JP2004207519A - Light emitting device - Google Patents

Light emitting device Download PDF

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Publication number
JP2004207519A
JP2004207519A JP2002375421A JP2002375421A JP2004207519A JP 2004207519 A JP2004207519 A JP 2004207519A JP 2002375421 A JP2002375421 A JP 2002375421A JP 2002375421 A JP2002375421 A JP 2002375421A JP 2004207519 A JP2004207519 A JP 2004207519A
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Prior art keywords
light
light emitting
emitting device
semiconductor
emitting element
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Inventor
祐次 ▲高▼橋
Yuji Takahashi
Kunihiro Jinme
邦博 甚目
Kenichi Koya
賢一 小屋
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Toyoda Gosei Co Ltd
Panasonic Holdings Corp
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Toyoda Gosei Co Ltd
Matsushita Electric Industrial Co Ltd
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Priority to JP2002375421A priority Critical patent/JP2004207519A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161—Disposition
    • H01L2224/16135—Disposition the bump connector connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip
    • H01L2224/16145—Disposition the bump connector connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip the bodies being stacked
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31—Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321—Disposition
    • H01L2224/32151—Disposition the layer connector connecting 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
    • H01L2224/32221—Disposition the layer connector connecting 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
    • H01L2224/32245—Disposition the layer connector connecting 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
    • H01L2224/45138—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/45144—Gold (Au) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting 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
    • H01L2224/48221—Connecting 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
    • H01L2224/48245—Connecting 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
    • H01L2224/48247—Connecting 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/484—Connecting portions
    • H01L2224/48463—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
    • H01L2224/48465—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device which prevents the occurrence of color shading and is easily manufactured, thereby intending to enhance the luminance. <P>SOLUTION: A semitransmissive optical reflection film 2A is provided upward of an LED chip 2 (on a side of a light emitting observation surface), so that a blue light L is radiated in an upward and side direction. The blue light L radiated from the side is reflected by a reflection surface of a cup 1B and radiated upward. Thus, the blue color L can be uniformly irradiated in a wide range with respect to a phosphor disposed not only in an upward direction of the LED chip 2, but also in a side direction thereof, to obtain a white light having no color shading. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、発光装置に関し、特に、発光ダイオード（Light-Emitting Diode：以下「ＬＥＤ」という。）から放射される光を蛍光体で吸収し、異なる波長の光に波長変換して放射させ、発光ダイオード放射光と波長変換光との混合光を放射させる発光装置に関する。
【０００２】
【従来の技術】
