Dissertations / Theses: 'White Phosphor'

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Al-Waisawy, Sara S. "Investigation of Color Phosphors for Laser-Driven White Lighting." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1417065501.

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2

Guricová, Patrícia. "Možnosti přípravy bíle emitujícího elektroluminiscenčního panelu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401921.

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The aim of this work is to prepare white emitting electroluminescent device using printing techniques. Preparation options are discussed in order to minimise reabsorption in the phosphor layer and thus increase the overall radiation intensity. Model devices were prepared, the active layer of phosphor printed in a pattern of stripes and circles. The impact of the applied voltage and frequency was studied on these devices. It has been shown that, in terms of white emission, it is better to use the patterns compared to the phosphor mixture. The ratios of emission intensities of both phosphors are more even, therefor closer to the white light. The output of this work is model designed to determine the necessary frequency area for obtaining the white emission of ACEL device.

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3

Little, Matthew Michael. "Feasibility of manipulating correlated color temperatures with a phosphor converted high-powered light emitting diode white light source." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/332.

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In this thesis we examine the feasibility of developing a white light source capable of producing colors between 2500 and 7500 Kelvin on the black-body radiator spectrum by simply adjusting amperage to a blue and ultraviolet (UV) light emitting diode (LED). The purpose of a lighting source of this nature is to better replicate daylight inside a building at a given time of day. This study analyzes the proposed light source using a 385 nm UV LED, a 457 nm blue LED, a 479 nm blue LED, a 562 nm peak cerium doped yttrium aluminum garnet (YAG:Ce) phosphor, and a 647 nm peak selenium doped zinc sulfide (ZnS:Se) phosphor. Our approach to this study initially examined optical performance of yellow-emitting phosphor (YAG:Ce) positioned at specific distances above a blue LED using polydimethylsiloxane (PDMS) as a substrate. An understanding of how phosphor concentration within the PDMS, the thickness of the PDMS, and how substrate distance from the LED die affected light intensity and color values (determined quantitatively by utilizing the 1931 CIE 2° Standard Observer) enabled equations to be developed for various lens designs to efficiently produce white light using a 457 nm peak wavelength LED. The combination of two luminescent sources (457 nm LED and YAG:Ce) provided a linear trend on the 1931 CIE diagram which required a red illumination source to obtain Kelvin values from 2500 to 7500. Red-emitting phosphor (ZnS:Se), selected to compliment the system, was dispersed with YAG:Ce throughout PDMS where they were stimulated with a blue LED thereby enabling all desired Kelvin values with differing concentration lenses. Stimulating ZnS:Se with the addition of a UV LED did not provide the ability to change the color value of the set up to the degree required. Many other factors resulted in the decision to remove the UV LED contribution from the multi-Kelvin light source design. The final design incorporated a combination of ZnS:Se and YAG:Ce stimulated with a blue LED to obtain a 2500 Kelvin value. A separate blue LED provides the means to obtain 7500 Kelvin light and the other color values in between, with a linear approximation, by adjusting the amperages of both LEDs. In addition to investigating the feasibility of obtaining the Kelvin values from 2500 to 7500, this thesis also examined the problem of ZnS:Se’s inability to cure in PDMS and a method to create a lens shape to provide equal color values at all points above a phosphor converted LED source. ZnS:Se was found to be curable in PDMS if first coated with a low viscosity silicon oil prior to dispersion within PDMS. The lens configuration consists of phosphors equally distributed in PDMS and cured in the shape of a Gaussian distribution unique to multiple factors in LED-based white light design.

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Nekrasova, Y. A., V. A. Aseev, N. V. Nikonorov, E. B. Kolobkova, O. A. Usov, and A. V. Nashchekin. "Red Emitting Phosphors Doped with Mn and Eu Ions for pc-WLEDs." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35375.

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A new red emitting phosphors based on oxyfluoride glass and glassceramics doped with europium and manganese ions were synthesized and their optical properties and structure were studied. The transparent ceramic matrices for phosphors were selected because they overcome traditional powder phosphors due to high chemical and thermal stability and low temperature sensitivity. The fluoride based red emitting phosphors combined with green one and blue emitting chip used to fabricate phosphor converted white LEDs with warm color temperature and improved color rendering indexes. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35375

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5

Dreyfuss, Sébastien. "Utilisation de phosphore blanc et d'aminophosphines pour la formation de nanocristaux d'InP." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30100/document.

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Ce travail de thèse porte sur la synthèse de nanocristaux de phosphure d'indium (InP) et en particulier sur l'utilisation de précurseurs phosphorés tels que le phosphore blanc et les aminophosphines. Les nanocristaux d'InP sont des matériaux semi-conducteurs prometteurs dans le cadre d'applications biologiques et optoélectroniques grâce à leur faible toxicité et à leurs spectres d'absorption et de fluorescence dans le visible. En outre, le phosphore blanc, allotrope le plus réactif du phosphore, est un produit industriel fabriqué à très grande échelle. Il est en effet à l'origine de tous les produits phosphorés à bas degrés d'oxydation tels que les phosphines. Sa fonctionnalisation directe visant à former des espèces chimiques nouvelles ou valorisables est un domaine de recherche actif. Alors que les nanocristaux d'InP sont traditionnellement synthétisés en utilisant une silylphosphine comme précurseur phosphoré, une nouvelle méthodologie reposant sur l'utilisation d'aminophosphines a émergé. Les aminophosphines étant plus facilement accessibles et manipulables que les silylphosphines, il s'agit d'une avancée importante pour le développement des nanocristaux d'InP. C'est pourquoi nous avons étudié précisément le mécanisme de formation de ces nanocristaux, en nous appuyant notamment sur la RMN, la spectrométrie de masse et les calculs DFT. Cette compréhension fine du mécanisme a permis l'optimisation de la synthèse des nanocristaux d'InP.L'utilisation du phosphore blanc pour former des nanocristaux d'InP repose sur la formation de nanoparticules d'indium monodisperses puis sur l'incorporation du phosphore à l'intérieur des nanoparticules. En partant d'une méthodologie de synthèse de nanoparticules d'indium de la littérature, nous avons découvert le paramètre central de la synthèse : la présence d'une quantité bien précise d'eau dans le solvant. Les nanoparticules d'indium ainsi formées sont oxydées en surface et doivent être activées afin de réagir avec le phosphore blanc.Enfin, la fonctionnalisation moléculaire du phosphore blanc avec des borohydrures pour former des liaisons P-H et par voie radicalaire pour former des silylphosphines est présentée
Ce travail de thèse porte sur la synthèse de nanocristaux de phosphure d'indium (InP) et en particulier sur l'utilisation de précurseurs phosphorés tels que le phosphore blanc et les aminophosphines. Les nanocristaux d'InP sont des matériaux semi-conducteurs prometteurs dans le cadre d'applications biologiques et optoélectroniques grâce à leur faible toxicité et à leurs spectres d'absorption et de fluorescence dans le visible. En outre, le phosphore blanc, allotrope le plus réactif du phosphore, est un produit industriel fabriqué à très grande échelle. Il est en effet à l'origine de tous les produits phosphorés à bas degrés d'oxydation tels que les phosphines. Sa fonctionnalisation directe visant à former des espèces chimiques nouvelles ou valorisables est un domaine de recherche actif. Alors que les nanocristaux d'InP sont traditionnellement synthétisés en utilisant une silylphosphine comme précurseur phosphoré, une nouvelle méthodologie reposant sur l'utilisation d'aminophosphines a émergé. Les aminophosphines étant plus facilement accessibles et manipulables que les silylphosphines, il s'agit d'une avancée importante pour le développement des nanocristaux d'InP. C'est pourquoi nous avons étudié précisément le mécanisme de formation de ces nanocristaux, en nous appuyant notamment sur la RMN, la spectrométrie de masse et les calculs DFT. Cette compréhension fine du mécanisme a permis l'optimisation de la synthèse des nanocristaux d'InP.L'utilisation du phosphore blanc pour former des nanocristaux d'InP repose sur la formation de nanoparticules d'indium monodisperses puis sur l'incorporation du phosphore à l'intérieur des nanoparticules. En partant d'une méthodologie de synthèse de nanoparticules d'indium de la littérature, nous avons découvert le paramètre central de la synthèse : la présence d'une quantité bien précise d'eau dans le solvant. Les nanoparticules d'indium ainsi formées sont oxydées en surface et doivent être activées afin de réagir avec le phosphore blanc.Enfin, la fonctionnalisation moléculaire du phosphore blanc avec des borohydrures pour former des liaisons P-H et par voie radicalaire pour former des silylphosphines est présentée

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6

Bhattacharyya, Koyel. "The functionalization of white phosphorus towards metal phosphide nanoparticles and organophosphines." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30008/document.

