JP4681059B2 - Fluorescent light-emitting diode - Google Patents
Fluorescent light-emitting diode Download PDFInfo
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- JP4681059B2 JP4681059B2 JP2009030346A JP2009030346A JP4681059B2 JP 4681059 B2 JP4681059 B2 JP 4681059B2 JP 2009030346 A JP2009030346 A JP 2009030346A JP 2009030346 A JP2009030346 A JP 2009030346A JP 4681059 B2 JP4681059 B2 JP 4681059B2
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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
- H01L2224/42—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
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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
- H01L2224/42—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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/30—Technical effects
- H01L2924/301—Electrical effects
- H01L2924/3025—Electromagnetic shielding
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Description
本発明は蛍光体を用いた半導体発光素子の蛍光体層から発光素子側に発光する蛍光を反射鏡によって前方に反射して効率を改善し、放射角による色斑と発光素子近傍の蛍光体劣化を防止した発光素子およびこの発光素子を使用した照明装置に関するものである。 The present invention improves the efficiency by reflecting the light emitted from the phosphor layer of the semiconductor light emitting element using the phosphor to the light emitting element side by a reflecting mirror to improve the efficiency. The present invention relates to a light-emitting element that prevents light emission and a lighting device using the light-emitting element.
半導体発光素子は小型、高効率、長寿命、低電圧動作、高速応答などの優れた特徴のため各種表示装置・交通信号機などに広く使用されている。
赤、緑、青の３原色発光素子の加法混色による白色光は単体の発光スペクトル幅が狭いために不連続なスペクトル特性を持つが、液晶表示装置は赤、緑、青の３色の発光素子による不連続なスペクトルでも３色の制御信号によりその中間色を表示するため３色の発光素子を用いた３原色白色光を利用可能である。３色の発光素子を円錐内面に設けて後方散乱によって混色する距離を長くする提案（図１７、特許文献１）は多重反射に伴って吸収が増えて効率が低下する。３色の発光素子を同一パッケージに収め、発光素子に近い部分の反射鏡の傾斜を急にして各発光素子と反射鏡の距離と角度の差異を緩和する提案があるが（図１８、特許文献２）、局部的条件でしか均等な混色が得られない。３色の発光素子を同一パッケージ内で十分に混色するのが難しく、素子の電源電圧が異なるなどの理由で下記の蛍光白色発光ダイオードが多く使用されている。
Semiconductor light emitting devices are widely used in various display devices and traffic signals because of their excellent features such as small size, high efficiency, long life, low voltage operation, and high speed response.
White light resulting from additive color mixing of red, green, and blue primary light emitting elements has discontinuous spectral characteristics due to the narrow emission spectrum width of a single substance, but the liquid crystal display device has three colors of red, green, and blue light emitting elements. Even in the discontinuous spectrum due to the three primary color white light using the three color light emitting elements can be used to display the intermediate color by the control signal of the three colors. The proposal (FIG. 17, Patent Document 1) in which three color light-emitting elements are provided on the inner surface of the cone to increase the color mixing distance by backscattering increases absorption due to multiple reflections and decreases efficiency. There is a proposal to reduce the difference in the distance and angle between each light emitting element and the reflecting mirror by placing three color light emitting elements in the same package and steepening the inclination of the reflecting mirror near the light emitting element (FIG. 18, Patent Document). 2) Uniform color mixing can be obtained only under local conditions. The following fluorescent white light-emitting diodes are often used because it is difficult to sufficiently mix the three-color light-emitting elements in the same package and the power supply voltages of the elements are different.
青色発光ダイオードの青色光をイットリウム・アルミニウム酸化物系蛍光体などの黄色蛍光体に照射した補色による蛍光白色発光ダイオードのスペクトルは先鋭な青色となだらかな黄色域の２つのピークから成っている（特許文献３）。赤色域が非常に少なく、緑にも大きなディップを持つ青みの強いスペクトル特性である。しかし、蛍光白色発光ダイオードは３原色の混色に比べて構造が簡単なため携帯電話などの液晶表示装置のバックライトなどとして多く利用されている。 The spectrum of a fluorescent white light-emitting diode with a complementary color obtained by irradiating the blue light of a blue light-emitting diode to a yellow phosphor such as an yttrium / aluminum oxide phosphor is composed of two peaks in a sharp blue and gentle yellow region (patent) Reference 3). It has a strong bluish spectral characteristic with very little red range and a large dip in green. However, fluorescent white light-emitting diodes are often used as backlights for liquid crystal display devices such as mobile phones because they have a simpler structure than mixed colors of the three primary colors.
半導体発光素子の発光効率の向上に伴って蛍光ランプに比べて小型化が可能な発光ダイオードによる照明への応用が進められ、半導体発光素子が点光源に近い特長を生かして放射角の狭いプロジェクターなどに使用され始めている。発光ダイオードは許容温度上昇が他の光源に比べて小さいため、大きな光束を得るのは多数のチップが必要になり高価である。普及には低価格化する必要があり、効率を重視されて青みの強いスペクトルになっている。
最も比視感度の高い黄緑色付近の蛍光体を青色発光ダイオードで励起して補色による蛍光白色光を一般照明に使用した場合、赤色域やディップ波長域の被照射体は連続スペクトルの白色光に比べて暗くなる。赤色蛍光体などを混合する方法やイットリウムの一部をガドリニウムに置換して長波長側にシフトし、演色性を改善しつつ効率向上する提案がある（特許文献３）。
With the improvement of the luminous efficiency of semiconductor light emitting devices, the application to lighting with light emitting diodes that can be reduced in size compared to fluorescent lamps has been promoted, projectors with a narrow emission angle by taking advantage of the features of semiconductor light emitting devices close to point light sources, etc. Has begun to be used. Since the allowable temperature rise of the light emitting diode is smaller than that of other light sources, it is expensive to obtain a large luminous flux because a large number of chips are required. In order to spread, it is necessary to reduce the price, and the spectrum is strongly bluish with emphasis on efficiency.
When the fluorescent light near yellowish green with the highest relative visibility is excited with a blue light-emitting diode and fluorescent white light by complementary color is used for general illumination, the irradiated object in the red or dip wavelength range becomes white light in the continuous spectrum. It becomes darker than that. There are proposals for mixing red phosphors and the like, and for replacing yttrium with gadolinium and shifting to the longer wavelength side to improve efficiency while improving color rendering (Patent Document 3).
蛍光白色発光ダイオードの蛍光体は透光性樹脂に分散してカップ状凹面鏡の内部または表面実装部品のモールド全体に分散されているが、光軸方向で青色光が多くなり傾斜角方向で黄色光が増大するなどの色斑が生じるため、カップ状凹面鏡を２段に分けて蛍光体分散樹脂の厚さを均一にする下段凹部と封止部材の形状を均一にする上段凹部に分割した提案（特許文献４）、分散状態の均一性を改善するために射出成型機を使用して粒子沈降を防止した提案（特許文献５）などがある。 The phosphor of the fluorescent white light-emitting diode is dispersed in a translucent resin and dispersed inside the cup-shaped concave mirror or the entire mold of the surface mount component. However, blue light increases in the optical axis direction and yellow light in the tilt angle direction. As a result, the cup-shaped concave mirror is divided into two steps to divide the phosphor-dispersed resin into a uniform thickness and a lower recess to make the sealing member uniform in shape. Patent Document 4) and a proposal (Patent Document 5) that uses an injection molding machine to prevent particle sedimentation in order to improve the uniformity of the dispersed state.
