—N: Eu-based silicon nitride according to the present invention has a composition and an emission spectrum different from those of the above-described phosphor of Sr—Ca—Si—N: Eu-based silicon nitride. It has a peak wavelength in the vicinity of 630.
[0096]
The nitride-based phosphor is a phosphor that wavelength-converts at least a part of a first emission spectrum and has at least one second emission spectrum in a region different from the first emission spectrum, The body relates to a phosphor characterized in that the body is Ca—Si—N: Eu-based silicon nitride to which Mn is added. The effect when Mn is added is the same as described above. However, Ca—Si—N: Eu-based silicon nitride to which Mn is added has a peak wavelength in the vicinity of 600 to 620.
[0097]
The Mn added to the silicon nitride phosphor is usually MnO.₂, Mn₂O₃, Mn₃O₄, Oxides such as MnOOH, or oxide hydroxides, but is not limited thereto, and may be Mn metal, Mn nitride, imide, amide, or other inorganic salts. It may be contained in the raw material. The silicon nitride contains O in its composition. It is considered that O is introduced from various Mn oxides as raw materials or promotes the effects of Eu diffusion, grain growth, and crystallinity improvement by Mn of the present nitride phosphor. In other words, the same effect can be obtained by adding Mn even if the Mn compound is changed to metal, nitride, or oxide, but the effect when using an oxide is rather great. As a result, a silicon nitride composition containing a trace amount of O is produced. Accordingly, the basic constituent elements are Sr—Ca—Si—O—N: Eu, Sr—Si—O—N: Eu, and Ca—Si—O—N: Eu. As a result, even when an Mn compound that does not contain oxygen is used, O can be introduced by using other raw materials such as Eu 2 O 3, the atmosphere, and the like, and the above problem can be solved without using a compound containing O.
The content of O is preferably 3% by weight or less with respect to the total composition amount. This is because the luminous efficiency can be improved.
[0098]
The silicon nitride preferably contains at least one selected from the group consisting of Mg, Sr, Ca, Ba, Zn, B, Al, Cu, Mn, Cr and Ni. By containing at least component constituent elements such as Mn, Mg, and B in the silicon nitride, it is possible to improve luminous efficiency such as luminous luminance and quantum efficiency. The reason for this is not clear, but it is thought that the inclusion of component constituent elements such as Mn and B in the basic constituent element makes the powder particle size uniform and large, and the crystallinity is remarkably improved. By improving the crystallinity, the wavelength of the first emission spectrum can be converted with high efficiency, and the phosphor having the second emission spectrum with good emission efficiency can be obtained. Further, the afterglow characteristics of the phosphor can be arbitrarily adjusted. In a display device such as a display or a PDP in which display is performed continuously and repeatedly, afterglow characteristics become a problem. For this reason, afterglow can be suppressed by adding a small amount of B, Mg, Cr, Ni, Al or the like to the basic constituent elements of the phosphor. Thereby, the phosphor according to the present invention can be used in a display device such as a display.
[0099]
In addition, additives such as Mn and B are MnO₂, Mn₂O₃, Mn₃O₄And H₃BO₃Even if such an oxide is added, the light emission characteristics are not deteriorated, and as described above, O is also considered to play an important role in the diffusion process. Thus, the inclusion of component constituent elements such as Mn, Mg, and B in the silicon nitride changes the particle size, crystallinity, and energy transfer path of the phosphor, and changes the absorption, reflection, and scattering, and light emission. This is because it greatly affects the light emission characteristics of the light emitting device such as light extraction and afterglow.