この出願の発明に関連する先行技術文献情報としては次のものがある。
【０００３】
【特許文献１】
特開２０００−２１６４３４号公報（図２）
図８は、特許文献１に示される発光装置の縦断面を示し、凹断面形状を有するパッケージ１０と、パッケージ１０の凹部１１内に収容されるＬＥＤチップ１２と、パッケージ１０の凹部１１内に収容された透光性樹脂による第１のコーティング部１３および第２のコーティング部１４と、パッケージ１０の外部に露出して設けられる外部電極１５と、外部電極１５とＬＥＤチップ１２とを電気的に接続するボンディングワイヤ１６とによって構成されており、第２のコーティング部１４にはＬＥＤチップ１２の発光に基づく可視光を吸収して波長変換された可視光を放射する蛍光物質１４Ａが含まれている。これにより、ＬＥＤチップ１２の発光に基づく光を波長変換して他の色の可視光を得ることができる。
【０００４】
例えば、青色系のＬＥＤチップ１２から放射された青色光を、青色光を吸収して黄色光を放射する蛍光物質１４Ａを含んだ第２のコーティング部１４に通過させると、青色光と波長変換光である黄色光とが混合されて補色による白色光を得ることができる。
【０００５】
【発明が解決しようとする課題】
しかし、従来の発光装置によると、ＬＥＤチップから放射される光量が全方位に対して均一とはならず、特に、ＬＥＤチップの上方へ放射される光量が側面等の他の方向に放射される光量と比べて大になるため、蛍光物質の光吸収量にばらつきが生じて一律な波長変換性が得られず、その結果、色むらが生じるという問題がある。
【０００６】
特許文献１に開示される発光装置では、第２のコーティング部の中心部分の厚さを周囲の厚さに対して大にすることにより第２のコーティング部を通過するあらゆる方向の光（例えば、中心を通る垂直光と中心を外れる斜めの光）の光路長を等しくして色むらの発生を抑制しているが、蛍光物質を所定の領域に所定の厚さで配置するための高度な樹脂成型性を要するだけでなく、中心部分の光吸収や散乱が大になって輝度の低下を生じるという不都合がある。
【０００７】
従って、本発明の目的は、色むらの発生を解消でき、製造が容易で輝度の向上を図ることのできる発光装置を提供することにある。
【０００８】
【課題を解決するための手段】
本発明は、上記目的を達成するため、発光面に垂直な方向に放射する光の一部を反射させ、その反射光の少なくとも一部を発光面に水平な方向に放射する半導体発光素子と、
前記半導体発光素子を収容し、内壁面を前記光の反射面とする素子収容部と、前記素子収容部に収容された前記半導体発光素子を封止し、前記光によって励起されて前記光の波長と異なった波長の励起光を放射する蛍光体を含んだ透光性樹脂部とを含むことを特徴とする発光装置を提供する。
【０００９】
このような構成によれば、半導体発光素子から面方向および発光面に水平な方向に光が放射されるので、光が分散し、素子収容部内の透光性樹脂部に光が行きわたるようになり、そのことによって蛍光体が充分に励起されて良好な波長変換性が得られる。
【００１０】
また、本発明の発光装置において、半導体発光素子を窒化ガリウム系化合物半導体、例えば、ＩｎＧａＮで構成すると、Ｉｎの組成比によって青色光の波長を任意に設定することができ、例えば、ＧａＮで構成すると、近紫外光を放射させることができる。
【００１１】
半導体発光素子が青色光を放射するときは、蛍光体として励起によって黄色光を放射するものを使用すると、白色ＬＥＤを得ることができ、また、蛍光体として励起によって赤色光および緑色光を放射するものを使用しても白色ＬＥＤを得ることができる。
【００１２】
また、半導体発光素子が近紫外光（あるいは紫外光）を放射するときは、蛍光体として励起によって赤、緑、及び青の各色の光を放射するものを使用すると白色ＬＥＤを得ることができる。
【００１３】
なお、本発明の発光装置は、白色ＬＥＤに限定されるものではなく、半導体発光素子の発光色と蛍光体の励起光の波長の組み合わせによって各種の色のＬＥＤを得ることができる。
【００１４】
【発明の実施の形態】
図１は、本発明の第１の実施の形態に係る発光装置を示し、（ａ）は縦断面図、（ｂ）は（ａ）のＬＥＤチップ２の部分拡大図である。この発光装置は、先端部にメタルステム１ａを有するリードフレーム１Ａと、メタルステム１ａに設けられて内面に光を反射させる反射面を有するカップ１Ｂと、リードフレーム１Ｃと、半透明の光反射膜２Ａを上部に設けられたＬＥＤチップ２と、ＬＥＤチップ２に設けられるＡｕバンプ３Ａおよび３Ｂと、サブマウント素子４と、サブマウント素子４をカップ１Ｂ内に固定するＡｇペースト５と、蛍光体を混入されてカップ１Ｂに注入される透光性樹脂６と、リードフレーム１Ｃとサブマウント素子４とを電気的に接続する金線のボンディングワイヤ７と、透明エポキシ樹脂部８とより構成されている。なお、（ｂ）においては透光性樹脂６の図示を省略している。
【００１５】
ＬＥＤチップ２は、例えば、ＧａＮ、ＧａＡｌＮ、ＩｎＧａＮ、ＩｎＧａＡｌＮ等の窒化ガリウム系化合物半導体やＺｎＳｅ（セレン化亜鉛）等で４５０ｎｍ〜４８０ｎｍの青色系で発光するように形成されており、光反射膜２Ａと、サファイア基板２Ｂと、ＡｌＮバッファ層２Ｃと、ｎ型半導体層２Ｄと、ｎ側電極２Ｅと、発光する層を有する多層２Ｋと、ｐ型半導体層２Ｆと、ｐ側電極２Ｇと、ＬＥＤチップ２の表面保護および光放射性を付与するための保護膜２Ｉを備え、サブマウント素子４にフリップチップ接合されている。このＬＥＤチップ２は、ｎ側電極２Ｅとｐ側電極２Ｇに駆動電圧を印加することによってｎ型半導体層２Ｄとｐ型半導体層２Ｆ間の多層２Ｋ内で面状に発光する。
【００１６】
光反射膜２Ａは、サファイア基板２Ｂの表面にスパッタリング法、真空蒸着法等の薄膜形成方法によって半透過性を有するアルミニウム膜を薄膜状に形成したものであり、サファイア基板２Ｂの組成や透光性を阻害することがなければ他の方法で形成しても良い。なお、形成される薄膜についてもアルミニウムに限定されることなく、膜厚に応じて光透過性の調整が可能であれば他の金属材料、あるいは金属以外の材料を用いても良い。また、側面方向への青色光の放射性に優れる材料を選択することが好ましい。
【００１７】
ｎ側電極２Ｅは、例えば、Ａｌ、Ｖ、Ｓｎ、Ｔｉ、Ｃｒ、Ｎｂ、Ｔａ、Ｍｏ、Ｗ、又はＨｆ等の金属又はこれらの合金を用いて形成することができる。なお、異なる組成の層が積層された二層あるいは多層構造としてもよく、例えば、ＶとＡｌの二層構造としても良い。
【００１８】
ｐ側電極２Ｇは、例えば、Ｒｈ、Ａｕ、Ｐｔ、Ａｇ、Ｃｕ、Ａｌ、Ｎｉ、Ｃｏ、Ｍｇ、Ｐｄ、Ｖ、Ｍｎ、Ｂｉ、Ｓｎ、又はＲｅ等の金属又はこれらの合金を用いて形成することができる。なお、異なる組成の層が積層された二層あるいは多層構造としても良い。
【００１９】
保護膜２Ｉは、例えば、ＳｉＯ2からなり、光透過性および絶縁性を有してＬＥＤチップ２の表面を保護する。なお、保護膜２ＩはＬＥＤチップ２の側面方向に対して青色光Ｌが放射されやすい膜厚で形成されている。
【００２０】
サブマウント素子４は、ｎ型のシリコン基板によって形成され、ＬＥＤチップ２を静電気から保護するためのツェナーダイオードとして動作する。また、Ａｕバンプ３Ａによってｐ側電極２Ｇと接続されるｎ側電極４Ａと、ｐ型半導体層４Ｂと、Ａｕバンプ３Ｂによってｎ側電極２Ｅと接続されるｐ側電極４Ｃと、Ａｇペースト５を介してカップ部１Ｂに電気的に接続されるｎ電極４Ｄと、ｎ型半導体層４Ｅとを有する。
【００２１】
透光性樹脂６は、エポキシ樹脂からなり、蛍光体としてＣｅ：ＹＡＧ（イットリウム・アルミニウム・ガーネット）を含有している。なお、透光性樹脂６として固化後に透明となるシリコン樹脂を用いても良い。
