JP2004327632A

JP2004327632A - Package for housing light emitting element and light emitting device

Info

Publication number: JP2004327632A
Application number: JP2003118972A
Authority: JP
Inventors: Daisuke Sakumoto; 大輔作本
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2003-04-23
Filing date: 2003-04-23
Publication date: 2004-11-18
Anticipated expiration: 2023-04-23
Also published as: JP4174366B2

Abstract

<P>PROBLEM TO BE SOLVED: To realize maintaining of airtightness for a long period and efficiently and stably taking out the light of a light emitting element to the outside by effectively suppressing the occurrence of cracks in a base or a connecting material in the manufacturing process of a package for housing the light emitting element and at an operating time of a light emitting device. <P>SOLUTION: The package for housing the light emitting element includes a base 1 having a placing part 1a for placing a light emitting element 3 at the central part of the upper surface, and a frame 2 connected at the lower end of the inner peripheral surface to the side face of the case 1 on the entire periphery. The frame 2 has an overhanging portion 2a made to extand in the placing part 1a side over the entire periphery of the inner peripheral surface of the upper side from the base 1 for the overall surface of the lower surface so as not to be brought into contact with the base 1. The height at the end of the placing part 1a side of its lower surface the overhanging part 2a is lower than the height of the light emitting part of the light emitting element 3. <P>COPYRIGHT: (C)2005,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１３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４に示す。図４において、パッケージは、上面の中央部に発光素子１３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１３を収納するための貫通孔が形成された、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、その上面に配線導体がタングステン（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モールド成型されて基体１１の内部に設置固定される。
【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、酸化アルミニウム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１２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が形成されており、発光素子１３から発光された光を枠体１２の内周面で反射することができる。そして、この光の反射率を向上させるために、枠体１２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等の接合材１５により、搭載部１１ａを枠体１２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１３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１３を覆うように充填し熱硬化させる。または、発光素子１３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１３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の上面に透光性の透光性蓋体１４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／℃程度である酸化アルミニウム質焼結体等から成る基体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１５で加熱し冷却して接合する際、接合材１５には基体１１と枠体１２との熱膨張係数差に起因する応力が発生しクラックを生じるとともに、この応力が接合材１５の破壊強度以上になると接合材１５が破壊される。また、基体１１には枠体１２との熱膨張係数差に起因する熱収縮の差により、基体１１を上側または下側に反らす曲げモーメントが生じ、この曲げモーメントによる応力で基体１１にクラックが生じるとともに、この応力が破壊強度以上になると基体１１が破壊される。その結果、パッケージは気密性を保持できなくなり、発光装置は長期間にわたる信頼性を維持できなくなるという問題点があった。
【０００８】
また、発光装置を作動時に発生した発光素子１３の熱がパッケージ全体に伝達することによっても、基体１１と枠体１２との接合部に熱膨張係数差に起因する応力が生じてクラックが発生する。その結果、発光装置を作動させる際のパッケージの気密性が保持できなくなり、発光装置は長期間にわたり正常かつ安定した作動が困難になるという問題点があった。
【０００９】
さらに、発光素子１３の熱により枠体１２が熱膨張することにより、枠体１２の内周面の形状が変形するため、その内周面で発光素子１３が発する光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１３から枠体１２の内周面で反射されて透光性蓋体１４へ入射する光の入射角度が安定せず、透光性蓋体１４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。
【００１０】
また、発光素子１３の光波長が４００ｎｍ以下で、基体１１と枠体１２との接合材１５がエポキシ樹脂等の樹脂接着剤から成る場合、樹脂が紫外光を吸収することにより劣化し、接合材１５の接合強度や耐湿性が著しく低下する。その結果、発光装置は長期間にわたり気密性を保持できなくなり、パッケージ内部に水分が浸透することで発光素子１３の特性が劣化したり、透光性蓋体１４に水滴等が付着したりして光損失が増加するという問題点があった。
【００１１】
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、基体および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の保持が困難となることを抑制するとともに、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、さらに、接合材の紫外光よる接合強度や耐湿性の劣化を抑制することにある。
【００１２】
【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が搭載される搭載部を有する基体と、該基体の側面に内周面の下端部が全周にわたって接合された枠体とを具備しており、該枠体は、前記基体よりも上側の前記内周面に全周にわたって、下面の全面が前記基体と接しないように前記搭載部側に張り出した張出部が形成されており、該張出部は、その下面の前記搭載部側の端の高さが前記発光素子の発光部の高さよりも低いことを特徴とする。
【００１３】
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が搭載される搭載部を有する基体と、この基体の側面に内周面の下端部が全周にわたって接合された枠体とを具備しており、枠体は、基体よりも上側の内周面に全周にわたって、下面の全面が基体と接しないように搭載部側に張り出した張出部が形成されており、この張出部は、その下面の搭載部側の端の高さが発光素子の発光部の高さよりも低いことから、枠体および基体が熱膨張により大きく寸法変化する方向、即ち、基体の上下面に平行な方向に対して、基体と枠体との接合面を直交させることができるため、枠体が基体よりも大きく熱膨張したとしても、その応力を基体の上下面に平行な方向にだけ作用させることができ、従来のような基体の端を上側または下側に反らそうとする曲げモーメントを著しく減少させることができる。その結果、基体が反るのを有効に低減することができ、基体や接合部に生じるクラックや、破壊強度以上の応力が生じることによる基体の破壊を有効に抑制できる。これにより、気密性を長期間にわたり保持できるとともに、正常かつ安定して作動させることができる発光素子収納用パッケージはとすることができる。
【００１４】
また、基体と枠体との熱膨張差によって生じる応力が接合部では小さくなるため、基体と枠体との接合面積を小さくすることができ、発光素子から生じた熱が基体から枠体に伝達されるのを有効に抑制することができる。
