JP3991612B2 - Light emitting element - Google Patents

Light emitting element Download PDF

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JP3991612B2
JP3991612B2 JP2001109819A JP2001109819A JP3991612B2 JP 3991612 B2 JP3991612 B2 JP 3991612B2 JP 2001109819 A JP2001109819 A JP 2001109819A JP 2001109819 A JP2001109819 A JP 2001109819A JP 3991612 B2 JP3991612 B2 JP 3991612B2
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light
light emitting
lens
emitting element
emitting device
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JP2002305328A (en
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英夫 朝川
大祐 薦田
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Nichia Corp
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Nichia Corp
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805Shape
    • H01L2224/4809Loop shape
    • H01L2224/48091Arched
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481Disposition
    • H01L2224/48151Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481Disposition
    • H01L2224/48151Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48257Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a die pad of the item
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/15Details of package parts other than the semiconductor or other solid state devices to be connected
    • H01L2924/181Encapsulation

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Description

【0001】
【発明の属する技術分野】
本発明は、所定の方向に均一な指向性を有し薄型で高出力の発光素子に関する。
【0002】
【従来の技術】
近年、窒化ガリウム系化合物半導体を用いて紫外領域から黄色の光を発光することができる発光ダイオードが開発されたことから、紫外領域から赤色までの幅広い領域の用途に対応して種々の発光素子の作製が可能になった。
これらの発光素子において、所定の方向に均一な指向性が要求される場合には、例えば樹脂が成形されてなるレンズと発光素子とを組み合わせて所定の指向特性を得ている。
【0003】
従来は、発光素子と組み合わせるレンズは、例えば、図13に示すように、キャスティングケース100のレンズ形状に対応する空洞内にリードフレーム101上に設けられた発光素子チップ102をセットして、その空洞内に透光性樹脂110を流し込んでレンズを形成する方法、又は、図14に示すように、成形金型104内に基板103上に設けられた発光素子チップ102をセットして、透光性樹脂111を射出成形することにより形成する方法等により作製されていた。
【0004】
【発明が解決しようとする課題】
しかしながら、従来の構成及び方法では、指向性のバラツキを十分小さく抑えることが難しく、また、薄型化が困難であるという問題点があった。
【0005】
そこで、本発明は、指向性のバラツキを十分小さく抑えることができ、かつ薄型化が可能な発光ダイオードとその製造方法を提供することを目的とする。
【0006】
【課題を解決するための手段】
本発明に係る発光素子は、互いに対向する第1の主面と第2の主面を有し、上記第1の主面を発光観測面としかつ上記第2の主面に正及び負の電極が形成された発光素子チップと、上記第1の主面上に形成されたレンズとを備え、
上記第1の主面の外周端部と上記レンズの外周端部とが実質的に一致し、かつ上記レンズの球面が上記外周端部より外側に膨らんで形成されていることを特徴とする。
このように、本発明に係る発光素子は、上記第1の主面の外周端部と上記レンズの外周端部とが実質的に一致するように上記発光面上のみにレンズが形成されているので、薄型化が図れる。
また、上記レンズの球面が上記レンズの外周端部より外側に膨らんで形成されているので、上記発光観測面である第1の主面の外周端部にいて輝線が観測されることを防止できる。
さらに、本発明に係る発光素子において、上記発光素子はさらに、光散乱粒子を含む遮光層を有し、該遮光層は上記発光素子チップの側面と上記レンズの外周端部及びその近傍とを連続的に覆うように設けられている。
これにより、実質的に発光した光を実質的に発光観測面のみから出力できるので、発光強度を向上させることができる。
【0007】
た、本発明に係る発光素子において、上記散乱粒子として酸化ケイ素、チタン酸バリウム、酸化チタン、酸化アルミニウムからなる群から選択される少なくとも1つを含む粒子を用いることができる。
【0008】
さらに、本発明に係る発光素子においては、上記発光素子チップを窒化物半導体発光素子チップとし、上記レンズは蛍光体を含むようにすることができる。
このようにすると、発光素子チップからの光と蛍光体からの光との混色による発光色が得られる。
また、上記蛍光体として、少なくともセリウムで付活されたイットリウム・アルミニウム・ガーネット系蛍光体を含む蛍光体を用いることができる。
さらに、上記発光素子チップは、主発光波長が530nm以下の可視光を発光するようにできる。
ここで、本発明におけるセリウムで付活されたイットリウム・アルミニウム・ガーネット系蛍光体は、広義に解釈するものとし、Yの少なくとも一部をGdやLa等に置換するもの、Alの少なくとも一部をInやGa等に置換するもの、Ceの少なくとも一部をTb等に置換するものを含む。他の蛍光体として、発光素子チップの発光スペクトル、蛍光体の発光スペクトルや励起スペクトルを考慮して、種々のものを利用することができるが、Eu及び/又はCrで付活されたCa−Al−Si−O−N系オキシナイトライド蛍光硝子やYS:Eu,Sr(POCl:Eu,(SrEr)O・Al等が挙げられる。