【００２２】
このように構成された発光装置において、リードフレーム１Ａおよび１Ｃに電圧を印加すると、ＬＥＤチップ２は多層２Ｋ内で面状に発光して波長４５０〜４８０ｎｍの青色光Ｌを放射する。
【００２３】
光反射膜２Ａは、青色光を反射するとともに半透過させてＬＥＤチップ２の上方に青色光Ｌを放射させる。青色光Ｌの一部は、蛍光体を励起することにより波長５５０〜５８０ｎｍの黄色光に波長変換される。この黄色光と青色光Ｌとが混合されることによって白色光が放射される。
【００２４】
また、光反射膜２Ａで反射された青色光Ｌは、ＬＥＤチップ２の側面より放射される。青色光Ｌの一部は、ＬＥＤチップ２の側方に配置される蛍光体を励起することにより黄色光に波長変換される。この黄色光と青色光Ｌとが混合されることによって白色光が放射される。また、側面より放射された青色光Ｌは、カップ１Ｂの反射面で反射されて上方に放射される。
【００２５】
カップ１Ｂで反射された青色光Ｌの一部は、光路上に配置される蛍光体を励起することにより黄色光に波長変換され、青色光Ｌと混合されることによって白色光を放射する。
【００２６】
上記した第１の実施の形態によると、ＬＥＤチップ２の上方（発光観測面側）に半透過性の光反射膜２Ａを設けて青色光Ｌを上方および側面方向に放射させるようにしたので、ＬＥＤチップ２の上方だけでなく側面方向に配置された蛍光体に対しても均一に青色光Ｌを照射することができ、広範囲にわたって色むらのない白色光を得ることができる。
【００２７】
また、側面方向に放射された青色光Ｌをカップ１Ｂで反射して上方に導くようにしているので、光路上に配置された蛍光体を励起することができ、波長変換効率が向上して白色光の輝度を向上させることができる。
【００２８】
また、青色光Ｌが分散されることによって、蛍光体の濃度を部分的に変化させるといった樹脂組成の調整や、高度な樹脂成形性を必要としないで容易に製造することができ、蛍光体の濃度（使用量）を低減することができる。
【００２９】
なお、上記した第１の実施の形態では、青色光と黄色光との混合に基づいて白色光を得る構成について説明したが、白色光を得る構成として、例えば、青色光によって励起されて緑色光を放射する第１の蛍光体と、青色光によって励起されて赤色光を放射する第２の蛍光体とを透光性樹脂６に混合し、赤色光、緑色光、および青色光の混合によって白色光を得るようにしても良い。
【００３０】
また、ＬＥＤチップ２についても青色光を放射するものに限定されず、例えば、近紫外光を放射するＬＥＤチップを用いるようにしても良い。この場合には、近紫外光によって励起されて赤色光、緑色光、および青色光を放射する蛍光体を透光性樹脂６に混合して用いることにより、白色光を得ることができる。
【００３１】
図２は、本発明の第２の実施の形態に係るＬＥＤチップ２を部分的に示し、サファイア基板２Ｂの表面に青色光を拡散させる光拡散材としてＳｉＯ2を混入させた光拡散層２Ｈを設けている。その他、図示しない構成については第１の実施の形態と同じである。
【００３２】
また、光拡散層２Ｈは、サファイア基板２Ｂを透過した青色光Ｌを光拡散材としての酸化チタンやアルミナによって反射および拡散させることにより、図示するようにＬＥＤチップ２の上方、斜め上方、側面方向、およびサファイア基板２Ｂ側に放射させるようにしても良い。
【００３３】
上記した第２の実施の形態によると、サファイア基板２Ｂの表面に光拡散材を混入させた光拡散層２Ｈを設けて青色光Ｌを反射および拡散させるようにしたので、ＬＥＤチップ２の上方だけでなく斜め上方や側面方向に配置された蛍光体に対しても光拡散に基づいて均一な青色光Ｌを照射することができ、広範囲にわたって色むらのない白色光を得ることができる。
【００３４】
図３は、本発明の第３の実施の形態に係るフリップチップ接合型の発光装置を示し、（ａ）はカップ１Ｂの部分断面図、（ｂ）は（ａ）のＬＥＤチップ２の部分拡大図である。この発光装置は、サファイア基板２Ｂの表面を粗面化した凹凸面２ｂを形成し、この凹凸面２ｂ上に光反射膜２Ａを設けている。また、ＬＥＤチップ２の表面には前述の保護膜（図示せず）が設けられている。光反射膜２Ａの構成および形成方法については第１の実施の形態で説明したものと同様であるので、重複する説明を省略する。
【００３５】
図３（ｂ）は、光反射膜２Ａにおける青色光Ｌの透過および反射を示し、多層２Ｋ内での発光に基づいて放射される青色光Ｌは、凹凸面２ｂへの入射位置に応じた方向に反射される反射光と、凹凸面２ｂを通過する際に偏光される半透過光となってＬＥＤチップ２の上方および側面方向から放射される。
【００３６】
上記した第３の実施の形態によると、光反射膜２Ａを設けられるサファイア基板２Ｂの表面を粗面化したので、光反射膜２Ａに入射する位置に応じた反射方向への青色光Ｌおよび半透過光を発生させることができ、第１の実施の形態の効果に加えて青色光Ｌの側面方向への拡散性がより高められる。これにより、ＬＥＤチップ２の上方だけでなく斜め上方や側面方向に配置された蛍光体に対しても広範囲に均一に青色光Ｌを照射することができ、色むらのない白色光を得ることができる。
【００３７】
図４は、本発明の第４の実施の形態に係るフェイスアップ接合型の発光装置を示し、ＬＥＤチップ２０は、発光観測面側から順にｐ側電極２Ｇと、ｐ型半導体層２Ｆと、ｎ側電極２Ｅと、ｎ型半導体層２Ｄと、ＡｌＮバッファ層２Ｃと、サファイア基板２Ｂとを備え、光拡散材９Ａを混入されたマウント９によってカップ１Ｂの底面に接着固定されている。また、ｐ側電極２Ｇとｎ側電極２Ｅには金線のボンディングワイヤ７が電気的に接続されており、ｎ側電極２Ｅ側のボンディングワイヤ７はリードフレーム１Ａと電気的に接続される。また、ＬＥＤチップ２０の表面には図示しない保護膜が設けられている。その他、第１および第３の実施の形態と同一の構成を有する部分については同一の引用数字を付しているので、重複する説明を省略する。
【００３８】
ｐ側電極２Ｇは、Ｃｏ／Ａｕ合金の導電性膜からなり、ｐ型半導体層２Ｆの表面全体を覆うように設けられるとともに、多層２Ｋ内での発光に基づく青色光Ｌを半透過させる膜厚で形成されている。なお、ｐ側電極２Ｇは、上記したＣｏ／Ａｕ合金の他に、例えば、Ｒｈ、Ａｕ、Ｐｔ、Ａｇ、Ｃｕ、Ａｌ、Ｎｉ、Ｃｏ、Ｍｇ、Ｐｄ、Ｖ、Ｍｎ、Ｂｉ、Ｓｎ、又はＲｅ等の金属又はこれらの合金を用いて形成することができる。中でも、Ｒｈ，Ｐｔは、ＧａＮ系半導体から成る青色ＬＥＤの発光波長に対して高い反射効率を有するため、好適なｐ電極材料として用いることができる。また、異なる組成の層が積層された二層あるいは多層構造としても良い。また、側面方向への青色光の放射性に優れる材料を選択することが好ましい。
【００３９】
マウント９は、扱いが容易で透光性を有するエポキシ樹脂等の樹脂材料を用いて形成されている。このマウント９に用いられる樹脂は、接着性を有すると共に、極めて小さいＬＥＤチップ２の側面にせり上がった場合でも側面で各層間がショートしないよう絶縁性を有することが好ましい。
【００４０】
このように構成された発光装置において、リードフレーム１Ａおよび１Ｃに電圧を印加すると、ＬＥＤチップ２は多層２Ｋ内で面状に発光して波長４５０〜４８０ｎｍの青色光Ｌを放射する。
【００４１】
ｐ側電極２Ｇは、青色光Ｌを半透過させることによってＬＥＤチップ２の上方に青色光Ｌを放射させる。青色光Ｌの一部は、蛍光体を励起することにより波長５５０〜５８０ｎｍの黄色光に波長変換される。この黄色光と青色光Ｌとが混合されることによって白色光が放射される。
【００４２】
