JP4735794B2 - Light emitting module - Google Patents

Description

【００１４】
Ｒ^１，Ｒ^２はメチル基、フェニル基、水素などであり、ジクロロ体のモノクロロ体に対する比を増加させることで重合度ｎが増加し、粘性の高いシリコーンオイルとなる。なお、対流効果を高めたい場合には、粘性のなるべく小さいものを使用することが望ましい（例えば、２５℃での粘度が１０００ｃＳｔ以下）。シリコーンオイルには多数の市販品があり、屈折率は１．３以上１．６以下の範囲で選択できる。例えばジメチルシリコーンオイル（屈折率：１．３以上１．４以下）の市販品としてＫＦ９６（信越化学工業（株）製）、メチルフェニルシリコーンオイル（屈折率：１．４以上１．５以下）の市販品としてＫＦ５０、ＫＦ５４（信越化学工業（株）製）、メチルハイドロジェンシリコーンオイル（屈折率：１．３以上１．４以下）の市販品としてＫＦ９９（信越化学工業（株）製）などを例示できる。特に、Ｒ^１、Ｒ^２のメチル基の一部をフェニル基で置き換えたメチルフェニルシリコーンオイルは、高屈折率であり、また、耐熱性や耐酸化性にも優れているので、本発明に好適に採用できる。
【００１５】
また、より高屈折率の液状モールド媒体（例えば屈折率１．６以上）としては、テトラブロモエタン（特に１，１，２，２−テトラブロモエタン：四臭化アセチレンともいう）を本発明に好適に採用できる。室温での屈折率は１．６４であり、透光性も高い。また、比重が２．９６と大きく、放熱特性にも優れる。他方、特開２００２−５３８３９号公報に開示されている、液状有機化合物にハロゲン化アンチモンを溶解させたものも、屈折率１．６以上の高屈折率を有する液状モールド媒体として用いることができる。
【００１６】
また、液状有機化合物中に該液状有機化合物よりも高屈折率の粒子を懸濁させた複合媒体を用いると、より高屈折率の液状モールド媒体を得ることができる。液状有機化合物としては、上記のシリコーンオイルやテトラブロモエタンなどを使用できる。また、高屈折率の粒子としては、Ｓｉ_３Ｎ_４（屈折率：２．１）、ＢＮ（屈折率：２．０）、ＡｌＮ（屈折率：２．２）、Ａｌ_２Ｏ_３（屈折率：１．８）、ＴｉＯ_２（屈折率：２．５）、ＺｒＯ_２、Ｓｉ（屈折率：３．５）、Ｇｅ（屈折率：４．０）、Ｓｂ_２Ｓ_３（屈折率：４．５）、ＳｉＣ（屈折率：３．２）などを採用でき、コロイド粒子として液状有機化合物中に分散させておくと、高屈折率と高い透光性とを両立できるので好ましい。この場合、粒子の平均粒径：１μｍ以下とするのがよく、より望ましくは、発光層部からの発光光束の中心波長よりも小粒径（特に一次粒子の平均粒径にて２〜１００ｎｍ）とすることで、散乱による透光性低下を顕著に抑制することができる。なお、屈折率向上効果とコロイド懸濁状態維持とを両立させる観点から、液状モールド媒体における高屈折率の粒子の含有率は５体積％以上２０体積％以下とするのがよい。なお、良好な懸濁状態を得るために適当な分散剤（ヘキサメタリン酸ナトリウム、縮合ナフタレンスルホン酸ナトリウム、種々の界面活性剤など）を添加することが可能である。
【００１７】
また、透光性殻体は、少なくとも最外層部が液状モールド媒体と空気との中間の屈折率を有する中間屈折率材料にて構成することができる。上記のような中間屈折率の層を有する透光性殻体を用いれば、液状モールド媒体の側から透光性殻体の周囲の空気層に向けて屈折率を漸減させることができる。これにより、発光光束が全反射により透光性殻体の内側に戻る現象が抑制でき、透光性殻体外への光取出し効率の向上により、より高輝度の発光モジュールが実現する。
【００１８】
この場合、透光性殻体の全体を上記のごとき中間屈折率の層として構成することができる。例えば、テトラブロモエタンや、高屈折材料粒子の懸濁により屈折率を１．６以上に高めた液状モールド媒体を用いる場合、アクリル樹脂、ポリメチルメタクリレート樹脂、スチレン樹脂など、屈折率が１．４５以上１．５５以下の周知の透明樹脂材料にて透光性殻体を構成すれば、光取出し効率の向上を図ることができる。他方、メチルフェニルシリコーンオイルなど、屈折率が１．４５以上１．５５以下の液状モールド媒体を用いる場合は、これと同等の屈折率を有する上記の透明樹脂材料にて透光性殻体を構成すると、液状モールド媒体から透光性殻体側への屈折率の減少効果がほとんどないため、光取出し効率の向上はあまり見込めない。そこで、液状モールド媒体と、透光性殻体の該液状モールド媒体と接する内層部とがいずれも屈折率が１．４５以上の材料からなる場合、透光性殻体の最外層部を屈折率１．４５未満のフッ素樹脂にて構成すると、光取出し効率を高めることができる。フッ素樹脂は、例えばポリフッ化ビニリデン、ポリテトラフルオロエチレン、４‐フルオロエチレン‐６‐フルオロプロピレン共重合体、４‐フルオロエチレン‐パーフルオロアルキルビニルエーテル共重合体、４‐フルオロエチレン‐エチレン共重合体、ポリビニルフルオライド、フルオロエチレン‐炭化水素系ビニルエーテル共重合体などを主体とする市販のものを使用できる。
【００１９】
また、液状モールド媒体は、発光層部からの発光光束を受けて該発光光束とピーク波長の異なる蛍光を発する蛍光材料を含有するものとして構成することができる。これにより、液状モールド媒体を発光媒体としても利用でき、蛍光材料の材質や配合比の調整により、照明光等に適した種々の発光スペクトルを容易に設計できる。また、液状モールド媒体の全体が略一様に発光するため、発光光束の分散効果が著しく、ひいては照明に適した指向性の小さい発光モジュールが実現する。この場合、発光素子チップの発光層部は、蛍光励起に適した光源波長を有している必要があり、近紫外から紫色ないし青色領域（ピーク波長：３００ｎｍ以上４７０ｎｍ以下）の発光が可能な発光層部、具体的には活性層がＩｎＡｌＧａＮあるいはＭｇＺｎＯにて構成されたダブルへテロ構造の発光層部を採用することが望ましい。
【００２０】
また、使用する蛍光材料は、例えば固体蛍光材料の粒子の形で液状有機材料中に懸濁させることができる（前述のコロイド粒子と同様の平均粒径設定が望ましく、また、分散剤の使用が可能である）。白色光を発光させたい場合は、蛍光ランプ等にて使用されている公知の蛍光体材料、例えばハロリン酸カルシウム（３Ｃａ_３（ＰＯ_４）_２・ＣａＦＣｌ／Ｓｂ，Ｍｎ）を使用でき、例えばＦとＣｌ，ＳｂとＭｎのそれぞれの量を調整することにより、種々の色温度の白色光を得ることができる。なお、赤・緑・青（ＲＧＢ）の３波長領域での幅の狭い発光を組み合わせれば、より演色性の優れた照明を実現できる。この場合、各色の蛍光体を混ぜて使うことになるが、代表的なものとして、例えばＹ_２Ｏ_３：Ｅｕ^３＋（Ｒ：中心波長６１１ｎｍ）、ＣｅＭｇＡｌ_１１Ｏ_１９：Ｔｂ^３＋（Ｇ：中心波長５４３ｎｍ）、ＢａＭｇ_２Ａｌ_１６Ｏ_２７：Ｅｕ^２＋（Ｂ：中心波長４５２ｎｍ）の組合せがある。
【００２１】
なお、種々の目的である程度の指向性を有した光源を得たい場合は、次のような構造を採用するとよい。すなわち、透光性殻体の壁部の、内面の一部領域を光取出壁部として使用し、内面の残余の領域に発光光束を反射させる反射層を設け、発光層部から光取出壁部に向かう直接光束に、反射層による反射光を重畳して取り出す。このようにすると、発光素子チップから液状モールド媒体側への光取出し効率を高めることができ、その高効率にて取り出された発光光束を、反射光を重畳させつつ光取出壁部から高強度にて照出することができる。
【００２２】
発光素子チップは発光駆動用の電極を有し、該電極から通電用の端子リード部が延出形成された構造とすることができる。この場合、液状モールド媒体は、発光素子チップとともに端子リード部の電極との接続側端部を覆う形で配置することができる。これによると、延出した端子リード部の長さにより発光素子チップを、透光性殻体内部の光取出に有利な最適の位置に容易に位置決めすることができる。また、発光素子チップと端子リード部とが流動性の高い液状モールド媒体により覆われるので、両者の結合部分に不要な圧力等がかかりにくく、断線等の不具合も生じにくい。
【００２３】
透光性殻体の壁部は、その形状の工夫により発光光束の内部全反射の抑制を図ることができる。具体的には、発光素子チップの光取出面に臨む壁部を、発光素子チップからみて外向きに凸な形態に湾曲した凸湾曲壁部とすることが、壁部各位置での接線に対する発光光束の入射角を大きくでき、上記の内部全反射を効果的に抑制できる。例えば、発光素子チップの第一主表面を主な光取出面として用いる場合、透光性殻体の壁部の、該第一主表面を延長した第一仮想平面に対向する部分の少なくとも一部を、該発光素子チップからみて外向きに凸な形態に湾曲した凸湾曲壁部としておけば、透光性殻体外への光取出し効率を向上することができる。また、透光性殻体の壁部は、発光素子チップの周側面を延長した仮想直柱体面に対向する部分の少なくとも一部を、発光素子チップから見て外向きに凸な形態に湾曲した凸湾曲壁部とすることで、発光素子チップの周側面からの発光光束を、透光性殻体の外部により効果的に取り出すことができる。さらに、透光性殻体の壁部を、発光素子チップの第二主表面を延長した第二仮想平面に対向する部分の少なくとも一部が、発光素子チップから見て外向きに凸な形態に湾曲した凸湾曲壁部としておけば、第二主表面側からの発光光束も、透光性殻体の外部に効果的に取り出すことができる。これらの要件を全て満たす透光性殻体の形状は、例えば、全体が球状、卵状又はナツメ状に形成されたものである。
【００２４】
発光素子チップは、発光層部からの発光光束に対して透光性を有する透光性基板を有し、該透光性基板の第一主表面が光取出面とされるとともに、該透光性基板の第二主表面上に発光層部よりもシート抵抗の低い高導電率層が形成され、その高導電率層上に発光層部が形成されてなり、発光層部の第二主表面側に電極としての第一電極が配置され、他方該発光層部の一部領域を切り欠く形で高導電率層の露出部が形成され、その露出部に電極としての第二電極が配置された構造とすることができる。端子リード部は、それら第一電極及び第二電極からそれぞれ、透光性基板の第一主表面から離間する向きに延出形成することができる。このようにすると、遮光体として作用する電極が発光素子チップの第二主表面側に集められ、端子リード部もその第二主表面側から延出する構成となるので、第一主表面側から発光を遮るものが排除され、光取出し効率を高める上でより有利な構造が実現する。
【００２５】
この場合、透光性殻体に開口を形成し、該開口を封止する形で端子モールド部を配置することができる。端子リード部は該端子モールド部を貫く形で配置されるとともにその第一端部が透光性殻体の内部空間に延出し、その先端に発光素子チップが接続される一方、第二端部は透光性殻体の外に位置することにより、発光素子チップへの電源供給端子を形成するものとして構成できる。このようにすると、端子リード部の保護を図る端子モールド部に、内部が液状モールド媒体で満たされた透光性殻体のシール部材を兼用させることができ、素子モジュールのコンパクト化を図ることができる。
【００２６】
【発明の実施の形態】
以下、本発明の実施の形態を、図面を用いて詳細に説明する。
（実施の形態１）
図１は、本発明の発光モジュールを用いた照明装置の一例を示すものである。該照明装置１は電燈形態に構成され、電球状の発光モジュール６４を有する。図２は、その発光モジュール６４の詳細を示すものであり、化合物半導体層の積層体からなる発光層部２４を有した発光素子チップ２０と、該発光素子チップ２０と直接接する形で該発光素子チップ２０の周囲空間を覆う液状モールド媒体３０と、該液状モールド媒体３０を発光素子チップ２０とともに収容・密封する透光性殻体６５とを有する。液状モールド媒体３０は、液状有機化合物を主体とし、発光層部２４からの発光光束ＬＢに対して透光性を有するものが使用される。また、透光性殻体６５は、発光層部２４からの発光光束ＬＢに対して透光性を有する固体材料からなるものである。
【００２７】
図３に示すように、発光素子チップ２０は、発光層部２４からの発光光束ＬＢに対して透光性を有する透光性基板７を有し、該透光性基板７の第一主表面ＭＳ１が光取出面とされる。また、透光性基板７の第二主表面ＭＳ２上には、発光層部２４よりもシート抵抗の低い高導電率層８が形成され、その高導電率層８上に発光層部２４が形成されている。
【００２８】
本実施形態においては、図１、図２に示すごとく、発光モジュール６４内に青色（Ｂ）、緑色（Ｇ）及び赤色（Ｒ）にてそれぞれ発光する３つの発光素子チップ２０が設けられ、各チップからの発光光束を混合することにより白色ないしそれに近い照明用光を発生させるようにしている。図３に示すように、いずれの発光素子チップ２０も発光層部２４は、内部量子効率を高めるために、ｎ型にドーピングされたｎ型クラッド層４と、ｐ型にドーピングされたｐ型クラッド層６とにより、ノンドープの活性層５を挟んだダブルへテロ構造が採用されている。青色系光源用の発光層部はＩｎ_ａＧａ_ｂＡｌ_{１−ａ−ｂ}Ｎ（０≦ａ≦１，０≦ｂ≦１，ａ＋ｂ≦１：以下、ＩｎＧａＡｌＮとも記載する）にて構成されている。この素子は、混晶比ａ，ｂの設定により、３６０ｎｍ以上５６０ｎｍ以下の範囲で、高強度を維持しつつ発光波長を容易に調整することができる。他方、緑色系光源用及び赤色系光源用の発光層部は、ダブルへテロ発光層部が（Ａｌ_ｘＧａ_１−ｘ）_ｙＩｎ_１−ｙＰ（ただし、０≦ｘ≦１，０≦ｙ≦１：以下、ＡｌＧａＩｎＰとも記載する）にて構成された素子とすることができる。この素子は、混晶比ｘ，ｙの設定により、５２０ｎｍ以上６７０ｎｍ以下の範囲で、高強度を維持しつつ発光波長を容易に調整することができる。これらの発光層部の構成はいずれも周知であるため、詳細な説明は省略する。
【００２９】
なお、透光性基板７は、ＩｎＧａＡｌＮ系の発光層部を有する発光素子チップについては、発光層部２４をＭＯＶＰＥ（Metal Organic Vapor Phase Epitaxy）により成長する際の成長用基板であるサファイア基板を流用できる。他方、ＡｌＧａＩｎＰ系の発光層部を有する発光素子チップについては、成長用の基板が透明性の低いＧａＡｓ基板が用いられる関係上、これをエッチング等により除去して、透光性基板７（材質は特に限定されず、サファイア基板やＧａＰ基板のほか、ガラス基板等の使用も可能である）を貼り合せる構成を採用できる。また、高導電率層８は、クラッド層６よりもハイドープの化合物半導体層（例えば、クラッド層６と同一混晶比のもの）にて形成することができる。
【００３０】
図３に示すように、発光層部２４のｎ型クラッド層４側には、Ａｕ等からなる第一電極９が配置され、他方該発光層部２４の一部領域を切り欠く形で高導電率層８の露出部が形成され、その露出部にＡｕ等からなる第二電極１５が配置されている（露出部は、周知のフォトリソグラフィー技術により形成できる）。端子リード部３１，３３は、それら第一電極９及び第二電極１５からそれぞれ、透光性基板７の第一主表面ＭＳ１から離間する向きに延出形成されている。従って、液状モールド媒体３０は、発光素子チップ２０とともに端子リード部３１，３３の電極９，１５との接続側端部も覆うものとなっている。本実施形態では、端子リード部３１及び３３の先端に、リード本体よりも径大の電極面に対向する接続ベース３２，３４がそれぞれ一体に設けられ、銀ペースト層などの導電層２５，２６を介して第一電極９及び第二電極１５とそれぞれ接続されている。端子リード部３１及び３３は、例えばＦｅ−４２質量％Ｎｉ合金などのＦｅ−Ｎｉ合金にて構成されている。
【００３１】