【００１５】
さらに、基体と張出部との間に空気層や、発光素子収納用パッケージ内部に充填される透明樹脂層をもうけることができるため、基体から枠体への熱抵抗が大きくなり、発光素子より発生した熱が基体を介して枠体に伝達するのを有効に抑制することができる。その結果、枠体の熱膨張によって生じる基体への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。また、枠体の熱膨張による内周面の変形や、枠体の変形に伴う透光性蓋体のずれ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安定かつ効率よく反射させて発光素子収納用パッケージの外部へ取り出すことができる。
【００１６】
また、発光素子の光波長が４００ｎｍ以下の紫外光で、基体と枠体との接合材がアクリル樹脂やエポキシ樹脂等の樹脂接着剤から成る場合、発光素子の紫外光が張出部によって遮光されるため、直接的に接合材に照射されることはなく、接合材が紫外光によって劣化して接合強度や耐湿性が低下するのを有効に抑制できる。その結果、長期間にわたり発光装置の高い気密性を保持することができるとともに、発光装置内部への水分の浸透による発光素子の特性劣化や透光性蓋体に水滴が付着することによる光学的な特性の劣化を抑制できる。
【００１７】
本発明の発光装置は、上記構成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、前記枠体の上面に取着された透光性蓋体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、枠体の熱膨張、熱収縮に起因する基体や接合材のクラックや破壊、剥がれ等を抑制し、長期間にわたって気密性を保持することができ、また、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る。その結果、発光素子の光を効率よく安定して発光素子収納用パッケージの外部に取り出すことができる発光装置とすることができる。
【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は枠体であり、主としてこれらで発光素子３を収容するためのパッケージが構成されており、この基体１の搭載部１ａに発光素子３を搭載し、枠体２の上面に、透光性蓋体４を取着することにより発光装置となる。
【００２０】
本発明のパッケージは、上面の中央部に発光素子３が搭載される搭載部１ａを有する基体１と、この基体１の側面に内周面の下端部が全周にわたって接合された枠体２とを具備しており、この枠体２は、基体１よりも上側の内周面に全周にわたって、下面の全面が基体１と接しないように、搭載部１ａ側に張り出した張出部２ａが形成されており、この張出部２ａは、その下面の搭載部１ａ側の端の高さが発光素子３の発光部の高さよりも低くなっている。即ち、基体１の上面と張出部２ａの下面との間に発光素子３の発光部の高さよりも低い隙間６を有している。
【００２１】
なお、発光部は、一般に発光素子３の上面に設けられているが、発光素子３の側面に設けられていてもよい。
【００２２】
基体１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絶縁体であり、発光素子３を支持する支持部材として機能し、その上面に発光素子３を搭載するための搭載部１ａを有している。
【００２３】
また、基体１がセラミックスから成る場合、搭載部１ａやその周囲、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層を形成した配線導体（図示せず）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配線導体層にＣｕ，Ｆｅ−Ｎｉ合金等の金属から成るリード端子（図示せず）が接合される。また、基体１が樹脂から成る場合、ＣｕやＦｅ−Ｎｉ合金等から成るリード端子がモールド成型された基体１の内部に設置固定されている。
【００２４】
そして、搭載部１ａにはＬＥＤ等の発光素子３が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）や、セラミックス等の粉末を樹脂に混入した接着材、半田、樹脂接着剤等の接合材５で接合される。そして、搭載部１ａの周囲の配線導体に発光素子３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。
【００２５】
なお、配線導体の露出する表面に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、これにより配線導体が酸化腐食するのを有効に防止できるとともに、発光素子３との接続や、ボンディングワイヤとの接続、リード端子との接続を強固にすることができる。
【００２６】
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、配線導体またはリード端子に電気的に短絡しないように、Ａｌ，Ａｇ，金（Ａｕ），白金（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。
【００２７】
本発明の枠体２は、基体１の側面に内周面の下端部が全周にわたって半田や樹脂接着剤等の接合材５で接合されており、この枠体２は、基体１よりも上側の内周面に全周にわたって、下面の全面が基体１と接しないように、搭載部１ａ側に張り出した張出部２ａが形成されており、この張出部２ａは、その下面の搭載部１ａ側の端の高さが発光素子３の発光部の高さよりも低くなっている。
【００２８】
これにより、枠体２および基体１が熱膨張により大きく寸法変化する方向、即ち、基体１の上下面に平行な方向に対して、基体１と枠体２との接合面を直交させることができるため、枠体２が基体１よりも大きく熱膨張したとしても、その応力を基体１の上下面に平行な方向にだけ作用させることができ、従来のような基体１の端を上側または下側に反らそうとする曲げモーメントを著しく減少させることができる。その結果、基体１が反るのを有効に低減することができ、基体１や接合部に生じるクラックや、破壊強度以上の応力が生じることによる基体１の破壊を有効に抑制できる。これにより、気密性を長期間にわたり保持できるとともに、正常かつ安定して作動させることができる発光素子収納用パッケージとすることができる。
【００２９】
また、基体１と枠体２との熱膨張差によって生じる応力が接合部では小さくなるため、基体１と枠体２との接合面積を小さくすることができ、発光素子３から生じた熱が基体１から枠体２に伝達されるのを有効に抑制することができる。
【００３０】
さらに、基体１と張出部２ａとの間に空気層や、パッケージ内部に充填される透明樹脂層をもうけることができるため、基体１から枠体２への熱抵抗が大きくなり、発光素子３より発生した熱が基体１を介して枠体２に伝達するのを有効に抑制することができる。その結果、枠体２の熱膨張によって生じる基体１への曲げモーメントを抑制でき、基体１にクラックや割れが発生するの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や、枠体２の変形に伴う透光性蓋体４のずれを有効に抑制できることから、発光素子３の光を枠体２の内周面で安定かつ効率よく反射させてパッケージの外部へ取り出すことができる。
【００３１】
また、発光素子３の光波長が４００ｎｍ以下の紫外光で、基体１と枠体２との接合材５がアクリル樹脂やエポキシ樹脂等の樹脂接着剤から成る場合、発光素子３の紫外光が張出部２ａによって遮光されるため、直接的に接合材５に照射されることはなく、接合材５が紫外光によって劣化して接合強度や耐湿性が低下するのを有効に抑制できる。その結果、長期間にわたり発光装置の高い気密性を保持することができるとともに、発光装置内部への水分の浸透による発光素子３の特性劣化や透光性蓋体４に水滴が付着することによる光学的な特性の劣化を抑制できる。
【００３２】
また、張出部２ａは、その内周面がパッケージの上側に向かうに伴って開口径が大きくなるように傾斜面にするとともに、この内周面の算術平均粗さを０．０１μｍ以下にすることが好ましい。その結果、発光素子３から横方向に出射される光を内周面にて上方向に反射させ効率よくパッケージの外部へ光を放射することができる。
【００３３】
なお、張出部２ａは、その内周面の算術平均粗さが０．０１μｍより大きい場合、張出部２ａの内周面で光が散乱するために、長距離へ光を伝搬させることが困難となり、発光装置の光度が劣化し易くなる。従って、張出部２ａの内周面を上側へ外側に広がるように形成するとともに、この内周面の算術平均粗さを０．０１μｍ以下にすることにより、発光素子３の光を効率よくパッケージ外部に出射し光度を上昇させることができるとともに、発光装置の遠方へより光を照射することができる。
【００３４】
さらに枠体２は、張出部２ａの下面の搭載部１ａ側の端の高さが発光素子３の高さよりも低く、即ち、基体１上面と張出部２ａの下面との間に、発光素子３の発光部と基体１との距離より小さい隙間６を有するように基体１の側面の全周にわたって接合材５により接合されている。これにより、基体１と張出部２ａとの間には、空気層やパッケージ内部に充填される熱伝導率が０．３Ｗ／ｍ・Ｋ程度である透明性のエポキシ樹脂による樹脂層が形成される。その結果、隙間６による基体１から枠体２への熱抵抗が大きくなり、発光素子３より基体１を介して枠体２に伝達する熱が抑制される。従って、枠体２の熱膨張による内周面の変形や透光性部材４のずれを有効に抑制できることから、発光素子３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。
【００３５】
また、枠体２は、図２に示すように、張出部２ａの下面の搭載部１ａ側の端に全周にわたって下側に突出した凸部２ｃを形成することが好ましい。これにより、発光素子３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、張出部２ａの下面の搭載部１ａ側の端に凸部２ｃを形成することで、発光素子３から横方向に出射される光が基体１と枠体２との隙間６に入るのを有効に遮断し、この光を張出部２ａの内周面で効率よく反射させることができる。
【００３６】
さらに、凸部２ｃにより枠体２の強度を補強することができ、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。その結果、発光素子３の光のパッケージの上側へ反射効率を良好に維持させることができる。