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Ce manuscrit présente une synthèse originale de nanoparticules de nickel(0). L'utilisation d'un précurseur de dioléylamide de nickel(II) conduit à un procédé versatile, robuste, et sans eau pour la production de particules ajustables en taille entre 4 et 11 nm de diamètre. Cette méthode a été étendue pour former de petites nanoparticules de fer(0) et de cobalt(0). Ces particules ont été examinées en ce qui concerne l'activité catalytique, y compris l'hydrosilylation d'un alcène terminal, l'hydrogénation sélective du phénylacétylène en styrène, et la réduction sous-stoechiométrique de l'azote en tris(triméthylsilyl)amine. Le phosphore blanc (P4) a été réagi stoechiométriquement avec les nanoparticules métalliques pour former les nanoparticules de phosphure métallique correspondantes. Le phosphore blanc a été alternativement fonctionnalisé en utilisant un superhydrure (LiBEt3H) pour former une espèce phosphanide stabilisée au borane, LiPH2(BEt3)2. Cette espèce a été utilisée pour synthétiser diverses phosphines, y compris la phosphine, la tris(triméthylsilyl)phosphine, et les triaroylphosphines. Les adduits labiles de triéthylborane ont été remplacés par BH3, ce qui a donné lieu à la formation de LiPH2(BH3)2, qui peut avoir des applications dans la formation de polymères P-B
This manuscript presents an original synthesis of nickel(0) nanoparticles. The use of a nickel(II) dioleylamide precursor results in a versatile, robust, water-free method for the production of size-tunable particles between 4 - 11 nm in diameter. This method was extended to form small iron(0) and cobalt(0) nanoparticles. These particles were examined for catalytic activity, including the hydrosilylation of a terminal alkene, the selective hydrogenation of phenylacetylene to styrene, and the substoichiometric reduction of nitrogen to tris(trimethylsilyl)amine. White phosphorus (P4) was stoichiometrically reacted with the metal(0) nanoparticles to form the corresponding metal phosphide nanoparticles. White phosphorus was alternatively functionalized using superhydride (LiBEt3H) to form a borane-stabilized phosphanide species, LiPH2(BEt3)2. This species was used to synthesize various phosphines, including phosphine, tris(trimethylsilyl)phosphine, and triaroylphosphines. The labile triethylborane adducts were replaced by BH3, resulting in the formation of LiPH2(BH3)2, which may have applications in the formation of P-B polymers

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7

Yan, Xiao. "Phosphors for lighting applications." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/6954.

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Trivalent rare earth cations (RE3+) activated nanometre-sized Y2O2S and Gd2O2S phosphors were prepared by converting hydroxycarbonate precursor powders during a firing process. The precursors were prepared using the urea homoprecipitation method. The choice of host crystal and dopant were optimised to meet the specific requirements for practical applications in the field of lighting, X-ray detection, and displays. Parameters that affect the luminescent properties of the resulting phosphors, such as doping concentration, excitation mechanism, firing temperature, and host lattice were investigated. Tb3+ and Er3+ co-doped Y2O2S and Gd2O2S were studied for their upconversion properties under 632.8 nm red laser excitation. The intensities of UC emission were affected by both doping concentration and host lattices. Tb3+ and Er3+ co-doped Y2O2S was found to show strong downconversion from Tb3+ and upconversion from Er3+. The presence of the Er3+ cations directly affects the Tb3+ down-converting properties by acting as centres for energy transfer. The possible energy transfer between Gd3+ and Er3+ should be responsible for the different trend of Er3+ upconversion intensity in Y2O2S and Gd2O2S. It has been established that the Tb3+ and Er3+ co-doped system is superior than the Yb3+ and Er3+ co-doped one. In the latter system the presence of Yb3+ reduces the efficiency of both upconversion and downconversion emission under red laser excitation. These phosphors show potential applications in the security and anti-fraud field. The novel ZnS:Mn QDs were prepared and successfully incorporated into GaN based photonic crystal (PC) holes to efficiently produce white light. The crystal structure and luminescent properties of the ZnS:Mn QDs were investigated as well as the factors affecting the filling rate. Zn1-xCdxS:Mn QDs were also investigated. The addition of Cd cations leads to a red shift in the PL excitation spectra of the Zn1-xCdxS:Mn QDs. The crystal structures and surface properties were also affected by the presence of Cd. Monodisperse PbS QDs with particle size of ~5 nm has been obtained using a similar aqueous reaction method.

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8

Armstrong, Kenneth Mark. "Catalytic synthesis of organophosphate plastics additives from white phosphorus." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2587.

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Triaryl phosphates were synthesized from white phosphorus and phenols in aerobic conditions and in the presence of iron catalysts and iodine. Full conversion to phosphates was achieved without the use of chlorine or chlorinated solvents, and the reactions do not produce acid waste. Triphenyl phosphate, tritolyl phosphate and tris(2,4-di-tert-butyl)phenyl phosphate were synthesized by this method with 100% conversion from P₄. Various iron(III) diketonates were used to catalyse the conversion. Mechanistic studies showed the reaction to proceed via the formation of phosphorus triiodide (PI₃), then diphenyl phosphoroiodidate (O=PI(OPh)₂) before the final formation of triphenyl phosphate (O=P(OPh)₃). The nucleophilic substitution of O=PI(OPh)₂ with phenol to form O=P(OPh)₃ was found to be the rate determining step. It was found that by modifying the reaction conditions the same catalytic systems could be used to synthesize triphenyl phosphite directly from P₄. Triphenyl phosphite was synthesized in selectivities of up to 60 %. The mechanism of these transformations was also elucidated. Independent syntheses of the intermediate in the reaction mechanism, O=P(OPh)₂I and its hydrolysis products diphenyl phosphate (O=P(OPh)₂OH) and tetraphenyl pyrophosphate ((O)P(OPh)₂-O-P(O)(OPh)₂) were developed from PI₃. The 2,4-di-tert-butyl phenol analogues of these compounds were also prepared. Bis-(2,4-di-tert-butylphenyl) phosphoroiodidate was then reacted with various alcohols to produce a series of mixed triorgano phosphates.

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9

Stephens, Frances H. (Frances Helen) 1977. "Activation of white phosphorus by molybdenum- and uranium tris-amides." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17841.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2004.
Vita.
Includes bibliographical references.
Molybdaziridine-hydride Mo(H)([eta]²-Me₂C=NAr)(N[i-Pr]Ar)₂ (1, Ar = 3,5-C₆H₃Me₂) acts as a source of its three-coordinate isomer Mo(N[i-Pr]Ar)₃ (2). This relationship has been probed via an investigation of the coordination chemistry of 1 and Mo(N[t-Bu]Ar)3 (3), a bulky analog of 2, with isocyanides RNC (R = 1-adamantyl, tert-butyl) and white phosphorus (P₄). A comparison of the rates and activation parameters of these reactions indicates that 2 is not an intermediate on the pathway from 1 to products, but rather than the molybdaziridine-hydride "opens" upon substrate binding in an associative process. Synthesis and characterization of 1:1 and 1:2 isocyanide adducts of 2 and 3, and bridging and terminal Pn compounds of molybdenum derived from the element P4 and their alcoholysis products are presented. The uranium tris-amide compounds (THF)U(N[R]Ar)₃ (R = t-Bu, 1-Ad) reacted with white phosphorus. The unique products contain a square tetraphosphorus moiety characterized formally as the dianion P₄â¡â¡₂â. Structural and theoretical analyses are provided for this system.
by Frances H. Stephens.
Ph.D.

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Tailliez, Antoine. "Effet de l’exsudation de citrate chez le lupin blanc sur la phytodisponibilité de l’uranium." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4335/document.

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L’étude proposée s’inscrit dans un contexte de contamination croissante de la pédosphère et fait le choix d’appréhender cette problématique via une approche centrée sur la rhizospère et sur les mécanismes gouvernant son évolution. Ces travaux s'intéressent à la relation entre l’uranium – un métal naturel ubiquiste non-essentiel – et le citrate – un acide organique de faible poids moléculaire exsudé par certaines espèces végétales poussant sur un milieu pauvre en phosphore. Parmi ces espèces particulières le lupin blanc (Lupinus albus) fait office de plante modèle. Un sol naturellement riche en uranium prélevé à l’affleurement d’une veine de pechblende a été étudié. L’objectif du travail a été de savoir si l’activité racinaire est suffisante pour provoquer la remobilisation de l’uranium dans la solution du sol et favoriser son transfert. Le système sol/plante a été étudié sur rhizotest et de manière découplée en hydroponie et en réacteurs fermés. Il a été démontré que la présence d’uranium dans un milieu contrôlé (hydroponie) stimule l’exsudation de citrate chez les lupins blancs qui ne sont pas carencés en phosphore et que cette exsudation de citrate favorise la solubilisation de l’uranium dans la solution du sol en réacteurs fermés. Ces résultats ont été confirmés par les observations faites sur rhizotest même si les valeurs obtenues dans ce cas étaient plus nuancées. Ceci justifie les approches utilisées et met en évidence leur complémentarité. Les résultats obtenus ont également permis d’apporter des informations concernant la toxicité de l’uranium, son internalisation dans les cellules racinaires ainsi que sur son transfert des racines aux parties aériennes
The present study is related to the context of pedosphere contamination increasing and chose to consider this issue through a focus on rhizosphere and mechanisms that govern its evolution. This work is oriented on the relation between uranium – a non-essential ubiquitous metal – and citrate – a low molecular weight organic acid exudated by specific species when grown on a phosphorus-deficient environment. Among these particular species white lupine (Lupinus albus) is considered as a model species. Furthermore, a natural soil containing huge amounts of uranium has been collected at the outcrop of a pitchblende vein and used during some experiments. The main aim of this PhD thesis was to determine if the root activity of white lupine is sufficient to cause the remobilization of uranium into soil solution and so to promote the transfer of this contaminant to the plant. The soil/plant system has been studied with rhizotests and by combining datas obtained with hydroponics experiments and batches tests. It has been demonstrated that the presence of uranium in a controlled growth medium (hydropony) stimulates citrate exudation in P-sufficient white lupine. More, this citrate exudation enhances uranium solubilization in soil solution in batches. These results have been confirmed by observations on rhizotest even if the values in this case were more nuanced. This justifies the employed approaches and highlights their coherence and complementarity. The results also allowed to provide additional information concerning uranium toxicity, its internalization in root cells as well as its transfer from roots to aerial parts

