JP2004259901A

JP2004259901A - Light emitting device and package for housing same

Info

Publication number: JP2004259901A
Application number: JP2003048349A
Authority: JP
Inventors: Daisuke Sakumoto; 大輔作本
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2003-02-25
Filing date: 2003-02-25
Publication date: 2004-09-16
Anticipated expiration: 2023-02-25
Also published as: JP4454237B2

Abstract

<P>PROBLEM TO BE SOLVED: To maintain higher air-tightness for a long period of time, effectively and stably extract light from a light emitting device to the outside of a package, reduce the manufacturing cost, shorten the assembling time, and ensure a higher manufacturing yield. <P>SOLUTION: The package for housing light emitting element is provided with a base material 1 formed of an insulator including a mounting part 1a formed of a conductive layer to mount the light emitting element 4 at the center area of the upper surface, and a frame body 2 which is joined to surround the mounting part 1a on the upper surface of the base material 1 and includes a through-hole 2a formed to become wide toward the upper side thereof at its internal circumferential surface. The frame body 2 is provided with a convex part 5 which is formed to the entire part of circumference at the internal circumferential part of the lower surface, and the convex part 5 is formed to be joined with the upper surface of the base material 1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、発光素子を収容するための発光素子収納用パッケージおよび発光装置に関する。
【０００２】
【従来の技術】
従来の発光ダイオード（ＬＥＤ）等の発光素子１０４を収容するための発光素子収納用パッケージ（以下、単にパッケージともいう）を図３に示す。図３において、パッケージは、上面の中央部に発光素子１４を搭載するための搭載部１１ａを有し、搭載部１１ａおよびその周辺からパッケージの内外を電気的に導通接続するリード端子やメタライズ配線等からなる配線導体（図示せず）が形成された絶縁体から成る基体１１と、基体１１の上面に接着固定され、中央部に発光素子１４を収納するための貫通孔１２ａが形成された、金属、樹脂またはセラミックス等からなる枠体１２とから主に構成される。
【０００３】
基体１１は酸化アルミニウム質焼結体（アルミナセラミックス）や窒化アルミニウム質焼結体，ムライト質焼結体，ガラスセラミックス等のセラミックス、またはエポキシ樹脂等の樹脂から成る。基体１１がセラミックスから成る場合、その上面にメタライズ配線がタングステン（Ｗ），モリブデン（Ｍｏ）−マンガン（Ｍｎ）等から成る金属ペーストを高温で焼成して形成される。また、基体１１が樹脂から成る場合、銅（Ｃｕ）や鉄（Ｆｅ）−ニッケル（Ｎｉ）合金等から成るリード端子が基体１１の内部にモールド成型され設置固定される。
【０００４】
また、枠体１２は、アルミニウム（Ａｌ）やＦｅ−Ｎｉ−コバルト（Ｃｏ）合金等の金属、アルミナ質焼結体等のセラミックスまたはエポキシ樹脂等の樹脂から成り、切削加工や金型成型または押し出し成型等の成型技術により形成される。さらに、枠体２の中央部には上方に向かうに伴って外側に広がる貫通孔１２ａが形成されており、貫通孔１０２ａの内周面の光の反射率を向上させる場合、この内周面にＡｌ等の金属が蒸着法やメッキ法により被着される。そして、枠体１２は、半田、銀ロウ等のロウ材または樹脂接合材により、搭載部１１ａを貫通孔１２ａの内周面で取り囲むように基体１１の上面に接合される。
【０００５】
そして、搭載部１１ａの周辺に配置した配線導体と発光素子１４の電極とをボンディングワイヤ（図示せず）を介して電気的に接続し、しかる後、枠体１２の内側にエポキシ樹脂やシリコーン樹脂等の透明樹脂を発光素子１４を覆うように充填し熱硬化させる。または、発光素子１４の周囲または表面に蛍光体や蛍光体を混入した透明樹脂を塗布した後に、枠体１２の内側に透明樹脂を充填し熱硬化させることで、発光素子１４からの光を蛍光体により波長変換し所望の波長スペクトルを有する光を取り出せる発光装置と成すことができる。そして、枠体１２の上面に透光性の蓋体１７を半田や樹脂接合材等で接合して発光装置となる。
【０００６】
【特許文献１】
特開２００１−３６１４８号公報
【０００７】
【発明が解決しようとする課題】