なお、発光素子チップ２０は、図２６に示すようにシリコン基板やＧａＡｓ基板などの導電性基板７’上に発光層部２４を形成し、さらに該発光層部２４上に電流拡散層２（発光層部２４がＡｌＧａＩｎＰの場合はＧａＰやＡｌＧａＡｓなど）を形成し、該電流拡散層２の一部領域を第一電極９にて覆った構造としてもよい。この場合、金属ステージ５３上に、Ａｇペースト等の金属導体ペースト３を介して発光素子チップ２０の導電性基板７’側を接続する。金属導体ステージ５３の発光素子チップ２０との接続面は凹面状に形成され、光取出の指向性が高められている。また、第一電極９は、導体金具５１に金属リード９ａにより接続されている。前述の端子リード部３１，３３は、金属ステージ５３及び導体金具５１にそれぞれ結合されている。
【００３２】
図２に戻り、液状モールド媒体３０は、発光光束ＬＢに対する透明性を有し、発光素子チップ２０（及び端子リード部３１及び３３）に対する腐食等を生じにくく、絶縁性及び耐水性の高い液状有機化合物、例えばシリコーンオイル（特に、メチルフェニルシリコーンオイル（屈折率１．４〜１．５））にて構成される。また、屈折率１．６以上のより高屈折率の液状モールド媒体として、テトラブロモエタン（四臭化アセチレンともいう）を用いることもできる。
【００３３】
また、図５に示すように、シリコーンオイルやテトラブロモエタンなどの液状有機化合物３０ａ中に該液状有機化合物３０ａよりも屈折率が高い高屈折率粒子１７０を懸濁させた複合媒体を液状モールド媒体３０として用いることもできる。高屈折率粒子１７０は、例えばＳｉ_３Ｎ_４、ＢＮ、ＡｌＮ、Ａｌ_２Ｏ_３、ＴｉＯ_２、ＺｒＯ_２、Ｓｉ、Ｇｅ、Ｓｂ_２Ｓ_３あるいはＳｉＣから選ばれる１種又は２種以上で構成でき、粒子の平均粒径は１μｍ以下、特に、発光層部２４からの発光光束ＬＢの中心波長よりも小粒径（特に一次粒子の平均粒径にて２〜１００ｎｍ）とすることで、散乱による透光性低下を顕著に抑制することができる。液状モールド媒体３０における高屈折率粒子１７０の含有率は５体積％以上２０体積％以下とする。
【００３４】
図２に戻り、透光性殻体６５は、アクリル樹脂等の透光性を有する樹脂（あるいはガラスでもよい）からなる基質６５ｍが主体となる中空成形体である。基質６５ｍ中に気泡やガラスあるいはセラミックよりなる光散乱粒子６５ｓを分散配合しておくか、あるいは内面をすりガラス状の面粗し部としておくことにより、光分散効果、ひいては各発光素子チップ２０からの光の混合効果を高めることができる。なお、透光性殻体６５の基質６５ｍの代わりに（あるいは、該基質６５とともに）、液状モールド媒体３０中に光散乱粒子を分散させておくこともできる。
【００３５】
なお、図２７の発光モジュール３６４のように、透光性殻体６５の壁部の、内面の一部領域を光取出壁部６５ｊとして使用し、内面の残余の領域に発光光束ＬＢを反射させる反射層６５ｒを設けることもできる。これにより、発光層部２４から光取出壁部６５ｊに向かう直接光束ＬＢに、反射層６５ｒによる反射光ＲＢを重畳して取り出すことができる。反射層６５ｒは、Ａｌ、ＡｇあるいはＡｕなどを主体とする金属膜として構成することができるほか、屈折率の相違する酸化物層あるいは透明樹脂層を交互にないし周期的に積層した多重反射膜あるいはＤＢＲ（Distributed Bragg Reflector）膜にて構成することも可能である。また、図２７においては、反射層６５ｒを透光性殻体６５の壁部内面に設けているが、外面に形成することも可能である（この場合、発光層部２４からの発光光束は、透光性殻体６５の壁部を経由して反射層６５ｒで反射されることになる）。さらに、図２８の発光モジュール４６４のように、透光性殻体６５の壁部を金属壁部２６５にて置き換え、該金属壁部２６５の内面を反射面として利用する形態も可能である。この場合、該金属壁部は放熱板の役割も果たし、冷却効果が高められる。
【００３６】
透光性殻体６５は開口６５ｑを有し、該開口６５ｑを封止する形で端子モールド部１６１が配置されている。端子リード部３１，３３は端子モールド部１６１を貫く形で配置され、第一端部が透光性殻体６５の内部空間に延出し、その先端に発光素子チップ２０が接続される一方、第二端部は透光性殻体６５の外に位置することにより、発光素子チップ２０への電源供給端子１３１，１３２を形成している。
【００３７】
透光性殻体６５の形状は、殻体壁部内面又は外面での全反射による光束の戻りを生じにくくするため、発光素子チップ２０の光取出面に臨む壁部を、発光素子チップ２０からみて外向きに凸な形態に湾曲した凸湾曲壁部を有するものとしている。図２５に示すごとく、この実施形態では、発光素子チップ２０の第一主表面ＭＰ１、第二主表面ＭＰ２及び周側面ＰＰがいずれも光取出面とされている。透光性殻体６５は発光素子チップ２０を取り囲む球状の壁部を有している。これは、幾何学的には、次のような条件を充足するものとなっている。すなわち、該第一主表面ＭＰ１を延長した第一仮想平面ＶＰ１に対向する部分Ｗ１、周側面ＰＰを延長した仮想直柱体面ＶＰ２に対向する部分Ｗ２、及び第二主表面ＭＰ２を延長した第二仮想平面ＶＰ３に対向する部分Ｗ３（開口６５ｑに臨む位置には当然、壁部は存在しない）が、いずれも、発光素子チップ２０から見て外向きに凸な形態に湾曲した凸湾曲壁部とされている（なお、部分Ｗ１，Ｗ２，Ｗ３は、部分的に互いに重なり合っている）。これらの要件を全て満たす透光性殻体６５の形状は、図１８に示すような球状形態のほか、図１９に示す卵状形態（あるいは回転楕円体状形態）、さらには図２０に示すナツメ状形態を例示できる。
【００３８】
また、図２１に示すように、透光性殻体６５は多面体状に形成することもできるし、図２２に示すように円筒状に形成することもできる。図２２では、発光素子チップ２０の周側面ＰＰの延長に臨む部分だけが凸湾曲壁部（円筒面状壁部）として形成されていると見ることもできる。
【００３９】
図２に戻り、端子モールド部１６１は、ポリプロピレン、ポリスチレン、ポリカーボネート等の熱可塑性樹脂により円柱状に形成され、端子リード部３１，３３と射出成形（インサート成形）により一体化されている。また、透光性殻体６５は射出成形ないしブロー成形により形成され、短尺筒状の開口リブ６５ｔが本体部から延出した形態を有する。開口リブ６５ｔの先端には前記の開口６５ｑが形成されるとともに、金属製の筒状の端子ケース６６が外周面に一体化されている。また、端子モールド部１６１と開口リブ６５ｔとの間には、透光性殻体６５内部の液状モールド媒体３０の液漏れを防ぐための、ゴム等からなるリング状のシール部材１６３が配置されている。また、端子ケース６６の後端部１６２ｃは、端子モールド部１６１の後端面に向けて内向きに加締められている。
【００４０】
本実施形態においては、シール部材１６３は、端子モールド部１６１の前端面外周縁部を切り欠く形で形成されたシール収容溝１６１ｇ内に配置されている。また、端子モールド部１６１の後端面外周縁にもシール収容溝１６１ｇが形成され、同様のシール部材１６３が配置されている。また、シール部材１６３に対応する位置にて端子ケース６６の外周面には、周方向の加締め部１６２ａ，１６２ｂが形成されている。また、端子モールド部１６１の内部には、各発光素子チップ２０への印加電圧を調整するための調整抵抗２１が埋設されている。さらに、透光性殻体６５の内部空間に面するシール部材１６３の前端面には、液状モールド媒体３０の体積膨張を吸収するための吸収空間１６１ｈが開口形成されている。
【００４１】
なお、透光性殻体６５を、シリコーンゴムなどの透光性を有する弾性体で構成することもできる。このような弾性体で透光性殻体６５を構成すると、液状モールド媒体３０の体積膨張を透光性殻体６５自体の弾性変形により吸収することができる。
【００４２】
発光モジュール６４の組み立ては以下のようにする。すなわち、端子ケース６６を一体成形した透光性殻体６５の内部に、開口６５ｑから液状モールド媒体３０を注ぎ入れる。他方、端子モールド部１６１（シール部材１６３はシール収容溝１６１ｇに予め嵌め込んでおけばよい）が一体化された端子リード部３１，３３及び発光素子チップ２０の組み立てアセンブリを用意し、発光素子チップ２０を液状モールド媒体３０内に浸漬しつつ、端子モールド部１６１を端子ケース６６の内側に挿入する。そして、端子ケース６６の後端部１６２ｃを端子モールド部１６１の後端面に向けて加締めるとともに、周方向の加締め部１６２ａ，１６２ｂを形成し、透光性殻体６５の内部を密封すれば組み立ては完了する。
【００４３】
図１に戻り、照明装置１は本体ケース７３を有し、該本体ケース７３に取付凹部１３３ａを有する光源ソケット１３３が設けられている。発光モジュール６４は端子ケース６６にて光源ソケット１３３の取付凹部１３３ａに挿入され、その底面に設けられた雌コネクタ状の駆動電圧出力端子２３１，２３２に電源供給端子１３１，１３２がそれぞれ差し込まれて装着される。駆動電圧出力端子２３１，２３２は、電力供給部７０の基板に接続され、さらに電力供給部７０への電力供給線１３４ａが、周知のスイッチボックス７２を経て、電源プラグ１３５を有した電源コード１３４に接続されている。
【００４４】
図４は、電力供給部７０に回路図の一例であり、電源部１０１からの出力電圧を発光素子駆動電圧に変換する電圧変換部９９，１２１を有する。本実施形態において、電源部は商用交流電源１０１であり、電圧変換部は、該商用交流電源を直流電圧に変換するＡＣ／ＤＣコンバータ９９を有する。ＡＣ／ＤＣコンバータ９９は、電源プラグ１３５にて商用交流電源１０１のコンセントに接続される。ＡＣ／ＤＣコンバータ９９は、商用交流電源１０１の電源電圧（例えば１００Ｖ）を所定の電圧（例えば５〜１５Ｖ）に降圧するトランス１４０と、降圧後の交流を整流するダイオードブリッジからなる整流部１４１を有する。整流部１４１による整流波形は、コンデンサ１４２にて平滑化された後、各発光素子チップ２０の駆動安定化電源回路１２１に分配入力される。駆動安定化電源回路１２１は、レギュレータＩＣ１２２（コンデンサ１２３，１２４は発振防止用である）を有し、ＡＣ／ＤＣコンバータ９９からの入力電圧を、各発光素子チップ２０に適した直流駆動電圧に変換して、アノード側駆動電圧出力端子１３１に出力する。なお、３つの発光素子チップ２０の共通化されたカソード端子６３は、接地側駆動電圧出力端子１３２を介して接地線Ｇに接続される。
【００４５】
図１の照明装置１の動作は以下の通りである。電源プラグ１３５を商用交流コンセントに差し込めば、電力供給部７０を介して発光モジュール６４の光源モジュール５０に給電され、所期のスペクトルの照明光にて電燈２６３を点灯することができる。なお、操作部７４によりスイッチボックス７２を操作すれば、光源モジュール５０への給電がＯＮ／ＯＦＦされ、照明装置１の点灯／消灯を簡単に行なうことができる。
【００４６】
そして、本発明の発光モジュール６４を用いることにより、以下のような効果が達成される。すなわち、図２に示すごとく、発光素子チップ２０の周囲空間が、従来の発光モジュールのような固形のモールド樹脂ではなく、液状モールド媒体３０にて覆われている。モールド媒体が液状であるため、媒体収縮による発光素子チップ２０への応力付加が本質的に生じず、発光層部２４の劣化等につながる影響をほとんど生じない。また、端子リード部３１，３３の断線や接触不良などの不具合も起こりにくい。一方、発光素子チップ２０からは紫外線成分が少なからず放出されるが、シリコーンオイルやテトラブロモエタンからなる液状モールド媒体３０は紫外線照射による変質が生じにくく、耐水性にも優れる。
【００４７】
さらに、モールド媒体が液状であるため、モールドの体積を大きくしても発光素子チップ２０への応力増加等は静水圧的な圧縮力が多少増加するだけで、発光素子チップ２０周辺への機械的なダメージを生ずる惧れがない。従って、発光光束ＬＢの分散性が高められ、照明用等に好適な指向性の小さい配向特性を容易に得ることができる。また、モールド媒体の厚さ（体積）を増加させることで、発光素子チップ２０への水分浸透等も進みにくく、耐久性がます。
【００４８】
また、さらに重要な効果は、媒体が液状なので、仮に発光素子チップ２０の周囲にて変質部分が生じても、対流ＣＦにより速やかに流動するので発光素子チップ２０の近傍に留まらず、透明性喪失などの劣化が進行しにくい。このとき、発光素子チップ２０の通電による発熱は、液状モールド媒体３０の対流ＣＦを促進する効果を有する。また、液状モールド媒体３０の対流ＣＦにより放熱効果が促進されるので、照明用等に大面積（例えば発光層部の１辺が３００μｍ以上１０００μｍ以下）及び大電流（例えば定格電流５０ｍＡ以上１０００ｍＡ以下、定格出力０．１Ｗ以上５Ｗ以下）のチップを使用した場合においても、発光モジュール６４の過度の温度上昇を生じにくく、発光素子チップ２０側に複雑なヒートシンク構造を考慮する必要もなくなる。液状モールド媒体３０の体積は、例えば、発光素子チップ２０の体積の１０倍以上１０^７倍以下に設定するのがよい。
【００４９】
なお、液状モールド媒体３０としてテトラブロモエタン（屈折率：１．６４）を用い、透光性殻体６５の全体をアクリル樹脂など屈折率が１．５前後（１．４５以上１．５５以下）の樹脂で構成すれば、液状モールド媒体３０側から透光性殻体６５を経て、その外側を取り巻く空気（屈折率：１．０）に向け、屈折率が段階的に減少するので、全反射による発光光束の戻りを効果的に抑制でき、光取出し効率をより向上することができる。他方、メチルフェニルシリコーンオイルなど、屈折率が１．５前後（１．４５以上１．５５以下）の液状モールド媒体３０を用いる場合は、図２に一点鎖線で示すように、前記アクリル樹脂等からなる透光性殻体６５の本体部（内層部）６５ｍの外側を、最外層部として、フッ素樹脂（屈折率が１．３以上１．４以下）からなる中間屈折率材料層６５ｗにて覆うと光取出し効率を高めることができる。
【００５０】
以下、本発明の発光モジュールの種々の別実施形態について説明する。なお、いずれも実施の形態１との共通部が多いので、主に相違点について説明し、共通部については実施の形態１と同一の符号を付与して詳細な説明は繰り返さない。
（実施の形態２）
図６の発光モジュール１６４は、発光素子チップ２００の発光層部２４は、ピーク波長の異なる複数の発光を合成することにより、合成後のスペクトルのピーク波長での発光強度を基準強度として、該基準強度の５％以上の発光強度を示す有効波長域が、５０ｎｍ以上の波長幅にわたって確保された、擬似連続スペクトルを有する光を発光出力するものとされている。
【００５１】
発光素子チップ２００の発光層部２４は、第一の発光層部２４ａと第二の発光層部２４ｂであり、いずれも、化合物半導体よりなるダブルへテロ発光層部（以下、単に発光層部という）２４ａ，２４ｂの活性層（図２、図３参照）が、バンドギャップエネルギーの相違する複数の発光単位層を含んで構成される。第一の発光層部２４ａは、発光単位層の発光波長が５２０ｎｍ以上７００ｎｍ以下の範囲で設定され、第二の発光層部２４ｂは、発光単位層の発光波長が３６０ｎｍ以上５６０ｎｍ以下の範囲で設定される。そして、発光素子チップ２００は、これらの２種の発光層部２４ａ，２４ｂからの発光を互いに混合して、例えば、熱放射型光源の連続スペクトルを擬似的に合成し、擬似連続スペクトルを有した可視光として発光出力する。
【００５２】
図７に示すように、発光層部２４ａは、（Ａｌ_ｘＧａ_１−ｘ）_ｙＩｎ_１−ｙＰ（ただし、０≦ｘ≦０．５５，０．４５≦ｙ≦０．５５）混晶からなる活性層５ａ（例えばノンドープのもの：ただし、必要に応じてドーパントの添加が可能である）を、ｐ型（Ａｌ_ｚＧａ_１−ｚ）_ｙＩｎ_１−ｙＰ（ただしｘ＜ｚ≦１）からなるｐ型クラッド層６ａとｎ型（Ａｌ_ｚＧａ_１−ｚ）_ｙＩｎ_１−ｙＰ（ただしｘ＜ｚ≦１）からなるｎ型クラッド層４ａとにより挟んだ構造を有する。また、発光層部２４ｂは、ノンドープＩｎ_ａＧａ_ｂＡｌ_{１−ａ−ｂ}Ｎ混晶からなる活性層５ｂを、ｐ型Ｉｎ_ａＧａ_ｂＡｌ_{１−ａ−ｂ}Ｎからなるｐ型クラッド層６ｂとｎ型Ｉｎ_ａＧａ_ｂＡｌ_{１−ａ−ｂ}Ｎからなるｎ型クラッド層４ｂとにより挟んだ構造を有する。なお、ここでいう「ノンドープ」とは、「ドーパントの積極添加を行なわない」との意味であり、通常の製造工程上、不可避的に混入するドーパント成分の含有（例えば１０^１３〜１０^１６／ｃｍ^３程度を上限とする）をも排除するものではない。本実施形態では、発光層部２４ａと発光層部２４ｂとを、透明導電性接続層（例えばＩＴＯ（Indium-TinOxide）などの導電性酸化物層）１１２により直列に貼り合せ、全体を単一の発光素子チップ２００としている。ただし、両発光層部２４ａ，２４ｂを個別の発光素子チップとして構成してもよい。