また、多層２Ｋ内から下方に放射される青色光Ｌはサファイア基板２Ｂを透過してマウント９に達する。マウント９は、混入された光拡散材９Ａによって青色光Ｌを拡散し、側面あるいは斜め上方に拡散光として放射する。放射された拡散光は、カップ１Ｂの反射面で反射されて上方に放射される。
【００４３】
カップ１Ｂで反射された青色光Ｌの一部は、光路上に配置される蛍光体を励起することにより黄色光に波長変換され、青色光Ｌと混合されることによって白色光を放射する。
【００４４】
上記した第４の実施の形態によると、多層２Ｋ内から上方に放射された青色光Ｌをｐ側電極２Ｇで半透過させるとともに、多層２Ｋ内から下方に放射された青色光Ｌを光拡散材９Ａを混入されたマウント９で拡散させるようにしたので、ＬＥＤチップ２の発光に基づく青色光Ｌを上方、斜め上方、および側面方向に効率良く拡散させることができる。特に、カップ１Ｂの底面付近に充分に青色光Ｌが行きわたることから、カップ１Ｂ内での波長変換効率がより向上して色むらのない白色光を得ることができる。
【００４５】
図５は、本発明の第５の実施の形態に係るフェイスアップ接合型の発光装置を示し、サファイア基板２Ｂの下方に光反射膜２Ａを設けたＬＥＤチップ２０をマウント９によってカップ１Ｂの底面に接着固定している構成について第４の実施の形態と相違し、その他については第４の実施の形態と同一の構成を有している。
【００４６】
上記した第５の実施の形態によると、多層２Ｋ内から上方に放射された青色光をｐ側電極２Ｇで半透過させるとともに多層２Ｋ内から下方に放射された青色光を光反射膜２Ａで反射して側面方向に放射させるようにしたので、第４の実施の形態と同様にＬＥＤチップ２の発光に基づく青色光を上方および側面方向に効率良く拡散させることができ、カップ１Ｂ内での波長変換効率が向上して色むらのない白色光を得ることができる。なお、マウント９に第４の実施の形態で説明した酸化チタン、アルミナ、ＳｉＯ2等の光拡散材９Ａを混入し、光反射膜２Ａを透過した半透過光を光拡散材９Ａに基づいて拡散させるようにしても良い。
【００４７】
また、上記した各実施の形態では、ＬＥＤチップ２の表面もしくは近傍に光放射性を改善する構成を有する発光装置を説明したが、例えば、ＬＥＤチップ２の層中に光放射性を改善する構成を設けても良い。係る構成として、例えば、ＬＥＤチップ２の発光波長に対してブラッグの回析条件を満たすように屈折率の異なる層を交互に積層して構成される分布型ブラッグ反射器（ＤＢＲ：Distributed Bragg Reflector）を用いることができる。
【００４８】
図６は、本発明の第６の実施の形態に係るフリップチップ接合型の発光装置の部分断面図を示し、ＬＥＤチップ２のｐ側電極２Ｇとｐ型半導体層２Ｆとの間にＤＢＲ２Ｊを有する。その他の構成については第３の実施の形態に係る発光装置と同一の構成を有することから、重複する説明を省略する。
【００４９】
上記した第６の実施の形態によると、多層２Ｋに対してサブマウント素子４側にＤＢＲ２Ｊを設けることにより、多層２Ｋ内から放射された青色光がＤＢＲ２Ｊで拡散されてサファイア基板２Ｂ方向に反射されるようになり、ＬＥＤチップ２の上方および斜め上方への光放射性を高めることができる。なお、ＬＥＤチップ２については上記したフリップチップ接合型に限定されず、例えば、フェイスアップ接合型であっても良い。
【００５０】
図７は、本発明の第７の実施の形態に係るフェイスアップ接合型の発光装置の部分断面図を示し、ＬＥＤチップ２０のＡｌＮバッファ層２Ｃとｎ型半導体層２Ｄとの間にＤＢＲ２Ｊを有する。その他の構成については第４の実施の形態に係る発光装置と同一の構成を有することから、重複する説明を省略する。
【００５１】
上記した第７の実施の形態によると、多層２Ｋに対してサファイア基板２Ｂ側にＤＢＲ２Ｊを設けることにより、多層２Ｋ内から放射された青色光がＤＢＲ２Ｊで拡散されてｐ側電極２Ｇ方向に反射されるようになり、ＬＥＤチップ２の上方および斜め上方への光放射性を高めることができる。なお、この構成によれば、第４の実施の形態でマウント９に混入していた光拡散材９Ａを用いなくても、第４の実施の形態と同様の効果が得られる。
【００５２】
なお、上記した各実施の形態で説明した構成は、白色に限定されることなく複数の光を混合して所望の発光色を得る発光装置に適用可能であり、特に、ＬＥＤを発光源とする発光装置に有効である。
【００５３】
また、上記した各実施の形態では、半導体発光素子としてｐ層とｎ層よりなるホモ接合型発光素子を採用した構成を説明したが、これに代わるものとして発光層の両側にｐ型およびｎ型のクラッド層を配置したダブルヘテロ型発光素子を採用できることは当然のことである。
【００５４】
【発明の効果】
以上説明したように、本発明の発光装置によると、カップ内に収容されたＬＥＤチップから放射される青色光を反射又は拡散に基づいて上方だけでなく斜め上方や側面方向にも放射させるようにしたため、色むらの発生を解消でき、製造が容易で輝度の向上を図ることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る発光装置を示し、（ａ）は縦断面図、（ｂ)は（ａ）のＬＥＤチップの部分拡大図である。
【図２】本発明の第２の実施の形態に係るＬＥＤチップの部分拡大図である。
【図３】本発明の第３の実施の形態に係る発光装置を示し（ａ）はカップの部分断面図、（ｂ）は（ａ）に示すＬＥＤチップの部分拡大図である。
【図４】本発明の第４の実施の形態に係る発光装置の部分断面図である。
【図５】本発明の第５の実施の形態に係る発光装置の部分断面図である。
【図６】本発明の第６の実施の形態に係る発光装置の部分断面図である。
【図７】本発明の第７の実施の形態に係る発光装置の部分断面図である。
【図８】特許文献１（特開２０００−２１６４３４号）に示される発光装置の縦断面図である。
【符号の説明】
１Ａ，リードフレーム １Ｂ，カップ部 １Ｃ，リードフレーム
１ａ，メタルステム ２，ＬＥＤチップ ２Ａ，光反射膜
２Ｂ，サファイア基板 ２Ｃ，バッファ層 ２Ｄ，ｎ型半導体層
２Ｅ，ｎ側電極 ２Ｆ，ｐ型半導体層 ２Ｇ，ｐ側電極 ２Ｈ，光拡散層
２Ｉ，保護膜 ２Ｊ，ＤＢＲ ２Ｋ，多層 ３Ａ，バンプ ３Ｂ，バンプ
４，サブマウント素子 ４Ａ，ｎ側電極 ４Ｂ，ｐ型半導体層 ４Ｃ，ｐ側電極４Ｄ，ｎ電極 ４Ｅ，ｎ型半導体層 ５，Ａｇペースト ６，透光性樹脂
７，ボンディングワイヤ ８，透明エポキシ樹脂部 ９，マウント
９Ａ，光拡散材 １０，パッケージ １１，凹部 １２，チップ
１３，コーティング部 １４，コーティング部 １４Ａ，蛍光物質
１５，外部電極 １６，ボンディングワイヤ ２０，ＬＥＤチップ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light-emitting device, and in particular, absorbs light emitted from a light-emitting diode (hereinafter, referred to as “LED”) with a phosphor, converts the wavelength into light of a different wavelength, emits the light, and emits light. The present invention relates to a light emitting device that emits a mixed light of a diode emission light and a wavelength conversion light.