しかしながら、上記従来のパッケージにおいては、その製造工程で、熱膨張係数が６×１０^−６／℃程度であるアルミナセラミックス等から成る基体１１と、熱膨張係数が２３×１０^−６／℃程度であるＡｌから成る枠体１２とを接合材で加熱し冷却して接合する場合、基体１１と枠体１２との熱膨張係数差に起因する内部応力が基体１１と枠体１２との接合部に集中する。また、発光装置を作動させる際に生じる発光素子１４の熱が基体１１を介して枠体１２に伝達し、基体１１および枠体１２が熱膨張する。その結果、互いに熱膨張係数が大きく相違する基体１１と枠体１２との接合部に生じる内部応力は上昇して、基体１１の枠体１２との接合部にクラックが生じ、発光装置の気密性を保持できなくなるという問題点があった。
【０００８】
また、発光素子１４の熱により枠体１２が熱膨張することにより、貫通孔１２ａの内周面の形状が変形し、その内周面で発光素子１４が発する光（放射エネルギー）を反射させて発光装置の外部に所望の放射角度、強度分布で効率よく放射させることができなくなる。その結果、発光素子１４から貫通孔１２ａの内周面で反射されて蓋体１３へ入射する光の入射角度が安定せず、蓋体１３下面で反射による損失が増大し、外部に放射される光が減少するとともに、発光装置の光の強度分布にむらが生じるという問題点があった。
【０００９】
また、発光素子１４の光を低損失かつ所望の放射角度、強度分布で発光装置の外部へ取り出すために、発光素子１４の光軸と枠体１２の中心軸とが高精度に合致するように調芯し、基体１１上に枠体１２を設置する必要がある。しかしながら、そのような調芯は難しいため、製造の作業性が低下して、パッケージの製造工程における歩留まりが著しく低下するとともに製造コストが増加するという問題点があった。
【００１０】
従って、本発明は上記従来の問題点に鑑みて完成されたものであり、その目的は、基体と枠体との接合部にクラックが生じて発光装置の気密性が破れるのを防ぐとともに、発光素子の光を外部に安定した所望の放射角度、強度分布で効率よく放射させることができ、また発光素子の光軸と枠体の中心軸とを容易に高精度に合致させて、高性能の発光装置を効率的に製造できるものとすることにある。
【００１１】
【課題を解決するための手段】
本発明の発光素子収納用パッケージは、上面の中央部に発光素子を搭載するための導体層から成る搭載部を有する絶縁体から成る基体と、該基体の上面に前記搭載部を取り囲んで接合された、内周面が上側に向かって広がるように形成された貫通孔を有する枠体とを具備している発光素子収納用パッケージにおいて、前記枠体は下面の内周部に全周にわたって凸部が形成されており、該凸部が前記基体の上面に接合されていることを特徴とする。
【００１２】
本発明の発光素子収納用パッケージは、枠体は下面の内周部に全周にわたって凸部が形成されており、その凸部が基体の上面に接合されていることから、発光素子収納用パッケージの製造工程や発光装置を作動させる際の熱によって、基体と枠体との熱膨張係数差に起因して生じる、基体の枠体との接合部の内部応力を凸部で吸収することができる。その結果、基体と枠体との接合部に生じるクラックや剥がれを有効に抑制することができる。したがって、発光装置は長期にわたり気密性を保持して正常に作動するものとなる。
【００１３】
また、凸部により基体から枠体へ伝わる熱に対する熱抵抗を増加させるとともに、凸部以外の基体と枠体との間に空気層が存在することにより、発光装置の作動時に発生する熱が基体から枠体に伝達するのを有効に遮断できる。その結果、枠体から基体に加わる曲げモーメントを抑制でき、基体にクラックや割れが発生するのを有効に抑制できる。
【００１４】
さらに、枠体が熱膨張してその内周面に変形が生じるのを有効に抑制できることから、発光素子の光を枠体の内周面で効率よく反射させて発光装置の外部へ取り出すことができる。
【００１５】
本発明の発光素子収納用パッケージにおいて好ましくは、前記基体の上面に前記搭載部を取り囲む溝が形成されており、前記枠体の中心軸と前記発光素子の光軸とが合致するように前記凸部が前記溝に嵌着されていることを特徴とする。
【００１６】
本発明の発光素子収納用パッケージは、好ましくは基体の上面に搭載部を取り囲む溝が形成されており、枠体の中心軸と発光素子の光軸とが合致するように凸部が溝に嵌着されていることから、基体に枠体の凸部を嵌着するだけで枠体の中心軸と発光素子の光軸とが合致することとなる。その結果、発光素子収納用パッケージの製造工程において手作業で高精度の組み立てを行なう必要がなくなり、組み立て時間が短縮されて、製造コストの削減および歩留まり向上を達成できる。また、発光素子の光軸と枠体の中心軸とが調芯されていることにより、安定した光の放射角度、強度分布が得られる発光装置となる。
【００１７】
本発明の発光装置は、本発明の発光素子収納用パッケージと、前記搭載部に搭載された発光素子と、該発光素子を覆う透明部材とを具備していることを特徴とする。
【００１８】
本発明の発光装置は、上記の構成により、基体と枠体との接合部にクラックが生じて気密性が破れるのを防ぐとともに発光素子の光を外部に安定した所望の放射角度、強度分布で効率よく放射させることができ、また発光素子の光軸と枠体の中心軸とを容易に高精度に合致させて高性能のものを効率的に製造できるという作用効果を有する。
【００１９】
【発明の実施の形態】
本発明の発光素子収納用パッケージについて以下に詳細に説明する。図１，図２は本発明のパッケージの実施の形態の一例を示す断面図であり、１は基体、２は枠体、３は蓋体であり、主としてこれらで発光素子４を収容するためのパッケージが構成されている。
【００２０】
本発明のパッケージは、上面の中央部に発光素子４を搭載する搭載部１ａを有する絶縁体から成る基体１と、基体１の上面に搭載部１ａを取り囲んで接合された、内周面が上側に向かって広がるように形成された貫通孔２ａを有する枠体２とを具備し、枠体２は下面の内周部に全周にわたって凸部５が形成されており、凸部５が基体１の上面に接合されているものである。
【００２１】
本発明における基体１は、酸化アルミニウム質焼結体（アルミナセラミックス），窒化アルミニウム質焼結体，ムライト質焼結体，ガラスセラミックス等のセラミックス、またはエポキシ樹脂等の樹脂から成る絶縁体であり、発光素子４を支持する支持部材として機能し、その上面に発光素子４を搭載するための搭載部１ａを有している。
【００２２】
