• Title, Summary, Keyword: Phosphor

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A Study on Manufacture of Phosphor Screen for Video Phone Tube (Video Phone Tube用 형광박의 제조에 관한 연구)

  • Woo, Jin-Ho
    • Journal of the Korean Printing Society
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    • v.22 no.2
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    • pp.123-138
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    • 2004
  • The video phone tube (VPT) of monochrome CRT have utilized home door phone, fish-finder and the rear watch monitors. Phosphor screen formation is made by electrodeposition spin coating and thermal transfer methods etc. Recently, thermal transfer method was developed, as a novel method, to form the phosphor surface for mnonchrom VPT. This method have advantages of simple process, automatization, clean environment, saving raw material and saving running-cost. In this study, it was developed new phosphor of VPT, and tested about phosphor paste properties. An experimental studies of VPT as a new phosphor property and improved VPT's manufacturing process shortening and brightness. As thermal transper method is a paste processing, it is important that rheology of phosphor effects on the formation of phosphor screen. Hence this paper was studied rheology properties of phosphor paste and the formation of phosphor screen had looked most suitable condition. Experimented thermal separation properties of low calcination temperature resin and the result analyzed comparison by TGA. Also, examined calcination properties to reduce remaining binder phosphor.

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Nano-Sized Phosphor by Reverse Emulsion Process and Precision Nozzle Phosphor Patterning

  • Park, Lee-Soon;Yoon, Hae-Sang;Han, Yoon-Soo;Im, Moo-Sik;Kwon, Young-Hwan
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.536-539
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    • 2004
  • A novel ink-jet printing method was investigated for fine patterning of phosphor layer in PDP using a precision nozzle printing. A reverse emulsion method was developed for the synthesis of nano-sized phosphor powder that could be formulated in the phosphor ink. The composition of the phosphor ink including charge controlling agents, solvent, dispersant and nano-sized phosphor powder was optimized for the fine patterning of phosphor layer for high resolution PDP.

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Evaluation of White LED Package Characteristics in Remote Phosphor Structure Depending on Phosphor Coatings (형광체 코팅에 따른 Remote Phosphor 구조의 백색 LED 패키지 특성 평가)

  • Jeong, Hee-Suk;Lee, Jung-Geun;Kang, Han-Lim;Hwang, Myung-Keun;Lee, Mi-Jae;Kim, Jin-Ho;Chae, Yoo-Jin;Lee, Young-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.4
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    • pp.330-334
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    • 2013
  • We developed a package of remote phosphor structure having blue LED chips and phosphors physically separated, and the characteristics were evaluated according to different classifications of phosphor coatings. Remote phosphor was produced by screen printing coating on glass substrate with phosphor content rated paste and heat treatment. After mounting Remote phosphor, which has been classified according to number of coatings, on top of blue LED chips, luminous flux, luminous efficacy, CCT and CRI were measured. The measurement results showed the most suitable characteristics of white LED package as a general light source when the content rate of phosphor in Remote phosphor was 80 wt.% with 3 layers of coatings and thickness over $12{\mu}m$.

Transition of Gd2O3:Eu Phosphor to GdBO3:Eu Phosphor with Boron Concentration in the Spray Pyrolysis (분무열분해 공정에서 붕소 농도에 따른 Gd2O3:Eu 형광체의 GdBO3:Eu 형광체로의 전환)

  • Koo, Hye-Young;Jung, Dae-Soo;Ju, Seo-Hee;Hong, Seung-Kwon;Kang, Yun-Chan
    • Korean Journal of Materials Research
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    • v.16 no.3
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    • pp.163-167
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    • 2006
  • The transition of europium-doped gadolinium oxide phosphor to gadolinium borate phosphor with the concentration of boron in the spray pyrolysis was investigated. The particles prepared from spray solution below 10 wt% boric acid of prepared phosphor had crystal structure of $Gd_2O_3:Eu$ phosphor, in which the crystallinity of the particles decreased with increasing the boron concentration. A single phase $GdBO_3:Eu$ phosphor particles were prepared from spray solution above 50 wt% boric acid of prepared phosphor. The phosphor particles prepared from spray solution with 20 wt% boric acid of prepared phosphor had no XRD peaks of $Gd_2O_3:Eu$ and $GdBO_3:Eu$ Therefore the phosphor particles prepared from spray solution with 20 wt% boric acid of prepared phosphor had the lowest photoluminescence intensity under ultraviolet and vacuum ultraviolet. $GdBO_3:Eu$ and $Gd_2O_3:Eu$ phosphor particles prepared from spray solutions with proper concentrations of boric acid had good photoluminescence intensity under vacuum ultraviolet. The morphology of the phosphor particles were strongly affected by the concentrations of boric acid added into spray solution.