【0009】
【発明の実施の形態】
以下、図面を参照しながら、本発明に係る実施の形態の発光素子について説明する。
本実施の形態の発光素子は、一方の主面にn電極とp電極とが形成され他方の主面を発光観測面とする発光素子チップ1と、レンズ20と、遮光膜30とを備え、レンズ20がパッケージ内に設けられた発光素子チップ1の発光観測面に形成されていることを特徴とし、これにより高い指向特性と発光輝度の向上を実現している。
以下、詳細に本実施の形態の発光素子について説明する。
【0010】
本実施の形態おいて、パッケージ50は、正電極板51と負電極板52とが樹脂54により連結されてなる底部電極部と、その底部電極部の上面に発光素子チップを収納する収納部が形成されるように該上面の周囲に接合された外枠53により構成される。
また、発光素子チップ1は、例えば、サファイアからなる基板10の上に、例えばn型窒化ガリウム系化合物半導体からなるn型半導体層11と、例えばp型窒化ガリウム系化合物半導体からなるp型半導体層12とが積層され、n型半導体層11及びp型半導体層12の上にそれぞれ、n電極14及びp電極13とが形成されて構成される。
【0011】
以上のように構成された発光素子チップ1は、図1に示すように、パッケージ50の正電極板51と負電極板52にそれぞれp電極13とn電極14とが対向するように配置され、例えば、半田、銀ペースト等の導電性接着材15,16や金バンプ等の金属により接合される。
そして、レンズ20は、以下の2つの条件を満足するように発光素子チップ1の発光観測面(第1の主面)上に形成されている。
第1に、レンズ20は、レンズ20の外周端部(発光素子チップ1とレンズ20とが接する境界におけるレンズ20の外周端部)が発光素子チップ1の発光観測面(第1の主面)の外周端部と実質的に一致するように形成される。
第2に、レンズ20は、レンズ20の球面がレンズ20の外周端部より外側に膨らむように、すなわち、レンズの光軸上の上方からレンズ20及び発光素子チップ1を見た時に、発光素子チップ1の発光観測面(第1の主面)の外周端部がレンズ20の球面によって覆い隠されるように形成される。
【0012】
また、遮光膜30は、発光素子チップが発光する光を反射散乱させる、例えば、TiOからなる光散乱粒子を含む樹脂等からなり、少なくとも発光素子チップ1の側面とレンズ20の球面におけるレンズ20の外周端部の近傍とを含むように、発光素子チップ1の周りに形成される。
このように、遮光膜30を、発光素子チップ1の側面とレンズ20の球面における外周端部の近傍とに亙って形成することにより、発光素子チップ1の側面から放出される光を遮光膜30により反射してレンズ20を介して出力できるので、より効果的に発光素子チップ1の側面から放出される光を利用することができ、発光出力を向上させることができる。
【0013】
また、本発明では、図1に示すように、散乱粒子を含む遮光膜は、発光素子チップ1のp電極13とn電極14の間にできる発光素子チップ1とパッケージ50の底部電極板との間の隙間にも形成することが、以下のような点でより好ましい(図1においてこの遮光膜は31の符号を付して示している。)。
すなわち、上述の位置に遮光膜31をさらに形成すると、発光素子チップ1の発光観測面を除く外表面が全て、遮光膜30,31と遮光性のある電極層(p電極13,n電極14)とによって覆われていることになり、発光層において発光した光を発光観測面から効果的に放出することができるので、発光効率を向上させることができる。
【0014】
次に、発光素子チップ1の発光観測面の外周端部1a付近におけるレンズ20、発光素子チップ1、遮光層30の位置関係について、図2を参照しながら、詳細に説明する。
レンズ20は、以下に説明する方法により形成されるので、実際に形成された後の、レンズ20の外周端部20aは、発光観測面の外周端部1aの若干下に位置することがある。しかしながら、発光素子チップ1の厚さが通常、80μm〜100であるのに対し、レンズ20が形成された後のレンズ20の外周端部20aと発光観測面の外周端部1aの間隔は通常10μm以下であり、本明細書において、この程度のずれは実質的に一致しているという。
また、遮光膜30は、発光素子チップ1の側面からレンズ20の外周端部の近傍に位置する球面とを連続して覆うように形成される。
【0015】
以上のように構成された実施の形態の発光素子は、レンズ20を、そのレンズ20の外周端部が発光素子チップ1の発光観測面の外周端部と実質的に一致するように、かつレンズ20の球面がレンズ20の外周端部より外側に膨らむように形成し、しかも遮光膜30を、発光素子チップ1の側面からレンズ20の外周端部の近傍に位置する球面とを連続して覆うように形成しているので、光軸に対して角度の大きい方向の光の強度を効果的に抑えることができ(図11における0度〜20度、160度〜180度付近)、全体的に均一な指向性が得られる。
【0016】
すなわち、従来のように発光素子チップ全体(発光素子チップの発光観測面と側面の両方)を覆うようにレンズを形成すると、長方体形状に形成されるパッケージにおいては、その長軸方向における指向性と短軸方向における指向性が異なるが、本実施の形態では、発光素子チップに直接レンズ20を形成するようにしているので、パッケージの形状に影響されることなく、方向性のない指向特性を実現できる。
【0017】
また、従来のように発光素子チップ全体を覆うようにレンズを形成すると、発光素子チップの発光観測面から出力される光と発光素子チップの側面から出力される光の量やダイシング状態(加工バリや形状)が変化すると、その変化により指向特性が変化することから、指向特性にばらつきが生じやすいが、本実施の形態の窒化物半導体発光素子では、発光観測面上に形成されたレンズ20と発光素子チップの側面を取り囲むように形成された遮光膜により、発光素子チップにより発光された光は実質的に発光観測面のみから出力されるので、指向特性のばらつきを小さくできる。
【0018】
次に、本実施の形態の発光素子におけるレンズの形成方法と遮光膜の形成方法について説明する。
(レンズの形成方法)
本形成方法では、まず、図3(a)(b)に示すように、発光素子チップ1の発光観測面上のほぼ中央にディスペンサーにより所定量のレンズ形成用樹脂21を塗布する。ここで、レンズ形成用樹脂21は例えば粘度が5000〜8000cpsのエポキシ樹脂に、例えば平均粒径7μmの石英ガラスフィラーが混合されてなり、ディスペンサーの吐出圧力を例えば1.5kgf/cm2に設定して、吐出時間を調節することにより一定量のレンズ形成用樹脂21を塗布する。
このように吐出されたレンズ形成用樹脂21は、図4(a)(b)に示すように、発光観測面の外周端部1aまで広がり、その吐出された樹脂21の量と粘度に対応した形状の球面を形成する。
【0019】
すなわち、発光観測面の外周端部1aまで広がった樹脂は、発光素子チップ1の側面は分割面であるために、滑らかな発光観測面とは異なり凹凸のある粗面となっており、発光観測面の端部1aの外側にさらに広がって流れ出すことはなく、表面張力により樹脂21の量と粘度に対応した形状の球面を形成することになる。