また、基体１の搭載部１ａ、その周囲、および基体１の枠体２内側から外側にかけて、パッケージの内外を電気的に導通接続するためのＷ，Ｍｏ，Ｍｎ等の金属粉末から成るメタライズ配線が形成されており、また、基体１の下面等の外部に露出した表面のメタライズ配線層にＣｕ，Ｆｅ−Ｎｉ合金等の金属から成るリード端子が接合される。そして、搭載部１ａにはＬＥＤ等の発光素子４が半田、樹脂接着剤、または銀等の金属粉末を樹脂に混入した銀（Ａｇ）−エポキシ樹脂等の接合材（Ａｇペースト）で接合される。そして、搭載部１ａの周囲のメタライズ配線に発光素子４の電極がボンディングワイヤ（図示せず）を介して電気的に接続される。
【００２３】
なお、メタライズ配線の露出する表面にＮｉや金（Ａｕ）等の耐食性に優れる金属を１〜２０μｍ程度の厚みで被着させておくのがよく、メタライズ配線が酸化腐食するのを有効に防止できるとともに、メタライズ配線と発光素子４との接続およびメタライズ配線とボンディングワイヤとの接続を強固にすることができる。したがって、メタライズ配線の露出表面には、厚さ１〜１０μｍ程度のＮｉメッキ層と厚さ０．１〜３μｍ程度のＡｕメッキ層とが電解メッキ法や無電解メッキ法により順次被着されていることがより好ましい。
【００２４】
また、基板１の上面には、基板１下面への光の透過を有効に抑制するとともに、基板１の上側に光を反射させるために、メタライズ配線に電気的に短絡しないように、Ａｌ，Ａｇ，Ａｕ，Ｐｔ，Ｃｕ等の金属を蒸着法やメッキ法により反射層として形成し、基板１の上方への光の反射率を向上させることが好ましい。
【００２５】
本発明の枠体２は、紫外光領域から可視光領域の光に対し反射率が高いＡｌ，Ａｇ，Ａｕ等の金属、または酸化アルミニウム質焼結体，窒化アルミニウム質焼結体，ムライト質焼結体，ガラスセラミックス等のセラミックス、またはエポキシ樹脂等の樹脂から成る。この枠体２の中心部には内周面が上側に向かうに伴って外側に広がっている貫通孔２ａが形成されている。また、枠体２がセラミックスから成る場合、その表面に反射率の高いＡｌ，Ａｇ，Ａｕ，Ｐｔ，Ｃｕ等の金属を蒸着法やメッキ法により反射層として形成することが好ましい。また、枠体２が樹脂から成る場合、その表面に反射率の高いＡｌ，Ａｇ，Ａｕ，Ｐｔ，Ｃｕ等の金属をメッキ法により反射層として形成することが好ましい。
【００２６】
また、枠体２は、下面の内周部に全周にわたって凸部５が形成されており、この凸部５が基体１の上面に搭載部１ａを取り囲むように、半田、樹脂接着剤、Ａｇペースト、２５０℃以上の融点を有するガラスフリット等の接合材で接合される。これにより、パッケージの製造工程における環境温度や発光素子を作動させた際の熱により生じる、基体１と枠体２との熱膨張係数差に起因する内部応力を凸部５で有効に吸収できる。
【００２７】
例えば、パッケージの製造工程で、熱膨張係数が約６×１０^−６℃であるアルミナセラミックスから成る基体１と、熱膨張係数が約２３×１０^−６℃であるＡｌから成る枠体２とを、接合材を加熱冷却して接合する場合、基体１と枠体２との熱膨張係数差によって生じる内部応力を凸部５で吸収する。また、発光装置を作動させた場合、発光素子４の熱により生じた基体１と枠体２との熱膨張係数差による内部応力を凸部５により緩和する。その結果、発光装置を作動させた際に基体１の凸部５との接合部に生じるクラックや剥がれ、枠体２の曲げモーメントによる基体１のクラックや割れの発生を有効に抑制できる。その結果、発光装置は長期にわたり気密性を保持できるととに、水分等の浸透による発光素子４の特性劣化や破損、蓋体３への水滴の付着による光損失や光散乱等を有効に抑制できる。
【００２８】
また、凸部５は、基体１から枠体２へ伝わる熱に対する熱抵抗を増大させるとともに、凸部５以外の基体１と枠体２との間に空気層が存在することにより、発光装置が作動した際に発光素子４から基体１を介して枠体２に伝達する熱を有効に遮断できる。即ち、基体１から枠体２への伝熱面積を凸部５により小さくすることで熱抵抗は大きくなり、基体１から枠体２へ伝達する熱が有効に抑制され、発光素子４が作動した際の熱による枠体２の熱膨張が小さくなる。その結果、基体１と枠体２との熱膨張差に起因し枠体２から基体１に加わる曲げモーメントが抑制され、基体１の凸部５との接合部に生じるクラックや剥がれ、基体１の割れを有効に抑制できる。また、枠体２の熱膨張による内周面の変形、その変形に伴う蓋体３のずれを有効に抑制できることから、発光素子４の光を枠体２の内周面で安定かつ効率よく反射して、パッケージの外部へ取り出すことができる。
【００２９】
また、枠体２の下面の内周部に全周にわたって凸部を形成することにより、発光素子４の側面より出射される光を効率よくパッケージの内側に反射させ、パッケージ外部に効率よく取り出すことができる。即ち、凸部により生じる基体１と枠体２との隙間をパッケージの外側に形成することで、発光素子４の側面より出射される光が基体１と枠体２との隙間に入射することなく貫通孔２ａの内周面に反射する。その結果、発光素子４の光を効率よくパッケージの上側に反射させることができる。
【００３０】
また、凸部５はその幅をｔとしたとき、０．５ｍｍ≦ｔ≦１ｍｍであることがよく、これにより、パッケージの製造工程や発光装置を作動させた際の基体１と枠体２との熱膨張差により生じる内部応力を凸部５で吸収し、基体１の凸部５との接合部のクラックや剥がれ、基体１の割れを有効に抑制できる。ｔが０．５ｍｍ未満の場合、枠体２を支える凸部５の強度が著しく低下し、発光装置の組み立て時や外部電気回路への実装時に発光装置に加わる外力によって凸部５が変形して枠体２と蓋体３とが傾き易くなる。その結果、枠体２の中心軸と発光素子４との光軸がずれて、発光素子４の光の放射角度、強度分布が変動するとともに、枠体２と基体１との接合強度が不十分となる。
【００３１】
また、ｔが１ｍｍを超える場合、凸部５の剛性が大きくなり、基体１と枠体２との熱膨張差により生じる内部応力の差を凸部５により十分に吸収することができない。その結果、基体１の凸部５との接合部に応力が集中してクラックが生じるとともに、枠体２の基体１に対する曲げモーメントが上昇し基体１にクラックが生じる。
【００３２】
また、凸部５はその高さをｓとしたとき、０．１ｍｍ≦ｓであることがよく、これにより、パッケージの製造工程や発光装置を作動させた際の基体１と枠体２との熱膨張差により生じる内部応力を凸部５で吸収し、基体１の凸部５との接合部のクラックや剥がれ、基体１の割れを有効に抑制できる。ｓが０．１ｍｍ未満の場合、基体１と枠体２との熱膨張差により生じる内部応力の差を凸部５により十分に吸収することができない。その結果、基体１の凸部５との接合部に生じる応力が上昇してクラックが生じるとともに、枠体２の基体１に対する曲げモーメントが上昇し基体１にクラックが生じる。