[0100]
In the Sr—Ca—Si—N: Eu-based silicon nitride, the molar ratio of Sr and Ca is preferably Sr: Ca = 1 to 9: 9 to 1. In particular, in the Sr—Ca—Si—N: Eu-based silicon nitride, the molar ratio of Sr and Ca is preferably Sr: Ca = 1: 1. By changing the molar ratio of Sr and Ca, the second emission spectrum can be shifted to the longer wavelength side. In Table 1 described later, the phosphors having the composition of Sr: Ca = 9: 1 and Sr: Ca = 1: 9 have peak wavelengths of 624 nm and 609 nm, whereas Sr: Ca = 7: 3 and Sr. : Ca = 6: 4 and Sr: Ca = 3: 7, Sr: Ca = 4: 6, and when the molar ratio of Sr and Ca is gradually changed, the peak wavelengths are 639 nm, 643 nm, 636 nm, and 642 nm as long wavelengths The peak wavelength can be shifted to the side. Thus, a phosphor having a peak wavelength on the longer wavelength side can be produced. Furthermore, when the molar ratio of Sr and Ca is changed, when Sr: Ca = 1: 1, a phosphor having a peak wavelength of 644 nm and the peak wavelength on the longest wavelength side can be manufactured. In addition, the luminance of light emission can be improved by changing the molar ratio of Sr and Ca.
[0101]
When the molar amount of Ca is increased with respect to Sr, the emission luminance is improved by 170.3% and 70.3% when Sr: Ca = 1: 9. Also, the quantum efficiency can be improved by changing the molar ratio of Sr and Ca. In Table 1, the quantum efficiency, which was 100% when Sr: Ca = 9: 1, is 167.7% when Sr: Ca = 5: 5, and the quantum efficiency is improved. Thus, the luminous efficiency can be improved by changing the molar ratio of Sr and Ca.
[0102]
It is preferable that the compounding quantity of Eu of the said phosphor is 0.003-0.5 mol with respect to corresponding Sr-Ca, Sr, and Ca. In particular, the Eu content of the phosphor is preferably 0.005 to 0.1 mol with respect to the corresponding Sr—Ca, Sr, and Ca. By changing the amount of Eu, the peak wavelength can be shifted to the long wavelength side. In addition, light emission efficiency such as light emission luminance and quantum efficiency can be improved. Tables 2 to 4 to be described later show test results obtained by changing the amount of Eu contained in silicon nitride of Sr—Ca—Si—N: Eu. In Table 2, for example, in Sr: Ca = 7: 3, when Eu is 0.005 mol with respect to Sr—Ca, the peak wavelength is 624 nm, the emission luminance is 100%, and the quantum efficiency is 100%. When Eu is 0.03 mol, the peak wavelength is 637 nm, the emission luminance is 139.5%, the quantum efficiency is 199.2%, and the emission efficiency is very good.
[0103]
The amount of Mn added to the phosphor is preferably 0.001 to 0.3 mol with respect to the corresponding Sr—Ca, Sr, and Ca. In particular, the amount of Mn added to the phosphor is preferably 0.0025 to 0.03 mol with respect to the corresponding Sr—Ca, Sr, and Ca. By adding Mn to the phosphor of silicon nitride during the raw material or the manufacturing process, it is possible to improve the light emission efficiency such as light emission luminance, energy efficiency, and quantum efficiency. Tables 5 to 9, which will be described later, show test results obtained by changing the amount of Mn added in the Ca—Si—N: Eu silicon nitride. In Tables 5 to 9, for example, silicon nitride added with 0.015 mol of Mn with respect to Ca, assuming that the emission luminance is 100% and the quantum efficiency is 100% with reference to a phosphor of silicon nitride without addition of Mn. The Ride phosphor has an emission luminance of 115.3% and a quantum efficiency of 117.4%. In this way, it is possible to improve light emission efficiency such as light emission luminance and quantum efficiency.