言いかえると、本方法は、発光素子チップの発光観測面の形状及び面積と、形成しようとするレンズ形状に基いて、レンズ形成用樹脂の粘度と塗布量とを設定することにより、所望の形状のレンズ20を形成するものである。
【0020】
次に、レンズ形成樹脂21を硬化させて固体化されたレンズ20とする。
ここで、レンズ形成樹脂21の硬化温度は、例えば、レンズ形成樹脂21のエポキシ樹脂が150℃以上のガラス転位点を有する場合、レンズを形状のばらつきなく一定の形状に形成するために、120℃,2時間で硬化させた後さらに、150℃,8時間で硬化させるなど、2段階で硬化させることが好ましい。
そして、レンズ形成樹脂21を硬化させてレンズ20とした後、例えば、反射散乱粒子(光散乱粒子)としてTiOが混合された樹脂をディスペンサーを用いて、発光素子チップの側面とレンズ20の外周端部の近傍とを少なくとも覆うように、発光素子チップ1の両側に塗布して硬化させる。
【0021】
以上のようにして、本実施の形態の発光素子は、上記製造方法を用いて、実質的に発光観測面の上のみにおいてレンズ20を形成することができるので、レンズ20の高さを従来の素子チップ全体を覆うレンズに比較して薄くできる。
また、本実施の形態の発光素子の製造方法において、レンズ20は、高価な金型等を使用することなく、樹脂の粘度と塗布量とを所望のレンズ形状に対応させて設定することにより所望のレンズ形状を形成しているので、金型を用いて形成される従来例に比較して、簡単でかつ安価に製造することができる。
【0022】
以上の実施の形態の窒化物半導体発光素子では、レンズ20に石英ガラスフィラーを混合した例について説明したが、本発明はこれに限られるものではなく、レンズ20に、発光素子チップにより発光された光の一部又は全部を吸収して吸収した光より長波長の光を放出する蛍光体を含有してもよい。
すなわち、レンズ20に石英ガラスフィラーを混合した場合には、発光素子チップが発生する光がそのまま(波長が変化することなく)レンズ20を介して出力されるので、発光色は発光素子チップの発光色となる。
これに対して、レンズ20が蛍光体を含む場合には、以下のように決定される発光色となる。
発光素子チップにより発光される光の一部を蛍光体が吸収する場合は、蛍光体からの光と発光素子チップからの光との混色により得られる光の発光色となる。また、発光素子チップにより発光された全部を蛍光体が吸収する場合、または発光素子チップが紫外光を発光しその紫外光を蛍光体が吸収して発光する場合は、蛍光体が発光する光の発光色となる。
【0023】
【実施例】
以下、本発明にかかる実施例について説明する。
実施例1
(発光素子チップ作製)
まず、発光素子チップとして、InGaNからなる発光層を有し主発光ピークが470nmのLEDチップを準備する。
このLEDチップは、MOCVD法を利用して、サファイア基板上に発光層等の窒化物半導体層を成膜して、所定のエッチング工程を経て所定の位置に電極を形成し、個々のチップに分割することにより作製することができる。
尚、発光層等の窒化物半導体層は、反応室内に洗浄したサファイア基板をセットし、反応ガスとして、TMG(トリメチル)ガス、TMI(トリメチルインジウム)ガス、TMA(トリメチルアルミニウム)ガス、アンモニアガス及びキャリアガスとして水素ガス、さらには不純物ガスとしてシランガス及びシクロペンタジアマグネシウムを利用して成膜することができる。
【0024】
(発光素子チップ実装)
次に、上述のようにして作製されたLEDチップをパッケージ50に電極同士を対向させ発光観測面(サファイア基板の裏面)を上にして実装する。
(レンズ形成)
次に、以下のようにしてレンズ20を形成する。
ガラス点移転が150℃以上である一液性熱硬化型のエポキシ樹脂に、平均粒径が15μmの組成式が(Y0.8Gd0.2Al12:Ceである蛍光体粉末を分散させ、粘度を5000cpsに調整する。
ここで、実施例1では、蛍光体の含有量は、重量比でエポキシ樹脂100に対して、蛍光体を45の割合とした。
【0025】
次に、蛍光体が混合された蛍光体混合エポキシ樹脂を、吐出圧力1.5kgf/cm、吐出時間0.4秒の条件で、LEDチップの発光観測面に塗布する。これにより、所定量の蛍光体混合エポキシ樹脂が発光観測面に塗布され、図3〜図5に示すようにレンズ形状が発光観測面上に形成される。
そして、このレンズ形状に形成された蛍光体混合エポキシ樹脂を120℃で2時間硬化した後さらに、150℃で8時間硬化する。
【0026】
(遮光膜形成)
次に、レンズ形成に用いたものと同様のエポキシ樹脂に、TiO2からなる反射散乱粒子を分散させ、粘度を5000cpsに調整する。
ここで、実施例1では、反射散乱粒子の含有量は、重量比でエポキシ樹脂100に対して、反射散乱粒子を30の割合とした。
そして、調整された反射散乱粒子混合エポキシ樹脂を、発光素子チップの周りに所定量だけ塗布した後、前述と同様の2段階で熱硬化する。
尚、遮光膜は、実施の形態で説明したように、発光素子チップ1の側面からレンズ20の外周端部の近傍の球面とを連続して覆うように形成する。
言いかえると、反射散乱粒子混合エポキシ樹脂の塗布量は、発光素子チップ1の側面からレンズ20の外周端部の近傍の球面とを連続して覆うように設定する。
以上のようにして、実施例1の窒化物半導体発光素子は作製される。
【0027】
以上のように作製された実施例1の窒化物半導体発光素子は、発光色は白色であり、図6に示す指向特性を有していた。
ここで、図6において、実線L1は、長軸方向d1(図8参照)における指向角に対する発光出力Poを示し、破線L2は短軸方向d2(図8参照)における指向角に対する発光出力Poを示す。
図6から明らかなように、本実施例の構成では、長軸方向d1及び短軸方向d2において、ほぼ等しい指向特性を有している。
【0028】
比較例1
比較例1の窒化物半導体発光素子は、実施例1の窒化物半導体発光素子において、レンズ20と遮光膜30とを形成することなく、実施例1と同様にして蛍光体が混合された蛍光体混合エポキシ樹脂を、図10に示すように、パッケージ50のチップ収納部に充填して硬化させたものである。
尚、この比較例1において、蛍光体混合エポキシ樹脂60の表面は、パッケージ50の外枠53の上面とほぼ一致し、かつ実質的に平坦になるように形成する。
すなわち、この比較例1の素子における蛍光体混合エポキシ樹脂は、発光素子チップからの光を遮光する遮光層及び集光させるレンズ形状を有していない。
【0029】
以上のように作製された比較例1の窒化物半導体発光素子は、発光色は白色であり、図7に示す指向特性を有していた。
ここで、図7において、実線L3は、長軸方向d1(図8参照)における指向角に対する発光出力Poを示し、破線L4は短軸方向d2(図8参照)における指向角に対する発光出力Poを示す。
図7から明らかなように、本実施例の構成では、長軸方向d1及び短軸方向d2において、ほぼ等しい特性を有しているが、指向性は実施例1に比較して均一でなく大きくばらつく。
【0030】
また、図6と図7とを比較することにより、実施例1の発光出力は、比較例1に比べて極めて大きくできることがわかる。
【0031】
実施例2.