【００５３】
図８は、第一の発光層部２４ａの活性層５ａの構造の一例をバンド図の形にて模式的に示すものである。また、図１１は、第二の発光層部２４ｂの活性層５ｂの構造の一例をバンド図の形にて模式的に示すものである。該活性層５ａ，５ｂにおいて発光単位層は、各々２つの障壁層Ｂ，Ｂに挟まれた井戸層Ｗ１‥Ｗｎよりなる。障壁層Ｂ，Ｂに挟まれた井戸層Ｗ１‥Ｗｎを発光単位層とすることで、井戸層内へのキャリア閉じ込め効果により、個々の発光単位層の発光効率を高めることができる。各井戸層Ｗ１‥Ｗｎの発光波長は、それぞれのバンドギャップエネルギーＥｇ１‥Ｅｇｎ（図８），Ｅｇ’１‥Ｅｇ’ｎ（図１１）（≡各井戸層でのＥｃ−Ｅｖの値：Ｅｃは伝導体底エネルギーレベル、Ｅｖは価電子帯頂エネルギーレベル）に応じて定まる。本実施形態では、各井戸層Ｗ１‥Ｗｎが全て異なるバンドギャップエネルギーを有し、それぞれ個別の発光単位層を形成している。つまり、１つの発光単位層に含まれる井戸層の数を１つとしている。ただし、同一バンドギャップエネルギーの複数の井戸層の組を発光単位層とすることもできる。
【００５４】
第一の発光層部２４ａ及び第二の発光層部２４ｂのいずれにおいても、上記複数の発光単位層、すなわち井戸層Ｗ１‥Ｗｎは、バンドギャップエネルギーの大小配列において、隣接するバンドギャップエネルギー間の差分値ΔＥが、０．４２ｅＶ以下、望ましくは０．２ｅＶ以下とされる。バンドギャップエネルギー間の差分値ΔＥが過度に大きくなると、単位スペクトルのピーク位置間の距離が大きくなりすぎ、合成された波形に大きな波打ちが生じて、滑らかなスペクトルが得られなくなる。なお、差分値ΔＥは、バンドギャップエネルギーが隣接する全ての発光単位層の組に対して等しく設定することもできるし、必要とする発光スペクトル形状に応じて、強度を意識的に高めたい波長域においては間隔を密とし、逆に強度を抑制したい波長域においては間隔を粗とするなど、少なくとも一部の発光単位層の組について不等間隔に設定することもできる。
【００５５】
例えば、得るべき擬似連続スペクトルが、白熱電球の連続スペクトルを模した擬似電球光スペクトルを有するように、第一の発光層部２４ａ及び第二の発光層部２４ｂの活性層５ａ，５ｂを設計している。図１５は、タングステンフィラメントを用いた白熱電球を、色温度約３０００Ｋにて発光させたときのスペクトル波形である。強度ピークは破線にて示すように、近赤外域の８００ｎｍ付近に存在し、可視光帯域での強度分布は、発光波長とともに増加する傾向となる。相当強度の赤外線を含むため、光源の温度上昇が生じやすいことが直ちに理解できる。
【００５６】
本発明においては、図１５の連続スペクトルを、複数の発光単位層からの種々の波長の単色光（発光単位）を組み合わせて、いわばデジタル的に合成し、擬似連続スペクトルとする。第一の発光層部２４ａにおいて、波長７００ｎｍ以上にて発光する井戸層を設けなければ、図１５に実線で示すように、赤外発光成分を大幅に削減できる。また、白熱電球の連続スペクトルにおいて短波長領域には、僅かではあるが有害な紫外線も含まれている。しかし、後述のように第二の発光層部２４ｂにおいて、波長３６０ｎｍ以下にて発光する井戸層を設けなければ、該紫外発光成分も削減できる。
【００５７】
本実施形態では、各活性層５ａ，５ｂを、以下のように構成している。すなわち、図９（第一の発光層部５ａ）及び図１２（第二の発光層部５ｂ）に示すように、複数の発光単位層は、発光波長の長い発光単位層（井戸層）ほど発光強度Ｉが高くなるように調整される。具体的には、発光波長の長い発光単位層ほど、井戸層の厚さもしくは数を大きくする。図１５に示すスペクトル波形に近づけるには、例えば、６５０ｎｍでの強度Ｉ650と５６０ｎｍでの強度Ｉ560との比Ｉ650／Ｉ560が１．４前後となるように設定する。
【００５８】
第一の発光層部２４ａ及び第二の発光層部２４ｂのいずれにおいても、その発光スペクトルは波長が長くなるにつれ、発光強度Ｉは増加する。しかし、発光波長に対する可視光の相対視感度は、図１０に示すように、明所では５５５ｎｍ付近で最大となる。図９および図１２には、視感度補正係数Ｖの波長依存性を示す曲線を一点鎖線にて示している。視感度補正強度は、発光強度Ｉと視感度補正係数Ｖとの積Ｖ・Ｉにて表すことができる。図９に示すように、第一の発光層部２４ａは発光強度Ｉと視感度補正係数Ｖとの波長依存性が逆傾向なので、視感度補正強度Ｖ・Ｉは、中間波長域、具体的には黄色域からオレンジ色域にピークを生ずる。他方、図１２に示すように、第二の発光層部２４ｂは発光強度Ｉと視感度補正係数Ｖとの波長依存性が同傾向なので、視感度補正強度Ｖ・Ｉは波長が長くなるとともに単調増加する。
【００５９】
そして、図７の発光素子チップ２００においては、長波長域側の第一の発光層部２４ａのスペクトルと短波長域側の第二の発光層部２４ｂのスペクトルとが合成されて出力される。その結果、第一の発光層部２４ａのスペクトル波形ＳＡの短波長側に、第二の発光層部２４ｂのスペクトル波形ＳＢが接続されて、図１３のような擬似電球光スペクトルが最終的に得られる。すなわち、擬似電球光スペクトルの発光強度Ｉは、図１５の白熱電球のスペクトル、すなわち視感度補正後の発光強度分布は、黄色域からオレンジ色域、すなわち５７０ｎｍ以上６４０ｎｍ以下に強度ピークを有し、白熱電球によく似た黄色味あるいはオレンジ色味を帯びた、暖かで柔らかい照明色が得られる。
【００６０】
なお、最終的な発光スペクトルの形状は、各波長の発光単位層の発光強度を、層数や層厚により調整することにより、所望のものを任意に形成できる。特に、自然光の演色性に近づけた照明光を得たい場合は、太陽光の連続スペクトルを模した擬似太陽光スペクトルを、擬似連続スペクトルとして合成すればよい。図１４は、可視領域の太陽光スペクトルを示すものであるが、色温度が６０００Ｋ前後と高いため、白熱電球と比べて、強度ピークは４００ｎｍ付近の短波長域に生ずる。また、可視光波長帯の略全域に渡って、波長が長くなるほど発光強度Ｉは減少する傾向を示す。従って、図９及び図１２とは全く逆に、複数の発光単位層は、発光波長の短い層ほど発光強度Ｉが高くなるように調整されればよい。
【００６１】
以上、熱放射型光源のスペクトル波形をなるべく忠実に再現したい場合の実施の形態について説明したが、これに限定されるものではない。例えば、白熱電球の発光スペクトルから青色系の波長域の可視光をカットしても、残った波長域のみで、白熱電球特有の黄色ないしオレンジ色の優位な照明色を擬似的に実現できることに変わりはない。この場合、第一の発光層部２４ａのみで光源モジュールを構成することができる。また、赤色系の波長域がカットされた照明光を得たい場合は、第二の発光層部２４ｂのみで光源モジュールを構成すればよい。
【００６２】
なお、上記の発光素子チップ２００は、複数の波長の発光光束が始めから混合されて放出されるので、透光性殻体６５あるいは液状モールド媒体３０は、光散乱粒子を配合せず透明に構成しても、色混合状態に分離を生じたりする不具合を生じにくい。そして、透光性殻体６５あるいは液状モールド媒体３０をいずれも透明に構成しておけば、液状モールド媒体３０中に光反射性の浮遊装飾体（例えば金属ラメなどである）３０ｄ（図１６）を分散しておくと、液状モールド媒体３０内に生ずる対流ＣＦによって透光性殻体６５内を該浮遊装飾体３０ｄがキラキラと舞い動き、面白い照明効果が得られる。
【００６３】
（実施の形態３）
図１７の発光モジュール２６４は、発光素子チップ３００が、近紫外から紫色ないし青色領域（ピーク波長：３００ｎｍ以上４７０ｎｍ以下）の発光が可能な発光層部２４を有している。該発光層部２４は、活性層及びクラッド層が、ＩｎＡｌＧａＮあるいはＭｇＺｎＯにて構成されたダブルへテロ構造を有する。そして、液状モールド媒体３０は、発光層部２４からの発光光束ＬＢを受けて該発光光束ＬＢとピーク波長の異なる蛍光ＬＬを発する蛍光材料３０Ｌを含有したものとされている。使用する蛍光材料３０Ｌは、固体蛍光材料粒子の形で液状有機材料中に懸濁されており、Ｙ_２Ｏ_３：Ｅｕ^３＋（Ｒ：中心波長６１１ｎｍ）、ＣｅＭｇＡｌ_１１Ｏ_１９：Ｔｂ^３＋（Ｇ：中心波長５４３ｎｍ）、ＢａＭｇ_２Ａｌ_１６Ｏ_２７：Ｅｕ^２＋（Ｂ：中心波長４５２ｎｍ）などの、各色の蛍光体を混合することにより種々の色調の照明光を得ることができる。この構成では液状モールド媒体３０自体が発光媒体として均一に発光するので、照明に適した指向性の小さい発光分布を容易に得ることができる。また、蛍光材料３０Ｌの材質や配合比の調整により、所望の発光スペクトルを容易に設計できる。
【００６４】
この場合、発光素子チップ３００からの発光光束が可視光を主体とするものである場合、その可視光束に、蛍光材料３０Ｌにて励起された異波長の可視光束を混合して放出させることができる。この場合、発光素子チップ３００を紫色ないし青色発光するものとして構成し、蛍光材料３０Ｌとして緑色系で発光するものと、赤色系で発光するものとを配合しておけば、発光素子チップ３００からの紫色ないし青色の発光光束に、蛍光材料３０Ｌからの緑色系ないし赤色系の発光光束が混合され、白色系の照明光を得ることができる。他方、発光素子チップ３００からの発光光束が近紫外光を主体とするものである場合は、蛍光材料３０Ｌとして、青色系で発光するもの、緑色系で発光するもの、及び赤色系で発光するものを配合しておくことで、蛍光材料３０Ｌからの各色の発光光束が混合され、白色系の照明光を得ることができる。いずれの場合（特に後者）においても、発光素子チップ３００からは、相当量の紫外線成分が放出されるが、液状モールド媒体３０のベースをなす液状有機化合物を前述のシリコーンオイルやテトラブロモエタンで構成しておくと、紫外線照射による変質が生じにくく、仮に変質が生じても対流によりその影響が軽減されるので、エポキシ樹脂モールドのような劣化の不具合を生じにくい。
【００６５】
（実施の形態４）
上記の実施形態では、照明装置をいずれも電燈状に構成していたが、本発明はこれに限られるものではない。図２３は、燃焼光源を模した照明装置の一例として、蝋燭状の外観を有する照明装置１００を構成した例である。該照明装置１００は、図６と基本構造が同一の光源モジュール６４’使用し、電力供給部７０により商用交流電源により点灯駆動する。そして、光源モジュール６４’の発光素子チップ２００の擬似連続スペクトルは、燃焼光の連続スペクトルを模した擬似燃焼光スペクトルを有するものである。具体的には、蝋燭光の連続スペクトルを模するため、図１５よりもさらに色温度の低い擬似連続スペクトル（例えば１５００Ｋ程度）が得られるように、活性層５ａ，５ｂが設計されている。発光色はさらにオレンジないし赤みの強いものとなる。
【００６６】
電力供給部７０は蝋燭の軸を模した本体２６２内に収容され、その先端に光源モジュール６４’が配置されるとともに、その外側を、炎の外観形状を真似た透明な透光性殻体６５で覆っている。また、液状モールド媒体３０も透明である。電力供給部７０は、本体２６２から引き出された電源コード１３４及び電源プラグ１３５を介して、コンセントより受電する。照明装置１００を点灯させると、発光素子チップ２００からの発光光束が液状モールド媒体３０の対流ＣＦにより揺らぎ、蝋燭の炎の雰囲気をリアルに再現することができる。
【００６７】
また、図２４の照明装置３００は、液状モールド媒体３０中に複数の発光素子チップ２０を配置した例である。この実施形態では、電力供給部７０を収容した横長のケース３０１内に発光素子チップ２０が長手方向に配列した形で配置されている。該ケース３０１に対し、液状モールド媒体３０にて満たされた同じく横長の透光性殻体３０２がシール部材１６３を介して嵌め合わされ、密封されている。
【００６８】
また、以上の実施形態では、可視光の発光モジュールを例にとって説明したが、本発明は赤外線発光モジュールへの適用も可能である。この場合、発光層部は、ＡｌＧａＡｓなど赤外域に発光波長を有するものとして構成すればよい。
【図面の簡単な説明】
【図１】本発明の発光モジュールを用いた照明装置の第一例を示す断面図。
【図２】本発明の発光モジュールの第一例を示す断面図。
【図３】図２の発光モジュールに使用する発光素子チップの断面構造を示す模式図。
【図４】図１の照明装置に使用する電力供給部の回路構成の一例を示す図。
【図５】本発明の発光モジュールの第二例を示す断面図。
【図６】本発明の発光モジュールの第三例を示す断面図。
【図７】図６の発光モジュールに使用する発光素子チップの断面構造を示す模式図。
【図８】図７の素子チップにおける第一の発光層部の、活性層の構成例を示すバンド図。
【図９】第一の発光層部による擬似連続スペクトルの概念説明図。
【図１０】可視光に対する相対視感度の波長依存性を示すグラフ。
【図１１】図７の素子チップにおける第二の発光層部の、活性層の構成例を示すバンド図。
【図１２】第二の発光層部による擬似連続スペクトルの概念説明図。
【図１３】第一の発光層部と第二の発光層部との合成スペクトルの概念図。
【図１４】可視光帯域の太陽光スペクトルを示す説明図。
【図１５】可視光帯域の白熱電球のスペクトルを示す説明図。
【図１６】本発明の発光モジュールの第四例を示す断面図。
【図１７】本発明の発光モジュールの第五例を示す断面図。
【図１８】本発明の発光モジュールに使用する透光性殻体形状の第一例を示す斜視図。
【図１９】同じく第二例を示す斜視図。
【図２０】同じく第三例を示す斜視図。
【図２１】同じく第四例を示す断面図及び斜視図。
【図２２】同じく第五例を示す断面図及び斜視図。
【図２３】本発明の発光モジュールを用いた照明装置の第二例を示す図。
【図２４】本発明の発光モジュールを用いた照明装置の第三例を示す図。
【図２５】透光性殻体形状の説明図。
【図２６】発光モジュールにおける発光素子チップの組付け形態の変形例を示す模式図。
【図２７】本発明の発光モジュールの第六例を示す断面図。
【図２８】本発明の発光モジュールの第七例を示す断面図。
【符号の説明】
１，１００，３００ 照明装置
７ 透光性基板
８ 高導電率層
９ 第一電極
１５ 第二電極
２０，２００ 発光素子チップ
ＭＰ１ 第一主表面
ＶＰ１ 第一仮想平面
ＰＰ 周側面
ＶＰ２ 仮想直柱体面
ＭＰ２ 第二主表面
ＶＰ３ 第二仮想平面
２４ 発光層部
ＬＢ 発光光束
３０ 液状モールド媒体
３０ａ 液状有機化合物
３０Ｌ 蛍光材料
３１，３３ 端子リード部
６４，１６４，２６４，３６４，４６４ 発光モジュール
６５ 透光性殻体
６５ｑ 開口
６５ｗ 中間屈折率材料層
６５ｍ 本体部（内層部）
６５ｊ 光取出壁部
６５ｒ 反射層
ＲＢ 反射光
１３１，１３２ 電源供給端子
１６１ 端子モールド部
１７０ 高屈折率粒子[0001]
The present invention relates to a light emitting module using a light emitting element chip made of a compound semiconductor.
[0002]
[Prior art]
[Patent Document 1]
JP 11-191641 A
[0003]