照明は光源の反射光により色を認識するため光源の分光特性が演色性に影響し、波長が欠けていると情報が欠落して正確な色再現が出来なくなる。撮像用光源として線光源に近い３波長冷陰極管が多く使用されているが各色の蛍光材料が線スペクトルのため波長特性の凹凸が大きく、冷陰極管はインバータが必要である。楕円筒反射鏡の線状に形成される焦点に発光ダイオードを配置し、読み取り面を他方の焦線とするスキャナー光源の提案が３原色の発光ダイオードで示されている（特許文献６）。連続スペクトルにするには更に多色の素子が必要になり、発光ダイオードの光度がピークの約半値になる波長幅は２０ｎｍ〜６０ｎｍのため６色〜９色を用いて可視光域をカバーする提案がある（特許文献７）。７種類の発光素子を基板中央付近に並べ、焦点面より浅い位置のレンズ内に封入し、焦点面の散乱材層で混色することにより各色の半値波長で繋げて白色光を形成し、線光源変換素子で変換してスキャナー光源としての応用が示されている。 Since illumination recognizes color by reflected light from the light source, the spectral characteristics of the light source affect the color rendering, and if the wavelength is missing, information is lost and accurate color reproduction cannot be achieved. A three-wavelength cold cathode tube close to a line light source is often used as an imaging light source. However, since the fluorescent materials of each color have a line spectrum, the wavelength characteristics have large irregularities, and the cold cathode tube requires an inverter. A proposal of a scanner light source in which a light emitting diode is arranged at a focal point formed in a linear shape of an elliptical cylindrical reflector and the reading surface is the other focal line is shown as a light emitting diode of three primary colors (Patent Document 6). In order to obtain a continuous spectrum, more multi-colored elements are required, and the wavelength width at which the luminous intensity of the light emitting diode is about half the peak is 20 nm to 60 nm, so a proposal to cover the visible light range using 6 to 9 colors. (Patent Document 7). Seven types of light-emitting elements are arranged near the center of the substrate, enclosed in a lens shallower than the focal plane, and mixed with the scattering material layer on the focal plane to form white light by connecting at half-value wavelengths of each color. An application as a scanner light source after conversion by a conversion element is shown.
カップ状凹面鏡底部に発光素子を設け、内部に蛍光体を分散した従来の蛍光白色発光ダイオードは蛍光体から前方に出射する蛍光を利用しているが、蛍光体から発光する方向は前方の出射方向の他に発光素子に戻る方向、カップ状の凹面鏡に出射する方向がある。発光素子に戻った光は屈折により発光素子内部に入射するか、入射角に応じて出射方向あるいは凹面鏡方向に反射する。多重に屈折・反射する際に吸収が発生する。前方に出射する蛍光の一部は別の蛍光体に当たって吸収が発生するが、発光素子方向に戻る場合も蛍光体粒子に当たり吸収が発生する。蛍光変換された波長が再び蛍光体に当たった場合は励起波長特性が蛍光域まで及んでいないので反射・吸収され、発光素子と蛍光体の間で反射を繰り返すことによって更に吸収が大きくなる。 A conventional fluorescent white light-emitting diode in which a light-emitting element is provided at the bottom of the cup-shaped concave mirror and phosphors are dispersed inside uses fluorescence emitted forward from the phosphor, but the direction of light emission from the phosphor is the forward emission direction Besides, there is a direction returning to the light emitting element and a direction emitting to the cup-shaped concave mirror. The light returning to the light emitting element is incident on the inside of the light emitting element due to refraction, or reflected in the emission direction or the concave mirror direction depending on the incident angle. Absorption occurs when refracting and reflecting multiple times. A part of the fluorescence emitted forward hits another phosphor and is absorbed, but when it returns to the light emitting element direction, the phosphor particles hit and absorb. When the fluorescence-converted wavelength hits the phosphor again, the excitation wavelength characteristic does not reach the fluorescence region, so that it is reflected and absorbed, and absorption is further increased by repeating reflection between the light emitting element and the phosphor.
蛍光白色発光ダイオードの蛍光体は透光性樹脂に分散してカップ状凹面鏡の内部または表面実装部品のモールド全体に分散されている。発光素子の近傍にも蛍光体が分散され、発光素子の近傍は距離の２乗に反比例して光束密度が高くなるために発光素子近傍ほど蛍光体が劣化し易くなる。発光素子の発熱が蛍光体に熱伝導し、アレニウス則に従って劣化を促進するため放熱構造が重要になっているが、発光素子近傍に分散されている蛍光体は熱によっても劣化を促進されている。 The phosphor of the fluorescent white light-emitting diode is dispersed in a translucent resin and dispersed in the inside of the cup-shaped concave mirror or the entire mold of the surface mount component. The phosphor is also dispersed in the vicinity of the light emitting element, and the luminous flux density increases in inverse proportion to the square of the distance in the vicinity of the light emitting element. The heat dissipation structure is important because the heat generated in the light-emitting element conducts heat to the phosphor and promotes deterioration according to the Arrhenius law. However, the phosphor dispersed in the vicinity of the light-emitting element is also promoted by heat. .
蛍光体の配合比と配合むらによって青の吸収が大きく変わり、指向性による色斑を生じるために均一に分散する提案が多くなされている。光軸上に青色光が多く、周辺光に黄色光が多くなるのを改善するために蛍光体を均一に分散して厚さを均一にする提案がある。しかし、蛍光体を均一に分散して蛍光体層の厚さを均一にしても、発光素子の光軸上と周辺部では蛍光体層の光路長が光軸付近よりも周辺部の方が長く、光軸上の蛍光体層厚ｔと周辺への光路長ｒとの比は数１で示される。
θが３０°では周辺方向に１５．５％長くなるために厚さが均一であっても周辺光に黄色蛍光が多くなり、色斑が発生している。
Many proposals have been made to uniformly disperse the blue to greatly change the blending ratio and blending unevenness of the phosphors and to produce color spots due to directivity. In order to improve the amount of blue light on the optical axis and the amount of yellow light in the ambient light, there has been a proposal to uniformly disperse phosphors to make the thickness uniform. However, even if the phosphor is uniformly dispersed to make the thickness of the phosphor layer uniform, the optical path length of the phosphor layer on the optical axis and the peripheral part of the light emitting element is longer in the peripheral part than in the vicinity of the optical axis. The ratio between the phosphor layer thickness t on the optical axis and the optical path length r to the periphery is expressed by Equation 1.
When θ is 30 °, it becomes 15.5% longer in the peripheral direction. Therefore, even if the thickness is uniform, yellow fluorescence increases in the ambient light, and color spots are generated.
青色発光ダイオードの青色光を黄色蛍光体に照射した補色による白色発光ダイオードは尖鋭なスペクトルの青色光となだらかな黄色光のスペクトルを持ち、赤色域と青緑色域が不足している。蛍光が進行方向の蛍光体に当たらずに透過すると黄色光を呈し、別の黄色蛍光体に当たると蛍光体が有色不透明で蛍光波長に対しては蛍光変換率が低いために吸収される。吸収を補って蛍光体配合比率を上げると更に効率が低下するため、蛍光白色発光ダイオードは効率を優先されて青色光スペクトルが大きい青白い光になっている。 A white light-emitting diode with a complementary color obtained by irradiating a yellow phosphor with blue light from a blue light-emitting diode has a sharp blue light and a gentle yellow light spectrum, and lacks a red region and a blue-green region. When the fluorescent light is transmitted without passing through the fluorescent material in the traveling direction, yellow light is emitted. When the fluorescent material hits another yellow fluorescent material, the fluorescent material is colored and opaque and is absorbed because the fluorescence conversion rate is low with respect to the fluorescent wavelength. When the phosphor blending ratio is increased by supplementing the absorption, the efficiency further decreases. Therefore, the fluorescent white light emitting diode is given priority to efficiency, and becomes blue light with a large blue light spectrum.