[0002]
[Prior art]
Prior art document information related to the invention of this application includes the following.
[0003]
[Patent Document 1]
JP 2000-216434 A (FIG. 2)
FIG. 8 shows a longitudinal section of the light emitting device disclosed in Patent Document 1, in which a package 10 having a concave cross-sectional shape, an LED chip 12 accommodated in a concave portion 11 of the package 10, and an LED chip 12 accommodated in the concave portion 11 of the package 10. Electrically connecting the first coating portion 13 and the second coating portion 14 made of the transparent resin, the external electrode 15 provided to be exposed to the outside of the package 10, and the external electrode 15 and the LED chip 12; The second coating portion 14 includes a fluorescent substance 14A that absorbs visible light based on light emission of the LED chip 12 and emits wavelength-converted visible light. Thereby, the wavelength of the light based on the light emission of the LED chip 12 can be converted to obtain visible light of another color.
[0004]
For example, when blue light emitted from the blue LED chip 12 is passed through the second coating portion 14 containing the fluorescent material 14A that absorbs blue light and emits yellow light, the blue light and the wavelength-converted light are emitted. Is mixed with the yellow light to obtain white light of a complementary color.
[0005]
[Problems to be solved by the invention]
However, according to the conventional light emitting device, the amount of light emitted from the LED chip is not uniform in all directions, and in particular, the amount of light emitted above the LED chip is emitted in another direction such as a side surface. Since it is larger than the amount of light, the amount of light absorbed by the fluorescent substance varies, so that uniform wavelength conversion cannot be obtained. As a result, color unevenness occurs.
[0006]
In the light emitting device disclosed in Patent Literature 1, light in all directions passing through the second coating portion (for example, by increasing the thickness of the central portion of the second coating portion with respect to the peripheral thickness) (for example, The optical path lengths of vertical light passing through the center and oblique light off the center are equalized to suppress the occurrence of color unevenness, but an advanced resin for arranging the fluorescent substance in a predetermined area at a predetermined thickness. In addition to the need for moldability, there is the disadvantage that the light absorption and scattering at the central portion increase and the luminance is reduced.
[0007]
Accordingly, an object of the present invention is to provide a light emitting device that can eliminate the occurrence of color unevenness, can be easily manufactured, and can improve luminance.
[0008]
[Means for Solving the Problems]
The present invention, in order to achieve the above object, to reflect a part of light emitted in a direction perpendicular to the light emitting surface, a semiconductor light emitting element that emits at least a part of the reflected light in a direction horizontal to the light emitting surface,
An element accommodating portion that accommodates the semiconductor light emitting element and has an inner wall surface that reflects the light, seals the semiconductor light emitting element accommodated in the element accommodating portion, and is excited by the light to emit the light. And a light-transmitting resin portion containing a phosphor that emits excitation light having a different wavelength.
[0009]
According to such a configuration, light is radiated from the semiconductor light emitting element in the surface direction and in the direction horizontal to the light emitting surface, so that the light is dispersed and the light is transmitted to the translucent resin part in the element housing part. As a result, the phosphor is sufficiently excited to obtain good wavelength conversion properties.
[0010]
Further, in the light-emitting device of the present invention, when the semiconductor light-emitting element is formed of a gallium nitride-based compound semiconductor, for example, InGaN, the wavelength of blue light can be arbitrarily set depending on the composition ratio of In. , Can emit near-ultraviolet light.
[0011]
When the semiconductor light emitting element emits blue light, if a phosphor that emits yellow light by excitation is used, a white LED can be obtained, and the phosphor emits red light and green light by excitation. A white LED can be obtained by using a light emitting diode.
[0012]
When the semiconductor light emitting element emits near-ultraviolet light (or ultraviolet light), a white LED can be obtained by using a phosphor that emits light of each color of red, green, and blue by excitation.
[0013]
Note that the light emitting device of the present invention is not limited to white LEDs, and LEDs of various colors can be obtained by combining the emission color of the semiconductor light emitting element and the wavelength of the excitation light of the phosphor.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
1A and 1B show a light emitting device according to a first embodiment of the present invention, wherein FIG. 1A is a longitudinal sectional view, and FIG. 1B is a partially enlarged view of the LED chip 2 of FIG. This light emitting device includes a lead frame 1A having a metal stem 1a at a tip, a cup 1B provided on the metal stem 1a and having a reflection surface for reflecting light on an inner surface, a lead frame 1C, and a translucent light reflecting film. 2A, an LED chip 2 provided on the upper part, Au bumps 3A and 3B provided on the LED chip 2, a submount element 4, an Ag paste 5 for fixing the submount element 4 in the cup 1B, and a phosphor. It is composed of a translucent resin 6 mixed and injected into the cup 1B, a bonding wire 7 of a gold wire for electrically connecting the lead frame 1C and the submount element 4, and a transparent epoxy resin portion 8. . Note that the illustration of the translucent resin 6 is omitted in FIG.
[0015]
The LED chip 2 is formed of, for example, a gallium nitride-based compound semiconductor such as GaN, GaAlN, InGaN, or InGaAlN, or ZnSe (zinc selenide) or the like so as to emit blue light of 450 nm to 480 nm, and has a light reflection film 2A. , A sapphire substrate 2B, an AlN buffer layer 2C, an n-type semiconductor layer 2D, an n-side electrode 2E, a multilayer 2K having a light emitting layer, a p-type semiconductor layer 2F, a p-side electrode 2G, and an LED chip. 2 is provided with a protective film 2I for protecting the surface and providing light emission, and is flip-chip bonded to the submount element 4. The LED chip 2 emits light in a planar manner in the multilayer 2K between the n-type semiconductor layer 2D and the p-type semiconductor layer 2F by applying a drive voltage to the n-side electrode 2E and the p-side electrode 2G.