実施例2の窒化物半導体発光素子は、実施例1の窒化物半導体発光素子において、レンズ20の蛍光体に代えて、石英ガラスフィラーを含有させた点以外は、実施例1と同様にして作製される。
ここで、実施例2において、石英ガラスフィラーの含有量は、重量比でエポキシ樹脂100に対して、石英ガラスフィラーを30の割合とした。
以上のようにして作製した実施例2の窒化物半導体発光素子の発光色は青色である(すなわち、図1に示す構造で発光色は青色である)。
【0032】
比較例2.
比較例2の窒化物半導体発光素子は、比較例1の窒化物半導体発光素子のパッケージ50の収納部に充填された樹脂において、蛍光体に代えて、石英ガラスフィラーを含有させた点以外は、比較例1と同様にして作製される。
以上のようにして作製した比較例2の窒化物半導体発光素子の発光色は青色である(図10に示す構造で発光色は青色である)。
【0033】
以上のようにして作製した実施例2の素子と比較例2の素子の発光強度と光出力とを比較してそれぞれ、図9(a)と図9(b)に示す。
図9(a)と図9(b)に示すように、実施例2の素子の発光強度及び光出力は、比較例2の素子に比べて、極めて高くできる。
尚、図9に示すデータは、実施例2の素子及び比較例2の素子とをそれぞれ600個(各3ロット)ずつ作製して、その平均値を示したものである。
【0034】
また、図11は、実施例2の発光素子の指向特性を示すグラフであり、実線L5は長軸方向d1の指向特性を示し、破線L6は短軸方向d2の指向特性を示す。
この実施例2の発光素子においても、実施例1と同様、長軸方向d1の指向特性と短軸方向d2の指向特性とはほぼ同一である。
【0035】
比較例3.
比較例3の発光素子は、比較例2の発光素子において、石英ガラスフィラーを含有させた樹脂の表面を平坦ではなく、レンズ形状にした以外は比較例2と同様に構成される。
この比較例3の発光素子の指向特性は、図12に示すようになる。
ここで、図12において、実線L7は長軸方向d1の指向特性であり、破線L8は短軸方向d2の指向特性である。
図12から明らかなように、比較例3の素子では、長軸方向d1と短軸方向d2では指向特性が異なる。
これに対して、本発明の発光素子では、長軸方向d1の指向特性と短軸方向d2の指向特性とをほぼ同一にできる。
【0036】
【発明の効果】
以上詳細に説明したように、本発明に係る発光素子は、上記第1の主面を発光観測面としかつ上記第2の主面に正及び負の電極が形成された発光素子チップの第1の主面上にレンズが形成され、かつそのレンズは上記第1の主面の外周端部と上記レンズの外周端部とが実質的に一致し、かつ上記レンズの球面が上記レンズの外周端部より外側に膨らむように形成されているので、薄型化が図れ、かつ発光観測面の外周端部において輝線が観測されるのを防止できる。
また、本発明に係る発光素子は、金型を用いることなくレンズを形成することができるので、安価に製造できる。
また、本発明に係る発光素子において、光散乱粒子を含む遮光層を上記発光素子チップの側面と上記レンズの外周端部及びその近傍とを連続的に覆うように設けることにより、発光した光を実質的に発光観測面のみから出力できるので、発光強度を向上させることができる。
【図面の簡単な説明】
【図1】 本発明に係る実施の形態の発光素子の構成を示す断面図である。
【図2】 図1の一部を拡大して示す断面図である。
【図3】 実施の形態の発光素子の製造方法において、発光素子チップの発光観測面上にレンズ形成用樹脂を塗布した直後の平面図(a)と断面図(b)である。
【図4】 実施の形態の発光素子の製造方法において、発光素子チップの発光観測面上にレンズ形成用樹脂を塗布し、レンズ形状が形成されたときの平面図(a)と断面図(b)である。
【図5】 実施の形態の発光素子の製造方法において、発光素子チップの周りに遮光膜を形成した後の平面図(a)と断面図(b)である。
【図6】 実施例1の窒化物半導体発光素子の指向特性を示すグラフである。
【図7】 比較例1の窒化物半導体発光素子の指向特性を示すグラフである。
【図8】 実施例及び比較例に使用したパッケージの長軸方向と短軸方向とを示す平面図である。
【図9】 実施例2の発光素子の特性と比較例2の発光素子の特性とを対比して示すグラフであり、(a)は光度を比較して示すグラフであり、(b)は光出力を比較して示すグラフである。
【図10】 比較例2の断面図である。
【図11】 実施例2の発光素子の指向特性を示すグラフである。
【図12】 比較例3の発光素子の指向特性を示すグラフである。
【図13】 従来例の発光素子において、キャスティングケースを用いてレンズを形成する場合の様子を示す断面図である。
【図14】 従来例の発光素子において、金型を用いてレンズを形成する場合の様子を示す断面図である。
【符号の説明】
1…発光素子チップ、
1a…発光観測面の外周端部、
10…基板、
11…n型半導体層、
12…p型半導体層12、
13…p電極、
14…n電極、
15,16…導電性接着材、
20…レンズ、
20a…レンズの外周端部、
21…レンズ形成用樹脂、
30,31…遮光膜、
50…パッケージ、
51…正電極板、
52…負電極板、
54…樹脂。
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thin, high-power light-emitting element having uniform directivity in a predetermined direction.
[0002]
[Prior art]
In recent years, light-emitting diodes that can emit yellow light from the ultraviolet region using gallium nitride compound semiconductors have been developed, so that various light-emitting elements can be used for a wide range of applications from the ultraviolet region to red. Production is now possible.
In these light emitting elements, when uniform directivity is required in a predetermined direction, for example, a lens formed of a resin and a light emitting element are combined to obtain predetermined directivity characteristics.
[0003]
Conventionally, as shown in FIG. 13, for example, a lens to be combined with a light emitting element is obtained by setting a light emitting element chip 102 provided on a lead frame 101 in a cavity corresponding to the lens shape of a casting case 100. A method of forming a lens by pouring translucent resin 110 into the inside, or, as shown in FIG. 14, a light emitting element chip 102 provided on a substrate 103 is set in a molding die 104 and translucent It was produced by a method of forming the resin 111 by injection molding.
[0004]
[Problems to be solved by the invention]
However, in the conventional configuration and method, there are problems that it is difficult to suppress variation in directivity sufficiently small and that it is difficult to reduce the thickness.
[0005]
Accordingly, an object of the present invention is to provide a light-emitting diode that can suppress variation in directivity sufficiently small and can be thinned, and a method for manufacturing the same.