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Nishiura, Shotaro. "Preparation and Optical Properties of Rare Earth Doped Ceramic Phosphors for White Light Emitting Diode." Kyoto University, 2013. http://hdl.handle.net/2433/175019.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(人間・環境学)
甲第17670号
人博第637号
新制||人||153(附属図書館)
24||人博||637(吉田南総合図書館)
30436
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授田部勢津久, 教授杉山雅人, 教授加藤立久
学位規則第4条第1項該当

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12

Janat, Mohamad Mussaddak. "Phosphorus fractions, movement and fertilizer requirements of grapes grown on White House soil." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184754.

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A two-year fertilizer study on a mature vineyard of Vita vinifera, C. V. Cabernet Sauvignon and Sauvignon blanc, has been conducted on White House sandy loam (fine, mixed, thermic Ustollic Haplargid), at Page Ranch, International Agricultural Center. Furthermore, eleven different varieties grown at Page Ranch and treated with different levels of nitrogen fertilizer were tested for total P content in plant tissue and NO₃-N. Moreover, in another site with similar soil, a Cabernet Sauvignon grown at the Vina Sonoita Vineyard was treated with both soil and foliar applications of P fertilizer, and was tested for total P content in plant tissue. Soil phosphorus (P) fractions of the White House soil were determined in order to evaluate the various forms of soil P and determine the most important form which contributes most to the availability index. The objectives of this study were to study the various inorganic P forms of White House soil, compare two methods of extracting available P (Olsen and Bray P.), and examine the relationships between soil pH, extractable Al, Fe, Mn, and Zn with the availability index of soil P. Furthermore, the effect of P rates and placement on the P status of plant tissue, grape yield, wine quality and petiole-P to blade-P ratio had been investigated. Three different placements of surface, 25 and 50 cm depth at rates of 88 g of P and 80 g of N per vine, were in RCB design in 1987. In 1988, three P rates of 0, 88, and 176 g of P and 207.5 g N per vine, and the two mentioned varieties CS and SB were arranged in RCB design with factorial type. The results showed that placements did not have a significant effect of P status in plant tissue and grape yield. Yet grapes showed a significant response to P fertilizer in terms of increasing P content in plant tissues and grape yield. Petiole P to Blade P ratios were calculated for the CS, and SB grown at Page Ranch, as well as for CS grown at Sonoita vineyard. This ratio is a good indicator for diagnosis of P status in a given vineyard. Nitrogen stress had its clear and profound effect on P content of grape petioles.

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Yang, Yen-Ting, and 楊妍庭. "Study of Phosphor Sedimentation Phenomenon of Phosphor-Converted White Light Emitting Diodes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/qxhcjy.

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碩士
國立高雄應用科技大學
電子工程系碩士班
103
By combining a blue light emitting diode (LED) as the light emitter and a yellow Ce3+:YAG phosphor mixed in silicone matrix, a white LED (WLED) has been fabricated. Batches of WLED are prepared by non curing of uniform mixture of Ce3+:YAG phosphors and silicone encapsulation. We record and plot its sedimentation phenomenon during twelve hours. The curve represents the color rendering properties of WLEDs and we select five specific points of time to analysis color rendering properties. Another batch of WLED with a complete curing process has been fabricated to compare color rendering properties, the effect of color shift, and optical properties with previous results. We define three periods in the curve to show different sedimentation phenomena, which are extreme period, variation period and stable period. When a WLED is at the beginning of variation period, it can get more color shift after curing. When a WLED is at the final stage of variation period, it can get less color shift after curing. When a WLED is at extreme period, it can get the best situation after curing. Therefore, the timing to cure and complete WLED fabrication is very important. In this thesis, we provide a way to select a best time of curing in fabricating WLEDs. This result can be a reference for the WLED fabrication.

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Chiu, Sheng-Huan, and 邱勝煥. "Enhancement of luminous efficiency by hybrid phosphor structure and flexible phosphor film in white LEDs." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/8492xb.

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碩士
國立交通大學
光電工程研究所
102
Recently, white Light-emitting diodes (LEDs) have been regarded as the next generation of environment lighting sources because of its small size, high efficiency, and longer lifetime, especially in solid-state lighting (SSL). In this thesis, we developed the new phosphor coating structure to improve the luminous efficiency of white LED by enhancing the utilization of blue ray in the LED package, which has the great potential to use in the large area and high power lighting application. First of all, the flexible phosphor film structure by spin coating method for both cold and warm white LED is demonstrated. The experiment result shows that the flexible phosphor film structure yielded higher lumen efficiency intensity than a conventional dispense structure due to the utilization of blue light. In addition, the flexible phosphor film is also combined with flip chip package to produce white light and proved that such techniques can produce highly efficient lighting source. Secondly, we demonstrated a novel “hybrid” phosphor structure for white LED. The hybrid phosphor structure produces more efficient luminosity than the conventional remote and conformal phosphor structures. Using a TFCalc32 simulation, the electric intensity of the hybrid phosphor structure was calculated for various thicknesses, and the enhanced use of blue rays was verified. Moreover, the hybrid phosphor structure shows more uniform angular correlated color temperature (CCT) by using ZrO2-dispensed and texture PDMS film-attached methods, respectively. Therefore, the hybrid structure provides an appropriate solution for the white LEDs.

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15

Kuo, Hsuan-Wei, and 郭炫偉. "The Spectrum Analysis and Prediction of Phosphor-converted White LED with Green and Red Phosphors." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/76794747574256952040.

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碩士
明新科技大學
光電系統工程系碩士班
103
Generally, the phosphor-converting white Light-Emitting-Diode (LED) packages are typically fabricated by blue chip coated with green and red phosphors. However, for the phosphor-converting white LED with green and red phosphors, the re-absorption between green and red phosphors would introduce intensity deviations of the green and red emissions. The package engineers will pay a lot of effort and take excessive time to achieve the correct chromaticity of the white LEDs. In this study, we provide a method to predict the spectrum of the white LEDs through experimental analysis. With the spectrum model, the deviations of the CIE 1931 x and y between the prediction and real sample is less than 0.002; the deviation of the CCT between the prediction and real sample is less than 20K; the deviation of the CRI between the prediction and real sample is less than 3. Finally, we provide a good method to predict the spectrum of the phosphor-converting white LED with green and red phosphors with high accuracy.

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16

Yang, Chih-Chiang, and 楊智強. "Research of White LEDs with Electrophoretic Deposition of Phosphor." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33829789069277491949.

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碩士
崑山科技大學
電機工程研究所
98
White Light Emitting Diode (WLED) is an environment-friendly and energy-saving light source ; as compared to traditional light sources, the WLED has long life with power-saving, environment-friendly, and many other advantages, has been considered as the core of the solid state lighting in the future. The method of traditional packages for white LED is powder-doped with a large number of silicone, in this way, we will meet the problem of phosphor powder settlement in the baking process, the settlement of phosphor powder, results in the uneven white light, the emitted light with non-uniform color, partial blue or yellow light. If we want to apply the white LED to luminaire or backlight module, the light color must be required to be very uniform to avoid the spot phenomenon. This article explores to the method of electrophoretic deposition, mix the YAG (Yttrium aluminum garnet, YAG) powder with the solution of isopropyl alcohol and magnesium nitrate. The YAG:Ce3+ itself is not electrically-conductive, by adding the magnesium nitrate, make the Mg＋attach to YAG:Ce3+ so the phosphor will be positively charged. Plating the YAG:Ce3+ on the chip surface uniformly by the method of electrophoretic deposition to improve the uniformity of the white LED phosphor and ensure the uniformity of white light. At the same coordinates, we compare the color uniformity of traditional packaging method and electrophoretic deposition, from the experimental results we can know, the CIE (X) and CIE (Y) difference of traditional packaging is 0.0165 and 0.0271 respectively ; as for the electrophoretic deposition, the CIE (X) and CIE (Y) difference is 0.0138 and 0.0246 ; besides the difference of CIE is smaller, the color temperature is also more concentrated. From the experimental results we can find, the electrophoretic deposition can be used to improve the CIE uniformity from each angle of the white LED.