  Semiconductor light-emitting devices have been developed with high-luminance types based on AlGaInP, InAlGaN, etc., but as a result of many years of progress in materials and device structures, the photoelectric conversion efficiency inside the devices has gradually reached the theoretical limit. Approaching. Therefore, when an element with higher luminance is to be obtained, the light extraction efficiency from the element is extremely important. In order to increase the light extraction efficiency, a method generally employed is a method of molding the periphery of the light emitting element chip with a resin having a high refractive index. The refractive index of the compound semiconductor constituting the light emitting element chip is generally high, and when the outside of the chip is filled with air having a small refractive index, the critical angle at which the emitted light flux is totally reflected on the chip surface and returns to the chip is reduced. Light extraction efficiency decreases. However, if the chip is covered with a highly refractive material such as epoxy resin, the difference in refractive index from the light emitting element chip is reduced.AtThe field angle is increased and the light extraction efficiency can be increased. This resin mold also functions as a passivation layer that protects the light emitting element chip from deterioration due to reaction with moisture in the atmosphere.
[0004]
[Problems to be solved by the invention]
However, the mold using an epoxy resin has the following problems.
(1) The epoxy resin is a thermosetting resin, and the shrinkage accompanying the curing treatment (curing) is remarkable. As a result, a large stress due to resin shrinkage is applied to the light emitting element chip during molding, and the light emitting layer portion is likely to be deteriorated. Also, problems such as disconnection and poor contact of energization leads connected to the electrodes of the light emitting element chip are likely to occur.
(2) The luminous flux from the light emitting element chip contains not only a visible light component having a desired wavelength but also a considerable amount of ultraviolet light components. In particular, in the case of a light emitting element chip in a short wavelength region such as blue or green, the amount of ultraviolet rays contained is also increased. The crosslinking shrinkage of the epoxy resin is likely to proceed by irradiation with ultraviolet rays, and the alteration such as crystallization is likely to proceed. In the former case, the resin shrinkage further proceeds, and the problem (1) is easily promoted. In the latter case, the transparency of the resin is lost, leading to deterioration in light extraction efficiency.
(3) Epoxy resin has a relatively high water permeability, and moisture and moisture contained in the use environment may permeate with time, leading to deterioration of the light emitting element chip.
[0005]
{Circle around (4)} Conventional light emitting elements generally use one of the main surface of the light emitting layer portion as a main light extraction surface, and therefore have a strong directivity in which the distribution of light flux is biased toward the light extraction surface. This is convenient when used as a display device or the like, but there is a difficulty that it is difficult to obtain a uniform and natural illumination effect, for example, in the use of an illumination device that has been studied recently. In this case, it is conceivable to increase the dispersibility of the emitted light flux by increasing the thickness of the resin mold and relieve the directivity that is too strong. In addition, increasing the mold thickness seems to be advantageous at first glance from the viewpoint of delaying the effect of moisture permeation (3). However, if the mold thickness is excessively increased, the shrinkage stress of the resin applied to the light emitting element chip is amplified, and the problem (1) is easily promoted. In addition, since the resin alteration due to ultraviolet rays that causes the problem (2) proceeds first from the vicinity of the light emitting element chip, if deterioration progresses around the chip, even if the remaining part of the mold is healthy It becomes useless as an element. For these reasons, even if the mold thickness of the epoxy resin is greatly increased, not only an effect commensurate with it can be expected, but also adverse effects such as an increase in resin shrinkage stress are undesirably increased.
(5) Although it is necessary to use a large, large-current chip for illumination or the like, heat generation during light emission is large. However, the heat dissipation effect cannot be expected with a small volume resin mold, and the heat sink structure associated with the element chip must be taken into account. Therefore, the structure of the entire light emitting module is complicated, leading to an increase in cost.
[0006]
The problem of the present invention is that the deterioration of the mold covering the light-emitting element chip over time can be greatly suppressed, and even if the mold thickness is increased, there is almost no influence of shrinkage stress and the like, and the heat dissipation is excellent. An object of the present invention is to provide a light emitting module that can stably maintain the extraction efficiency over a long period of time and can improve the dispersibility of the luminous flux, and thus has suitable performance for illumination and the like.
[0007]
[Means for solving the problems and actions / effects]
  In order to solve the above problems, the light emitting module of the present invention is:
  A light emitting element chip having a light emitting layer portion composed of a laminate of compound semiconductor layers;
  A liquid mold medium having translucency with respect to the luminous flux from the light emitting layer part and covering the surrounding space of the light emitting element chip in direct contact with the light emitting element chip;
  A light-transmitting shell that contains and seals a liquid mold medium together with a light-emitting element chip, made of a solid material that transmits light emitted from the light-emitting layer portion,
  Have
  The liquid mold medium is mainly composed of a liquid organic compound,
  The refractive index of the liquid mold medium is set to 1.3 or more,
  The liquid organic compound that forms the liquid mold medium is tetrabromoethane.The
The translucent shell is composed of an intermediate refractive index material having at least the outermost layer portion having an intermediate refractive index between the liquid molding medium and air,
Both the liquid mold medium and the inner layer portion of the translucent shell contacting the liquid mold medium are made of a material having a refractive index of 1.45 or more, while the outermost layer portion of the translucent shell is a refractive index of 1. . Made of less than 45 fluororesinIt is characterized by that.