[0006]
[Means for Solving the Problems]
A light-emitting element according to the present invention has a first main surface and a second main surface facing each other, the first main surface being a light emission observation surface, and positive and negative electrodes on the second main surface. A light emitting element chip formed with a lens formed on the first main surface,
The outer peripheral end of the first main surface substantially coincides with the outer peripheral end of the lens, and the spherical surface of the lens bulges outward from the outer peripheral end.
As described above, in the light emitting device according to the present invention, the lens is formed only on the light emitting surface so that the outer peripheral end portion of the first main surface and the outer peripheral end portion of the lens substantially coincide with each other. Therefore, the thickness can be reduced.
Further, since the spherical surface of the lens is formed to bulge outward from the outer peripheral end portion of the lens, it is possible to prevent bright lines from being observed at the outer peripheral end portion of the first main surface which is the emission observation surface. .
Furthermore, in the light emitting device according to the present invention, the light emitting device further includes a light shielding layer containing light scattering particles, and the light shielding layer continuously connects the side surface of the light emitting device chip and the outer peripheral edge of the lens and the vicinity thereof. It is provided so that it may cover.
Thereby, the emitted light can be output substantially only from the emission observation surface, so that the emission intensity can be improved.
[0007]
Also, in the light emitting device according to the present invention, it is possible to use particles comprising silicon oxide, barium titanate as the scattering particles, titanium oxide, at least one member selected from the group consisting of aluminum oxide.
[0008]
Furthermore, in the light emitting device according to the present invention, the light emitting device chip may be a nitride semiconductor light emitting device chip, and the lens may include a phosphor.
In this way, a light emission color can be obtained by mixing the light from the light emitting element chip and the light from the phosphor.
As the phosphor, a phosphor containing at least cerium-activated yttrium / aluminum / garnet phosphor can be used.
Furthermore, the light emitting element chip can emit visible light having a main emission wavelength of 530 nm or less.
Here, the yttrium-aluminum-garnet phosphor activated by cerium in the present invention shall be interpreted in a broad sense, in which at least a part of Y is replaced with Gd, La, etc., and at least a part of Al is replaced. Including those substituting for In or Ga and those substituting at least a part of Ce with Tb or the like. As other phosphors, various materials can be used in consideration of the emission spectrum of the light-emitting element chip, the emission spectrum and excitation spectrum of the phosphor, and Ca—Al activated by Eu and / or Cr. -Si-O-N-based oxynitride phosphor glass or Y 2 O 2 S: Eu, Sr 5 (PO 4) 3 Cl: Eu, include (SrEr) O · Al 2 O 3 or the like.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, light-emitting elements according to embodiments of the present invention will be described with reference to the drawings.
The light-emitting element of the present embodiment includes a light-emitting element chip 1 in which an n-electrode and a p-electrode are formed on one main surface and the other main surface is an emission observation surface, a lens 20, and a light-shielding film 30. The lens 20 is formed on the light emission observation surface of the light emitting element chip 1 provided in the package, thereby realizing high directivity and improvement in light emission luminance.
Hereinafter, the light-emitting element of this embodiment will be described in detail.
[0010]
In the present embodiment, the package 50 includes a bottom electrode portion in which a positive electrode plate 51 and a negative electrode plate 52 are connected by a resin 54, and a storage portion for storing a light emitting element chip on the top surface of the bottom electrode portion. The outer frame 53 is formed around the upper surface so as to be formed.
In addition, the light emitting element chip 1 includes, for example, an n-type semiconductor layer 11 made of an n-type gallium nitride compound semiconductor and a p-type semiconductor layer made of a p-type gallium nitride compound semiconductor, for example, on a substrate 10 made of sapphire. 12 are stacked, and an n-electrode 14 and a p-electrode 13 are formed on the n-type semiconductor layer 11 and the p-type semiconductor layer 12, respectively.
[0011]
The light-emitting element chip 1 configured as described above is arranged so that the p-electrode 13 and the n-electrode 14 face the positive electrode plate 51 and the negative electrode plate 52 of the package 50, respectively, as shown in FIG. For example, the conductive adhesives 15 and 16 such as solder and silver paste, and metal such as gold bumps are used for bonding.
The lens 20 is formed on the light emission observation surface (first main surface) of the light emitting element chip 1 so as to satisfy the following two conditions.
First, in the lens 20, the outer peripheral end portion of the lens 20 (the outer peripheral end portion of the lens 20 at the boundary where the light emitting element chip 1 and the lens 20 are in contact) is the light emission observation surface (first main surface) of the light emitting element chip 1. It is formed so as to substantially coincide with the outer peripheral end portion.
Secondly, when the lens 20 and the light emitting element chip 1 are viewed from above the optical axis of the lens so that the spherical surface of the lens 20 bulges outward from the outer peripheral end of the lens 20, the light emitting element 20 The outer peripheral end of the light emission observation surface (first main surface) of the chip 1 is formed so as to be covered with the spherical surface of the lens 20.
[0012]
The light-shielding film 30 is made of, for example, a resin containing light scattering particles made of TiO 2 that reflects and scatters light emitted from the light-emitting element chip, and at least the lens 20 on the side surface of the light-emitting element chip 1 and the spherical surface of the lens 20. Is formed around the light emitting element chip 1 so as to include the vicinity of the outer peripheral end of the light emitting element chip 1.
In this way, by forming the light shielding film 30 over the side surface of the light emitting element chip 1 and the vicinity of the outer peripheral end portion of the spherical surface of the lens 20, the light emitted from the side surface of the light emitting element chip 1 is shielded. Since it can be reflected by 30 and output through the lens 20, the light emitted from the side surface of the light emitting element chip 1 can be used more effectively, and the light emission output can be improved.
[0013]
Further, in the present invention, as shown in FIG. 1, the light shielding film containing scattering particles is formed between the light emitting element chip 1 formed between the p electrode 13 and the n electrode 14 of the light emitting element chip 1 and the bottom electrode plate of the package 50. It is more preferable to form the gaps between them in the following points (in FIG. 1, this light-shielding film is indicated by 31).
That is, when the light shielding film 31 is further formed at the above-described position, all of the outer surfaces except the light emission observation surface of the light emitting element chip 1 and the light shielding films 30 and 31 and the light shielding electrode layer (p electrode 13 and n electrode 14). Since the light emitted from the light emitting layer can be effectively emitted from the light emission observation surface, the light emission efficiency can be improved.