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17

Chen, Ching-Yi, and 陳靜儀. "Study of multi-function phosphor modeling for white LEDs." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/41403929323744117088.

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博士
國立中央大學
光電科學與工程學系
101
In this thesis, we studies the precise phosphor modeling of the white LEDs. We have developed the CRI calculation modeling, optical modeling, and thermal modeling of the phosphor. It can be applied for the material selection before the white light LED packaging and analysis of efficiency and color performance of white LEDs. The color variation due to the heating can be further analyzed. Firstly, the prediction calculation of CRI performance have been performed by a linearly calculation model. The mapping of CRI distribution on the color coordinate has been calculated by the adjusting of spectra ratio of blue chip and two color phosphor. The calculation results have been verified by the experiments of real package. The developed calculation modeling is simple and useful for predicting chromatic behaviors of a white LED with two phosphors. In the optical modeling, the scattering light can be simulated with Mie scattering based on Monte Carlo ray tracing in phosphor layer. Then use the experiment result and combine the simulation to fitting the effective absorption and conversion coefficients. Since the ability of absorption of the phosphor depend on the wavelength of excitation light, we combine the absorption spectrum of the green phosphor with the ratio of the phosphor absorption to modify the output spectrum of blue light. And we use the absorption spectrum of the red phosphor and the emission spectrum of the green phosphor to analysis the re-absorption effect. Finally, with the verification of real packages and the simulations, we successfully demonstrate the two phosphors model with double layers. The development of phosphor optical modeling can be applied to any recipe of phosphors for the prediction of chromatic performance and the analysis of package efficiency of white LED with difference package. In the thermal modeling, we combine the thermal effect of the phosphor with the optical model to build up the thermal model of phosphor. The thermal model can simulate color coordinate with various temperature. Finally, we can predict the variation of color behavior with different operation temperature in the white LED package.

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18

Wang, Jen-li, and 王仁里. "Luminescence properties of white-emitting phosphor SrSiO3 doped Dy3+ for use in white LEDs." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/2t8cw4.

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碩士
國立中山大學
光電工程研究所
95
White light generation through phosphors excitation by UV-LED has become an important subject in WLED. In our study, compounds of SrSiO3：Dy3+ white-emitting phosphors are synthesized via hydrothermal method. In this study, the effects of annealing temperature, annealing time, contents of Dy3+ on the relative emission intensity of the phosphors are judicially investigated. Meanwhile, WLED produces a plenty of heat energy to cause phosphors high temperature when WLED is excited by electrical energy. The emission spectra of the phosphors are investigated excited by Hg arc lamp (λ=365nm) under high temperature environment. Another, two distinct emission bands from SrSiO3：Dy3+ phosphors are found to be around 480nm and 572nm when the phosphor is excited by Hg arc lamp(λ=365nm). The combination of these two emissions forms a white light like color to naked eyes, showing that SrSiO3：Dy3+ presents to be a promising phosphor for applications in fabricating white-light-emitting diodes through UV pumping.

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19

Kong, Hsieng-jen, and 孔祥仁. "Study of phosphor characteristic for high-power white LED package." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/88451570421095057342.

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碩士
國立中央大學
光電科學研究所
97
In this thesis, we study YAG phosphor characteristic including scattering model, absorption coefficient and conversion efficiency. Mie scattering theory and Monte-Carlo ray tracing are used to describe the scatter of light in the phosphor layer. By fitting absorption coefficient and conversion efficiency of phosphor through experiment and simulation, we have successfully built an optical phosphor model. Furthermore, via using different blue sources to analyze absorption coefficient and conversion efficiency of phosphor, the validity of phosphor model is enhanced. Finally, since re-absorption effect decreases absorption coefficient and conversion efficiency, we analyze this effect by comparing different spectra from experiments.

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20

Tu, Huang-Tsung, and 凃皇總. "The characteristics of white LEDs with curved remote phosphor layer." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/92338106137051542844.

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碩士
明新科技大學
電子工程研究所
102
For the phosphor-converted LEDs (pcLEDs), the enhancement of the package efficiency is always an important issue. For the typical structures of the pcLEDs, a phosphor layer is close to the contour of the LED chip. Then a large portion of converted light from the phosphor would impinge on the LED chip and be absorbed by the LED chip. Therefore, the package efficiency of the pcLEDs will be low. To improve the package efficiency for pcLEDs, the remote phosphor structure with the phosphor layer placed at a sufficiently large distance from the LED chip was proposed. The remote phosphor structure lowers the probability of a light from the phosphor and directly hitting the absorptive LED chip, thereby improving the package efficiency. However, for the conventional remote phosphor structure with flat remote phosphor layer, there is still a large probability of a light being trapped in the flat remote phosphor layer owing to the total internal reflection on the interface between phosphor layer and air. Therefore, the efficiency of the pcLEDs with remote phosphor structure will be limited. In this paper, a new packaging structure of white LEDs that employs a curved remote phosphor layer for remote phosphor configuration is proposed. The pcLED with curved remote phosphor structure will promotea high package efficiency owing to the low total internal reflection on the interface between phosphor layer and air. The optical simulations were used to analysis the package efficiency and angular chromaticity of the curved remote phosphor structures with different curvatures. At the meantime, the pcLEDs with the some configurations were packaged and measured to conform the simulation results for the curved remote phosphor structures.

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21

Chen, Chiao-wen, and 陳巧雯. "The Study of High Power White Phosphor-Conversion LED Package." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/36663890116136963317.

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碩士
國立中山大學
光電工程研究所
94
Light emitting diodes (LEDs) are generally used in daily life. Our major target is to increase the brightness of LED. We study the package of white phosphor-conversion light emitting diodes (PC-LEDs) and analyze the effect on the luminous flux and color temperature from different locations and concentrations of phosphor coatings and deposition of phosphor. In this study, the color temperature and luminous flux are measured. When the phosphor is placed on the top of the reflected cup with 1.5% of concentration, or on the bottom with 7% of concentration, or when it fills the reflected cup with 1.5% of concentration, the luminous flux is about 40 lm under the CIE 1931 color coordinate of (0.33,0.33). We also studied the effect on deposition of phosphor of two different viscosities of resin used to package white PC-LED. The luminous flux which is packaged with higher viscosity resin is about 12% higher than the one found with the lower viscosity resin. After two hours of deposition, the luminous flux of the white PC-LED which is packaged with the resin of lower viscosity increased 4%, and the one packaged with the resin of higher viscosity increased 7%.

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22

Lin, Ming-Te, and 林明德. "Study of Ring Remote Phosphor for White LED Optical structure." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/34654708495890403263.

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博士
國立中央大學
機械工程研究所
100
In this thesis, we analysis the package efficiency and the CRI based on the different phosphor-packaged LEDs. First, we design an inverted cone lens with its side of the lens around a ring phosphor layer structure in the transmissive package for the phosphor layer. The optimized lens not only reduces chip absorption probability of phosphor layer emission light but also enhances the package extraction efficiency. Second, we discuss about the LEDs with the reflective package for the phosphor layer. We mixed BaSO4 and phosphor in the reflective case. We find out the condition high color rendering index due to different proportions with phosphor and BaSO4. Finally, we make several samples of white LED products based on our result. We successfully get the LEDs with high efficiency and high color rendering index and verify our simulation.

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23

Lin, Yu-Lin, and 林育霖. "Optimization of The Backend Phosphor Process for White LED Package." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/73exn6.

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碩士
國立虎尾科技大學
光電與材料科技研究所
102
The LED lighting has become the main stream of the next generation''s lighting source. As high efficiency has been emphasized nowadays the cost consideration is indeed one of the important factor that makes LED the main lighting source. Under the requirement of low cost, the cost for packaging is relatively more important as high illumination and CRI are being considered. In order to achieve a better efficiency, recent LED process introduces the centrifugal sedimentation process technology to accelerate the sedimentation of phosphor and shortens the process waiting time to reduce the packaging cost. However, the cost of introducing centrifugal process is the consumption of phosphor. According to the past studies, using the centrifugal process would consume 4% more phosphor under the same color temperature. As the packaging process emphasizes every bit on cost reduction, it is helpful for cost control if the phosphor usage could be reduced. This research took EMC 3535 as the lighting component for testing and studied on utilizing different conditions and measures for glue solidification in order to reduce phosphor consumption during packaging process and thereby reduce the packaging cost furthermore. From the test result we concluded that by using the hot plate to heat up the frame the glue could be solidified in a short time. Under such method by changing the phosphor proportion in the phosphor glue, the CIE position could be maintained the same after centrifugal processing and presents no difference in illumination and CRI comparison. Therefore, using the hot plate as the solidification method the consumption of phosphor could be effectively reduced. The test in this research showed that under the requirement of same color temperature it could reduce 5% of phosphor consumption

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24

HUANG, LI-YU, and 黃立宇. "Fabricating Excellent Full-Spectrum of White LEDs by Doping Phosphor into Encapsulant and Covering Glass Phosphor Piece." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/d2xxnc.