【００３３】
また、凸部５の断面積に依存する熱抵抗が小さくなり、発光素子４から基体１を介して枠体２に伝達する熱が増加し、それによる枠体２の熱膨張が大きくなる。例えば、熱膨張係数が約６×１０^−６℃であるアルミナセラミックスから成る基体１と、熱膨張係数が約２３×１０^−６℃であるＡｌから成る枠体２との熱膨張の差が大きくなり、基体１と枠体２とに生じる内部応力の差が大きくなる。その結果、基体１の凸部５との接合部に応力が集中してクラックや剥がれ、基板１に割れが生じる。また、枠体２の熱膨張により貫通孔２ａの内周面の形状が変化して、貫通孔２ａの内周面で反射されて蓋体３へ入射する光の入射角度が安定せず、蓋体３下面で反射される光の成分が増大して損失が増加する。その結果、パッケージ外部に取り出される光の強度が劣化するとともに、パッケージ外部に取り出される光の放射角度が安定せずに発光装置から放射される光に強度のむらが生じる。
【００３４】
また、枠体２は、下面の外周部にも凸部が形成されていることが好ましい。これにより、枠体２の下面の外周部が凸部により支持固定されて、枠体２が熱により変形するのをより効果的に防ぐことができる。この凸部は枠体２の下面の外周部に全周にわたって形成されていないのがよく、この場合、基体１の上面と枠体２の下面との間の隙間に外部から空気が出入りして枠体２を冷却することができる。
【００３５】
本発明において、図２に示すように、基体１の上面に搭載部１ａを取り囲む溝６が形成されており、枠体２の中心軸と発光素子４の光軸とが合致するように凸部５が溝６に嵌着されていることが好ましい。これにより、発光素子４の光軸と枠体２の中心軸とを手作業で位置合わせする必要がなくなり、容易かつ高精度に調芯される。従って、パッケージの組み立ての作業性が大幅に向上して、組み立て時間の短縮、製造コストの削減、歩留まりの向上が達成される。
【００３６】
また、蓋体７はガラス、サファイア、石英、またはエポキシ樹脂，シリコーン樹脂，アクリル樹脂等の樹脂（プラスチック）などの透光性材料から成り、枠体２内側に設置された、発光素子４、メタライズ配線、ボンディングワイヤ、発光素子４を覆う透明樹脂等を保護するとともに、パッケージ内部を気密に封止する。また、蓋体７をレンズ状にすることにより光学レンズの機能を付加することによって、発光素子４の光を集光または分散させて所望の放射角度、強度分布で発光素子の光をパッケージ外部に取り出すことができる。
【００３７】
かくして、本発明のパッケージは、基体１の搭載部１ａに発光素子４を搭載するとともに、発光素子４をボンディングワイヤおよびメタライズ配線を介してパッケージの外部の外部電気回路に電気的に導通させ、しかる後、枠体２の内側に透明樹脂を充填し熱硬化させて発光素子４を覆う被覆層を形成し、枠体２の上面に透光性の蓋体３を半田や樹脂接着剤等で接合し発光装置となる。また、発光素子４の周囲または表面に蛍光体もしくは蛍光体を混入した透明樹脂を塗布した後、発光素子４を覆う透明樹脂を充填し熱硬化させ、枠体２の上面に透光性の蓋体３を半田や樹脂接着剤等で接合することにより、発光素子４の光を蛍光体により波長変換し所望の波長スペクトルを有する光を取り出すことができる発光装置となる。
【００３８】
なお、本発明は上記の実施の形態に限定されず、本発明の要旨を逸脱しない範囲内で種々の変更を行うことは何等支障ない。
【００３９】
【発明の効果】
本発明の発光素子収納用パッケージは、枠体は下面の内周部に全周にわたって凸部が形成されており、その凸部が基体の上面に接合されていることから、発光素子収納用パッケージの製造工程や発光装置を作動させる際の熱によって、基体と枠体との熱膨張係数差に起因して生じる、基体と枠体との接合部の内部応力を凸部で吸収することができる。その結果、基体の枠体との接合部に生じるクラックや剥がれを有効に抑制することができる。したがって、発光装置は長期にわたり気密性を保持して正常に作動するものとなる。
【００４０】
また、凸部により基体から枠体へ伝わる熱に対する熱抵抗を増加させるとともに、凸部以外の基体と枠体との間に空気層が存在することにより、発光装置の作動時に発生する熱が基体から枠体に伝達するのを有効に遮断できる。その結果、枠体から基体に加わる曲げモーメントを抑制でき、基体にクラックや割れが発生するのを有効に抑制できる。
【００４１】
さらに、枠体が熱膨張してその内周面に変形が生じるのを有効に抑制できることから、発光素子の光を枠体の内周面で効率よく反射させて発光装置の外部へ取り出すことができる。
【００４２】
本発明の発光素子収納用パッケージは、好ましくは基体の上面に搭載部を取り囲む溝が形成されており、枠体の中心軸と発光素子の光軸とが合致するように凸部が溝に嵌着されていることから、基体に枠体の凸部を嵌着するだけで枠体の中心軸と発光素子の光軸とが合致することとなる。その結果、発光素子収納用パッケージの製造工程において手作業で高精度の組み立てを行なう必要がなくなり、組み立て時間が短縮されて、製造コストの削減および歩留まり向上を達成できる。また、発光素子の光軸と枠体の中心軸とが調芯されていることにより、安定した光の放射角度、強度分布が得られる発光装置となる。
【００４３】
本発明の発光装置は、本発明の発光素子収納用パッケージと、搭載部に搭載された発光素子と、発光素子を覆う透明部材とを具備していることにより、基体と枠体との接合部にクラックが生じて気密性が破れるのを防ぐとともに発光素子の光を外部に安定した所望の放射角度、強度分布で効率よく放射させることができ、また発光素子の光軸と枠体の中心軸とを容易に高精度に合致させて高性能のものを効率的に製造できるという作用効果を有する。
【図面の簡単な説明】
【図１】本発明の発光素子収納用パッケージについて実施の形態の一例を示す断面図である。
【図２】本発明の発光素子収納用パッケージについて実施の形態の他の例を示す断面図である。
【図３】従来の発光素子収納用パッケージの断面図である。
【符号の説明】
１：基体
１ａ：搭載部
２：枠体
２ａ：貫通孔
３：蓋体
４：発光素子
５：凸部
６：溝[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light emitting element housing package and a light emitting device for housing a light emitting element.