【００３７】
なお、この凸部２ｃは、張出部２ａの付け根の部分の下面に凹部を設けることにより形成してもよい。これにより、張出部２ａと基体１との距離が大きくなり、発光素子３で発生した熱が基体１より張出部２ａに伝わるのをより有効に抑制することができる。
【００３８】
また、このような凸部２ｃは、張出部２ａの下面に全周にわたって形成する必要はなく、少なくとも枠体２の変形が生じ易い部位に形成すればよい。このような枠体２の変形が生じ易い部位とは、例えば、枠体２の内周面の開口が四角形状等の角を有する多角形状であればこの角の部位であり、また、発光素子３が多角形状であれば、発光素子３の角部に対応する部位である。
【００３９】
また、枠体２は、図３に示すように、張出部２ａと下端部２ｂとの間に切欠き部２ｄを設けることが好ましい。これにより、パッケージ製造工程におけるパッケージへの加熱や冷却により、または、発光装置を作動する際に発光素子３から発生した熱により、枠体２が熱膨張したり熱収縮したりして基体１と枠体２との接合部に応力が生じたとしても、切欠き部２ｄを有することによって変形し易くなった張出部２ａが適度に変形することにより応力を吸収することができる。その結果、基体１と枠体２との接合部に生じる応力が有効に抑制され、基体１や接合材５に生じるクラックや破壊を抑制でき、発光装置を長期間にわたり正常かつ安定して作動させることができる。
【００４０】
なお、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。例えば、枠体２がセラミックスや樹脂から成る場合、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。
【００４１】
また、接合材５は、半田、無機フィラーを含有する樹脂接着剤、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から成る。パッケージに長期間にわたる気密性が必要とされる場合、基体１と枠体２とを半田やガラスフリットから成る接合材５で接合することが好ましい。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３の特性劣化や破損、透光性蓋体４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。
【００４２】
接合材５は樹脂接着剤や無機フィラーを含有する樹脂接着剤を用いるのがよい。これにより、枠体２と基体１との熱膨張差によりこれらの接合部に応力が生じたとしても、接合材５が弾性率が比較的低い樹脂を含んでいるので、この応力を有効に吸収することができる。
【００４３】
このような樹脂を含有する接合材５を用いるとともに、発光素子３から発光される光が４００ｎｍ以下の紫外光を含む場合、樹脂が紫外光により劣化するのを、張出部２ａにより有効に抑制することができる。即ち、発光素子３の紫外光が張出部２ａによって遮光されるため、直接的に接合材５に照射されることはなく、接合材５が紫外光によって劣化して接合強度や耐湿性が低下するのを有効に抑制できる。その結果、長期間にわたり発光装置の高い気密性を保持することができるとともに、発光装置内部への水分の浸透による発光素子３の特性劣化や透光性蓋体４に水滴が付着することによる光学的な特性の劣化を抑制できる。
【００４４】
また、透光性蓋体４はガラス、サファイア、石英、またはエポキシ樹脂，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３、配線導体、ボンディングワイヤ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、透光性蓋体４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３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３の光をパッケージ外部に取り出すことができる。
【００４５】
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３を搭載するとともに、発光素子３の電極をボンディングワイヤ等で配線導体に接続し、枠体２の上面に透光性蓋体４を半田や樹脂接着剤等で接合することにより発光装置となる。なお、発光素子３を保護して光出射効率を良好に維持するために、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３を覆う被覆層を形成することが好ましい。
【００４６】
また、発光素子３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３を覆う透明樹脂を充填し熱硬化させ、枠体２の上面に透光性蓋体４を半田や樹脂接着剤等で接合することにより、発光素子３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。
【００４７】
なお、本発明は上記の実施の形態の例に限定されず、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。
【００４８】
【発明の効果】
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が搭載される搭載部を有する基体と、この基体の側面に内周面の下端部が全周にわたって接合された枠体とを具備しており、枠体は、基体よりも上側の内周面に全周にわたって、下面の全面が基体と接しないように搭載部側に張り出した張出部が形成されており、この張出部は、その下面の搭載部側の端の高さが発光素子の発光部の高さよりも低いことから、枠体および基体が熱膨張により大きく寸法変化する方向、即ち、基体の上下面に平行な方向に対して、基体と枠体との接合面を直交させることができるため、枠体が基体よりも大きく熱膨張したとしても、その応力を基体の上下面に平行な方向にだけ作用させることができ、従来のような基体の端を上側または下側に反らそうとする曲げモーメントを著しく減少させることができる。その結果、基体が反るのを有効に低減することができ、基体や接合部に生じるクラックや、破壊強度以上の応力が生じることによる基体の破壊を有効に抑制できる。これにより、気密性を長期間にわたり保持できるとともに、正常かつ安定して作動させることができる発光素子収納用パッケージはとすることができる。
【００４９】
また、基体と枠体との熱膨張差によって生じる応力が接合部では小さくなるため、基体と枠体との接合面積を小さくすることができ、発光素子から生じた熱が基体から枠体に伝達されるのを有効に抑制することができる。
【００５０】
さらに、基体と張出部との間に空気層や、発光素子収納用パッケージ内部に充填される透明樹脂層をもうけることができるため、基体から枠体への熱抵抗が大きくなり、発光素子より発生した熱が基体を介して枠体に伝達するのを有効に抑制することができる。その結果、枠体の熱膨張によって生じる基体への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。また、枠体の熱膨張による内周面の変形や、枠体の変形に伴う透光性蓋体のずれ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安定かつ効率よく反射させて発光素子収納用パッケージの外部へ取り出すことができる。
【００５１】
また、発光素子の光波長が４００ｎｍ以下の紫外光で、基体と枠体との接合材がアクリル樹脂やエポキシ樹脂等の樹脂接着剤から成る場合、発光素子の紫外光が張出部によって遮光されるため、直接的に接合材に照射されることはなく、接合材が紫外光によって劣化して接合強度や耐湿性が低下するのを有効に抑制できる。その結果、長期間にわたり発光装置の高い気密性を保持することができるとともに、発光装置内部への水分の浸透による発光素子の特性劣化や透光性蓋体に水滴が付着することによる光学的な特性の劣化を抑制できる。
【００５２】
本発明の発光装置は、上記構成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、枠体の上面に取着された透光性蓋体とを具備していることにより、枠体の熱膨張、熱収縮に起因する基体や接合材のクラックや破壊、剥がれ等を抑制し、長期間にわたって気密性を保持することができ、また、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る。その結果、発光素子の光を効率よく安定して発光素子収納用パッケージの外部に取り出すことができる発光装置とすることができる。
【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】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４】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：張出部
３：発光素子
４：蓋体
５：接合材
６：隙間[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light emitting element housing package for housing a light emitting element and a light emitting device.
[0002]
[Prior art]
FIG. 4 shows a conventional light emitting element housing package (hereinafter, simply referred to as a package) for housing a light emitting element 13 such as a light emitting diode (LED). In FIG. 4, the package has a mounting portion 11a for mounting the light emitting element 13 at the center of the upper surface, and lead terminals and metallized wiring for electrically connecting the inside and outside of the package from the mounting portion 11a and its periphery. A base 11 made of an insulator on which a wiring conductor (not shown) made of a metal, a metal, which is adhered and fixed to the upper surface of the base 11 and has a through hole formed in the center portion for housing the light emitting element 13; It is mainly composed of a frame 12 made of resin or ceramics.