[0016]
The light reflecting film 2A is formed by forming a semi-transmissive aluminum film in a thin film shape on a surface of a sapphire substrate 2B by a thin film forming method such as a sputtering method or a vacuum evaporation method. May be formed by another method as long as it is not hindered. Note that the thin film to be formed is not limited to aluminum, and another metal material or a material other than metal may be used as long as the light transmittance can be adjusted according to the film thickness. Further, it is preferable to select a material having excellent blue light emission in the side direction.
[0017]
The n-side electrode 2E can be formed using a metal such as Al, V, Sn, Ti, Cr, Nb, Ta, Mo, W, or Hf, or an alloy thereof, for example. Note that a two-layer structure or a multilayer structure in which layers having different compositions are stacked, for example, a two-layer structure of V and Al may be used.
[0018]
The p-side electrode 2G is formed using, for example, a metal such as Rh, Au, Pt, Ag, Cu, Al, Ni, Co, Mg, Pd, V, Mn, Bi, Sn, or Re, or an alloy thereof. be able to. Note that a two-layer or multilayer structure in which layers having different compositions are stacked may be used.
[0019]
The protective film 2I is made of, for example, SiO 2 and has a light transmitting property and an insulating property to protect the surface of the LED chip 2. Note that the protective film 2I is formed to have a thickness that allows the blue light L to be easily emitted in the side direction of the LED chip 2.
[0020]
The submount element 4 is formed of an n-type silicon substrate, and operates as a Zener diode for protecting the LED chip 2 from static electricity. Further, the n-side electrode 4A connected to the p-side electrode 2G by the Au bump 3A, the p-type semiconductor layer 4B, the p-side electrode 4C connected to the n-side electrode 2E by the Au bump 3B, and the Ag paste 5 And an n-type semiconductor layer 4E electrically connected to the cup portion 1B.
[0021]
The translucent resin 6 is made of an epoxy resin and contains Ce: YAG (yttrium aluminum garnet) as a phosphor. Note that a silicon resin that becomes transparent after solidification may be used as the translucent resin 6.
[0022]
In the light emitting device thus configured, when a voltage is applied to the lead frames 1A and 1C, the LED chip 2 emits a planar light in the multilayer 2K and emits blue light L having a wavelength of 450 to 480 nm.
[0023]
The light reflecting film 2 </ b> A reflects the blue light and transmits the blue light L above the LED chip 2 by partially transmitting the blue light. A part of the blue light L is converted into a yellow light having a wavelength of 550 to 580 nm by exciting the phosphor. By mixing the yellow light and the blue light L, white light is emitted.
[0024]
The blue light L reflected by the light reflection film 2A is emitted from the side surface of the LED chip 2. A part of the blue light L is converted into a yellow light by exciting a phosphor disposed on the side of the LED chip 2. By mixing the yellow light and the blue light L, white light is emitted. Further, the blue light L emitted from the side surface is reflected by the reflection surface of the cup 1B and emitted upward.
[0025]
A part of the blue light L reflected by the cup 1B is converted into a yellow light by exciting a phosphor disposed on the optical path, and emits white light by being mixed with the blue light L.
[0026]
According to the above-described first embodiment, the semi-transmissive light reflection film 2A is provided above the LED chip 2 (on the light emission observation surface side), and the blue light L is emitted upward and in the side direction. It is possible to uniformly irradiate the blue light L not only on the LED chip 2 but also on the phosphors arranged in the side direction, and it is possible to obtain white light without color unevenness over a wide range.
[0027]
Further, since the blue light L radiated in the side direction is reflected by the cup 1B and guided upward, the phosphor disposed on the optical path can be excited, the wavelength conversion efficiency is improved, and the white light is improved. The brightness of light can be improved.
[0028]
Further, by dispersing the blue light L, adjustment of the resin composition such as partial change of the concentration of the phosphor and production of the phosphor without the need for advanced resin moldability can be easily performed. The concentration (amount used) can be reduced.
[0029]
In the first embodiment described above, a configuration in which white light is obtained based on a mixture of blue light and yellow light is described. However, as a configuration in which white light is obtained, for example, green light excited by blue light and A first phosphor that emits red light and a second phosphor that emits red light when excited by blue light are mixed with the translucent resin 6, and white light is mixed by mixing red light, green light, and blue light. Light may be obtained.
[0030]
Further, the LED chip 2 is not limited to the one that emits blue light. For example, an LED chip that emits near-ultraviolet light may be used. In this case, white light can be obtained by mixing a phosphor excited by near-ultraviolet light and emitting red light, green light, and blue light with the translucent resin 6.
[0031]
FIG. 2 partially shows an LED chip 2 according to a second embodiment of the present invention, and includes a light diffusion layer 2H in which SiO 2 is mixed as a light diffusion material for diffusing blue light on the surface of a sapphire substrate 2B. Provided. Otherwise, the configuration not shown is the same as that of the first embodiment.
[0032]
Further, the light diffusion layer 2H reflects and diffuses the blue light L transmitted through the sapphire substrate 2B with titanium oxide or alumina as a light diffusion material, so as to be above, diagonally above, and laterally above the LED chip 2 as illustrated. And the sapphire substrate 2B.
[0033]
According to the second embodiment described above, the light diffusion layer 2H in which the light diffusion material is mixed is provided on the surface of the sapphire substrate 2B to reflect and diffuse the blue light L. In addition, it is possible to irradiate uniform blue light L based on light diffusion to phosphors disposed obliquely upward or in the side direction, and to obtain white light without color unevenness over a wide range.
[0034]
3A and 3B show a light emitting device of a flip chip bonding type according to a third embodiment of the present invention, wherein FIG. 3A is a partial sectional view of a cup 1B, and FIG. 3B is a partial enlarged view of the LED chip 2 of FIG. FIG. In this light emitting device, an uneven surface 2b obtained by roughening the surface of a sapphire substrate 2B is formed, and a light reflecting film 2A is provided on the uneven surface 2b. Further, the above-mentioned protective film (not shown) is provided on the surface of the LED chip 2. Since the configuration and the forming method of the light reflecting film 2A are the same as those described in the first embodiment, the overlapping description will be omitted.
[0035]
FIG. 3B shows transmission and reflection of the blue light L in the light reflection film 2A, and the direction of the blue light L emitted based on the light emission in the multilayer 2K depends on the incident position on the uneven surface 2b. The light is reflected from the LED chip 2 and radiated from above and on the side of the LED chip 2 as semi-transmitted light polarized when passing through the uneven surface 2b.
[0036]
According to the above-described third embodiment, the surface of the sapphire substrate 2B on which the light reflecting film 2A is provided is roughened, so that the blue light L and the half light in the reflecting direction corresponding to the position of incidence on the light reflecting film 2A. Transmitted light can be generated, and in addition to the effects of the first embodiment, the diffusivity of the blue light L in the side direction can be further enhanced. As a result, the blue light L can be uniformly radiated over a wide range not only above the LED chip 2 but also to the phosphors disposed diagonally above or in the side direction, and white light without color unevenness can be obtained. it can.