[0104]
The phosphor is a phosphor obtained by mixing a phosphor of Sr—Ca—Si—N: Eu-based silicon nitride and a phosphor of Sr—Si—N: Eu-based silicon nitride. For example, a phosphor of Sr—Ca—Si—N: Eu silicon nitride has an emission spectrum near 650 nm, whereas a phosphor of Sr—Si—N: Eu silicon nitride emits light near 620 nm. Has a spectrum. This is because a phosphor having a peak wavelength at a desired position in the wavelength range of 620 to 650 nm can be produced by mixing a desired amount thereof. Here, the present invention is not limited to the above combinations, but a phosphor obtained by mixing a phosphor of Sr—Ca—Si—N: Eu-based silicon nitride and a phosphor of Ca—Si—N: Eu-based silicon nitride, Sr—Ca— A phosphor in which a phosphor of Si-N: Eu-based silicon nitride, a phosphor of Sr-Si-N: Eu-based silicon nitride and a phosphor of Ca-Si-N: Eu-based silicon nitride are mixed is also manufactured. can do. Even with these combinations, a phosphor having a peak wavelength at a desired position in the wavelength range of 600 to 680 nm can be produced.
[0105]
The phosphor is preferably a phosphor having an average particle diameter of 3 μm or more. The phosphors of Sr—Ca—Si—N: Eu, Sr—Si—N: Eu, and Ca—Si—N: Eu silicon nitride to which Mn is not added have an average particle size of about 1 to 2 μm. However, the silicon nitride to which Mn is added has an average particle size of 3 μm or more. Due to the difference in particle size, there is an advantage that if the particle size is large, the light emission luminance is improved and the light extraction efficiency is increased.
[0106]
The phosphor preferably has a residual amount of Mn of 1000 ppm or less. This is because the above effect can be obtained by adding Mn to the phosphor.
In the above phosphor, at least a part of Mn can be substituted with B, and the addition of B can obtain the same effect as the addition of Mn.
[0107]
<Ca-Al-Si-ON-based oxynitride glass phosphor>
The Ca—Al—Si—O—N-based oxynitride glass phosphor is expressed in terms of mol% and represents CaCO.₃ In terms of CaO: 20-50 mol%, Al₂O₃ : 0 to 30 mol%, SiO: 25 to 60 mol%, AlN: 5 to 50 mol%, rare earth oxide or transition metal oxide: 0.1 to 20 mol%, and the total of the five components is 100 mol% A phosphor using oxynitride glass as a base material.
In addition, in the phosphor using oxynitride glass as a base material, the nitrogen content is preferably 15 wt% or less, and other rare earth element ions serving as a sensitizer in addition to rare earth oxide ions are used as rare earth oxides. It is preferable to contain as a co-activator in content in the range of 0.1-10 mol% in fluorescent glass.
[0108]
CaCO as a component of this phosphor₃ Is a raw material of CaO, which not only widens the vitrification range, but also can contain a large amount and a stable amount of rare earth ions or transition metal ions serving as emission centers in the fluorescent glass. The range of 30 mol% is more preferable. In addition, the content of the rare earth oxide or transition metal oxide that becomes the luminescence center ion by easily replacing the Ca 2+ ion at the Ca 2+ site with Sr 2+ or Ba 2+ ion is within the range of 0.1 to 20 mol% as described above. It becomes possible to control freely.
[0109]
AlN and Al₂O₃Is used to change the nitrogen content. 40 to 10 mol% AlN, Al₂O₃Is more preferably in the range of 0 to 20 mol%. SiO₂Is one of the glass forming components, and lowers the melting temperature of the glass melt by combining with CaO. The range of 30 to 40 mol% is more preferable.
[0110]
Rare earth oxide or transition metal oxide is a raw material for doping rare earth ions such as Eu2 +, Eu3 +, Ce3 +, Tb3 + or transition metal ions such as Cr3 +, Mn2 + into glass, and has a glass composition limit of 20 mol% or less. It is activated in the range, and has a strong luminescence intensity at an activation amount of 0.5 to 10 mol% in which concentration quenching of the emission center is not observed.