[0003]
The base 11 is made of a ceramic such as an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, a glass ceramic, or a resin such as an epoxy resin. When the base 11 is made of ceramics, the wiring conductor is formed on the upper surface by firing a metal paste made of tungsten (W), molybdenum (Mo) -manganese (Mn) or the like at a high temperature. When the base 11 is made of resin, a lead terminal made of copper (Cu), iron (Fe) -nickel (Ni) alloy, or the like is molded and fixed inside the base 11.
[0004]
The frame 12 is made of a metal such as an aluminum (Al) or Fe-Ni-cobalt (Co) alloy, a ceramic such as an aluminum oxide sintered body, or a resin such as an epoxy resin. It is formed by a molding technique such as extrusion molding. Further, a through hole is formed at the center of the frame 12 and extends outward as it goes upward, so that light emitted from the light emitting element 13 can be reflected by the inner peripheral surface of the frame 12. Then, in order to improve the reflectance of the light, a metal such as Al is applied to the inner peripheral surface of the frame body 12 by a vapor deposition method or a plating method. Then, the frame body 12 is joined to the upper surface of the base body 11 by a brazing material such as solder, silver brazing or the like, or a bonding material 15 such as a resin bonding material so as to surround the mounting portion 11 a with the inner peripheral surface of the frame body 12.
[0005]
Then, the wiring conductor disposed around the mounting portion 11a and the electrode of the light emitting element 13 are electrically connected via a bonding wire (not shown), and thereafter, an epoxy resin or a silicone resin is provided inside the frame body 12. A transparent resin such as is filled so as to cover the light emitting element 13 and is thermally cured. Alternatively, a phosphor or a transparent resin containing a phosphor is applied around or on the surface of the light emitting element 13, and then the transparent resin is filled into the inside of the frame body 12 and thermally cured, so that the light from the light emitting element 13 emits the fluorescent light. The light emitting device can convert the wavelength by the body and extract light having a desired wavelength spectrum. Then, a light-transmitting light-transmitting lid 14 is joined to the upper surface of the frame body 12 with a solder, a resin joining material, or the like to form a light emitting device.
[0006]
[Patent Document 1]
JP 2001-36148 A
[0007]
[Problems to be solved by the invention]
However, in the above conventional package, the coefficient of thermal expansion is 6 × 10 ^-6 / Substrate having a thermal expansion coefficient of 23 × 10 ^-6 When the frame 12 made of Al having a temperature of about / ° C. is joined by heating and cooling with the joining material 15, a stress is generated in the joining material 15 due to a difference in thermal expansion coefficient between the base 11 and the frame 12. Cracks are generated, and when this stress is equal to or greater than the breaking strength of the bonding material 15, the bonding material 15 is broken. Further, a bending moment that causes the base 11 to bend upward or downward due to a difference in thermal contraction caused by a difference in thermal expansion coefficient between the base 11 and the frame 12 is generated, and a crack is generated in the base 11 by the stress due to the bending moment. At the same time, when the stress is equal to or higher than the breaking strength, the base 11 is broken. As a result, the package cannot maintain airtightness, and the light emitting device cannot maintain reliability for a long time.
[0008]
Also, when the heat of the light emitting element 13 generated during operation of the light emitting device is transmitted to the entire package, a stress due to a difference in thermal expansion coefficient is generated in a joint portion between the base 11 and the frame body 12 and cracks are generated. . As a result, there is a problem that the airtightness of the package cannot be maintained when the light emitting device is operated, and it is difficult for the light emitting device to operate normally and stably for a long period of time.