演色性を改善するために広い波長帯域にわたって蛍光体を混合するとき、変換効率と比視感度に応じた蛍光体の配合比率で混合する必要がある。比視感度・変換効率の低い赤色などでは長波長蛍光体の量が増え、長波長の蛍光体から発せられた光は短波長の蛍光体では吸収だけで蛍光変換されないので更に蛍光体を増やす必要が生じる。黄色蛍光が黄色蛍光体に当たる確率、赤色蛍光が赤色蛍光体に当たる確率も増大して効率が低下する。このため、複数種の蛍光体を混合分散して連続スペクトルの白色光を実現するのは効率が低下する問題がある。 When mixing phosphors over a wide wavelength band in order to improve color rendering, it is necessary to mix with a phosphor blending ratio corresponding to the conversion efficiency and specific luminous efficiency. The amount of long-wavelength phosphors increases in red with low specific luminous efficiency and conversion efficiency, and light emitted from long-wavelength phosphors is absorbed only by short-wavelength phosphors and is not converted to fluorescence. Occurs. The probability that the yellow fluorescent light hits the yellow fluorescent material and the probability that the red fluorescent light hits the red fluorescent material also increase, and the efficiency decreases. For this reason, there is a problem that the efficiency is lowered when a plurality of kinds of phosphors are mixed and dispersed to realize white light having a continuous spectrum.
発光素子を同一パッケージに配置し、発光素子近傍の反射鏡の傾斜を急にするなどの構造によって混色する提案は各発光素子から反射鏡への距離と角度が異なるのでチップの並びに従った色斑を生じる。正反射による混色が難しいために散乱層を利用して後方散乱させて散乱距離を長く取るなどの混色のため反射光が光源側に戻り、多重反射の際に吸収されて効率が低下する問題がある。外部で効率の良い混色手段がないために、蛍光白色発光ダイオードは蛍光体を混合して混色する方法に帰結している。 The proposal to mix colors by arranging the light emitting elements in the same package and steeply tilting the reflecting mirror near the light emitting elements is different in distance and angle from each light emitting element to the reflecting mirror. Produce. Since color mixing by regular reflection is difficult, there is a problem that reflected light returns to the light source side due to color mixing such as long scattering distance by using a scattering layer, and the efficiency is reduced due to absorption in multiple reflection. is there. Since there is no efficient color mixing means outside, the fluorescent white light-emitting diode results in a method of mixing phosphors and mixing colors.
蛍光体分散膜７を焦点とする蛍光反射凹面鏡３に発光素子１からの励起光１６を透過する開口部２３を設け、前記透過開口部に交差して開口とする発光素子周囲凹面鏡２を設け、その内部に発光素子を設けた構造から成っている。発光素子から開口部を通して蛍光体分散膜に励起光を照射し、変換された蛍光１６を、蛍光体分散膜を焦点とする蛍光反射凹面鏡で反射して出射する。蛍光体分散膜を焦点とする焦点距離の大きな凹面鏡を蛍光反射凹面鏡と呼び、発光素子の周囲の凹面鏡を発光素子周囲凹面鏡と呼ぶことにする。図１は発光素子周囲凹面鏡を楕円鏡で構成し、蛍光体分散膜の半径を発光素子チップ寸法にして狭い放射角を実現する構造を示している。発光素子から楕円鏡を経由した励起光は焦点にある蛍光体に集光すると蛍光体は全方向に発光する。蛍光体から発光素子側の半空間に発せられた蛍光は発光素子周囲凹面鏡の開口部面積は蛍光反射凹面鏡に比べて小さいので、蛍光体の後方側に発光した蛍光は蛍光反射凹面鏡に殆どが照射される。蛍光体の前方に発光された蛍光は蛍光体を焦点とするレンズを設けることにより平行光に変換して前方に出射する。蛍光反射凹面鏡を放物面鏡または放物線近似曲率円球面鏡にすると、前方のレンズによる平行光と同様に蛍光を平行光として出射することが出来る。 An opening 23 for transmitting the excitation light 16 from the light emitting element 1 is provided in the fluorescent reflecting concave mirror 3 having the phosphor dispersion film 7 as a focal point, and a light emitting element surrounding concave mirror 2 is provided as an opening crossing the transmission opening, It has a structure in which a light emitting element is provided. The phosphor dispersion film is irradiated with excitation light from the light emitting element through the opening, and the converted fluorescence 16 is reflected by a fluorescent reflecting concave mirror having the phosphor dispersion film as a focal point and emitted. A concave mirror having a large focal length with the phosphor dispersion film as a focal point is called a fluorescent reflecting concave mirror, and a concave mirror around the light emitting element is called a light emitting element surrounding concave mirror. FIG. 1 shows a structure in which the concave mirror around the light emitting element is formed of an elliptical mirror and the radius of the phosphor dispersion film is set to the size of the light emitting element chip to realize a narrow emission angle. When the excitation light passing through the elliptical mirror from the light emitting element is condensed on the phosphor in focus, the phosphor emits light in all directions. Fluorescence emitted from the phosphor in the half space on the light emitting element side has a smaller opening area of the concave mirror around the light emitting element than the fluorescent reflecting concave mirror, so most of the fluorescence emitted from the rear side of the phosphor irradiates the fluorescent reflecting concave mirror. Is done. Fluorescence emitted in front of the phosphor is converted into parallel light by providing a lens having the phosphor as a focal point, and emitted forward. If the fluorescent reflecting concave mirror is a parabolic mirror or a parabolic approximate curvature spherical mirror, the fluorescent light can be emitted as parallel light in the same manner as the parallel light from the front lens.
楕円鏡の焦点から発光して他方の焦点に集光するとき、発光素子が各辺約２５０μｍの有限寸法を有するため、発光素子寸法と同等程度に集光する。楕円鏡による反射光は蛍光体に集光するが、発光素子からの直接光は拡散光なので蛍光体分散膜径が小さいと焦点の周囲に逸れて蛍光変換されなくなるので周囲に反射鏡を設けて逸れた励起光を蛍光体分散膜に反射している。カップ状反射鏡内部に蛍光体を分散している従来の白色発光ダイオードよりも蛍光体の分散密度を高め、蛍光体体積を発光素子と同等程度の蛍光体体積で塊状に密集すると前方に透過し難くなるので蛍光体を透明樹脂に分散した円形膜が適している。蛍光体を透明樹脂に分散した膜を蛍光体分散膜あるいは蛍光体膜と称することにする。蛍光体分散膜にして被照射面積を拡大すると励起光が逸れるのを削減することが出来る。径の大きな蛍光体分散膜の場合は発光素子周囲凹面鏡を楕円鏡のみならず円錐鏡、円筒鏡、照明装置形状によっては角錐鏡も使用可能である。 When light is emitted from the focal point of the ellipsoidal mirror and condensed on the other focal point, the light emitting element has a finite dimension of about 250 μm on each side, and therefore the light is condensed to the same extent as the dimension of the light emitting element. The reflected light from the elliptical mirror is focused on the phosphor, but the direct light from the light emitting element is diffused light, so if the phosphor dispersion film diameter is small, it will be displaced around the focal point and will not be converted to fluorescence. The deviated excitation light is reflected on the phosphor dispersion film . When the phosphor dispersion density is increased compared to the conventional white light emitting diode in which the phosphor is dispersed inside the cup-shaped reflector, and the phosphor volume is concentrated in a lump with a phosphor volume equivalent to that of the light emitting element, it is transmitted forward. A circular film in which a phosphor is dispersed in a transparent resin is suitable because it becomes difficult. A film in which a phosphor is dispersed in a transparent resin is referred to as a phosphor dispersion film or a phosphor film. When the irradiation area is enlarged by using a phosphor dispersion film, it is possible to reduce the escape of excitation light. In the case of a phosphor dispersion film having a large diameter, not only an elliptical mirror but also a conical mirror, a cylindrical mirror, and a pyramid mirror can be used depending on the shape of the illumination device.