[0008]
In the light emitting module of the present invention, the surrounding space of the light emitting element chip is covered with a liquid mold medium mainly composed of a liquid organic compound. The translucent shell functions as a container for the liquid mold medium. Thereby, the fault of the conventional light emitting element module using a solid mold material like an epoxy resin can be solved as follows.
(1) Since the mold medium is in a liquid state, stress is not applied to the light emitting element chip due to the medium shrinkage. In addition, compressive stress may occur due to the volume expansion of the medium, but since the medium is liquid, the stress transmitted to the light-emitting element chip is isotropic, causing almost no influence on the deterioration of the light-emitting layer. Absent. In addition, problems such as disconnection and poor contact of energization leads connected to the electrodes of the light emitting element chip are extremely difficult to occur.
{Circle around (2)} When irradiated with an ultraviolet component from the light emitting element chip, the liquid mold medium may be altered, but the medium itself is liquid, so there is no possibility that it will lead to problems such as stress addition.
[0009]
(3) Since the molding medium is liquid, increasing the volume of the mold does not lead to an increase in stress on the light emitting element chip. Accordingly, the dispersibility of the emitted light flux is enhanced, and an orientation characteristic having a small directivity suitable for illumination or the like can be easily obtained. Further, since the thickness of the mold medium is increased, it is possible to delay the penetration of moisture and moisture contained in the use environment from reaching the light emitting element chip, and the durability can be increased.
{Circle around (4)} Since the medium is liquid, the altered portion quickly flows due to diffusion or convection and does not stay in the vicinity of the light emitting element chip, and deterioration such as loss of transparency is unlikely to proceed. In particular, when heat is generated by energization of the light emitting element chip, the convection of the liquid mold medium is promoted, and the replacement of the deteriorated medium in the vicinity of the light emitting element chip further proceeds, so that the above effect is enhanced. Therefore, when the volume of the mold medium is increased, localization of the deteriorated portion to the light-emitting element chip does not occur, and a sustained effect corresponding to the increase in volume can be expected.
(5) The heat dissipation effect can be promoted by the convection flow of the liquid mold medium, and even when a large large current chip is used for lighting, etc., there is no need to consider a complicated heat sink structure, and the element module can be manufactured at low cost. Can be configured. This effect becomes more significant as the volume of the liquid mold medium is increased.
[0010]
It is desirable to use a liquid mold medium having a refractive index as large as possible from the viewpoint of increasing the critical angle for total reflection and thus improving the light extraction efficiency from the light emitting element chip. For example, if a material having a refractive index of 1.3 or higher, desirably 1.4 or higher, light extraction efficiency equivalent to or higher than that of conventional epoxy resins can be realized.
[0011]
Moreover, the following items are mentioned as desirable characteristics that the liquid mold medium should have.
(1) Excellent transparency to the luminous flux.
(2) It must be inert so that it does not easily corrode light emitting element chips.
(3) The material should have a moisture content as low as possible and hardly permeate moisture (in this respect, it is desirable to use a liquid mold medium mainly composed of a liquid organic compound).
(4) Excellent insulation.
(5) The material should be low in volatility and less likely to cause ignition or combustion.
[0012]
Examples of the liquid organic compound forming the liquid mold medium that satisfies the above-described characteristics include silicone oil. Silicone oil is a compound having a general formula represented by the following molecular formula, a linear chain obtained by condensation polymerization of a raw material containing dialkyldichlorosilane as a main component and trialkylmonochlorosilane for the terminal by hydrolysis. Is a molecule.
[0013]
[Chemical 1]

[0014]
R¹, R²Is a methyl group, a phenyl group, hydrogen, and the like. Increasing the ratio of the dichloro form to the monochloro form increases the degree of polymerization n, resulting in a highly viscous silicone oil. In order to enhance the convection effect, it is desirable to use a material having a viscosity as small as possible (for example, the viscosity at 25 ° C. is 1000 cSt or less). There are many commercially available silicone oils, and the refractive index can be selected in the range of 1.3 to 1.6. For example, as commercial products of dimethyl silicone oil (refractive index: 1.3 to 1.4), KF96 (manufactured by Shin-Etsu Chemical Co., Ltd.), methylphenyl silicone oil (refractive index: 1.4 to 1.5). KF50, KF54 (manufactured by Shin-Etsu Chemical Co., Ltd.) as commercially available products, KF99 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. as commercial products of methyl hydrogen silicone oil (refractive index: 1.3 to 1.4) It can be illustrated. In particular, R¹, R²A methylphenyl silicone oil in which a part of the methyl group is replaced with a phenyl group has a high refractive index and is excellent in heat resistance and oxidation resistance, and can be suitably used in the present invention.
[0015]
Further, as a liquid mold medium having a higher refractive index (for example, a refractive index of 1.6 or more), tetrabromoethane (particularly 1,1,2,2-tetrabromoethane: also referred to as acetylene tetrabromide) is used in the present invention. It can be suitably employed. The refractive index at room temperature is 1.64 and the translucency is high. Moreover, specific gravity is as large as 2.96, and it is excellent also in the thermal radiation characteristic. On the other hand, what dissolved antimony halide in the liquid organic compound currently disclosed by Unexamined-Japanese-Patent No. 2002-53839 can be used as a liquid mold medium which has a high refractive index of 1.6 or more.
[0016]
Further, when a composite medium in which particles having a higher refractive index than that of the liquid organic compound are suspended in the liquid organic compound, a liquid mold medium having a higher refractive index can be obtained. As the liquid organic compound, the above-mentioned silicone oil, tetrabromoethane, or the like can be used. Moreover, as high refractive index particles, Si₃N₄(Refractive index: 2.1), BN (refractive index: 2.0), AlN (refractive index: 2.2), Al₂O₃(Refractive index: 1.8), TiO₂(Refractive index: 2.5), ZrO₂, Si (refractive index: 3.5), Ge (refractive index: 4.0), Sb₂S₃(Refractive index: 4.5), SiC (refractive index: 3.2), etc. can be adopted, and when dispersed in a liquid organic compound as colloidal particles, both high refractive index and high translucency can be achieved. preferable. In this case, the average particle diameter of the particles is preferably 1 μm or less, and more preferably smaller than the center wavelength of the luminous flux from the light emitting layer (particularly, the average particle diameter of primary particles is 2 to 100 nm). By doing, the translucency fall by scattering can be suppressed notably. In addition, from the viewpoint of achieving both the effect of improving the refractive index and maintaining the colloidal suspended state, the content of the high refractive index particles in the liquid mold medium is preferably 5% by volume or more and 20% by volume or less. In addition, in order to obtain a favorable suspended state, it is possible to add an appropriate dispersing agent (sodium hexametaphosphate, condensed sodium naphthalene sulfonate, various surfactants, etc.).
[0017]
The translucent shell can be formed of an intermediate refractive index material having at least an outermost layer portion having an intermediate refractive index between the liquid mold medium and air. If a translucent shell having an intermediate refractive index layer as described above is used, the refractive index can be gradually reduced from the liquid mold medium side toward the air layer around the translucent shell. As a result, the phenomenon that the emitted light flux returns to the inside of the translucent shell due to total reflection can be suppressed, and the light extraction module with higher brightness is realized by improving the light extraction efficiency to the outside of the translucent shell.
[0018]
In this case, the entire translucent shell can be configured as an intermediate refractive index layer as described above. For example, when using a liquid molding medium whose refractive index is increased to 1.6 or more by suspending highly refractive material particles such as tetrabromoethane, an acrylic resin, polymethyl methacrylate resin, styrene resin, or the like has a refractive index of 1.45. If the translucent shell is composed of a known transparent resin material of 1.55 or less, the light extraction efficiency can be improved. On the other hand, when a liquid mold medium having a refractive index of 1.45 or more and 1.55 or less, such as methylphenyl silicone oil, is used, the translucent shell is composed of the transparent resin material having the same refractive index as this. Then, since there is almost no effect of decreasing the refractive index from the liquid mold medium to the translucent shell, the improvement of the light extraction efficiency cannot be expected much. Therefore, when both the liquid mold medium and the inner layer portion of the translucent shell that is in contact with the liquid mold medium are made of a material having a refractive index of 1.45 or more, the outermost layer portion of the translucent shell is used as the refractive index. If it is made of a fluororesin of less than 1.45, the light extraction efficiency can be increased. The fluororesin is, for example, polyvinylidene fluoride, polytetrafluoroethylene, 4-fluoroethylene-6-fluoropropylene copolymer, 4-fluoroethylene-perfluoroalkyl vinyl ether copolymer, 4-fluoroethylene-ethylene copolymer, Commercially available products mainly composed of polyvinyl fluoride, fluoroethylene-hydrocarbon vinyl ether copolymer and the like can be used.
[0019]
In addition, the liquid mold medium can be configured to contain a fluorescent material that receives the emitted light beam from the light emitting layer portion and emits fluorescence having a peak wavelength different from that of the emitted light beam. Accordingly, the liquid mold medium can be used as a light emitting medium, and various emission spectra suitable for illumination light can be easily designed by adjusting the material and blending ratio of the fluorescent material. In addition, since the entire liquid mold medium emits light substantially uniformly, a light-emitting module having a remarkable light beam dispersion effect and a small directivity suitable for illumination is realized. In this case, the light emitting layer portion of the light emitting element chip needs to have a light source wavelength suitable for fluorescence excitation, and can emit light in the near ultraviolet to purple to blue region (peak wavelength: 300 nm to 470 nm). It is desirable to employ a light emitting layer portion having a double hetero structure in which the layer portion, specifically, the active layer is made of InAlGaN or MgZnO.
[0020]
The fluorescent material to be used can be suspended in the liquid organic material, for example, in the form of particles of a solid fluorescent material (an average particle size setting similar to that of the colloidal particles described above is desirable, and the use of a dispersant is also preferred. Is possible). When it is desired to emit white light, a known phosphor material used in fluorescent lamps, such as calcium halophosphate (3Ca₃(PO₄)₂CaFCl / Sb, Mn) can be used, and white light with various color temperatures can be obtained by adjusting the amounts of F and Cl, Sb and Mn, for example. In addition, if the light emission having a narrow width in the three wavelength regions of red, green, and blue (RGB) is combined, it is possible to realize illumination with better color rendering. In this case, phosphors of various colors are mixed and used. As a typical example, for example, Y₂O₃: Eu³⁺(R: center wavelength 611 nm), CeMgAl₁₁O₁₉: Tb³⁺(G: center wavelength 543 nm), BaMg₂Al₁₆O₂₇: Eu²⁺(B: center wavelength 452 nm).
[0021]
In order to obtain a light source having a certain degree of directivity for various purposes, the following structure may be employed. That is, a partial region of the inner surface of the wall portion of the translucent shell is used as the light extraction wall portion, and a reflection layer that reflects the emitted luminous flux is provided in the remaining region of the inner surface, and the light extraction wall portion from the light emission layer portion. The reflected light from the reflective layer is superimposed on the direct light beam directed to In this way, the light extraction efficiency from the light emitting element chip to the liquid mold medium side can be increased, and the emitted light flux extracted with high efficiency can be increased from the light extraction wall portion while superimposing the reflected light. Can be illuminated.
[0022]
The light emitting element chip can have a structure in which an electrode for driving light emission is provided, and a terminal lead portion for energization is extended from the electrode. In this case, the liquid molding medium can be disposed so as to cover the end portion on the connection side with the electrode of the terminal lead portion together with the light emitting element chip. According to this, the light emitting element chip can be easily positioned at an optimum position advantageous for light extraction inside the translucent shell by the length of the extended terminal lead portion. Further, since the light emitting element chip and the terminal lead portion are covered with a liquid mold medium having high fluidity, unnecessary pressure or the like is not easily applied to the joint portion between them, and problems such as disconnection are hardly caused.
[0023]
The wall portion of the translucent shell can suppress total internal reflection of the luminous flux by devising the shape. Specifically, the wall facing the light extraction surface of the light-emitting element chip is a convex curved wall that curves outwardly as viewed from the light-emitting element chip. The incident angle of the light beam can be increased, and the total internal reflection can be effectively suppressed. For example, when the first main surface of the light emitting element chip is used as the main light extraction surface, at least a part of the portion of the wall portion of the translucent shell that faces the first virtual plane extending the first main surface If it is provided as a convex curved wall portion curved outwardly as viewed from the light emitting element chip, the light extraction efficiency to the outside of the translucent shell can be improved. Further, the wall portion of the translucent shell is curved in a shape that protrudes outward as viewed from the light emitting element chip, at least a part of the portion facing the virtual straight body surface extending the peripheral side surface of the light emitting element chip. By using the convex curved wall portion, the luminous flux from the peripheral side surface of the light emitting element chip can be effectively extracted from the outside of the translucent shell. Furthermore, at least a part of the portion of the translucent shell facing the second virtual plane extending from the second main surface of the light emitting element chip is convex outward as viewed from the light emitting element chip. If the curved convex curved wall is used, the luminous flux from the second main surface side can also be effectively taken out of the translucent shell. The shape of the translucent shell satisfying all of these requirements is, for example, formed as a whole in a spherical shape, an egg shape, or a jujube shape.
[0024]
The light-emitting element chip includes a light-transmitting substrate that transmits light emitted from the light-emitting layer, and the first main surface of the light-transmitting substrate serves as a light extraction surface. A high conductivity layer having a sheet resistance lower than that of the light emitting layer portion is formed on the second main surface of the conductive substrate, and the light emitting layer portion is formed on the high conductivity layer. The second main surface of the light emitting layer portion A first electrode as an electrode is disposed on the side, and an exposed portion of the high conductivity layer is formed by cutting out a partial region of the light emitting layer portion, and a second electrode as an electrode is disposed in the exposed portion. Structure. The terminal lead portion can be formed extending from the first electrode and the second electrode in a direction away from the first main surface of the translucent substrate. In this case, since the electrodes acting as the light shielding body are collected on the second main surface side of the light emitting element chip, and the terminal lead portion also extends from the second main surface side, the first main surface side Anything that blocks light emission is eliminated, and a more advantageous structure is realized in increasing the light extraction efficiency.