[0009]
Further, since the shape of the inner peripheral surface of the frame 12 is deformed by the thermal expansion of the frame 12 due to the heat of the light emitting element 13, the light emitted from the light emitting element 13 is reflected on the inner peripheral surface to allow the light emitting device to operate. It is not possible to efficiently radiate the desired radiation angle and intensity distribution to the outside. As a result, the angle of incidence of light that is reflected from the light emitting element 13 on the inner peripheral surface of the frame 12 and enters the translucent lid 14 is not stable, and the loss due to reflection on the lower surface of the translucent lid 14 increases. In addition, there is a problem that the light radiated to the outside decreases and the light intensity distribution of the light emitting device becomes uneven.
[0010]
When the light wavelength of the light emitting element 13 is 400 nm or less and the bonding material 15 between the base 11 and the frame 12 is made of a resin adhesive such as an epoxy resin, the resin is deteriorated by absorbing ultraviolet light, and the bonding material is deteriorated. The bonding strength and moisture resistance of No. 15 are significantly reduced. As a result, the light-emitting device cannot maintain airtightness for a long period of time, and the moisture permeates into the package to deteriorate the characteristics of the light-emitting element 13 or cause water droplets or the like to adhere to the translucent lid 14. There is a problem that light loss increases.
[0011]
Therefore, the present invention has been completed in view of the above-mentioned conventional problems, and an object of the present invention is to cause cracks in a base and a joint between the base and the frame, making it difficult to maintain the airtightness of the light emitting device. It is possible to efficiently emit the light of the light emitting element to the outside at a desired emission angle and intensity distribution stably, and to suppress the deterioration of the bonding strength and moisture resistance of the bonding material due to ultraviolet light. It is in.
[0012]
[Means for Solving the Problems]
The light-emitting element housing package of the present invention includes a base having a mounting portion on which a light-emitting element is mounted at a central portion of an upper surface, and a frame having a lower end portion of an inner peripheral surface joined to a side surface of the base over the entire circumference. The frame body is formed with an overhanging portion that overhangs the mounting portion side so that the entire lower surface does not contact the base body over the entire inner peripheral surface above the base body. The projecting portion is characterized in that a height of an end of the lower surface on the mounting portion side is lower than a height of a light emitting portion of the light emitting element.
[0013]
The light-emitting element housing package of the present invention includes a base having a mounting portion on which a light-emitting element is mounted at a center portion of an upper surface, and a frame body having a lower end portion of an inner peripheral surface joined to a side surface of the base over the entire circumference. The frame body is provided with an overhang on the inner peripheral surface above the base over the entire circumference so as to protrude toward the mounting portion so that the entire lower surface does not contact the base. Since the height of the end of the lower surface on the mounting portion side is lower than the height of the light emitting portion of the light emitting element, the direction in which the frame and the base greatly change in size due to thermal expansion, that is, parallel to the upper and lower surfaces of the base. Since the joining surface between the base and the frame can be orthogonal to the desired direction, even if the frame thermally expands more than the base, the stress acts only in the direction parallel to the upper and lower surfaces of the base. The end of the substrate can be turned upside down or down It can significantly reduce the bending moment and so. As a result, it is possible to effectively reduce the warpage of the base, and it is possible to effectively suppress the cracks generated in the base and the joints and the breakage of the base due to the occurrence of stress greater than the breaking strength. Accordingly, a light emitting element housing package that can maintain airtightness for a long period of time and can operate normally and stably can be obtained.
[0014]
Further, since the stress generated by the difference in thermal expansion between the base and the frame is reduced at the joint, the bonding area between the base and the frame can be reduced, and the heat generated from the light emitting element is transferred from the base to the frame. Can be effectively suppressed.
[0015]
Furthermore, since an air layer or a transparent resin layer filled in the light emitting element housing package can be provided between the base and the overhanging portion, the thermal resistance from the base to the frame increases, and the Transfer of the generated heat to the frame via the base can be effectively suppressed. As a result, the bending moment to the base caused by the thermal expansion of the frame can be suppressed, and the occurrence of cracks and cracks in the base can be effectively suppressed. In addition, since the deformation of the inner peripheral surface due to the thermal expansion of the frame and the displacement of the light-transmitting lid due to the deformation of the frame can be effectively suppressed, the light of the light emitting element can be stably and efficiently emitted on the inner peripheral surface of the frame. The light is well reflected and can be taken out of the light emitting element storage package.
[0016]
In addition, when the light wavelength of the light emitting element is ultraviolet light of 400 nm or less and the bonding material between the base and the frame is made of a resin adhesive such as an acrylic resin or an epoxy resin, the ultraviolet light of the light emitting element is shielded by the overhang portion. Therefore, the bonding material is not directly irradiated to the bonding material, and it is possible to effectively suppress deterioration of the bonding material due to ultraviolet light and reduction in bonding strength and moisture resistance. As a result, the light-tightness of the light-emitting device can be maintained for a long period of time, and the characteristics of the light-emitting element deteriorate due to the penetration of moisture into the light-emitting device, and the optical characteristics due to water droplets adhering to the light-transmitting lid. Deterioration of characteristics can be suppressed.
[0017]
The light-emitting device of the present invention includes the light-emitting element storage package having the above configuration, a light-emitting element mounted on the mounting portion, and a translucent lid attached to an upper surface of the frame. It is characterized by.
[0018]
The light-emitting device of the present invention, by the above-described configuration, suppresses cracking, destruction, peeling, and the like of the base and the bonding material caused by thermal expansion and thermal contraction of the frame, and can maintain airtightness for a long period of time. Further, the light of the light emitting element can be efficiently emitted to the outside at a desired stable emission angle and intensity distribution. As a result, a light-emitting device can be obtained in which light from the light-emitting element can be efficiently and stably extracted to the outside of the light-emitting element housing package.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
The light emitting element housing package of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an embodiment of a package according to the present invention, wherein 1 is a base, 2 is a frame, and these mainly constitute a package for accommodating the light emitting element 3. A light emitting device is obtained by mounting the light emitting element 3 on the mounting portion 1a of the base 1 and attaching the translucent lid 4 to the upper surface of the frame 2.