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25

Ting, Zi-yan, and 丁姿妍. "Optical Modeling of YAG Phosphor in Higher Concentration for White LEDs." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/u724se.

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碩士
國立中央大學
照明與顯示科技研究所
102
In this thesis, we have successfully built up an optical modeling of YAG phosphor in higher concentration with conformal coating. The optical modeling process includes scattering modeling, absorption coefficient and conversion efficiency. We simulate the scattering properties in YAG phosphor with Mie scattering theory based on Monte Carlo ray tracing. The simulation includes the optical behaviors of blue lights and yellow lights. The experimental measurement results are applied to figure out the absorption coefficient and conversion efficiency. Since the absorption and the emission of the phosphor is a function of incident wavelength, we introduce a β factor to increase the accuracy of phosphor simulation. Finally, we analyze the spectrum, color coordinate, packaging efficiency, and angular correlated color temperature distribution of white LEDs at different correlated color temperatures for the experimental and simulative results to verify the precision.

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26

Chiu, Chih-Shan, and 邱治善. "Color Tunable Phosphor-converted White Light-emitting Diodes for Fishing Lamp." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/96xjpq.

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碩士
國立臺灣科技大學
光電工程研究所
104
This paper will develop a fishing lamp can meet all requirements for fishing, based on this research to product development goals. Whole fishing process there are two main requirements first need white light for night fishing lights, for the second item needed a poly fish lamp can gather fish capturing increased, a poly fish lamp needs to meet these two requirements, required tunable optical properties. Fishing lights source using light emitting diode (LED). The LED is based on the principle of a multiple phosphors blend excited by different wavelengths and their combinations. Furthermore, the LED is comprised of three excitation chips of which are a green light chip (λpeak=530nm) and a purple light chip (λpeak=408nm) and a blue light chip (λpeak=466nm); the phosphor blend is mixing transparent resin with yellow and two species green phosphors, and through phosphor tablets experiment to determine target spectrum. Make a LED can reach white lighting and meet the spectrum of fish-eye vision function. In this paper, experimental results, CRI Ra 80, correlated color temperature of 9283K white light illumination and the spectrum a fish-eye (Carp) coverage of 90% of the fish-eye (Carp) visual function. The LED data into the simulation software and construction of fishing lights under water product prototype and its optical simulation of products, away from the light source light attenuation 20 m approaching zero, away from the light source 5m radiant flux is about 1.94 (W/m2), to reach the needs of fishing.

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27

Chen, Ching-Yi, and 陳靜儀. "The study of optical modeling of silicate phosphor for white LED." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/58412756928074354085.

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碩士
國立中央大學
光電科學研究所
96
In this thesis, we study the optical model to precisely describe optics and color distribution of the lights emitted by a blue LED covered with silicate phosphors. The optical model starts Mie scattering model and Monte Carlo ray tracing to describe the scattering of the lights when they are propagated in the phosphors, and the ray tracing is performed with blue and yellow rays. Through simulation and experimental measurement, we have successfully built an optical model, which can be applied to decide some package parameters in a white LED and to avoid color dispersion of the light pattern. Besides, we observed some interesting effects such as thermal decay and re-absorption of the phosphors. These effects could limit the validity of the optical model and need more study to make the optical model more correct.

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28

Li, Jia-Lin, and 李佳霖. "The optoelectronic analysis white LED chip applied by yellow phosphor film." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46309361008418329435.

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碩士
雲林科技大學
光學電子工程研究所
97
In 1996, Nichia Chemical Company in Japan developed yttrium aluminum garnet (YAG) phosphor which can emit yellow fluorescence by blue light excitation, This technology also can lead to high-efficiency white light. White LED is a new product in illumination field and its marketing potential is also highly expected. In comparison with bulbs and fluorescent lamps, white LED has some advantages, such like smaller volume, low heat generation, lower operating power, longer lifetime, higher response speed and lower environmental impact. 　　In my thesis, optoelectronic analysis of white LED chip applied by yellow phosphor film will be discussed. There are two components making up for white LED. The largest different design of new structure in our study is to coat a yellow phosphor thin film on the back of blue LED. Comparing to conventional white LED which is casted phosphor epoxy on the LED lead frame, our white LED has some advantages, such as the phosphor layer is uniform, lower cost, convenient process and higher radiant efficiency. And in our study, optoelectronic properties of our new white chip structure design such like different chip sizes, different thickness of phosphor layer, different glue will be discussed.

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29

Huang, Yu-Hang, and 黃桓俞. "Study of white Light-emitting diode with a jet phosphor layer." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/19249232433006185390.

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碩士
崑山科技大學
電子工程研究所
99
Light Emitting Diode (LED) is an environmentally friendly energy saving lighting, this study proposes a novel pulse jet (Pulsed Jet) phosphor technology, YAG:Ce3+ evenly spread terror on the blue grain, improve and enhance the luminous efficiency white uniform; the other hand, anti-doping in the phosphor powder in precipitation can reduce the amount of fluorescent powder to add and improve saturation current and improve light efficiency. In this study, the first use of Pulsed Jet YAG:Ce3+ Blu-ray crystal, The results indicate that Pulsed Jet terror way of flux coating can be improved 7.08%, the uniformity of terror than the traditional way of phosphor coating to enhance the 7%, Pulsed Jet Tu terror way of phosphor thickness of 216 μm; the other hand, settling on anti-doped YAG:Ce3+, 2.9% to enhance the luminous flux; the last use of Pulsed Jet YAG:Ce3+ and doped precipitated powder coated anti-terror Blu-ray crystal, luminous flux than the traditional LED upgrade 10.3%, but when the operation current of 900 mA, Pulsed Jet precipitated powder anti-doping in YAG:Ce3+ high power LED''s luminous flux than in the undoped high-power LED just high-throughput improved 18%。

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30

Chen, Cheng-Chien, and 陳正健. "Study of Package Efficiency and Reliability of Phosphor-converted White LED." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/34123725679877053009.

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博士
國立中央大學
光電科學與工程學系
101
In this thesis, we analyzed the package efficiency of white light LEDs and proposed a method to evaluate the lifetime of LED lamps rapidly. Based on the well-constructed YAG phosphor optical model, we analyzed the difference of package efficiency with six different package structures under the same correlated color temperature. And we discussed the influence of the package loss by changing the reflectivity of the substrate and the absorption coefficient of the die. Then we verified the experimental results with simulation data and investigated the difference of package loss with experimental package. In order to figure out the effect of different thickness and concentration of phosphors on the performance of LEDs, we demonstrated a method to calculate the phosphor particle numbers and studied the relationship among phosphor particle numbers, light output and correlated color temperature of LEDs under remote package type and dispensing package type. And we can simplify the parameter of LED package by using phosphor particle numbers. Finally, we proposed a method to estimate the lifetime of LED lamps quickly and this method can reduce the time for detection. We applied the accelerated test method to build up the relationship among the junction temperature of LEDs and lifetime, then we established the function of lighting decay and difference of junction temperature, we also decided the method to get the initial points. Finally, we combined all those methods to evaluate the lifetime of LEDs lamps rapidly and verified the results with the experimental data. And we suggested a value of lighting decay for the practical application.

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31

Lin, Yen-Chen, and 林彥臣. "Phosphor Packaging Design of white LED with Optical-Thermal-Electrical Coupling." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/qad7rf.

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碩士
國立中央大學
能源工程研究所
105
White LED is an important candidate of new generation solid state lightening. Understanding the mechanism of how is the interaction between current, light and heat is an essential task for us. In this study, finite element method (FEM) and Monte Carlo statistics method are applied to optical-electrical-thermal coupled numerical model. Obtaining the light source from IQE calculation. Coupling with the phosphor packaging numerical model in order to analyze the temperature distribution, light output power, CCT, and CRI of phosphor-converted white LED. The blue LED and yellow phosphor is chosen as the material of white LED. The packaging with and without phosphor are investigated. From the comparison, the result obtained from numerical simulation can correctly fit to the experimental result. The self-heating of phosphor layer is the main reason that caused the hotspot in phosphor layer for phosphor-converted white LED. Based on the previous analysis, double phosphor layer packaging was proposed. The concentration of inner layer is always higher than outer layer, and the CCT of white LED is set to be about 6300K. With higher inner concentration, the absorption of die is enhanced, caused the color shift and higher junction temperature. Lower inner concentration can lead to lower junction temperature, however the maximum temperature of phosphor layer is higher as an exchange, due to the heat generation mostly happened at outer layer. Based on these analysis of simulation, better LED device is expected to be realize.