[0025]
In this case, the terminal mold part can be arranged in such a manner that an opening is formed in the translucent shell and the opening is sealed. The terminal lead portion is disposed so as to penetrate the terminal mold portion, and its first end portion extends into the inner space of the translucent shell, and the light emitting element chip is connected to the tip thereof, while the second end portion Can be configured to form a power supply terminal to the light emitting element chip by being positioned outside the translucent shell. In this way, the terminal mold part that protects the terminal lead part can also be used as the sealing member of the translucent shell whose inside is filled with the liquid molding medium, and the element module can be made compact. it can.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 shows an example of an illumination device using the light emitting module of the present invention. The illuminating device 1 is configured in the form of an electric lamp, and has a light bulb-shaped light emitting module 64. FIG. 2 shows the details of the light emitting module 64, and the light emitting element chip 20 having the light emitting layer portion 24 made of a laminated body of compound semiconductor layers and the light emitting element in direct contact with the light emitting element chip 20. The liquid mold medium 30 covers the space around the chip 20, and the translucent shell 65 that houses and seals the liquid mold medium 30 together with the light emitting element chip 20. The liquid mold medium 30 is mainly composed of a liquid organic compound and has translucency with respect to the emitted light beam LB from the light emitting layer portion 24. The translucent shell 65 is made of a solid material having translucency with respect to the luminous flux LB from the light emitting layer portion 24.
[0027]
As shown in FIG. 3, the light-emitting element chip 20 includes a translucent substrate 7 having translucency with respect to the luminous flux LB from the light-emitting layer portion 24, and the first main surface of the translucent substrate 7. MS1 is the light extraction surface. Further, a high conductivity layer 8 having a sheet resistance lower than that of the light emitting layer portion 24 is formed on the second main surface MS2 of the translucent substrate 7, and the light emitting layer portion 24 is formed on the high conductivity layer 8. Has been.
[0028]
In the present embodiment, as shown in FIGS. 1 and 2, three light emitting element chips 20 that emit light in blue (B), green (G), and red (R) are provided in the light emitting module 64, respectively. By mixing the luminous flux from the chip, white or near illumination light is generated. As shown in FIG. 3, in each light emitting element chip 20, the light emitting layer portion 24 includes an n type cladding layer 4 doped n-type and a p type cladding doped p type in order to increase the internal quantum efficiency. A double hetero structure with a non-doped active layer 5 sandwiched between the layers 6 is employed. Light emitting layer for blue light source is In_aGa_bAl_1-abN (0 ≦ a ≦ 1, 0 ≦ b ≦ 1, a + b ≦ 1: hereinafter, also referred to as InGaAlN). This device can easily adjust the emission wavelength while maintaining high intensity in the range of 360 nm or more and 560 nm or less by setting the mixed crystal ratios a and b. On the other hand, the light emitting layer portion for the green light source and the red light source has a double hetero light emitting layer portion (Al_xGa_1-x)_yIn_1-yIt is possible to obtain an element composed of P (however, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1: hereinafter also referred to as AlGaInP). This element can easily adjust the emission wavelength while maintaining high intensity in the range of 520 nm to 670 nm by setting the mixed crystal ratios x and y. Since the structure of these light emitting layer parts is well known, detailed description is omitted.
[0029]
For the light-emitting element chip having an InGaAlN-based light emitting layer portion, the light-transmitting substrate 7 is a sapphire substrate that is a growth substrate when the light emitting layer portion 24 is grown by MOVPE (Metal Organic Vapor Phase Epitaxy). it can. On the other hand, for a light emitting element chip having an AlGaInP-based light emitting layer portion, a growth substrate is a low-transparency GaAs substrate. There is no particular limitation, and a configuration in which a glass substrate or the like can be used in addition to a sapphire substrate or a GaP substrate can be employed. The high conductivity layer 8 can be formed of a compound semiconductor layer that is more highly doped than the cladding layer 6 (for example, having the same mixed crystal ratio as the cladding layer 6).
[0030]
As shown in FIG. 3, the first electrode 9 made of Au or the like is disposed on the n-type clad layer 4 side of the light emitting layer portion 24, and on the other hand, a part of the light emitting layer portion 24 is notched so as to be highly conductive. An exposed portion of the rate layer 8 is formed, and a second electrode 15 made of Au or the like is disposed on the exposed portion (the exposed portion can be formed by a well-known photolithography technique). The terminal lead portions 31 and 33 are formed to extend from the first electrode 9 and the second electrode 15 in directions away from the first main surface MS1 of the translucent substrate 7, respectively. Therefore, the liquid molding medium 30 covers the light emitting element chip 20 and the connection side end portions of the terminal lead portions 31 and 33 with the electrodes 9 and 15. In the present embodiment, connection bases 32 and 34 facing the electrode surface having a diameter larger than that of the lead body are integrally provided at the tips of the terminal lead portions 31 and 33, respectively, and conductive layers 25 and 26 such as a silver paste layer are provided. The first electrode 9 and the second electrode 15 are connected to each other. The terminal lead portions 31 and 33 are made of, for example, an Fe—Ni alloy such as an Fe-42 mass% Ni alloy.
[0031]
As shown in FIG. 26, the light emitting element chip 20 has a light emitting layer portion 24 formed on a conductive substrate 7 ′ such as a silicon substrate or a GaAs substrate, and further a current diffusion layer 2 (light emitting layer) on the light emitting layer portion 24. In the case where the layer part 24 is AlGaInP, GaP, AlGaAs or the like may be formed, and a part of the current diffusion layer 2 may be covered with the first electrode 9. In this case, the conductive substrate 7 ′ side of the light emitting element chip 20 is connected to the metal stage 53 via the metal conductor paste 3 such as Ag paste. The connection surface of the metal conductor stage 53 with the light emitting element chip 20 is formed in a concave shape, and the directivity of light extraction is enhanced. The first electrode 9 is connected to the conductor metal fitting 51 by a metal lead 9a. The terminal lead portions 31 and 33 are coupled to the metal stage 53 and the conductor fitting 51, respectively.
[0032]
Returning to FIG. 2, the liquid mold medium 30 is transparent to the light emission light beam LB, hardly corrodes the light emitting element chip 20 (and the terminal lead portions 31 and 33), and is a liquid organic having high insulation and water resistance. It is comprised with a compound, for example, silicone oil (especially methylphenyl silicone oil (refractive index 1.4-1.5)). Further, tetrabromoethane (also referred to as acetylene tetrabromide) can be used as a liquid mold medium having a higher refractive index of 1.6 or higher.
[0033]
In addition, as shown in FIG. 5, a composite medium in which high refractive index particles 170 having a higher refractive index than that of the liquid organic compound 30a are suspended in a liquid organic compound 30a such as silicone oil or tetrabromoethane is used as a liquid mold medium. 30 can also be used. The high refractive index particle 170 is, for example, Si.₃N₄, BN, AlN, Al₂O₃TiO₂, ZrO₂, Si, Ge, Sb₂S₃Alternatively, it can be composed of one or more selected from SiC, and the average particle diameter of the particles is 1 μm or less, in particular, smaller than the center wavelength of the emitted light beam LB from the light emitting layer portion 24 (particularly the average particle size of the primary particles). By setting the diameter to 2 to 100 nm, it is possible to remarkably suppress a decrease in translucency due to scattering. The content of the high refractive index particles 170 in the liquid mold medium 30 is set to 5% by volume or more and 20% by volume or less.
[0034]
Returning to FIG. 2, the translucent shell 65 is a hollow molded body mainly composed of a substrate 65m made of translucent resin (or glass) such as acrylic resin. By dispersing and blending light scattering particles 65s made of bubbles, glass or ceramic in the substrate 65m, or by setting the inner surface as a ground glass-like roughened portion, the light dispersion effect, and hence from each light emitting element chip 20 is obtained. The light mixing effect can be enhanced. In addition, instead of the substrate 65m of the translucent shell 65 (or together with the substrate 65), light scattering particles may be dispersed in the liquid mold medium 30.
[0035]
Note that, as in the light emitting module 364 of FIG. 27, a part of the inner surface of the wall portion of the translucent shell 65 is used as the light extraction wall portion 65j, and the emitted light beam LB is reflected on the remaining region of the inner surface. A reflective layer 65r can also be provided. Thereby, the reflected light RB from the reflective layer 65r can be extracted by being superimposed on the direct light beam LB from the light emitting layer portion 24 toward the light extraction wall portion 65j. The reflective layer 65r can be configured as a metal film mainly composed of Al, Ag, Au, or the like, or a multiple reflective film in which oxide layers or transparent resin layers having different refractive indexes are alternately or periodically stacked. A DBR (Distributed Bragg Reflector) film may be used. In FIG. 27, the reflective layer 65r is provided on the inner surface of the wall portion of the translucent shell 65, but can also be formed on the outer surface (in this case, the luminous flux from the light emitting layer portion 24 is The light is reflected by the reflective layer 65r through the wall of the translucent shell 65). Furthermore, as in the light emitting module 464 of FIG. 28, a configuration in which the wall portion of the translucent shell 65 is replaced with a metal wall portion 265 and the inner surface of the metal wall portion 265 is used as a reflection surface is also possible. In this case, the metal wall portion also serves as a heat sink, and the cooling effect is enhanced.
[0036]
The translucent shell 65 has an opening 65q, and the terminal mold portion 161 is disposed so as to seal the opening 65q. The terminal lead portions 31 and 33 are disposed so as to penetrate the terminal mold portion 161, the first end portion extends into the inner space of the translucent shell 65, and the light emitting element chip 20 is connected to the tip of the terminal lead portion 31 and 33. The two end portions are located outside the translucent shell 65, thereby forming power supply terminals 131 and 132 for the light emitting element chip 20.
[0037]
The shape of the translucent shell 65 makes it difficult for the light beam to return due to total reflection on the inner or outer surface of the shell wall, so that the wall facing the light extraction surface of the light emitting element chip 20 is separated from the light emitting element chip 20. It is assumed that it has a convex curved wall portion that is curved outwardly. As shown in FIG. 25, in this embodiment, the first main surface MP1, the second main surface MP2, and the peripheral side surface PP of the light emitting element chip 20 are all light extraction surfaces. The translucent shell 65 has a spherical wall that surrounds the light emitting element chip 20. This geometrically satisfies the following conditions. That is, the portion W1 facing the first virtual plane VP1 extending the first main surface MP1, the portion W2 facing the virtual straight body surface VP2 extending the peripheral side surface PP, and the second extending the second main surface MP2. A portion W3 facing the virtual plane VP3 (there is no wall portion naturally at the position facing the opening 65q) is a convex curved wall portion that is curved outwardly as viewed from the light emitting element chip 20. (Note that the portions W1, W2, and W3 partially overlap each other). The shape of the translucent shell 65 that satisfies all of these requirements is not only a spherical shape as shown in FIG. 18, but also an egg-like shape (or a spheroid shape) shown in FIG. The shape can be illustrated.
[0038]
Moreover, as shown in FIG. 21, the translucent shell 65 can be formed in a polyhedron shape, or can be formed in a cylindrical shape as shown in FIG. In FIG. 22, it can also be seen that only a portion facing the extension of the peripheral side surface PP of the light emitting element chip 20 is formed as a convex curved wall portion (cylindrical surface wall portion).
[0039]
Returning to FIG. 2, the terminal mold portion 161 is formed in a cylindrical shape from a thermoplastic resin such as polypropylene, polystyrene, or polycarbonate, and is integrated with the terminal lead portions 31 and 33 by injection molding (insert molding). The translucent shell 65 is formed by injection molding or blow molding, and has a form in which short cylindrical opening ribs 65t extend from the main body. The opening 65q is formed at the tip of the opening rib 65t, and a metal cylindrical terminal case 66 is integrated with the outer peripheral surface. In addition, a ring-shaped seal member 163 made of rubber or the like is disposed between the terminal mold portion 161 and the opening rib 65t to prevent the liquid mold medium 30 inside the translucent shell 65 from leaking. Yes. Further, the rear end portion 162 c of the terminal case 66 is crimped inward toward the rear end surface of the terminal mold portion 161.
[0040]
In the present embodiment, the seal member 163 is disposed in a seal accommodation groove 161g formed by cutting out the outer peripheral edge of the front end surface of the terminal mold portion 161. In addition, a seal housing groove 161g is formed in the outer peripheral edge of the rear end surface of the terminal mold portion 161, and a similar seal member 163 is disposed. Further, circumferential crimping portions 162 a and 162 b are formed on the outer peripheral surface of the terminal case 66 at a position corresponding to the seal member 163. An adjustment resistor 21 for adjusting the voltage applied to each light emitting element chip 20 is embedded in the terminal mold portion 161. Further, an absorption space 161 h for absorbing the volume expansion of the liquid mold medium 30 is formed in the front end surface of the seal member 163 facing the internal space of the translucent shell 65.
[0041]
In addition, the translucent shell 65 can also be comprised with the elastic body which has translucency, such as a silicone rubber. When the translucent shell 65 is constituted by such an elastic body, the volume expansion of the liquid mold medium 30 can be absorbed by elastic deformation of the translucent shell 65 itself.
[0042]
The light emitting module 64 is assembled as follows. That is, the liquid molding medium 30 is poured into the translucent shell 65 integrally formed with the terminal case 66 from the opening 65q. On the other hand, an assembly assembly of the terminal lead portions 31 and 33 and the light emitting element chip 20 integrated with the terminal mold portion 161 (the sealing member 163 may be fitted in the seal receiving groove 161g in advance) is prepared, and the light emitting element chip is prepared. The terminal mold portion 161 is inserted into the terminal case 66 while the 20 is immersed in the liquid mold medium 30. Then, the rear end portion 162c of the terminal case 66 is caulked toward the rear end surface of the terminal mold portion 161, the caulking portions 162a and 162b in the circumferential direction are formed, and the inside of the translucent shell 65 is sealed. The assembly is complete.
[0043]
Returning to FIG. 1, the lighting device 1 includes a main body case 73, and the main body case 73 is provided with a light source socket 133 having a mounting recess 133 a. The light emitting module 64 is inserted into the mounting recess 133a of the light source socket 133 by the terminal case 66, and the power supply terminals 131 and 132 are respectively inserted into the female connector-like drive voltage output terminals 231 and 232 provided on the bottom surface thereof. Is done. The drive voltage output terminals 231 and 232 are connected to the substrate of the power supply unit 70, and the power supply line 134 a to the power supply unit 70 is connected to the power cord 134 having the power plug 135 via the known switch box 72. It is connected.