[0020]
The package according to the present invention includes a base 1 having a mounting portion 1a on which a light emitting element 3 is mounted at a center portion of an upper surface, and a frame 2 having a lower end portion of an inner peripheral surface joined to a side surface of the base 1 over the entire circumference. The frame 2 has an overhang 2a projecting toward the mounting portion 1a so that the entire lower surface does not contact the base 1 over the entire inner peripheral surface above the base 1. The overhang 2a is formed such that the height of the end of the lower surface thereof on the side of the mounting portion 1a is lower than the height of the light emitting portion of the light emitting element 3. That is, a gap 6 that is lower than the height of the light emitting portion of the light emitting element 3 is provided between the upper surface of the base 1 and the lower surface of the overhang portion 2a.
[0021]
In addition, the light emitting unit is generally provided on the upper surface of the light emitting element 3, but may be provided on the side surface of the light emitting element 3.
[0022]
The base 1 is an insulator made of a ceramic such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a glass ceramic, or a resin such as an epoxy resin, and supports the light emitting element 3. It functions as a member, and has a mounting portion 1a for mounting the light emitting element 3 on its upper surface.
[0023]
When the base 1 is made of ceramics, metal powders such as W, Mo, and Mn for electrically connecting the inside and outside of the package to and from the mounting portion 1a and the periphery thereof and from the inside to the outside of the frame 2 of the base 1 are provided. A wiring conductor (not shown) having a metallized layer made of Cu is formed, and a lead made of a metal such as Cu, Fe-Ni alloy or the like is formed on the wiring conductor layer on the surface exposed to the outside such as the lower surface of the base 1. Terminals (not shown) are joined. When the base 1 is made of a resin, a lead terminal made of Cu, an Fe—Ni alloy, or the like is installed and fixed inside the molded base 1.
[0024]
In the mounting portion 1a, the light emitting element 3 such as an LED or the like is mixed with a bonding material (Ag paste) such as a silver (Ag) -epoxy resin obtained by mixing a metal powder such as silver into a resin or a powder such as a ceramic. It is joined by a joining material 5 such as an adhesive, a solder, and a resin adhesive. Then, the electrodes of the light emitting element 3 are electrically connected to the wiring conductors around the mounting portion 1a via bonding wires (not shown).
[0025]
Preferably, a metal having excellent corrosion resistance, such as Ni or gold (Au), having a thickness of about 1 to 20 μm is applied to the exposed surface of the wiring conductor to effectively prevent the wiring conductor from being oxidized and corroded. In addition to this, the connection with the light emitting element 3, the connection with the bonding wire, and the connection with the lead terminal can be strengthened.
[0026]
In addition, on the upper surface of the substrate 1, the transmission of light to the lower surface of the substrate 1 is effectively suppressed, and the light is reflected to the upper side of the substrate 1 so as not to be electrically short-circuited to a wiring conductor or a lead terminal. It is preferable that a metal such as Al, Ag, gold (Au), platinum (Pt), or Cu is formed as a reflective layer by a vapor deposition method or a plating method to improve the reflectance of light above the substrate 1.
[0027]
In the frame 2 of the present invention, the lower end portion of the inner peripheral surface is joined to the side surface of the base 1 with a joining material 5 such as solder or a resin adhesive over the entire circumference. An overhang 2a is formed over the entire inner peripheral surface of the base member 1 so as to protrude toward the mounting portion 1a so that the entire lower surface does not come into contact with the base 1. The overhang 2a is formed on the mounting portion of the lower surface. The height of the end on the 1a side is lower than the height of the light emitting portion of the light emitting element 3.
[0028]
Accordingly, the joining surface between the base 1 and the frame 2 can be orthogonal to the direction in which the dimensions of the frame 2 and the base 1 greatly change due to thermal expansion, that is, the direction parallel to the upper and lower surfaces of the base 1. Therefore, even if the frame body 2 thermally expands more than the base body 1, the stress can be applied only in the direction parallel to the upper and lower surfaces of the base body 1, and the end of the base body 1 can be moved upward or downward as in the related art. The bending moment which is going to warp can be significantly reduced. As a result, the warpage of the base 1 can be effectively reduced, and cracks generated in the base 1 and the joints, and destruction of the base 1 due to generation of a stress higher than the breaking strength can be effectively suppressed. Thus, a light emitting element housing package that can maintain airtightness for a long period of time and can operate normally and stably can be provided.
[0029]
Further, since the stress generated by the difference in thermal expansion between the base 1 and the frame 2 is reduced at the joint, the bonding area between the base 1 and the frame 2 can be reduced, and the heat generated from the light emitting element 3 It is possible to effectively suppress the transmission from 1 to the frame 2.
[0030]
Further, since an air layer or a transparent resin layer filled in the package can be provided between the base 1 and the overhang portion 2a, the thermal resistance from the base 1 to the frame 2 increases, and the light emitting element 3 The transmission of the generated heat to the frame 2 via the base 1 can be effectively suppressed. As a result, the bending moment to the base 1 caused by the thermal expansion of the frame 2 can be suppressed, and the occurrence of cracks and cracks in the base 1 can be effectively suppressed. In addition, since the deformation of the inner peripheral surface due to the thermal expansion of the frame 2 and the displacement of the translucent cover 4 due to the deformation of the frame 2 can be effectively suppressed, the light of the light emitting element 3 is transferred to the inner periphery of the frame 2. The light can be stably and efficiently reflected on the surface and taken out of the package.
[0031]
When the light wavelength of the light emitting element 3 is 400 nm or less and the bonding material 5 between the base 1 and the frame 2 is made of a resin adhesive such as an acrylic resin or an epoxy resin, the ultraviolet light of the light emitting element 3 is stretched. Since the light is shielded by the protrusion 2a, the bonding material 5 is not directly irradiated to the bonding material 5, and the bonding material 5 can be effectively prevented from being deteriorated by ultraviolet light to lower the bonding strength and the moisture resistance. As a result, the light-tightness of the light-emitting device can be maintained for a long period of time, and the characteristics of the light-emitting element 3 are degraded due to the penetration of moisture into the light-emitting device, and the optical properties due to water droplets adhering to the light-transmitting lid 4. Characteristic degradation can be suppressed.