[0002]
[Prior art]
FIG. 3 shows a light emitting element housing package (hereinafter also simply referred to as a package) for housing a light emitting element 104 such as a conventional light emitting diode (LED). In FIG. 3, the package has a mounting portion 11a for mounting the light emitting element 14 at the center of the upper surface, and leads, metallized wiring, etc. that electrically connect the mounting portion 11a and its periphery to the inside and outside of the package. A base 11 made of an insulator on which a wiring conductor (not shown) made of metal is formed, and a through-hole 12a that is bonded and fixed to the upper surface of the base 11 and accommodates the light emitting element 14 at the center. And a frame 12 made of resin or ceramics.
[0003]
The substrate 11 is made of an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, ceramics such as glass ceramics, or a resin such as an epoxy resin. When the substrate 11 is made of ceramics, the metallized wiring is formed on its upper surface by firing a metal paste made of tungsten (W), molybdenum (Mo) -manganese (Mn) or the like at a high temperature. Further, when the base 11 is made of resin, lead terminals made of copper (Cu), iron (Fe) -nickel (Ni) alloy, or the like are molded and installed in the base 11.
[0004]
The frame 12 is made of a metal such as aluminum (Al) or Fe-Ni-cobalt (Co) alloy, a ceramic such as an alumina-based sintered body, or a resin such as an epoxy resin. It is formed by a molding technique such as molding. Furthermore, a through-hole 12a is formed in the central portion of the frame body 2 so as to spread outward as it goes upward. To improve the light reflectance of the inner peripheral surface of the through-hole 102a, A metal such as Al is deposited by vapor deposition or plating. The frame 12 is joined to the upper surface of the base 11 by a brazing material such as solder, silver brazing, or a resin bonding material so as to surround the mounting portion 11a with the inner peripheral surface of the through hole 12a.
[0005]
And the wiring conductor arrange | positioned around the mounting part 11a and the electrode of the light emitting element 14 are electrically connected via a bonding wire (not shown), and after that, an epoxy resin or a silicone resin is placed inside the frame 12. A transparent resin such as is filled so as to cover the light emitting element 14 and is cured by heat. Alternatively, a fluorescent material or a transparent resin mixed with a fluorescent material is applied around or on the surface of the light-emitting element 14, and then the transparent resin is filled inside the frame body 12 and thermally cured, so that the light from the light-emitting element 14 is fluorescent. A light emitting device capable of extracting light having a desired wavelength spectrum after wavelength conversion by a body can be obtained. And the translucent cover body 17 is joined to the upper surface of the frame 12 with solder, a resin bonding material, etc., and it becomes a light-emitting device.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-36148
[Problems to be solved by the invention]
However, the above conventional packaging, in its manufacturing process, the substrate 11 made of alumina ceramics or the like is the thermal expansion coefficient of 6 × 10 -6 ^/ ℃ about, a thermal expansion coefficient of 23 × 10 -6 ^/ ℃ about When the frame body 12 made of a certain aluminum is heated and cooled with a bonding material, the internal stress caused by the difference in thermal expansion coefficient between the base body 11 and the frame body 12 is applied to the joint portion between the base body 11 and the frame body 12. concentrate. Further, heat of the light emitting element 14 generated when the light emitting device is operated is transmitted to the frame body 12 through the base body 11, and the base body 11 and the frame body 12 are thermally expanded. As a result, the internal stress generated in the joint portion between the base body 11 and the frame body 12 having greatly different coefficients of thermal expansion increases, and a crack occurs in the joint portion between the base body 11 and the frame body 12. There is a problem that it becomes impossible to hold.
[0008]
Further, when the frame 12 is thermally expanded by the heat of the light emitting element 14, the shape of the inner peripheral surface of the through hole 12 a is deformed, and the light (radiant energy) emitted from the light emitting element 14 is reflected by the inner peripheral surface. The light cannot be efficiently emitted outside the light emitting device at a desired radiation angle and intensity distribution. As a result, the incident angle of the light reflected from the light emitting element 14 on the inner peripheral surface of the through hole 12a and entering the lid body 13 is not stable, and the loss due to reflection increases on the lower surface of the lid body 13 and is emitted to the outside. There is a problem in that the light intensity is reduced and the light intensity distribution of the light emitting device is uneven.
[0009]
Further, in order to extract the light from the light emitting element 14 to the outside of the light emitting device with a low loss and a desired radiation angle and intensity distribution, the optical axis of the light emitting element 14 and the central axis of the frame 12 are matched with high accuracy. It is necessary to align the frame body 12 on the substrate 11. However, since such alignment is difficult, there is a problem that the workability of the manufacturing is lowered, the yield in the manufacturing process of the package is remarkably lowered, and the manufacturing cost is increased.
[0010]
Accordingly, the present invention has been completed in view of the above-described conventional problems, and the object thereof is to prevent the light-emitting device from breaking the airtightness caused by cracks at the joint between the base and the frame, and to emit light. The light of the element can be efficiently emitted to the outside with a desired radiation angle and intensity distribution that is stable, and the optical axis of the light emitting element and the center axis of the frame body can be easily matched with high accuracy to achieve high performance. It is to be able to manufacture the light emitting device efficiently.
[0011]
[Means for Solving the Problems]
The light-emitting element storage package of the present invention is bonded to a base body made of an insulator having a mounting portion made of a conductor layer for mounting a light-emitting element at the center of the upper surface, and surrounding the mounting portion on the upper surface of the base body. In addition, in the light emitting element storage package comprising a frame body having a through-hole formed so that the inner peripheral surface expands upward, the frame body is a convex portion on the entire inner periphery of the lower surface. The protrusion is bonded to the upper surface of the substrate.
[0012]
In the light emitting element storage package according to the present invention, the frame body has a convex portion formed on the inner peripheral portion of the lower surface over the entire circumference, and the convex portion is joined to the upper surface of the base. The internal stress at the joint between the base body and the frame body, which is caused by the difference in thermal expansion coefficient between the base body and the frame body, can be absorbed by the convex portions due to the heat generated when the light emitting device is operated . As a result, it is possible to effectively suppress cracks and peeling occurring at the joint between the base and the frame. Therefore, the light emitting device operates normally while maintaining airtightness for a long time.