発光素子体積と同量の蛍光体体積０．０１５６ｍｍ３を半径０．６ｍｍの円形蛍光体分散膜にすると１４μｍの厚さになる。蛍光変換して蛍光のみを利用する場合は平均粒径１０μｍの蛍光体を断面視で千鳥に配置すると充填率が高いために蛍光体粒子間の透過光を防止しつつ、蛍光体からの蛍光を前方に放射することが出来る。蛍光体分散膜厚を厚くすると蛍光が前方に透過せずに前方の蛍光体で吸収されるため、稠密に充填せずに蛍光体の体積充填率を制御して励起光と蛍光のスペクトルバランスをとることが出来る。 When a phosphor volume of 0.0156 mm 3 having the same amount as the light emitting element volume is formed into a circular phosphor dispersion film having a radius of 0.6 mm, the thickness becomes 14 μm. When fluorescent conversion is used and only fluorescent light is used, the fluorescent material having an average particle diameter of 10 μm is arranged in a staggered manner in a cross-sectional view, and the filling rate is high. Can radiate forward. If the phosphor dispersion film thickness is increased, the fluorescence will not be transmitted forward but will be absorbed by the front phosphor, so the volume balance of the phosphor will be controlled without dense packing, and the spectral balance of excitation light and fluorescence will be adjusted . I can take it .
励起光と蛍光のスペクトルバランスをとる場合は、蛍光体膜は前方のみならず蛍光反射凹面鏡方向にも発光するため、蛍光体粒子１２の他に白色粒子１３を混合して励起光を反射し、前方への励起光透過率に概略一致させる必要がある。蛍光体と白色粒子を透明樹脂に混合してフィルム成形する場合は蛍光体と白色粒子の体積充填率で透過率を設定することが出来る。白色粒子の体積と反射率の積に相当する透明粒子を混合して表面全体に塗布することにより励起光の透過率と反射率を同等にすることも出来る。透過部を透明粒子として扱い、図２に蛍光体粒子・白色粒子・透明粒子混合物を単層の千鳥に並べた模式図を示す。 When balancing the spectrum of excitation light and fluorescence, the phosphor film emits light not only in the front direction but also in the direction of the fluorescence reflecting concave mirror, so the white particles 13 are mixed in addition to the phosphor particles 12 to reflect the excitation light, It is necessary to roughly match the forward excitation light transmittance. When the phosphor and white particles are mixed with a transparent resin to form a film, the transmittance can be set by the volume filling rate of the phosphor and the white particles. By mixing transparent particles corresponding to the product of the volume of white particles and the reflectance and applying the mixture to the entire surface, the transmittance and reflectance of the excitation light can be made equal. The transmission part is treated as transparent particles, and FIG. 2 shows a schematic diagram in which phosphor particles, white particles, and transparent particle mixtures are arranged in a single layer staggered pattern.
図２において蛍光体・白色粒子混合物と透過部による蛍光体膜を８個の全粒子で模式化し、蛍光体を半数の４個、白色粒子を２個、透明粒子を２個で示している。白色粒子は酸化マグネシウム（反射率０．９８）、シリカ、酸化チタンなどの高反射率物質が適し、反射率を１で近似し、透過部または透明粒子の透過率を１で近似すると前方への励起光の透過光量と蛍光反射鏡方向への励起光反射光量を等しくすることが出来る。励起光Ｉを受けた蛍光体の蛍光変換効率αとして、前方と後方の空間に同量の蛍光を発し、蛍光体が半数のため前方・後方とも蛍光量はＩ・α／４である。 In FIG. 2, a phosphor film composed of a phosphor / white particle mixture and a transmission part is schematically represented by all eight particles, and half of the phosphors, four white particles, and two transparent particles are shown. For white particles, highly reflective substances such as magnesium oxide (reflectance: 0.98), silica, titanium oxide, etc. are suitable. When the reflectance is approximated by 1 and the transmittance of the transmission part or transparent particle is approximated by 1, the forward direction is increased. The transmitted light amount of the excitation light can be made equal to the reflected light amount of the excitation light toward the fluorescent mirror. As the fluorescence conversion efficiency α of the phosphor that has received the excitation light I, the same amount of fluorescence is emitted in the front and rear spaces, and since the number of phosphors is half, the amount of fluorescence is I · α / 4 for both the front and rear.
発光素子周囲凹面鏡は蛍光体に効率良く照射するには細長い形状が適し、楕円鏡の場合は数２における楕円鏡の長軸径をａ、短軸径をｂとするとａ／ｂの比が大きいほど図３のように細長い形状になる。
蛍光反射凹面鏡の焦点を楕円鏡の蛍光体側焦点の手前側にずらすと、楕円鏡の蛍光体側焦点に集光する光は蛍光反射凹面鏡の焦点の周囲に図１の場合よりも大きな直径の円環内を透過する。この円の寸法で蛍光体膜を形成すると、図１における焦点付近の蛍光体膜よりも直径が大きいので直接光が蛍光体を逸れるのを削減出来る。蛍光体膜から蛍光体膜の平面方向と斜め前方に発光する成分を遮光しつつ蛍光反射鏡方向に変換するための反射鏡を設けている。
発光素子周囲凹面鏡を楕円鏡にして焦点に絞りを設けて焦点通過後の拡散光を蛍光体に照射する構造も可能だが、直接光を絞りに集光して効率低下を防ぐ必要がある。
The concave mirror around the light emitting element is suitable to have an elongated shape for efficiently irradiating the phosphor. In the case of an elliptical mirror, the ratio of a / b is large when the major axis diameter of the elliptical mirror in Equation 2 is a and the minor axis diameter is b. As shown in FIG.
When the focal point of the fluorescent reflecting concave mirror is shifted to the front side of the phosphor side focal point of the elliptical mirror, the light condensed on the fluorescent side focal point of the elliptical mirror is around the focal point of the fluorescent reflecting concave mirror. It penetrates inside. If the phosphor film is formed with this circular dimension, the diameter of the phosphor film is larger than that of the phosphor film near the focal point in FIG. A reflecting mirror is provided for converting the light emitting component from the phosphor film to the plane direction of the phosphor film and obliquely forward while converting the component to the fluorescence reflecting mirror direction.
A structure in which the concave mirror around the light emitting element is an elliptical mirror and a diaphragm is provided at the focal point to irradiate the phosphor with the diffused light after passing through the focal point is also possible. However, it is necessary to condense the light directly onto the diaphragm to prevent a reduction in efficiency.
図４では放物面鏡焦点にある蛍光体から発せられて平行光に変換された状態を示しているが、蛍光体円形膜の径が大きくなるほど蛍光反射凹面鏡の点に入射する焦点と外周部でずれが大きくなり、蛍光反射凹面鏡の反射光は拡散光成分を持つ。蛍光体膜からの光を平行光に変換する場合、蛍光体膜の外周部における平行光からの誤差角度θは、蛍光体膜の半径ｒ、放物面鏡の座標（ｘ，ｙ）、蛍光反射放物面鏡の焦点距離ｐにより図６、数３で示される。
蛍光体膜の径による平行光からの誤差は図４と図６に示すように蛍光反射鏡の頂部に近いほど放射角度が広くなり、周辺では放射角が狭くなる。このため、図１のような径の小さな蛍光体膜では放射角の狭い用途に適し、図２のような発光素子周囲凹面鏡の開口径以上ある蛍光体膜の場合は放射角の広い用途に適している。
FIG. 4 shows a state where the light is emitted from the phosphor at the focal point of the parabolic mirror and converted into parallel light. However, the focal point and the outer peripheral portion incident on the point of the fluorescent reflecting concave mirror as the diameter of the phosphor circular film increases. The deviation becomes large and the reflected light of the fluorescent reflecting concave mirror has a diffused light component. When the light from the phosphor film is converted into parallel light, the error angle θ from the parallel light at the outer periphery of the phosphor film is the radius r of the phosphor film, the coordinates (x, y) of the parabolic mirror, the fluorescence This is shown in FIG. 6 and Equation 3 by the focal length p of the reflective parabolic mirror.
As shown in FIGS. 4 and 6, the error from the parallel light due to the diameter of the phosphor film becomes wider as it gets closer to the top of the fluorescent mirror, and becomes narrower in the periphery. For this reason, the phosphor film with a small diameter as shown in FIG. 1 is suitable for applications with a narrow emission angle, and the phosphor film with a diameter larger than the opening diameter of the concave mirror around the light emitting element as shown in FIG. 2 is suitable for applications with a wide emission angle. ing.