[0032]
In addition, the overhang portion 2a has an inclined surface such that the opening diameter increases as the inner peripheral surface goes toward the upper side of the package, and the arithmetic average roughness of the inner peripheral surface is 0.01 μm or less. Is preferred. As a result, light emitted in the lateral direction from the light emitting element 3 is reflected upward by the inner peripheral surface, and the light can be efficiently emitted to the outside of the package.
[0033]
When the arithmetic mean roughness of the inner peripheral surface of the overhang portion 2a is larger than 0.01 μm, the light is scattered on the inner peripheral surface of the overhang portion 2a, so that the light can be propagated over a long distance. It becomes difficult, and the luminous intensity of the light emitting device is easily deteriorated. Therefore, the light from the light emitting element 3 can be efficiently packaged by forming the inner peripheral surface of the overhang portion 2a so as to extend upward and outward and making the arithmetic average roughness of the inner peripheral surface 0.01 μm or less. The light can be emitted to the outside and the luminous intensity can be increased, and the light can be applied to a far side of the light emitting device.
[0034]
Further, the frame 2 has a lower end of the lower surface of the overhang portion 2a on the side of the mounting portion 1a lower than the height of the light emitting element 3, that is, a light emission between the upper surface of the base 1 and the lower surface of the overhang portion 2a. The bonding material 5 is joined over the entire periphery of the side surface of the base 1 so as to have a gap 6 smaller than the distance between the light emitting portion of the element 3 and the base 1. As a result, a resin layer made of a transparent epoxy resin having a thermal conductivity of about 0.3 W / m · K filled in the air layer or the package is formed between the base 1 and the overhang portion 2 a. You. As a result, the thermal resistance from the base 1 to the frame 2 due to the gap 6 increases, and the heat transmitted from the light emitting element 3 to the frame 2 via the base 1 is suppressed. Therefore, since the deformation of the inner peripheral surface due to the thermal expansion of the frame 2 and the displacement of the translucent member 4 can be effectively suppressed, the light of the light emitting element 3 is stably and efficiently reflected by the inner peripheral surface of the frame 2. , Can be taken out of the package.
[0035]
In addition, as shown in FIG. 2, the frame 2 preferably has a convex portion 2c that protrudes downward over the entire circumference at an end of the lower surface of the overhang portion 2a on the mounting portion 1a side. Thereby, the light emitted from the side surface of the light emitting element 3 can be efficiently reflected inside the package, and can be efficiently extracted outside the package. That is, by forming the convex portion 2c at the end of the lower surface of the overhang portion 2a on the side of the mounting portion 1a, light emitted in the lateral direction from the light emitting element 3 enters the gap 6 between the base 1 and the frame 2. Can be effectively blocked, and this light can be efficiently reflected by the inner peripheral surface of the overhang portion 2a.
[0036]
Further, the strength of the frame body 2 can be reinforced by the protrusions 2c, and the frame body 2 can be more effectively prevented from being deformed by heat. As a result, the reflection efficiency of the light of the light emitting element 3 toward the upper side of the package can be favorably maintained.
[0037]
In addition, this convex part 2c may be formed by providing a concave part on the lower surface of the base part of the overhang part 2a. As a result, the distance between the overhang portion 2a and the base 1 is increased, so that the heat generated in the light emitting element 3 can be more effectively prevented from being transmitted from the base 1 to the overhang portion 2a.
[0038]
Further, such a convex portion 2c does not need to be formed over the entire lower surface of the overhang portion 2a, and may be formed at least in a portion where the deformation of the frame body 2 easily occurs. The portion where the deformation of the frame body 2 is likely to occur is, for example, a portion of the inner peripheral surface of the frame body 2 if the opening on the inner peripheral surface is a polygonal shape having a corner such as a square shape. If 3 is a polygonal shape, it is a portion corresponding to a corner of the light emitting element 3.
[0039]
In addition, as shown in FIG. 3, the frame 2 preferably has a notch 2d between the overhang 2a and the lower end 2b. As a result, the frame 2 thermally expands or contracts due to heating or cooling of the package in the package manufacturing process, or heat generated from the light emitting element 3 when the light emitting device is operated. Even if stress is generated in the joint with the frame 2, the stress can be absorbed by appropriately deforming the overhanging portion 2a which is easily deformed due to the presence of the notch 2d. As a result, stress generated at the joint between the base 1 and the frame 2 is effectively suppressed, cracks and breakage occurring in the base 1 and the joining material 5 can be suppressed, and the light emitting device operates normally and stably for a long period of time. be able to.
[0040]
The frame 2 is made of a metal such as Al, Ag, or Au having a high reflectance with respect to light in the ultraviolet region to the visible region, or an aluminum oxide sintered body, an aluminum nitride sintered body, or a mullite sintered body. It is made of a body, ceramics such as glass ceramics, or a resin such as epoxy resin. For example, when the frame 2 is made of a ceramic or resin, it is preferable to form a metal such as Al, Ag, Au, Pt, or Cu having a high reflectivity on the surface as a reflective layer by an evaporation method or a plating method.
[0041]
The bonding material 5 is made of solder, a resin adhesive containing an inorganic filler, a resin adhesive, an Ag paste, a glass frit having a melting point of 250 ° C. or more, or the like. If the package requires long-term airtightness, it is preferable to join the base 1 and the frame 2 with a joining material 5 made of solder or glass frit. As a result, the light-emitting device can maintain airtightness for a long period of time, and can also cause deterioration or damage of the characteristics of the light-emitting element 3 due to permeation of moisture or the like, light loss or light scattering due to the attachment of water droplets to the translucent lid 4, and the like. Can be effectively suppressed.
[0042]
As the bonding material 5, a resin adhesive or a resin adhesive containing an inorganic filler is preferably used. As a result, even if a stress is generated in the joint between the frame 2 and the base 1 due to a difference in thermal expansion between the frame 2 and the base 1, the joining material 5 contains a resin having a relatively low elastic modulus, so that the stress is effectively absorbed. can do.
[0043]
When the bonding material 5 containing such a resin is used and the light emitted from the light emitting element 3 contains ultraviolet light of 400 nm or less, the resin is effectively prevented from being deteriorated by the ultraviolet light by the overhang portion 2a. can do. That is, since the ultraviolet light of the light emitting element 3 is shielded by the overhang portion 2a, it does not directly irradiate the bonding material 5, and the bonding material 5 is deteriorated by the ultraviolet light, and the bonding strength and the moisture resistance are reduced. Can be effectively suppressed. As a result, the light-tightness of the light-emitting device can be maintained for a long period of time, and the characteristics of the light-emitting element 3 are degraded due to the penetration of moisture into the light-emitting device, and the optical properties due to water droplets adhering to the light-transmitting lid 4. Characteristic degradation can be suppressed.