[0111]
Oxynitride glass is obtained by substituting part of oxygen with nitrogen. By introducing nitrogen, chemical bonds in the glass network structure are strengthened, and in addition to thermal properties such as glass transition temperature and softening temperature, mechanical properties are also observed. It is known that properties and chemical properties are remarkably improved (for example, Japanese Patent Publication No. 7-37333).
[0112]
In the present phosphor, the nitrogen content in the glass can move the peak position of the emission spectrum by controlling the nitrogen content in a glass composition range of 15 wt% or less. Further, the excitation spectrum of the oxynitride glass phosphor The peak wavelength inside can be adjusted in the range from ultraviolet to green. Since the shift of the emission peak wavelength gradually changes from yellow to red, the phosphor can be easily multicolored by changing the nitrogen content. A more preferable nitrogen content is 4 to 7 wt%.
[0113]
There are two typical methods for producing oxynitride glass, one is a method of melting using nitride as a nitrogen source, and the other method is a porous material produced by a sol-gel method or the like. There is a method of nitriding glass with ammonia gas.
[0114]
Since the former method decomposes nitrides at a high temperature at the time of melting, it is very difficult to increase the nitrogen content to 10 wt% or more. For example, by synthesizing these glasses under a nitrogen pressure of 10 atm, An oxynitride glass containing a relatively large amount of nitrogen is obtained. Such oxynitride glass is further excellent in mechanical strength and chemical stability.
[0115]
Fluorescent glass basically contains only one type of emission center. However, two kinds of rare earth elements may be included in the fluorescent glass. Two effects can be listed as the effect of simultaneously doping these two types into the fluorescent glass. One is a sensitizing action, and the other is to newly form a trap level of carriers to improve the expression and improvement of long afterglow and the thermoluminescence. Combinations in which the sensitizing action is observed generally include Tb3 + ions for Eu3 + ions and Ce3 + ions for Tb3 + ions.
[0116]
In order to use other rare earth element ions (Gd3 +, Tb3 +, Dy3 + or Sm3 + ions) in addition to Eu2 + (or Ce3 +) ions as a sensitizer, 0.1 to 10 mol of these rare earth oxides in the fluorescent glass. % Content can be included as a co-activator.
[0117]
The nitrogen content of this Ca—Al—Si—O—N-based oxynitride glass is reported to be about 5.5 wt%, and the composition of this oxynitride glass is used as the base glass of the phosphor of the present invention. Can be used.
[0118]
As a method for producing a Ca—Al—Si—O—N-based oxynitride glass phosphor, the above-described conventionally known method can be used. In that case, a rare earth oxide is used as a raw material and mixed with other raw materials. Fluorescent glass is synthesized by heating and melting in a nitrogen atmosphere using this as a starting material.
[0119]
For example, rare earth oxide, metal oxide CaO (← CaCO₃, Al₂ O₃ , SiO₂ ) Can be synthesized by melting at a high temperature, for example, about 1700 ° C. At this time, Al₂ O₃ By changing the proportion of AlN, the nitrogen content in the glass can be changed.
[0120]
<Example of using a combination of phosphors>
Each of the following examples is an example constituting a white light emitting device, and there are various combinations of LED chips and phosphors constituting the white light emitting device, and the present invention is limited to the following. Just to be sure that it is not a thing.
(1) In the light-emitting devices of Embodiments 1 to 3,
(I) Blue light emitting LED chip,
(Ii) Yellow-green phosphor (Y₃Al₅O₁₂: Ce) and red-emitting phosphor (Sr)_0.679Ca_0.291 Eu_0.015)₂Si₅N₈) Is used.
In the light emitting device according to the present invention, a white light emitting device can be configured by such a combination, and color unevenness due to the use of a plurality of phosphors can be improved.