[0014]
Next, the positional relationship between the lens 20, the light emitting element chip 1, and the light shielding layer 30 in the vicinity of the outer peripheral end 1a of the light emission observation surface of the light emitting element chip 1 will be described in detail with reference to FIG.
Since the lens 20 is formed by the method described below, the outer peripheral end 20a of the lens 20 after being actually formed may be located slightly below the outer peripheral end 1a of the emission observation surface. However, while the thickness of the light emitting element chip 1 is usually 80 μm to 100 μm, the distance between the outer peripheral end 20a of the lens 20 after the lens 20 is formed and the outer peripheral end 1a of the light emission observation surface is usually 10 μm. In the present specification, it is said that this degree of deviation substantially matches.
The light shielding film 30 is formed so as to continuously cover the spherical surface located in the vicinity of the outer peripheral end portion of the lens 20 from the side surface of the light emitting element chip 1.
[0015]
The light emitting element according to the embodiment configured as described above includes the lens 20 such that the outer peripheral end of the lens 20 substantially coincides with the outer peripheral end of the light emission observation surface of the light emitting element chip 1. The spherical surface 20 is formed so as to swell outward from the outer peripheral end portion of the lens 20, and the light shielding film 30 is continuously covered from the side surface of the light emitting element chip 1 to the spherical surface located in the vicinity of the outer peripheral end portion of the lens 20. Therefore, the intensity of light in a direction with a large angle with respect to the optical axis can be effectively suppressed (in the vicinity of 0 to 20 degrees and 160 to 180 degrees in FIG. 11). Uniform directivity can be obtained.
[0016]
That is, when the lens is formed so as to cover the entire light emitting element chip (both the light emission observation surface and the side surface of the light emitting element chip) as in the conventional case, in the package formed in a rectangular shape, the orientation in the long axis direction In this embodiment, since the lens 20 is formed directly on the light emitting element chip, the directivity characteristic without directivity is not affected by the shape of the package. Can be realized.
[0017]
In addition, when the lens is formed so as to cover the entire light emitting element chip as in the past, the amount of light output from the light emission observation surface of the light emitting element chip and the amount of light output from the side surface of the light emitting element chip and the dicing state (processing variation). If the directional characteristics change due to the change, the directional characteristics tend to vary. However, in the nitride semiconductor light emitting device of the present embodiment, the lens 20 formed on the emission observation surface The light shielding film formed so as to surround the side surface of the light emitting element chip allows the light emitted by the light emitting element chip to be output substantially only from the light emission observation surface, so that variation in directivity can be reduced.
[0018]
Next, a method for forming a lens and a method for forming a light shielding film in the light-emitting element of this embodiment will be described.
(Lens formation method)
In this forming method, first, as shown in FIGS. 3A and 3B, a predetermined amount of lens forming resin 21 is applied to the approximate center on the light emission observation surface of the light emitting element chip 1 by a dispenser. Here, the lens forming resin 21 is formed by mixing, for example, an epoxy resin having a viscosity of 5000 to 8000 cps and a quartz glass filler having an average particle diameter of 7 μm, for example, and setting the discharge pressure of the dispenser to 1.5 kgf / cm 2, for example. A certain amount of lens forming resin 21 is applied by adjusting the discharge time.
As shown in FIGS. 4A and 4B, the lens forming resin 21 thus discharged spreads to the outer peripheral end 1a of the emission observation surface, and corresponds to the amount and viscosity of the discharged resin 21. Form a spherical surface.
[0019]
That is, the resin extending to the outer peripheral end 1a of the light emission observation surface is a rough surface having irregularities unlike the smooth light emission observation surface because the side surface of the light emitting element chip 1 is a divided surface. The surface does not further spread outside the end 1a of the surface, and a spherical surface having a shape corresponding to the amount and viscosity of the resin 21 is formed by the surface tension.
In other words, the present method sets the desired shape by setting the viscosity and the coating amount of the lens forming resin based on the shape and area of the light emission observation surface of the light emitting element chip and the lens shape to be formed. This lens 20 is formed.
[0020]
Next, the lens forming resin 21 is cured to obtain a solidified lens 20.
Here, for example, when the epoxy resin of the lens forming resin 21 has a glass transition point of 150 ° C. or more, the curing temperature of the lens forming resin 21 is 120 ° C. in order to form the lens in a constant shape without variation in shape. It is preferable to cure in two stages, for example, after curing in 2 hours and then curing at 150 ° C. for 8 hours.
Then, after the lens-forming resin 21 is cured to form the lens 20, for example, a resin mixed with TiO 2 as reflection scattering particles (light scattering particles) is used as a side surface of the light emitting element chip and the outer periphery of the lens 20. It is applied and cured on both sides of the light emitting element chip 1 so as to cover at least the vicinity of the end portion.
[0021]
As described above, the light emitting element of the present embodiment can form the lens 20 substantially only on the light emission observation surface by using the above manufacturing method. It can be made thinner than a lens that covers the entire element chip.
Further, in the method for manufacturing a light-emitting element according to the present embodiment, the lens 20 is desired by setting the viscosity and application amount of the resin corresponding to the desired lens shape without using an expensive mold or the like. Therefore, it can be manufactured easily and inexpensively as compared with the conventional example formed using a mold.
[0022]
In the nitride semiconductor light emitting device of the above embodiment, the example in which the quartz glass filler is mixed with the lens 20 has been described. However, the present invention is not limited to this, and the lens 20 emits light by the light emitting device chip. You may contain the fluorescent substance which discharge | releases the light of longer wavelength than the light which absorbed a part or all of light and absorbed.
That is, when the quartz glass filler is mixed with the lens 20, the light generated by the light emitting element chip is output as it is (without changing the wavelength) through the lens 20, so that the emission color is the light emission of the light emitting element chip. Become a color.
On the other hand, when the lens 20 includes a phosphor, the emission color is determined as follows.
When the phosphor absorbs a part of the light emitted from the light emitting element chip, the light emission color is obtained by mixing the light from the phosphor and the light from the light emitting element chip. In addition, when the phosphor absorbs all the light emitted by the light emitting element chip, or when the light emitting element chip emits ultraviolet light and the ultraviolet light absorbs and emits light, the phosphor emits light. It becomes a luminescent color.
[0023]
【Example】
Examples according to the present invention will be described below.
Example 1
(Light emitting element chip fabrication)
First, an LED chip having a light emitting layer made of InGaN and having a main light emission peak of 470 nm is prepared as a light emitting element chip.