[0037]
FIG. 4 shows a face-up junction type light emitting device according to a fourth embodiment of the present invention. The LED chip 20 includes a p-side electrode 2G, a p-type semiconductor layer 2F, and an n-type electrode in order from the emission observation surface side. A side electrode 2E, an n-type semiconductor layer 2D, an AlN buffer layer 2C, and a sapphire substrate 2B are provided, and are adhesively fixed to the bottom surface of the cup 1B by a mount 9 mixed with a light diffusing material 9A. Also, a gold bonding wire 7 is electrically connected to the p-side electrode 2G and the n-side electrode 2E, and the bonding wire 7 on the n-side electrode 2E is electrically connected to the lead frame 1A. In addition, a protective film (not shown) is provided on the surface of the LED chip 20. In addition, parts having the same configuration as those of the first and third embodiments are denoted by the same reference numerals, and redundant description will be omitted.
[0038]
The p-side electrode 2G is made of a conductive film of a Co / Au alloy, is provided so as to cover the entire surface of the p-type semiconductor layer 2F, and has a thickness that allows the blue light L based on light emission in the multilayer 2K to be partially transmitted. It is formed with. The p-side electrode 2G may be made of, for example, Rh, Au, Pt, Ag, Cu, Al, Ni, Co, Mg, Pd, V, Mn, Bi, Sn, or Re in addition to the Co / Au alloy described above. Etc. or an alloy thereof. Above all, Rh and Pt can be used as a suitable p-electrode material because they have high reflection efficiency with respect to the emission wavelength of a blue LED made of a GaN-based semiconductor. Further, a two-layer or multilayer structure in which layers having different compositions are stacked may be used. Further, it is preferable to select a material having excellent blue light emission in the side direction.
[0039]
The mount 9 is formed using a resin material such as an epoxy resin which is easy to handle and has a light transmitting property. It is preferable that the resin used for the mount 9 has an adhesive property and an insulating property so that even when the resin rises to the side surface of the extremely small LED chip 2, the layers are not short-circuited on the side surface.
[0040]
In the light emitting device thus configured, when a voltage is applied to the lead frames 1A and 1C, the LED chip 2 emits a planar light in the multilayer 2K and emits blue light L having a wavelength of 450 to 480 nm.
[0041]
The p-side electrode 2G emits the blue light L above the LED chip 2 by partially transmitting the blue light L. A part of the blue light L is converted into a yellow light having a wavelength of 550 to 580 nm by exciting the phosphor. By mixing the yellow light and the blue light L, white light is emitted.
[0042]
The blue light L emitted downward from inside the multilayer 2K passes through the sapphire substrate 2B and reaches the mount 9. The mount 9 diffuses the blue light L by the mixed light diffusing material 9A and emits the diffused light to the side surface or obliquely upward. The emitted diffused light is reflected by the reflecting surface of the cup 1B and emitted upward.
[0043]
A part of the blue light L reflected by the cup 1B is converted into a yellow light by exciting a phosphor disposed on the optical path, and emits white light by being mixed with the blue light L.
[0044]
According to the above-described fourth embodiment, the blue light L emitted upward from inside the multilayer 2K is semi-transmitted by the p-side electrode 2G, and the blue light L emitted downward from inside the multilayer 2K is a light diffusing material. Since 9A is diffused by the mixed mount 9, the blue light L based on the light emission of the LED chip 2 can be efficiently diffused upward, obliquely upward, and in the side direction. In particular, since the blue light L sufficiently spreads near the bottom surface of the cup 1B, the wavelength conversion efficiency in the cup 1B is further improved, and white light without color unevenness can be obtained.
[0045]
FIG. 5 shows a face-up junction type light emitting device according to a fifth embodiment of the present invention. An LED chip 20 provided with a light reflection film 2A below a sapphire substrate 2B is mounted on a bottom surface of a cup 1B by a mount 9. The fourth embodiment differs from the fourth embodiment in the configuration of the adhesive fixing, and has the same configuration as the fourth embodiment in other respects.
[0046]
According to the fifth embodiment, the blue light emitted upward from inside the multilayer 2K is semi-transmitted by the p-side electrode 2G, and the blue light emitted downward from inside the multilayer 2K is reflected by the light reflection film 2A. As described in the fourth embodiment, the blue light based on the light emission of the LED chip 2 can be efficiently diffused upward and in the side direction, and the wavelength in the cup 1B can be increased. Conversion efficiency is improved, and white light without color unevenness can be obtained. Incidentally, the titanium oxide described in the fourth embodiment in mount 9, alumina, mixed with light diffusing material 9A such as SiO 2, based on the semi-transmissive light transmitted through the light reflective film 2A on the light diffusing member 9A diffusion You may make it do.
[0047]
Further, in each of the above-described embodiments, the light emitting device having the structure for improving the light emitting property on or near the surface of the LED chip 2 has been described. However, for example, a structure for improving the light emitting property is provided in the layer of the LED chip 2. May be. As such a configuration, for example, a distributed Bragg reflector (DBR) configured by alternately stacking layers having different refractive indices so as to satisfy Bragg diffraction conditions with respect to the emission wavelength of the LED chip 2. Can be used.
[0048]
FIG. 6 is a partial cross-sectional view of a flip-chip junction type light emitting device according to a sixth embodiment of the present invention, and has a DBR 2J between a p-side electrode 2G of the LED chip 2 and a p-type semiconductor layer 2F. . The other configuration has the same configuration as that of the light emitting device according to the third embodiment, and a duplicate description will be omitted.
[0049]
According to the above-described sixth embodiment, by providing the DBR 2J on the submount element 4 side with respect to the multilayer 2K, the blue light radiated from inside the multilayer 2K is diffused by the DBR 2J and reflected toward the sapphire substrate 2B. As a result, it is possible to enhance the light emission properties above and diagonally above the LED chip 2. The LED chip 2 is not limited to the flip chip bonding type described above, and may be, for example, a face-up bonding type.
[0050]
FIG. 7 is a partial cross-sectional view of a face-up junction type light emitting device according to a seventh embodiment of the present invention, and has a DBR 2J between the AlN buffer layer 2C and the n-type semiconductor layer 2D of the LED chip 20. . The other configuration has the same configuration as that of the light emitting device according to the fourth embodiment, and a duplicate description will be omitted.