発光素子周囲凹面鏡の開口径を小さくすると、蛍光体膜から発光素子周囲凹面鏡開口部に戻る光量の比率を下げることが出来る。発光素子周囲凹面鏡開口部に戻る光量の比率は図７のように蛍光体から開口部までの半径ｒとした全球面の面積に占める楕円鏡開口部面積の比である。全放射光量に対する発光素子周囲凹面鏡開口部への放射比率は、光軸と開口部境界を結ぶ線が光軸となす角度αとし、数４のように球全体の表面積Ｔに対する開口部面積Ｓとの比で表すことが出来る。
蛍光反射凹面鏡の半径を５ｍｍ、発光素子周囲凹面鏡の開口半径１ｍｍとすると、
α＝１１．５°よりＳ／Ｔ＝０．０１で、発光素子周囲凹面鏡に戻る光量は無視出来る。
If the aperture diameter of the concave mirror around the light emitting element is reduced, the ratio of the amount of light returning from the phosphor film to the concave mirror aperture around the light emitting element can be reduced. The ratio of the amount of light returning to the concave mirror opening around the light emitting element is the ratio of the elliptical mirror opening area to the total spherical area with radius r from the phosphor to the opening as shown in FIG. The ratio of radiation to the concave mirror opening around the light emitting element with respect to the total amount of radiated light is an angle α formed by a line connecting the optical axis and the boundary between the optical axis and the optical axis. It can be expressed by the ratio.
When the radius of the fluorescent reflecting concave mirror is 5 mm and the opening radius of the concave mirror around the light emitting element is 1 mm,
Since α = 11.5 ° and S / T = 0.01, the amount of light returning to the concave mirror around the light emitting element is negligible.
蛍光反射凹面鏡は目的放射角に応じて蛍光体面積と凹面鏡曲線を選択することが出来、製造の容易な球面鏡、拡散光を形成する双曲線鏡など目的に応じて採用出来る。図４と図１０は光軸を開いた形状の回転放物面鏡で外周方向に平行光を反射し、屈折面で方向変換して径全体から出射している。図８は楕円鏡を使用して焦点に向かう光を凹屈折面で平行光に変換することにより薄型化した例を示している。図８における蛍光体前方の凸面鏡は前方への拡散光を後方の蛍光反射凹面鏡に反射して放物面鏡の周辺部の光束密度が低いのを補う効果を持たせている。図９は図２の構成による表面実装部品を示す分解斜視図である。図１０は回転放物面鏡を砲弾型発光ダイオードの一方のリードに設け、もう一方のリードに発光素子周囲凹面鏡を設けて反射鏡を分割してボンディングワイヤを短縮する例を示している。 The fluorescent reflecting concave mirror can select the phosphor area and concave mirror curve according to the target radiation angle, and can be adopted according to the purpose, such as a spherical mirror that is easy to manufacture and a hyperbolic mirror that forms diffuse light. 4 and 10 show a parabolic mirror having an open optical axis, which reflects parallel light in the outer peripheral direction, changes the direction on the refracting surface, and emits the light from the entire diameter. FIG. 8 shows an example in which the light is reduced in thickness by converting light toward the focal point into parallel light on the concave refractive surface using an elliptical mirror. The convex mirror in front of the phosphor in FIG. 8 has an effect of compensating the low light flux density in the peripheral part of the parabolic mirror by reflecting the forward diffused light to the rear fluorescent reflecting concave mirror. FIG. 9 is an exploded perspective view showing the surface-mounted component having the configuration shown in FIG. FIG. 10 shows an example in which a rotating paraboloid mirror is provided on one lead of a bullet-type light emitting diode, a concave mirror around the light emitting element is provided on the other lead, and the reflecting mirror is divided to shorten the bonding wire.
蛍光体膜から前方に発光する蛍光は拡散光のため、蛍光反射凹面鏡の出射光と整合するように放射角度を狭めるため凸レンズを設けた状態を図１、図４、図１０などに示す。凸レンズだけでなく反射鏡も使用することが出来、蛍光体膜から前方に拡散する蛍光を放物面鏡で平行光に変換する状態を図１１に示す。鉛直方向に出射するために平面鏡で方向変換している。図１１の構造は発光素子周囲凹面鏡が横向きのため薄型化が可能である。 Since the fluorescence emitted forward from the phosphor film is diffused light, a state in which a convex lens is provided to narrow the radiation angle so as to match the emitted light of the fluorescent reflecting concave mirror is shown in FIGS. A reflecting mirror as well as a convex lens can be used, and FIG. 11 shows a state in which fluorescence diffused forward from the phosphor film is converted into parallel light by a parabolic mirror. In order to emit light in the vertical direction, the direction is changed by a plane mirror. The structure shown in FIG. 11 can be thinned because the concave mirror around the light emitting element faces sideways.
蛍光体膜を形成するには蛍光体粒子にバインダーを付着させて透明フィルムに塗布する方法、バインダーを付着させた透明フィルムに蛍光体粒子を吹き付ける方法、蛍光体と樹脂を混練した後にフィルム成形する方法などにより蛍光体膜を形成することが出来る。励起光が紫外線の場合は未充填部分があると紫外線が透過するので蛍光体粒子を稠密に充填する必要がある。励起光を透過させて使用する場合は透明部分を設けて透過率を設定するが、蛍光体・白色粒子・透明粒子混合物をバインダーを塗布した透明フィルムに付着させると被覆率を制御するよりも容易である。
蛍光体・白色粒子・透明粒子混合物膜を所定形状に裁断して蛍光反射鏡の焦点に設置して更に樹脂で被覆することにより光学系の形成と同時に保護機能を兼ねることが出来る。
発光ダイオードの楕円鏡焦点付近まで樹脂モールドしている過程で、モールド表面に蛍光体粒子・白色粒子・透光粒子を適切な比率で混合した分散体を付着させた後に更に樹脂モールドする方法にすると予め蛍光体膜を形成する工程を省くことも出来る。
蛍光体膜から蛍光体膜の平面方向と斜め前方に発光する成分を蛍光反射鏡方向に変換するための反射鏡を設けるには反射膜を被覆したフィルムに蛍光体粒子・白色粒子・透明粒子混合物を塗布する、または反射膜を後工程で設ける製法などで形成することが出来る。
To form a phosphor film, a method of applying a binder to a phosphor film and applying it to a transparent film, a method of spraying phosphor particles on a transparent film to which a binder is attached, a film formation after kneading phosphor and resin A phosphor film can be formed by a method or the like. When the excitation light is ultraviolet light, if there is an unfilled portion, the ultraviolet light is transmitted, so that it is necessary to densely fill the phosphor particles. If the excitation light is transmitted and used, a transparent part is provided to set the transmittance. However, if the phosphor, white particles, and transparent particle mixture is attached to a transparent film coated with a binder, it is easier than controlling the coverage. It is.
The phosphor / white particle / transparent particle mixture film is cut into a predetermined shape, placed at the focal point of the fluorescent reflector, and further covered with a resin, so that the protective function can be achieved simultaneously with the formation of the optical system.
In the process of resin molding up to the vicinity of the elliptical mirror focal point of the light emitting diode, if a dispersion mixed with phosphor particles, white particles, and translucent particles in an appropriate ratio is attached to the mold surface, then resin molding is performed. The step of forming the phosphor film in advance can be omitted.
To provide a reflecting mirror for converting the light emitting component from the phosphor film to the plane direction and obliquely forward of the phosphor film into the direction of the fluorescent reflector, a mixture of phosphor particles, white particles, and transparent particles on a film coated with the reflecting film Or a manufacturing method in which a reflective film is provided in a later step.