Effect of PVA Polymerization on Synthesis of YAG:Ce3+ Phosphor Powders Prepared by a Solid-liquid Hybrid Route (PVA 중합도가 고상-액상 혼합 방식에 의한 YAG:Ce3+ 형광체 분말 합성에 미치는 영향)

  • Kim, A-Reum;Lee, Sang-Jin
    • Journal of the Korean Ceramic Society
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    • v.51 no.5
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    • pp.424-429
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    • 2014
  • YAG:$Ce^{3+}$ phosphor powders were synthesized using $Al(OH)_3$ seeds by means of a PVA-polymer-solution route. Various types of PVA with different molecular weights (different polymerization) were used. All dried precursor gels were calcined at $500^{\circ}C$ and then heated at $1500^{\circ}C$ in a mix of nitrogen and hydrogen gases. The final powders were characterized via XRD, SEM, PSA, PL, and PKG analyses. The phosphor properties and morphologies of the synthesized powders were dependent on the PVA type. As the molecular weight of the PVA was increased, the particle size gradually decreased with agglomeration, and the luminous intensity of the phosphor increased. However, the phosphor powder prepared from the PVA exhibiting very high molecular weight, showed a 531 nm (blue) shift from the 541 nm (yellow) wavelength of the YAG:$Ce^{3+}$ phosphor. Finally, the synthesized YAG:$Ce^{3+}$ phosphor powder prepared from the PVA with 89,000 - 98,000 molecular weight showed phosphor properties similar to those of a commercial phosphor powder, but without a post-treatment process.

Selection of a Remote Phosphor Configuration to Enhance the Color Quality of White LEDs

  • Anh, Nguyen Doan Quoc;Le, Phan Xuan;Lee, Hsiao-Yi
    • Current Optics and Photonics
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    • v.3 no.1
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    • pp.78-85
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    • 2019
  • The remote phosphor structure has been proven to bear greater luminous efficiency than both the conformal phosphor and in-cup phosphor structures; however, controlling its color quality is much more challenging. To solve this dilemma, various researchers have proposed dual-layer phosphor and triple-layer phosphor configuration as techniques to enhance the display brightness of white LEDs (WLEDs). Likewise, this study picked one of these configurations to utilize in multichip WLEDs with five distinct color temperatures in the range from 5600 to 8500 K, for the purpose of improving the optical properties of WLEDs, such as color rendering index (CRI), color quality scale (CQS), luminous efficacy (LE), and chromatic homogeneity. According to the results of this research, the triple-layer phosphor configuration has superior performance compared to other configurations in terms of CRI, CQS, and LE, and yields higher chromatic stability for WLEDs.

The Effect of Squeezing Parameters on the Fabrication Behavior of Phosphor Films (스퀴징 공정변수에 따른 형광체막 성형 거동에 관한 연구)

  • Park, J.Y.;Lee, J.W.;Yoon, G.S.
    • Transactions of Materials Processing
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    • v.24 no.2
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    • pp.95-100
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    • 2015
  • It was confirmed that when phosphor slurry is formed in the cavity of an elastic mold, the pressure distribution of the phosphor slurry varies as a function of the major squeegee parameters (squeegee angle, squeegee velocity, and the viscosity of the phosphor slurry). The higher the slurry viscosity, the faster the squeegee velocity, and the smaller the squeegee angle, the higher the filling completeness of the phosphor slurry. The optimum conditions for complete filling of the phosphor slurry were found when the squeegee angle was between 30 to 45 degrees, squeegee velocity at 40 to 70mm/sec, and the viscosity of the phosphor slurry composite was at 6,556 cps (i.e. phosphor content around 50 wt. %).

Analysis of the Temperature Dependence of Phosphor Conversion Efficiency in White Light-Emitting Diodes

  • Ryu, Guen-Hwan;Ryu, Han-Youl
    • Journal of the Optical Society of Korea
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    • v.19 no.3
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    • pp.311-316
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    • 2015
  • We investigate the temperature dependence of the phosphor conversion efficiency (PCE) of the phosphor material used in a white light-emitting diode (LED) consisting of a blue LED chip and yellow phosphor. The temperature dependence of the wall-plug efficiency (WPE) of the blue LED chip and the PCE of phosphor are separately determined by analyzing the measured spectrum of the white LED sample. As the ambient temperature increases from 20 to $80^{\circ}C$, WPE and PCE decrease by about 4.5% and 6%, respectively, which means that the contribution of the phosphor to the thermal characteristics of white LEDs can be more important than that of the blue LED chip. When PCE is decomposed into the Stokes-shift efficiency and the phosphor quantum efficiency (QE), it is found that the Stokes-shift efficiency is only weakly dependent on temperature, while the QE decreases rapidly with temperature. From 20 to $80^{\circ}C$ the phosphor QE decreases by about 7% while the Stokes-shift efficiency changes by less than 1%.

Optical Properties of Color Conversion Lens for White LED Using B2O3-Bi2O3-ZnO Glass (B2O3-Bi2O3-ZnO계 유리를 이용한 백색 LED용 색변환 렌즈의 광 특성)

  • Chae, Yoo-Jin;Lee, Mi-Jai;Kim, Jin-Ho;Hwang, Jong-Hee;Lim, Tae-Young;Jeong, Hee-Suk;Lee, Young-Sik;Kim, Deuk-Jung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.8
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    • pp.614-619
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    • 2013
  • Recently, remote phosphor is reported for white LED enhancing of phosphor efficiency compared with conventional phosphor-based W-LED. In this study, Remote phosphor was produced by screen printing coating on glass substrate with phosphor contents rated paste and heat treatment. The paste consists of phosphor, lowest softening glass frit and organic binders. Remote phosphor can be well controlled by varying the phosphor content rated paste. After mounting remote phosphor on top of blue LED chip, CCT, CRI, and luminance efficiency were measured. The measurement results showed that CCT, CRI, and luminance efficiency were 6,645, 68, and 1,16l m/W in phosphor 80 wt.% remote phosphor sintered at $600^{\circ}C$.