This LED chip uses a MOCVD method to form a nitride semiconductor layer such as a light-emitting layer on a sapphire substrate, forms an electrode at a predetermined position through a predetermined etching process, and divides it into individual chips It can produce by doing.
A nitride semiconductor layer such as a light emitting layer has a cleaned sapphire substrate set in a reaction chamber, and TMG (trimethyl) gas, TMI (trimethylindium) gas, TMA (trimethylaluminum) gas, ammonia gas and A film can be formed using hydrogen gas as a carrier gas and silane gas and cyclopentadiamagnesium as impurity gases.
[0024]
(Light emitting element chip mounting)
Next, the LED chip fabricated as described above is mounted with the electrodes facing each other and the light emission observation surface (the back surface of the sapphire substrate) facing up.
(Lens formation)
Next, the lens 20 is formed as follows.
A phosphor having an average particle diameter of 15 μm and a composition formula of (Y 0.8 Gd 0.2 ) 3 Al 5 O 12 : Ce on a one-component thermosetting epoxy resin having a glass point transfer of 150 ° C. or higher Disperse the powder and adjust the viscosity to 5000 cps.
Here, in Example 1, the content of the phosphor was set to a ratio of 45 with respect to the epoxy resin 100 in weight ratio.
[0025]
Next, the phosphor-mixed epoxy resin mixed with the phosphor is applied to the emission observation surface of the LED chip under the conditions of a discharge pressure of 1.5 kgf / cm 2 and a discharge time of 0.4 seconds. As a result, a predetermined amount of the phosphor-mixed epoxy resin is applied to the emission observation surface, and a lens shape is formed on the emission observation surface as shown in FIGS.
The phosphor-mixed epoxy resin formed in this lens shape is cured at 120 ° C. for 2 hours, and further cured at 150 ° C. for 8 hours.
[0026]
(Shading film formation)
Next, reflective scattering particles made of TiO 2 are dispersed in the same epoxy resin used for lens formation, and the viscosity is adjusted to 5000 cps.
Here, in Example 1, the content of the reflection / scattering particles was 30 by weight with respect to the epoxy resin 100 in terms of weight ratio.
Then, after applying a predetermined amount of the adjusted reflection / scattering particle mixed epoxy resin around the light emitting element chip, it is thermally cured in the same two steps as described above.
As described in the embodiment, the light shielding film is formed so as to continuously cover the side surface of the light emitting element chip 1 and the spherical surface near the outer peripheral end of the lens 20.
In other words, the coating amount of the reflection / scattering particle mixed epoxy resin is set so as to continuously cover the side surface of the light emitting element chip 1 and the spherical surface in the vicinity of the outer peripheral end of the lens 20.
As described above, the nitride semiconductor light emitting device of Example 1 is manufactured.
[0027]
The nitride semiconductor light emitting device of Example 1 manufactured as described above has a white luminescent color and has the directivity shown in FIG.
Here, in FIG. 6, a solid line L1 indicates the light emission output Po with respect to the directivity angle in the long axis direction d1 (see FIG. 8), and a broken line L2 indicates the light emission output Po with respect to the directivity angle in the short axis direction d2 (see FIG. 8). Show.
As is apparent from FIG. 6, the configuration of this example has substantially the same directivity characteristics in the major axis direction d1 and the minor axis direction d2.
[0028]
Comparative Example 1
The nitride semiconductor light emitting device of Comparative Example 1 is a phosphor in which the phosphor is mixed in the same manner as in Example 1 without forming the lens 20 and the light shielding film 30 in the nitride semiconductor light emitting device of Example 1. As shown in FIG. 10, the mixed epoxy resin is filled in the chip housing portion of the package 50 and cured.
In the first comparative example, the surface of the phosphor mixed epoxy resin 60 is formed so as to substantially coincide with the upper surface of the outer frame 53 of the package 50 and to be substantially flat.
That is, the phosphor-mixed epoxy resin in the element of Comparative Example 1 does not have a light shielding layer for shielding light from the light emitting element chip and a lens shape for condensing light.
[0029]
The nitride semiconductor light emitting device of Comparative Example 1 manufactured as described above had a luminescent color of white and had the directivity shown in FIG.
Here, in FIG. 7, the solid line L3 indicates the light emission output Po with respect to the directivity angle in the long axis direction d1 (see FIG. 8), and the broken line L4 indicates the light emission output Po with respect to the directivity angle in the short axis direction d2 (see FIG. 8). Show.
As is apparent from FIG. 7, the configuration of the present embodiment has substantially the same characteristics in the major axis direction d1 and the minor axis direction d2, but the directivity is not uniform and large as compared with the first embodiment. It varies.
[0030]
Further, by comparing FIG. 6 with FIG. 7, it can be seen that the light emission output of Example 1 can be significantly increased as compared with Comparative Example 1.
[0031]
Example 2
The nitride semiconductor light emitting device of Example 2 is manufactured in the same manner as in Example 1 except that the nitride semiconductor light emitting device of Example 1 includes a quartz glass filler instead of the phosphor of the lens 20. Is done.
Here, in Example 2, the content of the quartz glass filler was 30 by weight with respect to the epoxy resin 100 in terms of weight ratio.
The light emission color of the nitride semiconductor light emitting device of Example 2 manufactured as described above is blue (that is, the light emission color is blue in the structure shown in FIG. 1).
[0032]
Comparative Example 2
The nitride semiconductor light emitting device of Comparative Example 2 is a resin filled in the housing part of the package 50 of the nitride semiconductor light emitting device of Comparative Example 1, except that a quartz glass filler is contained instead of the phosphor. It is produced in the same manner as Comparative Example 1.
The light emission color of the nitride semiconductor light emitting device of Comparative Example 2 manufactured as described above is blue (the light emission color is blue in the structure shown in FIG. 10).
[0033]
FIG. 9A and FIG. 9B respectively show the emission intensity and light output of the device of Example 2 and the device of Comparative Example 2 manufactured as described above.
As shown in FIGS. 9A and 9B, the light emission intensity and light output of the device of Example 2 can be made extremely higher than those of the device of Comparative Example 2.
The data shown in FIG. 9 shows the average value of 600 devices (3 lots each) of Example 2 and Comparative Example 2.
[0034]
FIG. 11 is a graph showing the directivity of the light emitting element of Example 2. The solid line L5 indicates the directivity in the long axis direction d1, and the broken line L6 indicates the directivity in the short axis direction d2.
In the light emitting element of Example 2, as in Example 1, the directivity characteristic in the major axis direction d1 and the directivity characteristic in the minor axis direction d2 are substantially the same.