従来の蛍光粒子分散体では空間に存在する他の蛍光体に多重反射して吸収されるが、蛍光体膜の場合は空間の多重反射・吸収は存在しないので複数種の蛍光体の蛍光変換効率で補正した成分比率で白色光あるいは多色光のスペクトルを設計し、実現することが出来る。
励起光から変換された蛍光のスペクトルは蛍光体の表面積比率と変換効率によるため、蛍光体分散層を透過する長さに由来する色の放射角依存性を解決することが出来る。
In conventional phosphor particle dispersions, multiple reflections are absorbed by other phosphors present in the space, but in the case of phosphor films, there is no spatial multiple reflection / absorption, so the fluorescence conversion efficiency of multiple types of phosphors The spectrum of white light or multicolor light can be designed and realized with the component ratio corrected in (1).
Since the fluorescence spectrum converted from the excitation light depends on the surface area ratio of the phosphor and the conversion efficiency, it is possible to solve the radiation angle dependency of the color derived from the length of transmission through the phosphor dispersion layer.
照明装置では複数の発光素子を使用して大きな光束を得るが、多成分蛍光体を単一の励起光で可視光帯域をカバーすると全て蛍光変換効率が掛かり、蛍光が他の蛍光体に当たるため効率が低下する。このため、複数の発光素子を使用する場合は複数励起光を採用して外部で混色した方が高効率である。光源部の発光素子は単一素子に限らず、励起波長特性が広い蛍光体を複数で構成して複数の励起光を含めた広帯域特性を実現可能だが、光源部に複数素子を設けると発光素子周囲凹面鏡の開口が大きくなり拡散光成分が増えるので放射角度が大きい用途に適している。 A lighting device uses multiple light emitting elements to obtain a large luminous flux. However, if a multi-component phosphor is covered with a single excitation light and covers the visible light band, all the fluorescence conversion efficiency is applied, and the fluorescence strikes other phosphors. Decreases. For this reason, when using a some light emitting element, it is more efficient to employ | adopt multiple excitation light and to mix colors outside. The light emitting element of the light source section is not limited to a single element, but it is possible to realize a broadband characteristic including a plurality of excitation lights by configuring a plurality of phosphors having a wide excitation wavelength characteristic, but if a plurality of elements are provided in the light source section, the light emitting element Since the aperture of the surrounding concave mirror becomes large and the diffused light component increases, it is suitable for applications with a large radiation angle.
照明装置は大きな光束を得るため発光素子を多数並べる必要から放熱が重要なため、放熱板を兼ねた三角波状反射格子に照射して混色する構造を図１２、図１３に示す。蛍光体を多成分で混合して白色光スペクトルを実現する方法に比べて効率が改善され、光源部反射鏡の内部に複数素子を設けるよりも狭い放射角を得ることが出来る。図１２の光源部は図２などの構造を半分に分割し、発光素子の発光方向を楕円鏡に向けた構造である。図１３の光源部は蛍光反射凹面鏡を楕円鏡にして前方の凸反射面により平行光に変換し、三角波状反射格子に照射している。これは図８の凹屈折面で平行光に変換する構造を凸面鏡に変形して方向変換させている。蛍光体前方は拡散光のため凸面鏡により後方の蛍光反射楕円鏡に反射している。 Since it is necessary to dissipate heat because an illuminating device needs to arrange a large number of light emitting elements in order to obtain a large luminous flux, FIGS. The efficiency is improved as compared with a method of realizing a white light spectrum by mixing phosphors with multiple components, and a narrower emission angle can be obtained than when a plurality of elements are provided inside the light source part reflecting mirror. The light source unit shown in FIG. 12 has a structure in which the structure shown in FIG. The light source unit shown in FIG. 13 converts the fluorescent reflecting concave mirror into an elliptical mirror, converts it into parallel light by the front convex reflecting surface, and irradiates the triangular wave reflecting grating. This is a structure in which the structure of converting into parallel light on the concave refracting surface in FIG. 8 is transformed into a convex mirror to change the direction. The front of the phosphor is diffused and reflected by the convex mirror to the rear fluorescent reflecting elliptical mirror.
蛍光体から発光素子側の半空間に発せられた蛍光を蛍光反射凹面鏡に照射して前方に反射して出射することにより、蛍光体から発光素子とその周辺に戻されて吸収されていた発光素子側の半空間の蛍光利用効率が向上する。
蛍光体膜は前方と後方に発光するため他の蛍光体粒子に吸収されることなく後方の蛍光反射凹面鏡と前方に出射することが出来る。
蛍光体膜の場合は空間の多重反射・吸収は存在しないので複数種の蛍光体の蛍光変換効率で補正した成分比率のスペクトルで出射する。このため、蛍光体分散層を透過する長さに由来する色の放射角依存性を解決することが出来る。
蛍光体膜は発光素子周囲凹面鏡の前方に設けられ、凹面鏡の反射光と発光素子からの直接光が照射されるために蛍光体の局部に集中することを避けることが出来る。このため、発光素子近傍に集中による蛍光体の劣化を防止することが出来る。
多成分系で混合して白色光スペクトルを実現する方法よりも外部で混色した方が効率を改善出来、発光素子を多数並べる照明用途では放熱板を兼ねた三角波状反射格子に照射して混色する構造により、蛍光体を励起する波長を最適化出来る。光源部反射鏡の内部に複数素子を設けるよりも狭い放射角を得ることが出来る。
蛍光体から発光素子方向に発せられた蛍光を蛍光反射凹面鏡により有効に出射することにより照明装置における発光素子の使用数量を削減し、損失の低減により放熱構造が簡単になる。このため、照明装置の製造コスト削減を行なうことが出来る。
The fluorescent light emitted from the phosphor to the light emitting element side half-space is irradiated to the fluorescent reflecting concave mirror and reflected and emitted forward, so that the light emitting element that has been absorbed from the phosphor to the light emitting element and its periphery is absorbed. The fluorescence utilization efficiency of the half space on the side is improved.
Since the phosphor film emits light forward and backward, it can be emitted forward to the rear fluorescent reflecting concave mirror without being absorbed by other phosphor particles.
In the case of a phosphor film, since there is no multiple reflection / absorption in space, light is emitted with a spectrum of component ratios corrected by the fluorescence conversion efficiency of a plurality of types of phosphors. For this reason, the radiation angle dependence of the color derived from the length which permeate | transmits a fluorescent substance dispersion layer can be solved.
The phosphor film is provided in front of the concave mirror around the light emitting element, and since the reflected light of the concave mirror and the direct light from the light emitting element are irradiated, it is possible to avoid concentrating on the local area of the phosphor. For this reason, deterioration of the phosphor due to concentration in the vicinity of the light emitting element can be prevented.
Mixing with a multi-component system to achieve a white light spectrum can improve efficiency by mixing colors externally, and in lighting applications where a large number of light emitting elements are arranged, the triangular wave reflection grating that also serves as a heat sink is irradiated and mixed. Depending on the structure, the wavelength for exciting the phosphor can be optimized. A narrower radiation angle can be obtained than when a plurality of elements are provided inside the light source reflection mirror.
By effectively emitting the fluorescence emitted from the phosphor toward the light emitting element by the fluorescent reflecting concave mirror, the number of light emitting elements used in the lighting device is reduced, and the heat dissipation structure is simplified by reducing the loss. For this reason, the manufacturing cost of the lighting device can be reduced.
説明の都合上、要部を拡大して表示するため必ずしも相似関係にはなっていない。
実施例１
蛍光体・白色粒子・透明粒子混合物による蛍光体膜を蛍光反射凹面鏡の焦点に設けた白色発光ダイオードの表面実装部品への実施例を説明する。図２、図４の断面図、図９の分解斜視図に示した構造である。蛍光体は膜状にして複数の混合物を用いることにより波長帯域を広く取ることが出来、他の粒子に当たって吸収を最小限に出来る。白色粒子と透明粒子は蛍光の総光量を変換効率で割った数値に対する励起光の比率で混合することにより目的の分光特性を得ることが出来る。白色粒子は酸化マグネシウム（反射率０．９８）、シリカ、酸化チタンなどの高反射率物質が適している。透明物質は透過率が高く、軟化温度の高いガラス、透明高分子が適している。前方への励起光の透過光量と蛍光反射鏡方向への励起光反射光量を等しくすると色バランスを良くすることが出来る。
Example 1
An embodiment of a surface-mounted component of a white light-emitting diode in which a phosphor film made of a phosphor / white particle / transparent particle mixture is provided at the focal point of a fluorescent reflecting concave mirror will be described. It is the structure shown in sectional drawing of FIG. 2, FIG. 4, and the exploded perspective view of FIG. The phosphor can be formed into a film and a wide wavelength band can be obtained by using a plurality of mixtures, and the absorption can be minimized by hitting other particles. White particles and transparent particles can be mixed with the ratio of the excitation light to the numerical value obtained by dividing the total amount of fluorescence by the conversion efficiency to obtain the desired spectral characteristics. As the white particles, a highly reflective material such as magnesium oxide (reflectance: 0.98), silica, or titanium oxide is suitable. As the transparent material, a glass or a transparent polymer having a high transmittance and a high softening temperature is suitable. The color balance can be improved by equalizing the transmitted light amount of the excitation light forward and the reflected light amount of the excitation light toward the fluorescent mirror.