[0044]
FIG. 4 is an example of a circuit diagram of the power supply unit 70, and includes voltage conversion units 99 and 121 that convert an output voltage from the power supply unit 101 into a light emitting element driving voltage. In the present embodiment, the power source unit is a commercial AC power source 101, and the voltage conversion unit includes an AC / DC converter 99 that converts the commercial AC power source into a DC voltage. The AC / DC converter 99 is connected to the outlet of the commercial AC power supply 101 through a power plug 135. The AC / DC converter 99 includes a transformer 140 that steps down the power supply voltage (for example, 100 V) of the commercial AC power supply 101 to a predetermined voltage (for example, 5 to 15 V), and a rectifier 141 that includes a diode bridge that rectifies the stepped-down AC. Have. The rectified waveform by the rectifier 141 is smoothed by the capacitor 142 and then distributed and input to the drive stabilization power supply circuit 121 of each light emitting element chip 20. The drive stabilization power supply circuit 121 has a regulator IC 122 (the capacitors 123 and 124 are for preventing oscillation), and converts the input voltage from the AC / DC converter 99 into a DC drive voltage suitable for each light emitting element chip 20. Then, it outputs to the anode side drive voltage output terminal 131. The common cathode terminal 63 of the three light emitting element chips 20 is connected to the ground line G via the ground side drive voltage output terminal 132.
[0045]
The operation of the lighting device 1 of FIG. 1 is as follows. If the power plug 135 is inserted into a commercial AC outlet, power is supplied to the light source module 50 of the light emitting module 64 via the power supply unit 70, and the electric lamp 263 can be turned on with illumination light having an intended spectrum. When the switch box 72 is operated by the operation unit 74, power supply to the light source module 50 is turned on / off, and the lighting device 1 can be easily turned on / off.
[0046]
And the following effects are achieved by using the light emitting module 64 of this invention. That is, as shown in FIG. 2, the surrounding space of the light emitting element chip 20 is covered with the liquid mold medium 30 instead of the solid mold resin as in the conventional light emitting module. Since the mold medium is in a liquid state, stress is not applied to the light emitting element chip 20 due to the medium contraction, and there is hardly any influence that leads to deterioration of the light emitting layer portion 24 or the like. In addition, problems such as disconnection and poor contact of the terminal lead portions 31 and 33 are unlikely to occur. On the other hand, a considerable amount of ultraviolet component is released from the light emitting element chip 20, but the liquid mold medium 30 made of silicone oil or tetrabromoethane is hardly changed by ultraviolet irradiation and has excellent water resistance.
[0047]
Furthermore, since the mold medium is in a liquid state, even if the mold volume is increased, an increase in stress on the light emitting element chip 20 only increases the hydrostatic compressive force slightly, and mechanical strength around the light emitting element chip 20 is increased. There is no fear of causing serious damage. Therefore, the dispersibility of the emitted light beam LB is enhanced, and an orientation characteristic with small directivity suitable for illumination or the like can be easily obtained. In addition, increasing the thickness (volume) of the mold medium makes it difficult for water to penetrate into the light-emitting element chip 20, thereby increasing durability.
[0048]
In addition, since the medium is liquid, even if an altered portion occurs around the light emitting element chip 20, the medium is rapidly flowed by the convection CF, so that the medium does not stay in the vicinity of the light emitting element chip 20 and the transparency is lost. Degradation is difficult to progress. At this time, heat generated by energization of the light emitting element chip 20 has an effect of promoting the convection CF of the liquid mold medium 30. Further, since the heat dissipation effect is promoted by the convection CF of the liquid mold medium 30, a large area (for example, one side of the light emitting layer portion is 300 μm or more and 1000 μm or less) and a large current (for example, a rated current of 50 mA or more and 1000 mA or less, Even when a chip with a rated output of 0.1 W or more and 5 W or less is used, an excessive temperature rise of the light emitting module 64 hardly occurs, and it is not necessary to consider a complicated heat sink structure on the light emitting element chip 20 side. The volume of the liquid mold medium 30 is, for example, 10 times or more the volume of the light emitting element chip 20 and 10⁷It is better to set it to double or less.
[0049]
In addition, tetrabromoethane (refractive index: 1.64) is used as the liquid mold medium 30, and the entire translucent shell 65 has a refractive index of approximately 1.5 (1.45 or more and 1.55 or less) such as acrylic resin. In this case, the refractive index gradually decreases from the liquid mold medium 30 side through the translucent shell 65 toward the air surrounding the outer side (refractive index: 1.0). It is possible to effectively suppress the return of the luminous flux due to the light, and to further improve the light extraction efficiency. On the other hand, when the liquid mold medium 30 having a refractive index of around 1.5 (1.45 to 1.55) such as methylphenyl silicone oil is used, as shown by a one-dot chain line in FIG. The outer side of the main body portion (inner layer portion) 65m of the translucent shell 65 is covered with an intermediate refractive index material layer 65w made of fluororesin (refractive index of 1.3 or more and 1.4 or less) as the outermost layer portion. And can improve the light extraction efficiency.
[0050]
Hereinafter, various other embodiments of the light emitting module of the present invention will be described. Since there are many common parts with the first embodiment, the differences are mainly described, and the common parts are denoted by the same reference numerals as those of the first embodiment, and the detailed description is not repeated.
(Embodiment 2)
In the light emitting module 164 of FIG. 6, the light emitting layer portion 24 of the light emitting element chip 200 combines a plurality of light emissions having different peak wavelengths, and uses the light emission intensity at the peak wavelength of the combined spectrum as a reference intensity. The effective wavelength region showing the emission intensity of 5% or more of the intensity is assumed to emit and output light having a quasi-continuous spectrum secured over a wavelength width of 50 nm or more.
[0051]
The light emitting layer portion 24 of the light emitting element chip 200 is a first light emitting layer portion 24a and a second light emitting layer portion 24b, both of which are double hetero light emitting layer portions (hereinafter simply referred to as light emitting layer portions) made of a compound semiconductor. ) The active layers 24a and 24b (see FIGS. 2 and 3) include a plurality of light emitting unit layers having different band gap energies. The first light emitting layer portion 24a is set in the range where the emission wavelength of the light emitting unit layer is 520 nm to 700 nm, and the second light emitting layer portion 24b is set in the range where the emission wavelength of the light emitting unit layer is 360 nm to 560 nm. Is done. The light emitting element chip 200 has a pseudo continuous spectrum by, for example, synthesizing the continuous spectrum of the heat radiation type light source by mixing the light emitted from the two types of light emitting layer portions 24a and 24b with each other. It emits light as visible light.
[0052]
As shown in FIG. 7, the light emitting layer portion 24a is made of (Al_xGa_1-x)_yIn_1-yActive layer 5a made of a mixed crystal of P (where 0.ltoreq.x.ltoreq.0.55, 0.45.ltoreq.y.ltoreq.0.55) (for example, non-doped layer: a dopant can be added if necessary) , P-type (Al_zGa_1-z)_yIn_1-yA p-type cladding layer 6a made of P (where x <z ≦ 1) and an n-type (Al_zGa_1-z)_yIn_1-yIt has a structure sandwiched between n-type cladding layers 4a made of P (where x <z ≦ 1). The light emitting layer portion 24b is made of non-doped In_aGa_bAl_1-abThe active layer 5b made of N mixed crystal is made p-type In_aGa_bAl_1-abN-type p-type cladding layer 6b and n-type In_aGa_bAl_1-abIt has a structure sandwiched between n-type cladding layers 4b made of N. The term “non-dope” as used herein means “does not actively add a dopant”, and contains an inevitable dopant component in a normal manufacturing process (for example, 10%).¹³-10¹⁶/ Cm³Is not excluded). In the present embodiment, the light emitting layer portion 24a and the light emitting layer portion 24b are bonded in series with a transparent conductive connection layer (for example, a conductive oxide layer such as ITO (Indium-TinOxide)) 112, and the whole is formed into a single unit. The light emitting element chip 200 is used. However, both the light emitting layer portions 24a and 24b may be configured as individual light emitting element chips.
[0053]
FIG. 8 schematically shows an example of the structure of the active layer 5a of the first light emitting layer portion 24a in the form of a band diagram. FIG. 11 schematically shows an example of the structure of the active layer 5b of the second light emitting layer portion 24b in the form of a band diagram. In the active layers 5a and 5b, the light emitting unit layer is composed of well layers W1 to Wn sandwiched between two barrier layers B and B, respectively. By using the well layers W1... Wn sandwiched between the barrier layers B and B as the light emitting unit layers, the light emission efficiency of the individual light emitting unit layers can be increased due to the carrier confinement effect in the well layers. The light emission wavelengths of the respective well layers W1... Wn are bandgap energies Eg1... Egn (FIG. 8), Eg′1... Eg′n (FIG. 11) (≡Ec-Ev value in each well layer: Ec The conductor bottom energy level, Ev, is determined according to the valence band top energy level. In this embodiment, each of the well layers W1... Wn has different band gap energies and forms individual light emitting unit layers. That is, the number of well layers included in one light emitting unit layer is one. However, a set of a plurality of well layers having the same band gap energy may be used as the light emitting unit layer.
[0054]
In both the first light emitting layer portion 24a and the second light emitting layer portion 24b, the plurality of light emitting unit layers, that is, the well layers W1... Wn, are arranged between adjacent band gap energies in a large and small arrangement of band gap energies. The difference value ΔE is set to 0.42 eV or less, preferably 0.2 eV or less. If the difference value ΔE between the band gap energies becomes excessively large, the distance between the peak positions of the unit spectrum becomes too large, resulting in a large wave in the synthesized waveform, and a smooth spectrum cannot be obtained. Note that the difference value ΔE can be set equal to the set of all light emitting unit layers adjacent to each other with the band gap energy, or the wavelength range where the intensity is consciously increased according to the required emission spectrum shape. For example, at least a part of the light emitting unit layers may be set at unequal intervals, for example, by narrowing the intervals and conversely increasing the intervals in the wavelength region where the intensity is desired to be suppressed.
[0055]
For example, the active layers 5a and 5b of the first light emitting layer portion 24a and the second light emitting layer portion 24b are designed so that the pseudo continuous spectrum to be obtained has a pseudo light bulb light spectrum simulating the continuous spectrum of an incandescent light bulb. ing. FIG. 15 shows a spectrum waveform when an incandescent bulb using a tungsten filament is caused to emit light at a color temperature of about 3000K. As indicated by the broken line, the intensity peak exists in the vicinity of 800 nm in the near infrared region, and the intensity distribution in the visible light band tends to increase with the emission wavelength. It can be readily understood that the temperature of the light source is likely to increase due to the fact that it includes a considerable intensity of infrared rays.
[0056]
In the present invention, the continuous spectrum of FIG. 15 is combined with monochromatic light (light emitting units) of various wavelengths from a plurality of light emitting unit layers, so to speak, and is digitally synthesized into a pseudo continuous spectrum. If the first light emitting layer portion 24a is not provided with a well layer that emits light at a wavelength of 700 nm or more, the infrared light emitting component can be greatly reduced as shown by the solid line in FIG. Further, in the continuous spectrum of the incandescent lamp, the short wavelength region includes a slight but harmful ultraviolet ray. However, if the well layer that emits light at a wavelength of 360 nm or less is not provided in the second light emitting layer portion 24b as described later, the ultraviolet light emitting component can also be reduced.
[0057]
In the present embodiment, each active layer 5a, 5b is configured as follows. That is, as shown in FIG. 9 (first light emitting layer portion 5a) and FIG. 12 (second light emitting layer portion 5b), the plurality of light emitting unit layers emit light as the light emitting unit layer (well layer) has a longer emission wavelength. The intensity I is adjusted to be high. Specifically, the thickness or number of the well layers is increased as the emission unit layer has a longer emission wavelength. In order to approach the spectrum waveform shown in FIG. 15, for example, the ratio I650 / I560 between the intensity I650 at 650 nm and the intensity I560 at 560 nm is set to about 1.4.
[0058]
In both the first light emitting layer portion 24a and the second light emitting layer portion 24b, the emission intensity I increases as the wavelength of the emission spectrum increases. However, as shown in FIG. 10, the relative visibility of visible light with respect to the emission wavelength is maximized in the vicinity of 555 nm in a bright place. In FIGS. 9 and 12, a curve indicating the wavelength dependence of the visibility correction coefficient V is indicated by a one-dot chain line. The visibility correction intensity can be represented by the product V · I of the light emission intensity I and the visibility correction coefficient V. As shown in FIG. 9, in the first light emitting layer portion 24a, the wavelength dependency between the light emission intensity I and the visibility correction coefficient V tends to be reversed. Produces a peak in the yellow to orange range. On the other hand, as shown in FIG. 12, since the wavelength dependency of the light emission intensity I and the visibility correction coefficient V is the same in the second light emitting layer portion 24b, the visibility correction intensity V · I is monotonous as the wavelength increases. To increase.
[0059]
In the light emitting element chip 200 of FIG. 7, the spectrum of the first light emitting layer portion 24a on the long wavelength region side and the spectrum of the second light emitting layer portion 24b on the short wavelength region side are synthesized and output. As a result, the spectrum waveform SB of the second light emitting layer portion 24b is connected to the short wavelength side of the spectrum waveform SA of the first light emitting layer portion 24a, and a pseudo bulb light spectrum as shown in FIG. 13 is finally obtained. It is done. That is, the emission intensity I of the pseudo-bulb light spectrum is the spectrum of the incandescent lamp in FIG. 15, that is, the emission intensity distribution after the visibility correction has an intensity peak from the yellow range to the orange range, that is, from 570 nm to 640 nm, A warm and soft lighting color with a yellowish or orange tint similar to an incandescent bulb is obtained.