[0013]
In addition, the thermal resistance to heat transmitted from the base to the frame by the convex portion is increased, and an air layer exists between the base and the frame other than the convex portion, so that the heat generated during the operation of the light emitting device is the base. Can be effectively blocked from transmitting to the frame. As a result, the bending moment applied to the base body from the frame can be suppressed, and the occurrence of cracks and cracks in the base body can be effectively suppressed.
[0014]
Furthermore, since it is possible to effectively suppress the frame body from thermally expanding and deforming on its inner peripheral surface, it is possible to efficiently reflect the light of the light emitting element on the inner peripheral surface of the frame body and take it out of the light emitting device. it can.
[0015]
Preferably, in the light emitting element storage package according to the present invention, a groove is formed on the upper surface of the base so as to surround the mounting portion, and the convex portion is formed so that a center axis of the frame body and an optical axis of the light emitting element coincide with each other. The portion is fitted in the groove.
[0016]
In the light emitting element storage package of the present invention, a groove surrounding the mounting portion is preferably formed on the upper surface of the base, and the convex portion is fitted in the groove so that the center axis of the frame and the optical axis of the light emitting element are aligned. Therefore, the center axis of the frame body and the optical axis of the light emitting element coincide with each other simply by fitting the convex portion of the frame body to the base. As a result, it is not necessary to perform high-precision assembly manually in the manufacturing process of the light-emitting element storage package, the assembly time is shortened, and the manufacturing cost can be reduced and the yield can be improved. In addition, since the optical axis of the light emitting element and the center axis of the frame are aligned, a light emitting device capable of obtaining a stable light emission angle and intensity distribution is obtained.
[0017]
The light-emitting device of the present invention includes the light-emitting element storage package of the present invention, a light-emitting element mounted on the mounting portion, and a transparent member that covers the light-emitting element.
[0018]
With the above configuration, the light emitting device of the present invention prevents cracks from occurring in the joint portion between the base and the frame and breaks hermeticity, and at the same time, emits light from the light emitting element with a desired radiation angle and intensity distribution that is stable to the outside. It has the effect of being able to radiate efficiently, and that the optical axis of the light emitting element and the central axis of the frame body can be easily matched with high accuracy to efficiently manufacture a high performance device.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The light emitting element storage package of the present invention will be described in detail below. 1 and 2 are cross-sectional views showing an example of an embodiment of the package of the present invention. Reference numeral 1 denotes a base body, 2 denotes a frame body, and 3 denotes a lid body. The package is configured.
[0020]
The package of the present invention has a base body 1 made of an insulator having a mounting portion 1a on which the light emitting element 4 is mounted at the center of the upper surface, and an inner peripheral surface joined to the upper surface of the base body 1 so as to surround the mounting portion 1a. And a frame body 2 having a through hole 2a formed so as to expand toward the surface. The frame body 2 has a convex portion 5 formed on the inner peripheral portion of the lower surface over the entire circumference. It is joined to the upper surface of.
[0021]
The substrate 1 in the present invention is an insulator made of an aluminum oxide sintered body (alumina ceramics), an aluminum nitride sintered body, a mullite sintered body, a ceramic such as a glass ceramic, or a resin such as an epoxy resin. It functions as a support member that supports the light emitting element 4, and has a mounting portion 1 a for mounting the light emitting element 4 on the upper surface thereof.
[0022]
Also, metallized wiring made of metal powder such as W, Mo, Mn and the like for electrically conducting and connecting the inside and outside of the package from the mounting portion 1a of the base 1 and its periphery and from the inside to the outside of the frame 2 of the base 1 is provided. A lead terminal made of a metal such as Cu or Fe—Ni alloy is joined to the metallized wiring layer formed on the surface and exposed to the outside such as the lower surface of the substrate 1. A light emitting element 4 such as an LED is bonded to the mounting portion 1a with a bonding material (Ag paste) such as silver (Ag) -epoxy resin in which a metal powder such as solder, a resin adhesive, or silver is mixed. . And the electrode of the light emitting element 4 is electrically connected to the metallization wiring around the mounting part 1a through a bonding wire (not shown).
[0023]
In addition, it is preferable to deposit a metal having excellent corrosion resistance such as Ni or gold (Au) with a thickness of about 1 to 20 μm on the exposed surface of the metallized wiring, and it is possible to effectively prevent oxidative corrosion of the metallized wiring. In addition, the connection between the metallized wiring and the light emitting element 4 and the connection between the metallized wiring and the bonding wire can be strengthened. Therefore, the Ni plating layer having a thickness of about 1 to 10 μm and the Au plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the exposed surface of the metallized wiring by an electrolytic plating method or an electroless plating method. It is more preferable.
[0024]
Further, on the upper surface of the substrate 1, Al and Ag are effectively prevented from being electrically short-circuited to the metallized wiring in order to effectively suppress the transmission of light to the lower surface of the substrate 1 and reflect the light to the upper side of the substrate 1. , Au, Pt, Cu or the like is preferably formed as a reflective layer by vapor deposition or plating to improve the reflectance of light above the substrate 1.
[0025]
The frame body 2 of the present invention is made of a metal such as Al, Ag, Au or the like having high reflectivity with respect to light from the ultraviolet light region to the visible light region, or an aluminum oxide sintered body, an aluminum nitride sintered body, and a mullite sintered body. It is made of a bonded body, ceramics such as glass ceramics, or resin such as epoxy resin. A through-hole 2a is formed at the center of the frame body 2 so as to spread outward as the inner peripheral surface moves upward. Further, when the frame 2 is made of ceramics, it is preferable that a metal such as Al, Ag, Au, Pt, or Cu having a high reflectance is formed on the surface thereof as a reflective layer by vapor deposition or plating. Further, when the frame 2 is made of a resin, it is preferable that a metal such as Al, Ag, Au, Pt, or Cu having a high reflectance is formed on the surface as a reflective layer by a plating method.
[0026]
Further, the frame body 2 has a convex portion 5 formed on the inner peripheral portion of the lower surface over the entire circumference. The convex portion 5 surrounds the mounting portion 1 a on the upper surface of the base 1, so that solder, resin adhesive, Ag Bonding is performed using a paste and a bonding material such as glass frit having a melting point of 250 ° C. or higher. Thereby, the internal stress resulting from the difference in thermal expansion coefficient between the base body 1 and the frame body 2 caused by the environmental temperature in the manufacturing process of the package or the heat generated when the light emitting element is operated can be effectively absorbed by the convex portion 5.