実施例２
発光素子周囲凹面鏡を一方のリードに設け、蛍光反射凹面鏡をもう一方のリードに設けた砲弾型白色発光ダイオードの実施例を説明する。砲弾型発光ダイオードは発光素子を載せるリードと電流を供給するリードに分割されるが、発光素子を載せるリードに発光素子周囲凹面鏡を設け、電流供給リードは蛍光反射凹面鏡を設けてボンディングワイヤを発光素子に接続している。発光素子周囲凹面鏡と蛍光反射凹面鏡を一体化すると深い凹面鏡のためボンディングワイヤが長くなるが、分割することにより長さを短縮出来る。
蛍光反射凹面鏡は光軸を開いた形状の放物面鏡にして前方の凸レンズを避け、外周方向に向かった光を屈折面で方向変換して蛍光体前方の凸レンズの指向性に一致させている。蛍光体の斜め上方に出射すると円錐形の屈折面に入射するので遮光を兼ねた反射鏡を設けて蛍光反射凹面鏡に反射している。
Example 2
An embodiment of a bullet-type white light emitting diode in which a concave mirror around the light emitting element is provided on one lead and a fluorescent reflecting concave mirror is provided on the other lead will be described. The bullet-type light emitting diode is divided into a lead for mounting the light emitting element and a lead for supplying current, but the lead for mounting the light emitting element is provided with a concave mirror around the light emitting element, and the current supply lead is provided with a fluorescent reflecting concave mirror to bond the bonding wire to the light emitting element Connected to. When the concave mirror surrounding the light emitting element and the fluorescent reflecting concave mirror are integrated, the bonding wire becomes long because of the deep concave mirror, but the length can be shortened by dividing the wire.
The fluorescent reflecting concave mirror is a parabolic mirror with an open optical axis, avoiding the front convex lens, and redirecting the light toward the outer peripheral direction with the refractive surface to match the directivity of the convex lens in front of the phosphor. . When the light is emitted obliquely above the phosphor, it enters the conical refracting surface. Therefore, a reflecting mirror also serving as a light shield is provided and reflected to the fluorescent reflecting concave mirror.
実施例３
蛍光体膜から前方に拡散する蛍光を放物面鏡で平行光に変換し、蛍光反射凹面鏡を放物面鏡にして平行光に変換した後に更に平面鏡で鉛直方向に出射する表面実装素子の実施例を説明する。光源部は楕円鏡を縦半分に分割し、発光素子の発光方向を楕円鏡に向けて楕円鏡を横方向にして薄型化した構造である。蛍光反射放物面鏡は上半分を利用した半円形で、蛍光を平行光に変換した後に４５°傾斜の平面鏡により鉛直方向に出射する構造である。蛍光体前方の蛍光は放物面鏡で鉛直方向に出射して平面鏡出射光に一致させている。発光素子を載せる放熱基板に前方放物面鏡と平面鏡を設けることが出来、透明樹脂を成型する際に蛍光体を設置した後に全体を成型し、楕円鏡と放物面鏡を蒸着、無電解メッキなどにより形成して平行光を出射する表面実装素子を製造することが出来る。
Example 3
Implementation of a surface-mount element that converts fluorescence diffused forward from the phosphor film into parallel light with a parabolic mirror, converts the fluorescent reflection concave mirror into a parabolic mirror, converts it into parallel light, and then emits it in the vertical direction with a plane mirror An example will be described. The light source unit has a thin structure in which the elliptical mirror is divided into vertical halves and the light emitting element is directed toward the elliptical mirror and the elliptical mirror is in the horizontal direction. The fluorescent reflecting parabolic mirror is a semicircular shape using the upper half, and is a structure in which fluorescence is converted into parallel light and then emitted in the vertical direction by a plane mirror inclined at 45 °. The fluorescence in front of the phosphor is emitted in the vertical direction by a parabolic mirror so as to coincide with the light emitted from the plane mirror. A front parabolic mirror and a plane mirror can be provided on the heat dissipation board on which the light emitting element is placed. After the phosphor is placed when molding the transparent resin, the whole is molded, and an elliptical mirror and a parabolic mirror are deposited, electroless It is possible to manufacture a surface-mount element that is formed by plating or the like and emits parallel light.
実施例４
青色発光ダイオードに黄色を中心とする蛍光体を用いた蛍光白色発光ダイオードと青緑色発光ダイオードに橙色を中心とする蛍光体を用いた蛍光白色発光ダイオードを混色して可視光域をカバーする白色光源装置の実施例として車両用前照灯について説明する。放射角などを変更すればスポットライトなどにも応用することが出来る。
左右の光源部の一方は青色発光ダイオードに黄色蛍光体を用いた蛍光白色発光ダイオード、他方は青緑色発光ダイオードに橙色蛍光体を用いた蛍光白色発光ダイオードである。
楕円鏡の一方の焦点に発光素子と他方の焦点に蛍光体を設け、励起光を受けた蛍光体から後方の楕円鏡に蛍光を発し、凸面鏡で平行光に変換して反射格子方向に照射している。
車両用前照灯の上下方向の放射角を１０°とすると、蛍光体膜の寸法による誤差角度４°を引いて反射格子に直行方向の放射角γを６°とする。このため反射格子を凸反射面にして、放射角γを決定するための頂部傾斜αと入射光の傾斜αは等しく、谷部傾斜βの関係を数５に示す。
数５より傾斜光と頂部の傾斜αは２８°、谷部の傾斜βは３４°である。反射格子に平行方向の放射角を２０°とし、反射格子短冊の長さを１４ｍｍとすると、数４より曲率半径は４０ｍｍである。
波数４の凸反射面格子を並べた構成の側面図を図１４、車両用前照灯の正面図を図１５に示す。
発光素子に４０ｍＡの順電流を流すと２光源で構成される１ユニットで０．２８Ｗになり、このユニットを横に１１列、縦に８列の計８８ユニット使用して変換効率６０ｌｍ／Ｗで１４８０ｌｍの光束を得られる。寸法は横１６０ｍｍ、縦１７０ｍｍである。混色したスペクトルを図１６に示す。すれ違いビームのときは下５列を点灯すると９２０ｌｍになり、図１５のようにユニットの配置にカットオフラインを設けて対向車への防眩効果を増すことが出来る。カットオフラインの斜めの反射格子は楕円鏡と双曲線鏡を組み合わせて台形状の反射格子にしたものである。図１５は左側走行車両の場合を正面視したもので、上３段を消灯してすれ違いビームの状態を示したものである。
反射格子はアルミニウムなどの金属鏡面を利用すると放熱板を兼用することが出来る。上記構成による走行ビームのときの全損失は２４．６Ｗである。反射格子ユニットのその周囲に３０ｍｍ幅の取り付けスペースを設けたときの放熱板寸法は横２２０ｍｍ、縦２３０ｍｍである。
この放熱板の後方にダクトを設け、風速ｕ＝１０ｍ／ｓ（３６ｋｍ／ｈ）以上の走行風または強制対流で冷却すると、数６により温度上昇は約２５℃である。放熱板からダクトの壁面全体に熱伝導して放熱に利用出来るので温度上昇を約２５℃よりも低下させることが出来る。数６は放熱板温度における空気の物性値を用いるので繰り返し計算が必要だが、収束条件付近の５０℃における物性値
プラントル数Ｐｒ：０．７１
熱伝導率λ：０．０２４１［Ｗ／ｍ℃］
動粘性係数ν：１．８６×１０−5［ｍ２／ｓ］
を用いてレイノルズ数Ｒｅ、ヌセルト数Ｎｕ、平均熱伝達率α、温度上昇Ｔは数６より求められる。放熱板の縦寸法Ｌ、横寸法Ｗとし、外気温度は２０℃とする。
A white light source covering the visible light range by mixing a fluorescent white light emitting diode using a phosphor centered on yellow with a blue light emitting diode and a fluorescent white light emitting diode using a phosphor centered on orange with a blue green light emitting diode. A vehicle headlamp will be described as an embodiment of the apparatus. It can be applied to spotlights by changing the radiation angle.