[0121]
(2) In the light emitting device of the first to third embodiments,
(I) Blue light emitting LED chip,
(Ii) Green-emitting phosphor (Y_2.965Al_3.00Ga₂O₁₂: Ce_0.035), A yellow light emitting phosphor (Ca—Al—Si—O—N-based oxynitride glass phosphor) and a red light emitting phosphor (Sr)_0.679Ca_0.291Eu_0.015)₂Si₅N₈) Is used.
In the light emitting device according to the present invention, even with such a combination, a white light emitting device can be configured, and color unevenness caused by using a plurality of phosphors can be improved.
[0122]
【The invention's effect】
As described above in detail, the chromaticity adjustment method of the light emitting device according to the present invention is based on the light-transmitting resin by changing the amount of the light-transmitting resin after the light-transmitting resin is cured. Since the step of adjusting the chromaticity by changing the ratio of the phosphor particles is included, fine adjustment of the chromaticity can be facilitated.
Moreover, according to the manufacturing method of the light-emitting device which concerns on this invention, a light-emitting device with small chromaticity variation can be manufactured.
Furthermore, according to the light emitting device of the present invention, a light emitting device with small chromaticity variation and high light emission intensity can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a light emitting device according to an embodiment of the present invention.
FIG. 2 is a graph showing a shift amount of chromaticity x value with respect to a resin polishing amount in the present embodiment.
FIG. 3 is a graph showing a variation distribution before and after chromaticity adjustment of a sample in the chromaticity adjustment method of the present embodiment.
FIG. 4 is a graph showing a variation distribution before chromaticity adjustment, after height unification, and after chromaticity adjustment of a sample in the chromaticity adjustment method of the present embodiment.
FIG. 5 is a graph showing the chromaticity before and after adjusting the chromaticity of a sample used for measuring the luminous intensity and measuring the light output characteristic in the present embodiment.
FIG. 6 is a graph showing measurement results of light intensity (a) and light output (b) of a sample before and after polishing for chromaticity adjustment in the present embodiment.
FIG. 7 is a cross-sectional view of a light emitting device of a modified example (No. 1) according to the present invention.
FIG. 8 is a schematic diagram for explaining the principle of the present invention.
FIG. 9 is a cross-sectional view showing a configuration of a light emitting device according to a second embodiment of the present invention and how chromaticity is adjusted.
FIG. 10 is a cross-sectional view of a light emitting device according to a third embodiment of the present invention.
11A is a plan view of a mask used for forming a translucent resin and FIG. 11B is an enlarged view of a part thereof in the manufacturing process of Embodiment 3; FIG.
12 is a diagram showing a flow of a translucent resin forming process in the manufacturing process of Embodiment 3. FIG.
13 is a cross-sectional view after forming a light-transmitting resin in the manufacturing process of Embodiment 3. FIG.
FIG. 14 is a cross-sectional view of a light emitting device of a modified example (No. 2) according to the present invention.
FIG. 15 is a cross-sectional view showing a modified example of the manufacturing method according to the present invention after grooves are formed on the surface before polishing.
16 is a cross-sectional view of the case where polishing is performed after forming the groove of FIG. 15. FIG.
[Explanation of symbols]
1a: storage section,
2 ... Package,
2a, 2b ... electrode leads,
5 ... Light emitting diode chip (LED chip),
8 ... Translucent resin,
8a ... wavelength conversion layer,
8b ... non-wavelength conversion layer,
22 ... Metal base,
22a, 22b ... thin metal plate,
81 ... phosphor particles,
100 ... Package assembly,
101: Insulating substrate,
101a ... through hole,
112 ... mask,
113 ... Opening.

Claims (8)

A method for adjusting the chromaticity of a light emitting device comprising: a light emitting element; and a translucent resin that includes phosphor particles and is formed to cover the light emitting element and cured.