[0027]
For example, the package manufacturing process, the substrate 1 having a thermal expansion coefficient of alumina ceramics is about 6 × 10 ^-6 ° C., and a frame body 2 having a thermal expansion coefficient of Al is about 23 × 10 ^-6 ° C. When the bonding material is heated and cooled for bonding, the internal stress generated by the difference in thermal expansion coefficient between the base body 1 and the frame body 2 is absorbed by the convex portion 5. Further, when the light emitting device is operated, the internal stress due to the difference in thermal expansion coefficient between the base body 1 and the frame body 2 caused by the heat of the light emitting element 4 is relieved by the convex portion 5. As a result, when the light-emitting device is operated, cracks and peeling occurring at the joint with the convex portion 5 of the base body 1, and generation of cracks and cracks in the base body 1 due to the bending moment of the frame body 2 can be effectively suppressed. As a result, the light-emitting device can maintain hermeticity for a long period of time, and effectively suppresses light loss, light scattering, and the like due to the deterioration and damage of the light-emitting element 4 due to the penetration of moisture and the like, and the attachment of water droplets to the lid 3. it can.
[0028]
In addition, the convex portion 5 increases the thermal resistance against heat transmitted from the base body 1 to the frame body 2, and an air layer exists between the base body 1 other than the convex portion 5 and the frame body 2, whereby the light emitting device The heat transmitted from the light emitting element 4 to the frame body 2 through the base 1 when operated can be effectively cut off. That is, by reducing the heat transfer area from the base body 1 to the frame body 2 by the convex portion 5, the thermal resistance is increased, the heat transferred from the base body 1 to the frame body 2 is effectively suppressed, and the light emitting element 4 is activated. The thermal expansion of the frame body 2 due to the heat at the time becomes small. As a result, the bending moment applied to the base body 1 from the frame body 2 due to the difference in thermal expansion between the base body 1 and the frame body 2 is suppressed, and cracks and peeling occurring at the joint between the base body 1 and the convex portion 5 occur. Cracks can be effectively suppressed. In addition, since the deformation of the inner peripheral surface due to the thermal expansion of the frame body 2 and the displacement of the lid body 3 accompanying the deformation can be effectively suppressed, the light of the light emitting element 4 is reflected stably and efficiently on the inner peripheral surface of the frame body 2. Then, it can be taken out of the package.
[0029]
Further, by forming a convex portion on the inner peripheral portion of the lower surface of the frame body 2 over the entire circumference, the light emitted from the side surface of the light emitting element 4 can be efficiently reflected inside the package and efficiently extracted outside the package. Can do. That is, by forming a gap between the base body 1 and the frame body 2 generated by the convex portion outside the package, light emitted from the side surface of the light emitting element 4 does not enter the gap between the base body 1 and the frame body 2. It reflects on the inner peripheral surface of the through hole 2a. As a result, the light of the light emitting element 4 can be efficiently reflected on the upper side of the package.
[0030]
Further, the convex portion 5 is preferably 0.5 mm ≦ t ≦ 1 mm, where t is the width thereof, whereby the base body 1 and the frame body 2 when the package manufacturing process and the light emitting device are operated, The internal stress generated by the difference in thermal expansion of the substrate 1 is absorbed by the convex portion 5, and cracks and peeling of the joint portion with the convex portion 5 of the base 1 can be effectively suppressed. When t is less than 0.5 mm, the strength of the convex portion 5 supporting the frame body 2 is remarkably lowered, and the convex portion 5 is deformed by an external force applied to the light emitting device when the light emitting device is assembled or mounted on an external electric circuit. The frame 2 and the lid 3 are easy to tilt. As a result, the optical axis between the center axis of the frame 2 and the light emitting element 4 is shifted, the light emission angle and intensity distribution of the light emitting element 4 vary, and the bonding strength between the frame 2 and the substrate 1 is insufficient. It becomes.
[0031]
Moreover, when t exceeds 1 mm, the rigidity of the convex part 5 becomes large, and the difference in internal stress caused by the thermal expansion difference between the base 1 and the frame body 2 cannot be sufficiently absorbed by the convex part 5. As a result, stress concentrates on the joint portion of the base body 1 with the convex portion 5 to cause cracks, and the bending moment of the frame body 2 with respect to the base body 1 increases to cause cracks in the base body 1.
[0032]
Further, when the height of the convex portion 5 is s, it is preferable that 0.1 mm ≦ s, so that the manufacturing process of the package and the base body 1 and the frame body 2 when the light emitting device is operated The internal stress generated by the difference in thermal expansion is absorbed by the convex portion 5, and cracks and peeling at the joint portion with the convex portion 5 of the base 1 can be effectively suppressed. When s is less than 0.1 mm, the difference in internal stress caused by the difference in thermal expansion between the base body 1 and the frame body 2 cannot be sufficiently absorbed by the convex portion 5. As a result, the stress generated at the joint portion of the base body 1 with the convex portion 5 is increased to cause a crack, and the bending moment of the frame body 2 with respect to the base body 1 is increased to cause a crack in the base body 1.
[0033]
Further, the thermal resistance depending on the cross-sectional area of the convex portion 5 is reduced, the heat transmitted from the light emitting element 4 to the frame body 2 through the base 1 is increased, and the thermal expansion of the frame body 2 is thereby increased. For example, the substrate 1 having a thermal expansion coefficient of alumina ceramics is about 6 × 10 ^-6 ° C., the difference in thermal expansion between the frame body 2 to the thermal expansion coefficient of Al is about 23 × 10 ^-6 ° C. is significantly Accordingly, the difference in internal stress generated between the base 1 and the frame 2 is increased. As a result, stress concentrates on the joint portion with the convex portion 5 of the base body 1 to crack or peel off, and the substrate 1 is cracked. Further, the shape of the inner peripheral surface of the through hole 2a changes due to the thermal expansion of the frame body 2, and the incident angle of the light that is reflected by the inner peripheral surface of the through hole 2a and enters the lid body 3 is not stable, and the lid The light component reflected by the lower surface of the body 3 increases, and the loss increases. As a result, the intensity of the light extracted outside the package is deteriorated, and the intensity of light emitted from the light emitting device is uneven because the emission angle of the light extracted outside the package is not stable.