[0060]
In addition, the final shape of the emission spectrum can be arbitrarily formed by adjusting the emission intensity of the emission unit layer of each wavelength according to the number of layers and the layer thickness. In particular, when it is desired to obtain illumination light that is close to the color rendering properties of natural light, a pseudo sunlight spectrum that simulates the continuous spectrum of sunlight may be synthesized as a pseudo continuous spectrum. FIG. 14 shows the sunlight spectrum in the visible region, but since the color temperature is as high as about 6000 K, the intensity peak occurs in a short wavelength region near 400 nm as compared with the incandescent bulb. Further, the emission intensity I tends to decrease as the wavelength increases over substantially the entire visible light wavelength band. Therefore, contrary to FIGS. 9 and 12, the plurality of light emitting unit layers may be adjusted so that the light emission intensity I becomes higher as the light emission wavelength is shorter.
[0061]
The embodiment in the case where it is desired to faithfully reproduce the spectrum waveform of the heat radiation type light source has been described above, but the present invention is not limited to this. For example, even if visible light in the blue wavelength range is cut from the emission spectrum of the incandescent light bulb, the dominant yellow or orange illumination color unique to the incandescent light bulb can be simulated in the remaining wavelength range only. There is no. In this case, a light source module can be comprised only by the 1st light emitting layer part 24a. In addition, when it is desired to obtain illumination light in which the red wavelength range is cut, the light source module may be configured with only the second light emitting layer portion 24b.
[0062]
In the light emitting element chip 200, since light beams having a plurality of wavelengths are mixed and emitted from the beginning, the translucent shell 65 or the liquid mold medium 30 is configured to be transparent without blending light scattering particles. Even so, it is difficult to cause a problem that separation occurs in the color mixture state. If both the translucent shell 65 and the liquid mold medium 30 are made transparent, a light-reflective floating decorative body (for example, metal glitter) 30d in the liquid mold medium 30 (FIG. 16). Is dispersed by the convection CF generated in the liquid mold medium 30, the floating decorative body 30 d moves sparkly in the translucent shell 65, and an interesting lighting effect is obtained.
[0063]
(Embodiment 3)
In the light emitting module 264 of FIG. 17, the light emitting element chip 300 includes a light emitting layer portion 24 capable of emitting light in the near ultraviolet to purple to blue region (peak wavelength: 300 nm or more and 470 nm or less). The light emitting layer portion 24 has a double hetero structure in which an active layer and a cladding layer are made of InAlGaN or MgZnO. The liquid mold medium 30 includes a fluorescent material 30L that receives the emitted light beam LB from the light emitting layer portion 24 and emits fluorescence LL having a peak wavelength different from that of the emitted light beam LB. The fluorescent material 30L to be used is suspended in the liquid organic material in the form of solid fluorescent material particles.₂O₃: Eu³⁺(R: center wavelength 611 nm), CeMgAl₁₁O₁₉: Tb³⁺(G: center wavelength 543 nm), BaMg₂Al₁₆O₂₇: Eu²⁺By mixing phosphors of various colors such as (B: center wavelength 452 nm), illumination light of various colors can be obtained. In this configuration, the liquid mold medium 30 itself emits light uniformly as a light emitting medium, so that a light emission distribution with a small directivity suitable for illumination can be easily obtained. Further, a desired emission spectrum can be easily designed by adjusting the material and blending ratio of the fluorescent material 30L.
[0064]
In this case, when the luminous flux from the light emitting element chip 300 is mainly composed of visible light, the visible luminous flux having a different wavelength excited by the fluorescent material 30L can be mixed and emitted. . In this case, the light emitting element chip 300 is configured to emit purple or blue light, and if the fluorescent material 30L is mixed with green light emitting material and red light emitting material, the light emitting device chip 300 can emit light from the light emitting device chip 300. The green or red light emitted from the fluorescent material 30L is mixed with the purple or blue light emitted, and white illumination light can be obtained. On the other hand, when the luminous flux from the light-emitting element chip 300 is mainly composed of near-ultraviolet light, the fluorescent material 30L emits blue light, green light, and red light. By mixing the light emission beams of the respective colors from the fluorescent material 30L, white illumination light can be obtained. In any case (especially the latter), a considerable amount of ultraviolet components are emitted from the light emitting element chip 300, but the liquid organic compound that forms the base of the liquid mold medium 30 is composed of the aforementioned silicone oil or tetrabromoethane. In this case, alteration due to ultraviolet irradiation is unlikely to occur, and even if alteration occurs, the influence is reduced by convection, and therefore, it is difficult to cause deterioration problems such as an epoxy resin mold.
[0065]
(Embodiment 4)
In the above embodiment, all of the lighting devices are configured in the shape of an electric rod, but the present invention is not limited to this. FIG. 23 shows an example in which a lighting device 100 having a candle-like appearance is configured as an example of a lighting device that simulates a combustion light source. The lighting device 100 uses a light source module 64 ′ having the same basic structure as that in FIG. 6, and is lit by a power supply unit 70 using a commercial AC power source. The pseudo continuous spectrum of the light emitting element chip 200 of the light source module 64 ′ has a pseudo combustion light spectrum simulating the continuous spectrum of combustion light. Specifically, in order to imitate the continuous spectrum of candlelight, the active layers 5a and 5b are designed so that a pseudo continuous spectrum (for example, about 1500 K) having a lower color temperature than that of FIG. 15 is obtained. The emission color is more orange or reddish.
[0066]
The power supply unit 70 is housed in a main body 262 simulating a candle shaft, and a light source module 64 ′ is disposed at the tip of the power supply unit 70, and a transparent translucent shell 65 imitating the external appearance of a flame is disposed on the outside. Covered with. The liquid mold medium 30 is also transparent. The power supply unit 70 receives power from an outlet via the power cord 134 and the power plug 135 drawn from the main body 262. When the illuminating device 100 is turned on, the luminous flux from the light emitting element chip 200 fluctuates by the convection CF of the liquid mold medium 30, and the atmosphere of the candle flame can be realistically reproduced.
[0067]
24 is an example in which a plurality of light emitting element chips 20 are arranged in the liquid molding medium 30. The lighting device 300 shown in FIG. In this embodiment, the light emitting element chips 20 are arranged in a longitudinal direction in a horizontally long case 301 containing the power supply unit 70. A horizontally long translucent shell 302 filled with the liquid mold medium 30 is fitted to the case 301 via a seal member 163 and sealed.
[0068]
Moreover, although the above embodiment demonstrated the light emitting module of visible light as an example, this invention is applicable also to an infrared light emitting module. In this case, the light emitting layer portion may be configured to have an emission wavelength in the infrared region such as AlGaAs.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first example of a lighting device using a light emitting module of the present invention.
FIG. 2 is a cross-sectional view showing a first example of a light emitting module of the present invention.
3 is a schematic diagram showing a cross-sectional structure of a light emitting element chip used in the light emitting module of FIG. 2;
4 is a diagram showing an example of a circuit configuration of a power supply unit used in the lighting device of FIG. 1. FIG.
FIG. 5 is a cross-sectional view showing a second example of the light emitting module of the present invention.
FIG. 6 is a cross-sectional view showing a third example of the light emitting module of the present invention.
7 is a schematic diagram showing a cross-sectional structure of a light-emitting element chip used in the light-emitting module of FIG.
8 is a band diagram showing a configuration example of an active layer of the first light emitting layer portion in the element chip of FIG.
FIG. 9 is a conceptual explanatory diagram of a pseudo continuous spectrum by a first light emitting layer part.
FIG. 10 is a graph showing the wavelength dependence of relative visibility with respect to visible light.
11 is a band diagram showing a configuration example of an active layer of a second light emitting layer portion in the element chip of FIG.
FIG. 12 is a conceptual explanatory diagram of a pseudo continuous spectrum by a second light emitting layer part.
FIG. 13 is a conceptual diagram of a combined spectrum of a first light emitting layer part and a second light emitting layer part.
FIG. 14 is an explanatory diagram showing a sunlight spectrum in a visible light band.
FIG. 15 is an explanatory diagram showing a spectrum of an incandescent bulb in the visible light band.
FIG. 16 is a cross-sectional view showing a fourth example of the light emitting module of the present invention.
FIG. 17 is a cross-sectional view showing a fifth example of the light emitting module of the present invention.
FIG. 18 is a perspective view showing a first example of a translucent shell shape used in the light emitting module of the present invention.
FIG. 19 is a perspective view showing a second example.
FIG. 20 is a perspective view showing a third example.
FIG. 21 is a sectional view and a perspective view showing a fourth example.
FIG. 22 is a cross-sectional view and a perspective view showing a fifth example.
FIG. 23 is a diagram showing a second example of a lighting device using the light emitting module of the present invention.
FIG. 24 is a diagram showing a third example of a lighting device using the light emitting module of the present invention.
FIG. 25 is an explanatory diagram of a translucent shell shape.
FIG. 26 is a schematic view showing a modification of the assembly mode of the light emitting element chips in the light emitting module.
FIG. 27 is a sectional view showing a sixth example of the light emitting module of the present invention.
FIG. 28 is a cross-sectional view showing a seventh example of the light emitting module of the present invention.
[Explanation of symbols]
1,100,300 Lighting device
7 Translucent substrate
8 High conductivity layer
9 First electrode
15 Second electrode
20,200 Light emitting device chip
MP1 first main surface
VP1 first virtual plane
PP circumferential side
VP2 Virtual cylinder surface
MP2 second main surface
VP3 second virtual plane
24 Light emitting layer
LB Luminous flux
30 Liquid mold media
30a Liquid organic compounds
30L fluorescent material
31, 33 Terminal lead
64,164,264,364,464 light emitting module
65 Translucent shell
65q opening
65w Intermediate refractive index material layer
65m body part (inner layer part)
65j Light extraction wall
65r reflective layer
RB reflected light
131,132 Power supply terminal
161 Terminal mold part
170 High refractive index particles

Claims (13)

A light emitting element chip having a light emitting layer portion composed of a laminate of compound semiconductor layers;
A liquid mold medium having translucency with respect to the luminous flux from the light emitting layer portion and covering the surrounding space of the light emitting element chip in direct contact with the light emitting element chip;
A light-transmitting shell that contains and seals the liquid mold medium together with the light-emitting element chip, which is made of a solid material that transmits light emitted from the light-emitting layer.
Have
The liquid mold medium is mainly composed of a liquid organic compound,
The refractive index of the liquid mold medium is set to 1.3 or more,
Ri said liquid organic compound is tetrabromoethane der constituting the liquid mold medium,
The translucent shell is composed of an intermediate refractive index material having at least an outermost layer portion having an intermediate refractive index between the liquid mold medium and air,
The liquid mold medium and the inner layer portion of the translucent shell contacting the liquid mold medium are both made of a material having a refractive index of 1.45 or more, while the outermost layer portion of the translucent shell is A light emitting module comprising a fluororesin having a refractive index of less than 1.45 .   The light emitting module according to claim 1, wherein the liquid mold medium is a composite medium in which particles having a higher refractive index than the liquid organic compound are suspended in the liquid organic compound.   The light emitting module according to claim 2, wherein an average particle diameter of the high refractive index particles is smaller than a center wavelength of an emitted light beam from the light emitting layer portion.   4. The light emitting module according to claim 2, wherein a dispersant (sodium hexametaphosphate, condensed sodium naphthalene sulfonate, various surfactants, etc.) is added to the liquid mold medium. The liquid mold medium, any of claims 1 to 4, wherein the receiving the emission beam from the light emitting layer portion are those containing a fluorescent material that emits different fluorescence of emitting light flux and peak wavelength The light emitting module according to claim 1. In the translucent shell, a partial region of the inner surface of the wall portion is used as a light extraction wall portion, and a reflective layer for reflecting the emitted luminous flux is provided in the remaining region of the inner surface, from the light emitting layer portion. to direct light beams toward the light extraction wall, the light emitting module according to any one of claims 1 to 5, characterized in that they were taken out by superimposing the light reflected by the reflective layer. The light emitting element chip has an electrode for light emission driving, and a terminal lead portion for energization is extended from the electrode, and the liquid mold medium includes the electrode of the terminal lead portion together with the light emitting element chip. the light emitting module according to any one of claims 1 to 6, characterized in that it is arranged so as to cover the connecting-side end portion of the. The wall portion of the translucent shell has a shape in which at least a part of the portion facing the first virtual plane extending the first main surface of the light emitting element chip is convex outward as viewed from the light emitting element chip. the light emitting module according to any one of claims 1 to 7, characterized in that formed by a curved convex curved wall portion. The wall portion of the translucent shell is curved in a shape in which at least a part of a portion facing the virtual straight body surface extending the peripheral side surface of the light emitting element chip is outwardly convex when viewed from the light emitting element chip. the light emitting module according to any one of claims 1 to 8 is the convex curved wall portion, characterized by comprising that. The wall portion of the translucent shell has a shape in which at least a part of the portion facing the second virtual plane extending the second main surface of the light emitting element chip is outwardly convex when viewed from the light emitting element chip. The light emitting module according to any one of claims 1 to 9 , wherein the light emitting module is a convex curved wall portion curved in a straight line. The translucent shell body, the light emitting module of claim 1 0, wherein the whole is formed spherical, egg-shaped or jujube shape. The light-emitting element chip has a light-transmitting substrate having a light-transmitting property with respect to a light flux emitted from the light-emitting layer portion, and the first main surface of the light-transmitting substrate is a light extraction surface. A high conductivity layer having a sheet resistance lower than that of the light emitting layer portion is formed on the second main surface of the translucent substrate, and the light emitting layer portion is formed on the high conductivity layer. A first electrode as the electrode is disposed on the second main surface side of the light emitting layer, and an exposed portion of the high conductivity layer is formed by cutting out a partial region of the light emitting layer portion, and the electrode is formed on the exposed portion. As the second electrode is arranged,
The terminal lead portion, which respectively from the first electrode and the second electrode, according to claim 7 or claim, characterized in that formed by extending formed in a direction away from the first major surface of the transparent substrate the light emitting module according to any one 1 1. An opening is formed in the translucent shell, and a terminal mold part is disposed so as to seal the opening, and the terminal lead part is disposed so as to penetrate the terminal mold part and its first end is The light emitting element chip extends to the inner space of the light transmissive shell body, and the light emitting element chip is connected to the tip of the light transmissive shell body, while the second end is located outside the light transmissive shell body. the light emitting module of claim 1 wherein forming the power supply terminal.

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