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32

Kuo-ChingCheng and 鄭國清. "The Synthesis of Silicate Phosphors for Near Ultraviolet Excitation and Application of Phosphor Films for Replaceable White LED." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/66674523212508314978.

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碩士
國立成功大學
電機工程學系
104
In this study, BaZr1-yHfySi3O9: Eu2+ and Li2SrSi1-yTiyO4: Eu2+ silicate phosphors were synthesized by the solid-state reaction method, which could be well excited by near-ultraviolet (UV) light. Using near-UV light-emitting diode (LED) chip to excite cyan and yellow color phosphors was a feasible way to generate white light. However, due to higher operating temperature for UV-LEDs, phosphors with better thermal stability became crucial. Thus, this work focused on improving the thermal stability and the luminous intensity. The thermal stability of the former was improved with increasing the concentration of Hf4+ ions. T50 value (the temperature at which the emission intensity falls to 50% of that at room temperature) was enhanced from 230 to 281 °C. Besides, the emission intensity of the latter was enhanced 14.15% by doping Ti4+. Because of their broad excitation spectra, these phosphors could be applied on the near-UV LEDs to form the phosphor-converted white LEDs (pc-WLEDs). The thermal stability of BaZr1-yHfySi3O9:Eu2+ phosphors enhanced due to the substitution of Zr4+ by Hf4+ ions, which affected smaller lattice vibrations by phonons from heating. Therefore, the activation energy was increased from 0.374 to 0.3832 eV, reducing the probabilities of non-radiative reaction. However, due to the doping of Hf4+, the emission intensity decreased apparently with the increasing concentration of Hf4+ with impurity phase.Finally, NH4Cl was added to raw material as flux and promoted the crystallization reaction. The optimal concentration of NH4Cl was found to be 6 wt%. Besides, Li2SrSi1-yTiyO4: Eu2+phosphors were doped by Ti4+, which leads to larger crystallite size, from 65.71 to 70.47 nm. The optimal concentration of Ti4+ was 2 mol% and the emission intensity could depend on the crystallite size. For the WLED application, BaZr1-yHfySi3O9:Eu2+ cyan phosphors and commercial (Ba, Sr, Ca)2SiO4:Eu2+ yellow phosphors were combined with near-UV-LEDs (λex=395-400 nm) to generate white light. In the past, the conventional dispensing technology was directly coating on chip. In this study, the reflector cup was combined with phosphor films to form replaceable white LEDs. It takes significant advantages for practical applications such as detachable, low-cost, and one LED with various parameters for characteristics of white LED. By modulating number of different pieces of phosphor films, it is suitable to find the optimal characteristics of the white LEDs. The optimum luminous efficiency, CIE coordinates, and CRI of the final proposed devices were 20.9158 lm/W, (0.325, 0.358), and 80.47, respectively.

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33

Cheng, Han-Hsiang, and 鄭翰翔. "Study of Emission Properties with Acceleration Aging of Phosphor-based White LEDs." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/mp8hze.

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碩士
國立中央大學
光電科學與工程學系
102
In this thesis, we measured and analyzed several blue LEDs emitting different peak wavelengths with YAG phosphor, and observed the variations in emission properties under specific accelerating condition. In the aging tests of LEDs, severe high temperature condition was applied to accelerate the whole measurement duration. After analyzing spectra of different samples within the aging process, the best choice of blue light chip with YAG phosphor has been decided for stable color performance over the whole lifetime of LEDs. Besides, in the thesis, a fitting model was used to extract the information of energy level from the spectral properties. The results of energy level analysis have been compared with literatures, and show the sufficient correspondences in calculating Stokes shift and 4f splitting to demonstrate the accuracy of the model.

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34

Lin, Hsin-ying, and 林欣瑩. "Study of Packaging Efficiency of White LEDs with Different Phosphor Coating Patterns." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/cv8585.

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碩士
國立中央大學
光電科學與工程學系
102
In this thesis, we develop the high-concentration white-LED packaging with phosphor matrix. Based on the high-concentration phosphor optical model, we change different phosphor patterns, the height of sidewall of cup, and the angles of sidewall of cup to construct our encapsulation structure under the same correlated color temperature. By varying the different simulation parameters, we analyze how the packaging efficiency will be influenced. In the following process, we have verification between simulation and experiment in order to analyze their differences. In the end, we consider the literature of low-concentration packaging structure, and compare the performance between simulation and experiment in packaging efficiency.

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35

Yang, Shang-Fu, and 楊上賦. "The Study of Blue Leaking Blocker in Aged Phosphor Converted White LEDs." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/6jd5nv.

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碩士
國立中央大學
光電科學與工程學系
103
In this thesis, we added the thermochromic materials into the pcW-LED to solve the blue light leakage during the pcW-LED aging process. The thermochromic materials could change their color and absorb the leaking blue light immediately when the temperature of the phosphor was too high. Furthermore, to begin with, we measured and analyzed several different materials in the experiment. Also, we predicted the temperature distribution inside the LED by applying thermal simulation in order to find the best location and shapes of the materials. Finally, we compared the result of the LED which thermochromic materials was applied with the LED without thermochromic materials to see if there were significantly different.

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36

Shu-ChiHuang and 黃姝綺. "Combustion Synthesis of Red Nitride CaAlSiN3:Eu2+ Phosphor for White Light LEDs." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34x2pg.

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博士
國立成功大學
化學工程學系
104
White light LED lighting is believed to replace the conventional lighting and becomes the next generation lighting device due to its advantages such as energy efficiency, long lifetime, compactness, environment friendliness and designable features. Phosphors are essential materials for the fabrication of the LED lighting devices and their properties significantly affect the performance of the devices. Among various types of phosphor, the type with red emission is considered to be the most urgent one to be developed for two main reasons: Its use can improve the color rendering of the currently commercialized LED lighting devices and conventional red phosphors suffer from poor thermal and chemical stability and low quantum efficiency. Recently, nitride phosphors have been discovered and shown to be ideal for application in LED lighting due to their superior properties such as high quantum efficiency, long wavelength (red) emission and high thermal and chemical stability. However, the methods that have been developed for synthesis of nitride phosphors mostly suffer from either severe synthesis conditions or involving the use of moisture or oxygen sensitive starting materials, resulting in high production costs and thus high market prices of the commercially available nitride phosphors, and limiting the application of the LED lighting devices. In the past few years, we developed a combustion synthesis method for nitride phosphors with advantages including simple and inexpensive equipment required, relatively low cost of the reactants, a fast reaction and short processing time, potential capability for mass production. Effects of N2 gas pressure and reactant compositions related to product yield and emission property will be discussed in this research.The research result reveals the that product yield, emission intensity and wavelength of CaAlSiN3:Eu2+ phosphor can be controlled via adjust the reactant compositions using thermal insulation apparatus. Moreover, effects of Ca content (in the reactant mixture) on the formation and the photoluminescence properties of CaAlSiN3:Eu2+ phosphor (CASIN) were investigated. The plate-like blue-green emission of AlN:Eu2+ phosphor, both of plate-like and bar-like orange-red emission of Ca-α-SiAlON:Eu2+ phosphor and plate-like ,bar-like and irregular-shaped (i.e., agglomerated fine particles) red emission of CaAlSiN3:Eu2+ phosphor can be synthesized at the same time with various Ca contents. The bar-like morphology of CaAlSiN3:Eu2+ seen to have stronger emission than the other two morphologies (i.e., plate-like and agglomerated fine particles of CaAlSiN3:Eu2+), The Ca and Eu contents (expressed as molar ratios) in the synthesized products were found to increase roughly with increasing Y but were both lower than the respective Ca and Eu contents in the reactant mixtures.The synthesized CaAlSiN3:Eu2+ phosphor absorbs light in the region of 220–600 nm and shows a broad band emission in the region of 500–800 nm under excited by the blue light (460 nm) and generates emission peaking at ~650 nm.

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37

Kan, Dunyen, and 康敦彥. "Model development and optimal design of phosphor-type white-light-emitting diodes." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/53168679416578370145.

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碩士
國立臺灣大學
應用力學研究所
94
White-light-emitting diode (white LED) is considered the next generation lightning source. However the conventional package of phosphor-type LED loses 30% to 50% energy. The thesis constructed a 1-dimentional model to describe the absorption and conversion of light propagating in a phosphor layer. Designing an experiment we can regress the coefficients in the model. We observe the energy loss term in the model and can optimize the phosphor-type white LED package.

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38

Chen, Bing-Qi, and 陳炳圻. "Dual phosphor-converted white LEDs modeling by using near-field chromatic data." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/97276560743385908536.