[0035]
Comparative Example 3
The light-emitting element of Comparative Example 3 is configured in the same manner as in Comparative Example 2 except that the surface of the resin containing the quartz glass filler is not flat but a lens shape in the light-emitting element of Comparative Example 2.
The directivity characteristics of the light emitting element of Comparative Example 3 are as shown in FIG.
Here, in FIG. 12, a solid line L7 is a directivity characteristic in the long axis direction d1, and a broken line L8 is a directivity characteristic in the short axis direction d2.
As is apparent from FIG. 12, in the element of Comparative Example 3, the directivity characteristics are different in the major axis direction d1 and the minor axis direction d2.
On the other hand, in the light emitting device of the present invention, the directivity in the long axis direction d1 and the directivity in the short axis direction d2 can be made substantially the same.
[0036]
【The invention's effect】
As described above in detail, the light-emitting element according to the present invention is the first light-emitting element chip in which the first main surface is an emission observation surface and the positive and negative electrodes are formed on the second main surface. A lens is formed on the main surface of the lens, the outer peripheral end of the first main surface substantially coincides with the outer peripheral end of the lens, and the spherical surface of the lens is the outer peripheral end of the lens. Therefore, it is possible to reduce the thickness and prevent the bright line from being observed at the outer peripheral end of the emission observation surface.
In addition, since the light emitting element according to the present invention can form a lens without using a mold, it can be manufactured at low cost.
Further, in the light emitting device according to the present invention, a light-shielding layer containing light scattering particles is provided so as to continuously cover the side surface of the light emitting device chip and the outer peripheral end of the lens and the vicinity thereof. Since the light can be output substantially only from the light emission observation surface, the light emission intensity can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a light emitting device according to an embodiment of the present invention.
2 is an enlarged cross-sectional view of a part of FIG.
FIGS. 3A and 3B are a plan view and a cross-sectional view immediately after a lens-forming resin is applied on a light emission observation surface of a light-emitting element chip in the method for manufacturing a light-emitting element according to the embodiment;
4A and 4B are a plan view and a cross-sectional view (b) when a lens-forming resin is applied to the light emission observation surface of the light-emitting element chip and a lens shape is formed in the method of manufacturing a light-emitting element according to the embodiment. ).
FIGS. 5A and 5B are a plan view and a cross-sectional view after a light-shielding film is formed around the light-emitting element chip in the method for manufacturing a light-emitting element according to the embodiment; FIGS.
6 is a graph showing directivity characteristics of the nitride semiconductor light emitting device of Example 1. FIG.
7 is a graph showing directivity characteristics of the nitride semiconductor light-emitting element of Comparative Example 1. FIG.
FIG. 8 is a plan view showing a major axis direction and a minor axis direction of packages used in Examples and Comparative Examples.
9 is a graph showing the characteristics of the light-emitting element of Example 2 in comparison with the characteristics of the light-emitting element of Comparative Example 2. FIG. 9A is a graph showing the comparison of luminous intensity, and FIG. It is a graph which compares and shows an output.
10 is a cross-sectional view of Comparative Example 2. FIG.
11 is a graph showing directivity characteristics of the light-emitting element of Example 2. FIG.
12 is a graph showing directivity characteristics of the light-emitting element of Comparative Example 3. FIG.
FIG. 13 is a cross-sectional view showing a state in which a lens is formed using a casting case in a conventional light emitting device.
FIG. 14 is a cross-sectional view showing a state where a lens is formed using a mold in a light emitting element of a conventional example.
[Explanation of symbols]
1 ... Light emitting element chip,
1a: the outer peripheral edge of the emission observation surface,
10 ... substrate,
11 ... n-type semiconductor layer,
12 ... p-type semiconductor layer 12,
13 ... p electrode,
14 ... n electrode,
15, 16 ... conductive adhesive,
20 ... Lens,
20a ... The outer peripheral edge of the lens,
21 ... Lens forming resin,
30, 31 ... light shielding film,
50 ... Package,
51 ... Positive electrode plate,
52 ... negative electrode plate,
54: Resin.

Claims (5)

互いに対向する第1の主面と第2の主面を有し、上記第1の主面を発光観測面としかつ上記第2の主面に正及び負の電極が形成された発光素子チップと、上記第1の主面上に形成されたレンズとを備え、
上記第1の主面の外周端部と上記レンズの外周端部とが実質的に一致し、かつ上記レンズの球面が上記外周端部より外側に膨らんで形成された発光素子であって、
上記発光素子はさらに、光散乱粒子を含む遮光層を有し、該遮光層は上記発光素子チップの側面と上記レンズの外周端部及びその近傍とを連続的に覆うように設けられていることを特徴とする発光素子。
A light emitting device chip having a first main surface and a second main surface facing each other, wherein the first main surface is a light emission observation surface, and positive and negative electrodes are formed on the second main surface; A lens formed on the first main surface,
A light emitting device in which an outer peripheral end portion of the first main surface and an outer peripheral end portion of the lens substantially coincide with each other, and a spherical surface of the lens bulges outward from the outer peripheral end portion ,
The light emitting device further comprises a light shielding layer including the light scattering particles, the light-shielding layer is provided, et al is so as to cover the outer peripheral end portion and its vicinity of the side surface and the lens of the light emitting device chip continuously A light emitting element characterized by the above.
上記散乱粒子は、酸化ケイ素、チタン酸バリウム、酸化チタン、酸化アルミニウムからなる群から選択される少なくとも1つを含む請求項記載の発光素子。The scattering particles, silicon oxide, barium titanate, titanium oxide, light-emitting device of claim 1, further comprising at least one selected from the group consisting of aluminum oxide. 上記発光素子チップは窒化物半導体発光素子チップであって、上記レンズは蛍光体を含む請求項1又は2に記載の発光素子。The light emitting device chip is a nitride semiconductor light emitting device chip, the lens is light emitting device according to claim 1 or 2 including a phosphor. 上記蛍光体は、少なくともセリウムで付活されたイットリウム・アルミニウム・ガーネット系蛍光体を含む請求項記載の発光素子。The light-emitting element according to claim 3 , wherein the phosphor includes at least an yttrium-aluminum-garnet phosphor activated with cerium. 前記発光素子チップは、主発光波長が530nm以下の可視光を発光する請求項1〜のうちのいずれか1つに記載の発光素子。The light emitting device chip, the light emitting device according to any one of claims 1-4 for the main emission wavelength to emit less visible light 530 nm.
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