One of the left and right light source units is a fluorescent white light emitting diode using a yellow phosphor as a blue light emitting diode, and the other is a fluorescent white light emitting diode using an orange phosphor as a blue green light emitting diode.
A light emitting element is provided at one focal point of the elliptical mirror, and a phosphor is provided at the other focal point. The fluorescent material that receives the excitation light emits fluorescence to the rear elliptical mirror, and is converted into parallel light by the convex mirror and irradiated in the direction of the reflection grating. ing.
If the vertical emission angle of the vehicular headlamp is 10 °, the error angle 4 ° due to the size of the phosphor film is subtracted to set the emission angle γ in the orthogonal direction to the reflection grating 6 °. For this reason, the reflection grating is a convex reflection surface, the apex inclination α for determining the radiation angle γ is equal to the inclination α of the incident light, and the relationship between the valley inclination β is shown in Equation 5.
From Equation 5, the tilted light and the top slope α are 28 °, and the valley slope β is 34 °. Assuming that the radiation angle parallel to the reflection grating is 20 ° and the length of the reflection grating strip is 14 mm, the radius of curvature is 40 mm from Equation 4.
FIG. 14 is a side view of a configuration in which convex reflection gratings with wave number 4 are arranged, and FIG. 15 is a front view of a vehicle headlamp.
When a forward current of 40 mA is passed through the light-emitting element, 0.28 W is achieved with one unit composed of two light sources, and this unit is used in a total of 88 units of 11 rows horizontally and 8 rows vertically, with a conversion efficiency of 60 lm / W. A light beam of 1480 lm can be obtained. The dimensions are 160 mm in width and 170 mm in length. The mixed spectrum is shown in FIG. In the case of a passing beam, when the lower five rows are turned on, the light becomes 920 lm, and a cut-off line can be provided in the unit arrangement as shown in FIG. 15 to increase the antiglare effect on the oncoming vehicle. The oblique reflection grating in the cut-off line is a trapezoidal reflection grating that combines an elliptical mirror and a hyperbolic mirror. FIG. 15 is a front view of the case of a left-side traveling vehicle, and shows the state of the passing beam with the upper three steps turned off.
The reflection grating can also be used as a heat sink when a metal mirror surface such as aluminum is used. The total loss of the traveling beam with the above configuration is 24.6W. When a 30 mm wide mounting space is provided around the reflection grating unit, the dimensions of the heat sink are 220 mm wide and 230 mm long.
When a duct is provided behind the heat radiating plate and cooled by traveling wind or forced convection of wind speed u = 10 m / s (36 km / h) or more, the temperature rise is about 25 ° C. according to Equation 6. Since the heat conduction from the heat sink to the entire wall surface of the duct can be used for heat dissipation, the temperature rise can be lowered below about 25 ° C. Since Equation 6 uses the physical property value of air at the heat sink temperature, it must be repeatedly calculated, but the physical property value at 50 ° C. near the convergence condition Prandtl number Pr: 0.71
Thermal conductivity λ: 0.0241 [W / m ° C.]
Kinematic viscosity coefficient ν: 1.86 × 10 −5 [m 2 / s]
Is used to obtain the Reynolds number Re, the Nusselt number Nu, the average heat transfer coefficient α, and the temperature rise T from Equation 6. The vertical dimension L and horizontal dimension W of the heat sink are set, and the outside air temperature is 20 ° C.
１：発光素子 ２：発光素子周囲凹面鏡
３：蛍光反射凹面鏡 ４：三角波状反射格子
５：凸面反射格子 ６：放物面鏡
７：蛍光体分散膜 ８：楕円鏡
１０：凸屈折面 １１：凹屈折面
１２：蛍光粒子 １３：白色粒子
１４：透明粒子 １５：屈折格子
１６：励起光 １７：蛍光
１８：透光物質 １９：平行光
２０：拡散光 ２１：凹面鏡
２２：凸面鏡 ２３：開口部
２５：平面反射面 ２６：遮光体
２９：基板 ３３：楕円
３５：端子 ３６：ボンディングワイヤ
４０：焦点 ４４：カットオフライン
1: light emitting element 2: concave mirror around light emitting element 3: fluorescent reflecting concave mirror 4: triangular wave reflecting grating 5: convex reflecting grating 6: parabolic mirror 7: phosphor dispersion film 8: elliptical mirror 10: convex refractive surface 11: concave Refractive surface 12: Fluorescent particles 13: White particles 14: Transparent particles 15: Refraction grating 16: Excitation light 17: Fluorescence 18: Translucent material 19: Parallel light 20: Diffused light 21: Concave mirror 22: Convex mirror 23: Aperture 25: Planar reflecting surface 26: light shield 29: substrate 33: ellipse 35: terminal 36: bonding wire 40: focal point 44: cut-off line
Claims (5)
透明物質に少なくとも蛍光体粒子を分散して薄膜に形成した蛍光体分散膜を蛍光反射凹面 鏡の焦点近傍に設けて透明樹脂でモールドした構造からなり、
発光素子から前記蛍光体分散膜に照射されて蛍光体分散膜の蛍光体粒子から透過方向の半 空間に発せられた蛍光は直接出射し、
蛍光体分散膜より発光素子側の半空間に発せられた蛍光は蛍光反射凹面鏡で反射して出射することを特徴とする蛍光変換発光ダイオード。 The opening of the concave mirror around the light emitting element provided with the light emitting element is matched with the hole provided in the top of the fluorescent reflecting concave mirror ,
Plus the structure is molded with a transparent resin is provided at least phosphor phosphor dispersed film particles dispersed was formed on a thin film in the vicinity of the focal point of the fluorescence reflecting concave mirror transparent material,
The fluorescence emitted from the phosphor particles of the phosphor dispersion film to the half space in the transmission direction is directly emitted from the phosphor dispersion film from the light emitting element ,
A fluorescence-converting light-emitting diode , wherein fluorescence emitted from a phosphor dispersion film to a half space on the light-emitting element side is reflected by a fluorescent reflecting concave mirror and emitted.
蛍光体分散膜を透過する方向に発せられた蛍光は直接出射し、
蛍光体分散膜より発光素子側の半空間に発せられた蛍光と、白色粒子により反射した励起 光は蛍光反射凹面鏡で反射して出射することを特徴とする請求項１に記載の蛍光変換発光ダイオード。The phosphor dispersion film by dispersing phosphor particles and white particles in a transparent material is formed on the thin film structure or Rannahli,
Fluorescence emitted in the direction of transmitting through the phosphor dispersion film is emitted directly,
The fluorescence-converted light-emitting diode according to claim 1, wherein the fluorescence emitted in the half space on the light-emitting element side from the phosphor-dispersed film and the excitation light reflected by the white particles are reflected and emitted by the fluorescence reflecting concave mirror. .
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| WO2014006501A1 (en) * | 2012-07-03 | 2014-01-09 | Yosi Shani | Planar remote phosphor illumination apparatus |
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