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碩士
國立臺灣科技大學
色彩與照明科技研究所
102
An innovative way of dual phosphors-converted white LED modeling is established and demonstrated. We use near-field chromatic luminance measurement data to investigate the effect of modeling parameters in Lighttools and propose some key parameters to predict characteristics of LEDs accurately. Because of dual phosphors LEDs, there are many varied parameters to affect results of simulation. It is not only overloading in Lightools but also inefficient. In order to decrease interaction of each parameter, there is an efficient method to be provided as well. The novel thing is that we use mean free path (MFP) to replace a concentration and particle size of phosphors without scattering and add Mie particle to describe scattering of phosphors specifically. It’s an equivalent phosphors model which can predict characteristic of dual phosphors-converted LEDs very well. For example, there is a strong dependence of the luminance and the color as a function of position on the LED surface of a phosphor-converted medium-power LED. Our method can accurately predict this phenomenon. Based on our model, we successfully predict characteristics of embedding LEDs in optical devices and coating LEDs with special materials.

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39

Ho, Hsin-ying, and 何信穎. "The study of optical modeling of YAG phosphor for white light LED." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/92366478962588108313.

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碩士
國立中央大學
光電科學研究所
96
In this thesis, in order to probe into phosphor powder in the optics characteristic of white light LED encapsulation and set up accurate optics model, we combine Monte-Carlo method and volume Mie scattering effect to simulate light transmit in phosphor powder, and record of the space distribution of photon absorbed; it is the new light source that be exciting phosphor, and the optics behavior described the white light LED by blue and yellow two times of light tracing. With the verification of the experiment and simulation, we succeed in setting up the optics model of equivalent YAG phosphor, and apply to the analysis of white light LED encapsulation, can find out the optimization result to the LED encapsulation that is designed by oneself, simulation is analysed all energy happens in it, extract efficiency, and the correlate colour temperature distributed in three-dimensional space.

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40

Chang, Ching-Kai, and 張淨剴. "Package Study of Organic Phosphor C545P Application for White Light-Emitting Diodes." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/35357788818880189905.

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碩士
國立成功大學
電機工程學系碩博士班
96
Recently, white light - emitting diodes (LEDs) are mostly achieved by suing blue LED pumping yellow phosphor. This type of device has higher luminous efficiency but bad color rendering index (CRI). In order to improve CRI of white LED, this thesis used organic material C545P to fabricate white light-emitting diode. Two methods were proposed to fabricate white LED. One is to use UV-LED (380nm) pumping organic phosphor C545P for white LED. The other is to use blue LED (460nm) pumping red/organic material C545P mixed phosphor for white LED. The experiments show that these two methods can obtain higher CIR of white LED. In the first method, it is difficult to use only one kind phosphor to improve the allocation of UV-LED pumping GRB phosphor. The second method can obtain better luminous efficiency and light intensity of white LED. In the same condition, it has higher CRI as compared with general blue LED pumping red/green mixed phosphor. The luminous efficiencies for this device are 40.7lm/W and 23.8lm/W at 20mA and 350mA, respectively. In other words, the fabrication of white LED with organic phosphor C545P can lead to excellent device performance.

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41

Pai, Yung-Min, and 白詠民. "Study of phosphor spray coated characteristic and fabrication for white LED package." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/72047825182905307760.

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碩士
國立交通大學
平面顯示技術碩士學位學程
102
This thesis is focused on the process stability improvement for light-emitting diode phosphor spray technology. The purpose is to provide a coating method for uniform phosphor coated layers and the solution for enhancing the angular correlated color temperature (CCT). The main findings of this study are (1) the needle worn-out time is one of the key factors determining the spray coating stability, the control of time interval and the pressure response time. With the optimization of the needle manipulation, we successfully achieve the coating stability within ± 5% from ± 20% error; (2) the uniform phosphor coated layers on the chip surface can be achieved with pulse mode spray technology; (3) The ZrO2 nano-particles sprayed on top of phosphor layer resulting multi-layer structure achieve the higher lumen output and the better angular CCT than those coated by the conventional dispensing method. This study offers a promising result for conserving the phosphor as well as replacing the traditional process.

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42

jeng, Yow-shiuan, and 鄭又瑄. "The studies of power efficiency with different phosphor parameters in white LEDs." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/04603491135103694114.

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碩士
國立中央大學
光電科學研究所
99
In this thesis, we studied on the power efficiency with different phosphor concentrations and thicknesses in white LEDs. Based on our silicate phosphor model, we used a blue light laser to excite phosphor plates with different concentrations and thicknesses and analysis the forward power, sideward power and backward power of each phosphor plate in the first time. We also did the experiment to verify our simulation and then used the measurement results to analysis the power efficiency in white LEDs later. Secondly, we changed the light source from a blue light laser to a blue LED and researched the power efficiency with different phosphor concentrations and thicknesses under the remote phosphor configuration. Besides, we also changed the surface reflectance in the simulation in order to figure out the reciprocal effects among phosphor concentration, phosphor thickness and power efficiency in white LEDs.

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43

Cheng, Wei-Yuan, and 鄭為元. "Improvement of Light Uniformity of White LED by Modding Deposition of Phosphor." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/51736242453712215392.

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碩士
崑山科技大學
光電工程研究所
99
In this paper, the study is divided into three parts. In the first two parts, we use silicone resin and YAG:Ce3+ powder respectively to be coated on the top of die. In the third part, we use novel materials to die bonding in the light-emitting diode (LED) . Part I: we use silicone resin to coat on the surface of die. When the chromaticity diagram (CIE) of the traditional package and the mold coating package is the same, We get the difference about 227 K between the maximum and minimum of the color temperature by the traditional package. Beside, the difference about 186 K between the maximum and minimum of the color temperature by the mold coating package. Compare with traditional package, the color temperature uniformity of mold package use silicone resin to coat raises 1%. Part II: In the second part, we use YAG:Ce3+ powder to coat on the top of die. When the chromaticity diagram (CIE) of the traditional package and the mold coating package is the same, We get the difference about 1789 K between the maximum and minimum of the color temperature by the traditional package. Beside, the difference about 1390 K between the maximum and minimum of the color temperature by the mold coating package. Compare with traditional package, the color temperature uniformity of mold package use YAG:Ce3+ powder to coat raises 7%. Part III: In the third part, we use DX-20 (epoxy) and novel materials as die attach. In the difference current under, the DX-20 and novel materials is no difference, The reliability of novel materials to set up in a long time under no significant decay. In the result, the novel materials can be the future star.

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44

Chen, Hou Jen, and 陳厚任. "Optoelectronic Properties of Phosphor Free Quantum Dot White Light Flip-Chip LEDs." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/74050396178000314091.

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碩士
長庚大學
光電工程研究所
101
The large lattice mismatch between InN and GaN caused. Growth film instability and spinodal decomposition thus no-uniform distribution of indium-rich aggregates with designed single and concentration formatted in this work behaved as self-assembled Quantum Dots (QDs). Fabricated can construct the phosphor free White light-emitting InGaN/GaN diode(LED), whose electroluminescence measurements show that the correspondent emitted white light is composed of wavelengths from 440 to 700 nm. The Flip-Chip (FC) structure here we proposed can let the heat sink of the QD LED rapidly to improve the heat dissipation problem and enhance the QD luminous efficiency. In this research, the chip LED and the sub-mount are FC bonded to produce a power LED with high thermal conductivity Au bumps (291W/mK) , using thermo-sonic bonding technology. After the whole Flip-Chip QD LED fabrication processes are accomplished, the correspondent IV, PL, EL measurements, are adopted to analyze their optical and electrical characteristics.

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45

MA, HAO-LUN, and 馬浩倫. "Improvement of properties of single-phase-white-light-emitting (La0.97Pr0.03)VO4 phosphor." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/zvcta9.

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碩士
國立虎尾科技大學
電子工程系碩士班
106
In this study, La(0.97)Pr(0.03)VO4 phosphor was prepared as the host material by sol-gel method. The first part was the host of phosphor with La(0.97)Pr(0.03)VO4. Different concentrations of Urea were added. The nitrogen ion in Urea replaces the oxygen ion in the host lattice to improve the luminescent properties of its phosphor powder. In the second part, La(0.97)Pr(0.03)VO4 was also used as the host of the phosphor, and different concentrations of PEG 2000 were added to investigate the influence of the doping concentration on the surface morphology and luminescent properties of the particles. In the first part, XRD results show that the structure is monoclinic LaVO4 crystal structure under the condition of holding temperature of 950 °C for 6 hours. With the increase of the concentration of urea added, no secondary phase was observed. In the SEM analysis, the surface morphology of the phosphor powder is mostly irregular sheet agglomeration. Under 315 nm excitation, the emission spectrum consists of 3P0→3H4,5,6,1D2→3H4 and 3P0→3F2 electronic transitions of Pr3+ ions. When the urea concentration 10 wt.%, the Pr3+ ion 3P0→3H4 electron transition intensity in the range of 480~510 nm is the strongest. The CIE chromaticity coordinates are located near the white light region with the increase of the urea concentration. In the second part, the results of XRD analysis showed that the structure was monoclinic LaVO4 crystal structure under the condition of holding temperature at 950°C for 6 hours. With the increase of PEG 2000 concentration, no secondary phase was observed. In the SEM analysis, the surface morphology of phosphor powder changed from irregular flakes to spherical particles with increasing concentration of PEG 2000. Under 315 nm excitation, the emission spectrum consists of 3P0→3H4,5,6,1D2→3H4 and 3P0→3F2 electronic transitions of Pr3+ ions. When the concentration of PEG 2000 10 g, the electronic transition of Pr3+ ion 3P0→3H4 in the range of 480~510 is the strongest. The CIE chromaticity coordinates shift from magenta to near white as the concentration of added PEG 2000 increases, and then shifts to the near-yellow position.