[0044]
The light-transmissive lid 4 is made of a light-transmissive material such as glass, sapphire, quartz, or a resin (plastic) such as an epoxy resin or an acrylic resin. It protects conductors and bonding wires and hermetically seals the inside of the package. Further, by forming the light-transmitting lid 4 into a lens shape to add the function of an optical lens, the light of the light emitting element 3 is condensed or dispersed, and the light of the light emitting element 3 is emitted at a desired emission angle and intensity distribution. Can be taken out of the package.
[0045]
Thus, in the package of the present invention, the light emitting element 3 is mounted on the mounting portion 1a of the base 1, and the electrodes of the light emitting element 3 are connected to the wiring conductors by bonding wires or the like. The light-emitting device is obtained by joining 4 with solder or resin adhesive. Note that, in order to protect the light emitting element 3 and maintain good light emission efficiency, it is preferable to form a coating layer that covers the light emitting element 3 by filling the inside of the frame 2 with a transparent resin and thermally curing the resin.
[0046]
In addition, after applying a phosphor or a transparent resin mixed with a phosphor to the periphery or the surface of the light emitting element 3, the transparent resin covering the light emitting element 3 is filled and thermally cured. By joining 4 with solder, resin adhesive, or the like, the light of the light emitting element 3 can be converted in wavelength by the phosphor to obtain a light having a desired wavelength spectrum.
[0047]
It should be noted that the present invention is not limited to the above-described embodiment, and that various changes may be made without departing from the scope of the present invention.
[0048]
【The invention's effect】
The light-emitting element housing package of the present invention includes a base having a mounting portion on which a light-emitting element is mounted at a center portion of an upper surface, and a frame body having a lower end portion of an inner peripheral surface joined to a side surface of the base over the entire circumference. The frame body is provided with an overhang on the inner peripheral surface above the base over the entire circumference so as to protrude toward the mounting portion so that the entire lower surface does not contact the base. Since the height of the end of the lower surface on the mounting portion side is lower than the height of the light emitting portion of the light emitting element, the direction in which the frame and the base greatly change in size due to thermal expansion, that is, parallel to the upper and lower surfaces of the base. Since the joining surface between the base and the frame can be orthogonal to the desired direction, even if the frame thermally expands more than the base, the stress acts only in the direction parallel to the upper and lower surfaces of the base. The end of the substrate can be turned upside down or down It can significantly reduce the bending moment and so. As a result, it is possible to effectively reduce the warpage of the base, and it is possible to effectively suppress the cracks generated in the base and the joints and the breakage of the base due to the occurrence of stress greater than the breaking strength. Accordingly, a light emitting element housing package that can maintain airtightness for a long period of time and can operate normally and stably can be obtained.
[0049]
Further, since the stress generated by the difference in thermal expansion between the base and the frame is reduced at the joint, the bonding area between the base and the frame can be reduced, and the heat generated from the light emitting element is transferred from the base to the frame. Can be effectively suppressed.
[0050]
Furthermore, since an air layer or a transparent resin layer filled in the light emitting element housing package can be provided between the base and the overhanging portion, the thermal resistance from the base to the frame increases, and the Transfer of the generated heat to the frame via the base can be effectively suppressed. As a result, the bending moment to the base caused by the thermal expansion of the frame can be suppressed, and the occurrence of cracks and cracks in the base can be effectively suppressed. In addition, since the deformation of the inner peripheral surface due to the thermal expansion of the frame and the displacement of the light-transmitting lid due to the deformation of the frame can be effectively suppressed, the light of the light emitting element can be stably and efficiently emitted on the inner peripheral surface of the frame. The light is well reflected and can be taken out of the light emitting element storage package.
[0051]
In addition, when the light wavelength of the light emitting element is ultraviolet light of 400 nm or less and the bonding material between the base and the frame is made of a resin adhesive such as an acrylic resin or an epoxy resin, the ultraviolet light of the light emitting element is shielded by the overhang portion. Therefore, the bonding material is not directly irradiated to the bonding material, and it is possible to effectively suppress deterioration of the bonding material due to ultraviolet light and reduction in bonding strength and moisture resistance. As a result, the light-tightness of the light-emitting device can be maintained for a long period of time, and the characteristics of the light-emitting element deteriorate due to the penetration of moisture into the light-emitting device, and the optical characteristics due to water droplets adhering to the light-transmitting lid. Deterioration of characteristics can be suppressed.
[0052]
The light-emitting device of the present invention includes the light-emitting element housing package having the above configuration, the light-emitting element mounted on the mounting portion, and the light-transmitting lid attached to the upper surface of the frame. It is possible to suppress cracking, destruction, peeling, etc. of the base and the bonding material due to thermal expansion and contraction of the frame, maintain airtightness for a long period of time, and stabilize the light of the light emitting element to the outside. Can be efficiently emitted with the radiation angle and intensity distribution of As a result, a light-emitting device can be obtained in which light from the light-emitting element can be efficiently and stably extracted to the outside of the light-emitting element housing package.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of an embodiment of a light emitting element housing package of the present invention.
FIG. 2 is a cross-sectional view showing another example of the embodiment of the light emitting element housing package of the present invention.
FIG. 3 is a cross-sectional view showing another example of the embodiment of the light emitting element housing package of the present invention.
FIG. 4 is a cross-sectional view of a conventional light emitting element storage package.
[Explanation of symbols]
1: Substrate
1a: mounting part
2: Frame
2a: Overhang
3: Light emitting element
4: Lid
5: Joining material
6: Clearance

Claims

A base having a mounting portion on which the light-emitting element is mounted at the center of the upper surface, and a frame having a lower end portion of the inner peripheral surface joined to the side surface of the base over the entire circumference, the frame being: Over the entire circumference of the inner peripheral surface above the base, an overhang is formed on the mounting portion side such that the lower surface does not contact the base, and the overhang is formed on the lower surface thereof. A light-emitting element housing package, wherein the height of the end on the mounting section side is lower than the height of the light-emitting section of the light-emitting element.

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 light-transmissive lid attached to an upper surface of the frame. apparatus.