[0051]
According to the seventh embodiment, by providing the DBR 2J on the sapphire substrate 2B side with respect to the multilayer 2K, the blue light emitted from inside the multilayer 2K is diffused by the DBR 2J and reflected in the direction of the p-side electrode 2G. As a result, it is possible to enhance the light emission properties above and diagonally above the LED chip 2. According to this configuration, the same effects as in the fourth embodiment can be obtained without using the light diffusing material 9A mixed in the mount 9 in the fourth embodiment.
[0052]
Note that the configuration described in each of the above embodiments is not limited to white and can be applied to a light emitting device that obtains a desired emission color by mixing a plurality of lights, and in particular, an LED is used as a light emission source. It is effective for light emitting devices.
[0053]
Further, in each of the above-described embodiments, the configuration in which the homojunction light emitting element including the p layer and the n layer is adopted as the semiconductor light emitting element has been described. However, as an alternative, the p type and the n type It is a matter of course that a double hetero type light emitting element having the above-mentioned cladding layer can be adopted.
[0054]
【The invention's effect】
As described above, according to the light emitting device of the present invention, the blue light radiated from the LED chip housed in the cup is radiated not only upward but also obliquely upward and sideward based on reflection or diffusion. Therefore, it is possible to eliminate the occurrence of color unevenness, facilitate manufacture, and improve luminance.
[Brief description of the drawings]
1A and 1B show a light emitting device according to a first embodiment of the present invention, wherein FIG. 1A is a longitudinal sectional view, and FIG. 1B is a partially enlarged view of the LED chip of FIG.
FIG. 2 is a partially enlarged view of an LED chip according to a second embodiment of the present invention.
3A and 3B show a light emitting device according to a third embodiment of the present invention, wherein FIG. 3A is a partial cross-sectional view of a cup, and FIG. 3B is a partially enlarged view of the LED chip shown in FIG.
FIG. 4 is a partial sectional view of a light emitting device according to a fourth embodiment of the present invention.
FIG. 5 is a partial sectional view of a light emitting device according to a fifth embodiment of the present invention.
FIG. 6 is a partial sectional view of a light emitting device according to a sixth embodiment of the present invention.
FIG. 7 is a partial sectional view of a light emitting device according to a seventh embodiment of the present invention.
FIG. 8 is a longitudinal sectional view of a light emitting device disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2000-216434).
[Explanation of symbols]
1A, lead frame 1B, cup 1C, lead frame 1a, metal stem 2, LED chip 2A, light reflection film 2B, sapphire substrate 2C, buffer layer 2D, n-type semiconductor layer 2E, n-side electrode 2F, p-type semiconductor layer 2G, p-side electrode 2H, light diffusion layer 2I, protective film 2J, DBR 2K, multilayer 3A, bump 3B, bump 4, submount element 4A, n-side electrode 4B, p-type semiconductor layer 4C, p-side electrode 4D, n Electrode 4E, n-type semiconductor layer 5, Ag paste 6, translucent resin 7, bonding wire 8, transparent epoxy resin part 9, mount 9A, light diffusing material 10, package 11, concave part 12, chip 13, coating part 14, Coating part 14A, fluorescent substance 15, external electrode 16, bonding wire 20, LED chip

Claims (10)

発光面に垂直な方向に放射する光の一部を反射させ、その反射光の少なくとも一部を発光面に水平な方向に放射する半導体発光素子と、
前記半導体発光素子を収容し、内壁面を前記光の反射面とする素子収容部と、前記素子収容部に収容された前記半導体発光素子を封止し、前記光によって励起されて前記光の波長と異なった波長の励起光を放射する蛍光体を含んだ透光性樹脂部とを含むことを特徴とする発光装置。A semiconductor light emitting element that reflects a part of light emitted in a direction perpendicular to the light emitting surface and emits at least a part of the reflected light in a direction horizontal to the light emitting surface,
An element accommodating portion that accommodates the semiconductor light emitting element and has an inner wall surface that reflects the light, seals the semiconductor light emitting element accommodated in the element accommodating portion, and is excited by the light to emit the light. And a light-transmitting resin portion containing a phosphor that emits excitation light having a different wavelength. 前記半導体発光素子は、窒化ガリウム系化合物半導体によって形成されることを特徴とする請求項１記載の発光装置。The light emitting device according to claim 1, wherein the semiconductor light emitting element is formed of a gallium nitride compound semiconductor. 前記透光性樹脂部は、前記半導体発光素子から放出される青色光によって励起された前記蛍光体から放射される黄色光と前記青色光との混合に基づく白色光を透過させることを特徴する請求項１記載の発光装置。The light-transmitting resin portion transmits white light based on a mixture of yellow light and blue light emitted from the phosphor excited by blue light emitted from the semiconductor light-emitting element. Item 2. The light emitting device according to Item 1. 前記半導体発光素子は、半透過性を有する光反射膜を表面に有することを特徴とする請求項１記載の発光装置。2. The light emitting device according to claim 1, wherein the semiconductor light emitting element has a semi-transmissive light reflecting film on a surface. 前記光反射膜は、粗面化された前記表面に設けられることを特徴とする請求項４記載の発光装置。The light emitting device according to claim 4, wherein the light reflecting film is provided on the roughened surface. 前記半導体発光素子は、前記光を拡散させる光拡散材を混入された光拡散層を表面に有することを特徴する請求項１記載の発光装置。The light emitting device according to claim 1, wherein the semiconductor light emitting element has a light diffusion layer on a surface of which a light diffusion material for diffusing the light is mixed. 前記表面は、前記半導体発光素子の発光観測面側であることを特徴とする請求項４記載又は第６項の発光装置。7. The light emitting device according to claim 4, wherein the surface is on a light emission observation surface side of the semiconductor light emitting element. 前記表面は、前記半導体発光素子の固定面側であることを特徴とする請求項４又は第６項記載の発光装置。The light emitting device according to claim 4, wherein the surface is a fixed surface side of the semiconductor light emitting element. 前記光反射膜は、前記素子収容部内にフリップチップ接合される前記半導体発光素子の発光観測面側に配置されるサファイア基板に積層された半透過性を有するアルミニウム膜であることを特徴とする請求項４記載の発光装置。The light reflecting film is a semi-transmissive aluminum film laminated on a sapphire substrate disposed on a light emission observing surface side of the semiconductor light emitting device to be flip-chip bonded in the device accommodating portion. Item 5. The light emitting device according to Item 4. 前記光反射膜は、前記素子収容部内にフェイスアップ接合される前記半導体発光素子の発光観測面側に配置されるｐ型半導体層に積層された半透過性を有するｐ側電極であることを特徴とする請求項４記載の発光装置。The light reflection film is a semi-transmissive p-side electrode laminated on a p-type semiconductor layer arranged on a light emission observation surface side of the semiconductor light emitting element that is face-up joined in the element accommodating portion. The light emitting device according to claim 4, wherein
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