[0034]
Moreover, it is preferable that the convex part is formed also in the outer peripheral part of the lower surface of the frame 2. As shown in FIG. Thereby, the outer peripheral part of the lower surface of the frame 2 is supported and fixed by the convex part, and the frame 2 can be more effectively prevented from being deformed by heat. It is preferable that this convex part is not formed in the outer peripheral part of the lower surface of the frame body 2 over the entire circumference. In this case, air enters and exits from the outside into the gap between the upper surface of the base body 1 and the lower surface of the frame body 2. The frame 2 can be cooled.
[0035]
In the present invention, as shown in FIG. 2, a groove 6 surrounding the mounting portion 1 a is formed on the upper surface of the base 1, and the convex portion is formed so that the center axis of the frame 2 and the optical axis of the light emitting element 4 coincide with each other. 5 is preferably fitted in the groove 6. As a result, it is not necessary to manually align the optical axis of the light emitting element 4 and the central axis of the frame body 2, and alignment is performed easily and with high accuracy. Therefore, the workability of assembling the package is greatly improved, and the assembling time is shortened, the manufacturing cost is reduced, and the yield is improved.
[0036]
The lid 7 is made of a light-transmitting material such as glass, sapphire, quartz, or a resin (plastic) such as an epoxy resin, a silicone resin, or an acrylic resin. The wiring, bonding wires, and transparent resin that covers the light emitting element 4 are protected, and the inside of the package is hermetically sealed. Further, by adding the function of an optical lens by making the lid 7 into a lens shape, the light of the light emitting element 4 is condensed or dispersed to make the light of the light emitting element outside the package with a desired radiation angle and intensity distribution. It can be taken out.
[0037]
Thus, the package of the present invention mounts the light emitting element 4 on the mounting portion 1a of the base 1, and electrically connects the light emitting element 4 to an external electric circuit outside the package via the bonding wire and the metallized wiring. Thereafter, a transparent resin is filled inside the frame 2 and thermally cured to form a coating layer that covers the light emitting element 4, and a translucent lid 3 is bonded to the upper surface of the frame 2 with solder, resin adhesive, or the like. It becomes a light emitting device. In addition, a phosphor or a transparent resin mixed with a phosphor is applied around or on the surface of the light-emitting element 4, and then, the transparent resin covering the light-emitting element 4 is filled and thermally cured. By joining the body 3 with solder, a resin adhesive, or the like, a light emitting device capable of taking out light having a desired wavelength spectrum by converting the wavelength of light of the light emitting element 4 with a phosphor.
[0038]
It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention.
[0039]
【The invention's effect】
In the light emitting element storage package according to the present invention, the frame body has a convex portion formed on the inner peripheral portion of the lower surface over the entire circumference, and the convex portion is joined to the upper surface of the base. The internal stress at the joint between the base body and the frame body caused by the difference in thermal expansion coefficient between the base body and the frame body can be absorbed by the convex portion due to the heat when the light emitting device is operated and the manufacturing process of . As a result, it is possible to effectively suppress cracks and peeling that occur at the joint between the base body and the frame. Therefore, the light emitting device operates normally while maintaining airtightness for a long time.
[0040]
In addition, the thermal resistance to heat transmitted from the base to the frame by the convex portion is increased, and an air layer exists between the base and the frame other than the convex portion, so that the heat generated during the operation of the light emitting device is the base. Can be effectively blocked from transmitting to the frame. As a result, the bending moment applied to the base body from the frame can be suppressed, and the occurrence of cracks and cracks in the base body can be effectively suppressed.
[0041]
Furthermore, since it is possible to effectively suppress the frame body from thermally expanding and deforming on its inner peripheral surface, it is possible to efficiently reflect the light of the light emitting element on the inner peripheral surface of the frame body and take it out of the light emitting device. it can.
[0042]
In the light emitting element storage package of the present invention, a groove surrounding the mounting portion is preferably formed on the upper surface of the base, and the convex portion is fitted in the groove so that the center axis of the frame and the optical axis of the light emitting element are aligned. Therefore, the center axis of the frame body and the optical axis of the light emitting element coincide with each other simply by fitting the convex portion of the frame body to the base. As a result, it is not necessary to perform high-precision assembly manually in the manufacturing process of the light-emitting element storage package, the assembly time is shortened, and the manufacturing cost can be reduced and the yield can be improved. In addition, since the optical axis of the light emitting element and the center axis of the frame are aligned, a light emitting device capable of obtaining a stable light emission angle and intensity distribution is obtained.
[0043]
The light-emitting device of the present invention includes the light-emitting element storage package of the present invention, the light-emitting element mounted on the mounting portion, and a transparent member that covers the light-emitting element. It is possible to prevent the occurrence of cracks in the airtightness and break the airtightness, and to efficiently radiate the light of the light emitting element to the outside with a desired radiation angle and intensity distribution that are stable, and the optical axis of the light emitting element and the central axis of the frame Can be easily manufactured with high accuracy, and a high performance product can be efficiently manufactured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a light-emitting element storage package according to the present invention.
FIG. 2 is a cross-sectional view showing another example of the embodiment of the light emitting element storage package of the present invention.
FIG. 3 is a cross-sectional view of a conventional light emitting element storage package.
[Explanation of symbols]
1: Base 1a: Mounting portion 2: Frame body 2a: Through hole 3: Cover body 4: Light emitting element 5: Convex portion 6: Groove

Claims

A base body made of an insulator having a mounting portion made of a conductor layer for mounting a light emitting element at the center of the upper surface, and an inner peripheral surface joined to the upper surface of the base body so as to surround the mounting portion. In the light emitting element storage package comprising a frame body having a through hole formed so as to expand, the frame body has a convex portion formed on the inner peripheral portion of the lower surface over the entire circumference. A package for housing a light emitting element, wherein the package is bonded to an upper surface of the base.

A groove surrounding the mounting portion is formed on the upper surface of the base body, and the convex portion is fitted into the groove so that a center axis of the frame body and an optical axis of the light emitting element coincide with each other. The light-emitting element storage package according to claim 1.

A light emitting device comprising the light emitting element storage package according to claim 1, a light emitting element mounted on the mounting portion, and a transparent member covering the light emitting element.