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46

Lu, Yi, and 盧奕. "High-brightness Laser White Light Based on Phosphor Characteristic Analysis and Measurement." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g327r3.

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碩士
國立臺灣大學
光電工程學研究所
107
In the past, LED solid-state lighting technology changed the way of 21st century lighting. Although these white LEDs can achieve efficiency of more than 150 (lm/W), but blue LED still has some significant performance limitations, including efficiency droop at high current density. The droop phenomenon limits the luminous power of the LED, making it difficult to meet the needs of high power density applications in today''s LED solid state lighting technology. With the development of high-power density applications, the development of laser (LD) technology has become more mature, coupled with the performance and stability of laser light at high power, compared with the previous LED lighting, significantly better performance. Therefore, in this paper, it is desirable to be able to use high current density blue lasers with lenses and yellow phosphors to produce high-brightness, with different concentrations and thickness parameters of the phosphor. We use power meter (Thorlabs PM100D), thermocoupler, infrared thermal imager (Fluke Ti32), and the integrating sphere for measuring the watt of high current density blue laser light parameters, the relationship between temperature and time, the luminance with the surface temperature of the phosphors, and the spectrum and the relationship between luminance efficiency and quantum efficiency with time, respectively. We choose a suitable phosphor to match the subsequent secondary optics design for further application.

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47

Chang, Shuo-Chieh, and 張碩傑. "The effect of laser speckle on phosphor converted white light color uniformity for laser-excited white light application." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/8u2u3w.

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碩士
國立臺灣科技大學
色彩與照明科技研究所
104
In this thesis, we study the optical characteristics of the phosphor converted white light excited by blue laser light source. Due to the high coherence of the laser light source, laser speckle cause by interference is unavoidable. In order to understand the influence of laser speckle on phosphor converted white light, we did a series of experiments and simulations to accurately build the phosphor and speckle model, and analyzed the relationship between the speckle contrast of laser speckle and the color difference of the white light on the surface of the phosphor and the white light projected on the screen by the collimating lens. The result shows that when the speckle contrast of the laser speckle decrease below 10%, the color performance of the white light excited by speckled light is almost the same as the white light excited by speckle-free light.

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48

Chang, Jin-kai, and 張晉凱. "Investigation of glass phosphor with color conversion capability for solid-state white lightings." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/9nr4v6.

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博士
國立中山大學
光電工程學系研究所
104
In recent years, due to the rising global environmental consciousness, solid-state lightings with high efficiency, low power consumption and long lifetime have become promising for the next-generation of lighting applications. In this dissertation, we utilize glass phosphors as the color converted layer for LED (Light-Emitting Diode) and OLED (Organic Light-Emitting Diode) devices. We propose the solutions for realizing white LEDs with wide range of CCT and highly efficient white OLED. In the first part of this dissertation, we used glass phosphor as the color converted layer for white LEDs. The glass phosphors were made by dispersing green (Lu3Al5O12:Ce3+), yellow (Y3Al5O12:Ce3+) and red (CaAlClSiN3:Eu2+) phosphor crystals with a suitable proportion into sodium-based glass matrix. The CIE coordinates of the white LEDs with the 0.95 mm thick glass phosphor composite of LuAG:Ce and CASN:Eu in a doping weight ratio of 8:2 was (CIEx,y=0.335,0.342) and the CRI of the white LEDs reached 87. Through adjusting the thickness of the glass phosphors, the white LEDs exhibit CCT ranging from 4246K to 6711K with CRI ranging and yield luminous efficiency up to 80 and 90 lm/W, respectively. The glass phosphor in this work provides an effective way for white LEDs to achieve both chromaticity tailorability and high efficiency. In the second part of the dissertation, we utilized glass phosphor as the substrate for white OLEDs. Prompted by the strong light-scattering ability of the fluorescent substrate (glass phosphor), it is possible to serve as a scattering color-conversion layer for white OLEDs. At a driving voltage of 13.6V, the CIE coordinates, CCT, and CRI of the white OLEDs with the substrate doped with YAG:Ce and CASN:Eu in a weight ratio of 3:5(Y3R5) were (CIEx,y=0.339,0.409), 5313K, and 81, respectively. The device exhibited maximum external quantum efficiency of 7.2%, maximum luminance of 6819 cd/m2. The maximum current efficiency and power efficiency of the device were 7.9 lm/W and 17.1cd/A, respectively. The device showed an excellent color rendering and color stability. The CIE coordinates of the device changed slightly with the driving voltage. In this work, we proposed a simplified white OLEDs composed by a blue OLED and a fluorescent substrate. Benefiting from its simplified device structures, the device exhibited excellent color stability and color rendering, this contribution shows the great potential of this kind of white OLEDs for the high color-quality lighting applications.

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49

Wang, Wen-Yu, and 王文佑. "Highly efficient white organic light-emitting diodes with microcavity and phosphor-conversion layer." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/89501914818738320535.

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碩士
義守大學
電子工程學系碩士班
99
Highly efficient white organic light-emitting diodes (WOLEDs) are studied combining iridium phosphorescent dye iridium(III)bis [(4,6-di-fluorophenyl)-pyridinato-N,C2''] (FIrpic) doped N, N_-dicarbazolyl-3, 5-benzene (mCP) blue phosphorescent OLED with an inorganic phosphor color conversion layer (CCL). The blue OLEDs emit electroluminescence (EL) spectrum with a dominant peak at 470 nm, and serve as the excitation source of the CCL. Cerium-doped gadolinium-yttrium garnet (YAG:Ce) yellow phosphor and CaMoO4:Eu3+ red phosphor are adopted as the materials to prepare the CCL. Experimental results reveal that the red light can be emitted from a CCL owing to its absorbability of the emission from a blue OLED and then mixes the unabsorbed blue emission to produce white light emission. Red phosphor layer was deposited by spin-coating on the backside of a blue OLED. A WOLED exhibits the CIE coordinates of (0.32, 0.40) when the concentration of red phosphor is 20 wt%. It shows a maximum luminous efficiency of 18.8 cd/A, external quantum efficiency of 9.1% at 2 mA/cm2, and a power efficiency of 8.48 lm/W at 0.5 mA/cm2. The microcavity OLEDs is constructured by inserting a silver (Ag) metal thin film between ITO anode and a hole injection layer (HIL) to act as a semi-transparent reflection anode. F4-TCNQ-doped m-MTDATA is used as a p-doping hole injection layer (p-HIL) to enhance the ability of hole injection. The structure of microcavity OLED is ITO/Ag(30 nm)/m-MTDATA:F4-TCNQ(105 nm, 3%)/α-NPB(20 nm)/mCP(10 nm)/mCP:FIrpic(30 nm, 10%)/TPBi(40 nm)/LiF/Al. Color purity has been improved in such a microcavity blue OLED. Moreover, at the concentration of red phosphor of 20 wt%, the CIE coordinates of a WOLED can be tuned from (0.32, 0.40) to (0.30, 0.34). It means the highly efficient WOLEDs with microcavity and a CCL has been successfully fabricated.

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50

Chiu, Yi-Shun, and 邱翼舜. "Effect of Phosphor Particle Size and Configuration on Light Extraction of White LED." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/10794031575444944439.

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碩士
崑山科技大學
光電工程研究所
99
In this paper, this study is divided into three parts. In the first parts, we investigate three phosphor particle sizes for light uniformity effect. Based on the result, the phosphor particle size is greater have better uniformity and high efficiency. Through the first experiment result extended to the second experiment; In the second parts, we use silicone resin to be mixed with phosphor powder made into a bulk of phosphor, After the phosphor bulk adhesive to chip surface and convention package method for comparison. Based on the result, the phosphor bulk package method and the operating current is 350 mA, the luminous flux is enhanced 16.8% and the uniformity improve by1%, and saturation current is about 820 mA. Experiment third; the phosphor doped in the silicon, and then coating on the glass by spin coating method to the package and condition package method for comparison. Based on the result, comparing with to tradition process, under the operating current of 350 mA and 700 mA, the novel process could enhance luminous is about 10.5% and 6.3%, respectively. And light uniformity enhance is about 4%. From the above experimental proved that novel process on the light and electrical properties better than tradition packaged.

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Dissertations / Theses on the topic 'White Phosphor'

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