The translucent resin comprises a wavelength conversion layer containing the phosphor particles and a non-wavelength conversion layer substantially not containing the phosphor particles,
The step of adjusting the chromaticity by changing the ratio of the phosphor particles to the translucent resin by changing the amount of the translucent resin in the non-wavelength conversion layer after curing the translucent resin. only including,
The step of adjusting the chromaticity is a step of adjusting the chromaticity by changing the thickness of the non-wavelength conversion layer that does not substantially contain the phosphor particles of the translucent resin. A chromaticity adjustment method for a light emitting device characterized by the above. Step, the light-transmitting resin after curing, the chromaticity adjustment method according to claim 1, wherein the step of adjusting the chromaticity by polishing the non-wavelength-converting layer for adjusting the chromaticity. The chromaticity adjustment method according to claim 2, wherein a surface of the non-wavelength conversion layer is roughened by polishing. The step of adjusting the chromaticity is performed by applying a translucent resin substantially free of phosphor particles on the translucent resin after curing the translucent resin. The chromaticity adjustment method according to claim 1, wherein the chromaticity adjustment method is a step of adjusting the color. A method of adjusting the chromaticity of a plurality of light-emitting devices each comprising a light-emitting element and a translucent resin that includes phosphor particles and is formed to cover the light-emitting element and cured,
The translucent resin comprises a wavelength conversion layer containing the phosphor particles and a non-wavelength conversion layer substantially not containing the phosphor particles,
An initial chromaticity measuring step of measuring the chromaticity of the plurality of light emitting devices after curing the translucent resin;
Based on the measured chromaticity, a plurality of the plurality of light emitting devices are provided by grouping the difference between the measured chromaticity and the target chromaticity within a preset range. Grouping process to divide into groups,
A polishing step for polishing the non-wavelength conversion layer , which is the upper layer portion of the translucent resin, by an amount set based on a difference from the target chromaticity for each group. Chromaticity adjustment method. A method of manufacturing a light emitting device, comprising: mounting a light emitting element in a package housing portion; filling the housing portion with a translucent resin containing phosphor particles so as to cover the light emitting element;
The viscosity of the translucent resin is adjusted so that more phosphor particles settle around the light emitting element than the surface layer portion until the translucent resin is cured, thereby curing the translucent resin. And the translucent resin comprises a wavelength conversion layer including the phosphor particles and a non-wavelength conversion layer substantially not including the phosphor particles, and
After curing the translucent resin, the phosphor for the translucent resin is polished by polishing the surface of the non-wavelength conversion layer that does not substantially contain the phosphor particles of the translucent resin. A method for manufacturing a light-emitting device, wherein the chromaticity is adjusted by changing a ratio of particles . The method for manufacturing a light emitting device according to claim 6 , further comprising forming a groove on the surface of the cured translucent resin before polishing the surface of the non-wavelength conversion layer . A pair of thin metal plates constituting the positive and negative electrodes are joined to the periphery of one surface of the metal base to form a storage portion and a metal base joined so as to be electrically separated by an insulating resin. A method of manufacturing a light emitting device including a package including a side wall portion and an LED chip provided in the storage portion,
By joining an insulating substrate in which a plurality of through-holes corresponding to the storage portions are formed in groups and a metal base plate having portions separated by the insulating resin corresponding to the through-holes, A first step of producing a package assembly comprising an assembly of a plurality of packages;
A second step of mounting the LED chip in the housing part of each package formed by the through hole;
The phosphor is applied and cured by stencil printing on the upper surface of the insulating substrate and in the through holes using a mask having one opening corresponding to each group, and the phosphor A third step of forming a translucent resin comprising a wavelength conversion layer containing particles and a non-wavelength conversion layer substantially free of phosphor particles;
After curing the translucent resin, the chromaticity is adjusted by changing the ratio of the phosphor particles to the translucent resin by changing the amount of the translucent resin in the non-wavelength conversion layer. 4 processes,
The step of adjusting the chromaticity is a step of adjusting the chromaticity by changing the thickness of the non-wavelength conversion layer that does not substantially contain the phosphor particles of the translucent resin. A method for manufacturing a light emitting device.

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