• Title/Summary/Keyword: Phosphor screen

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Optical Properties of Graphene Doped ZnS:(Cu,Al) Inorganic Electroluminescence Devices by Screen Printing (Graphene을 첨가하여 스크린 프린팅으로 제작한 ZnS:Cu,Al 무기 전계발광 소자의 광특성)

  • Jo, Sung Ho;Lee, Sang Nam
    • Korean Journal of Optics and Photonics
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    • v.26 no.5
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    • pp.265-268
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    • 2015
  • An inorganic electroluminescence device based on a green ZnS:(Cu,Al) phosphor was fabricated by a screen printing method. Graphene was added to the phosphor layer to increase the electroluminescence intensity. As the graphene concentration increased, the photoluminescence intensity decreased; on the other hand, the electroluminescence intensity increased, up to 0.6 wt%.

Qualitative Evaluation of 2D Dosimetry System for Helical Tomotherapy (2차원 토모테라피 선량측정시스템의 정성적 평가)

  • Ma, Sun Young;Jeung, Tae Sig;Shim, Jang Bo;Lim, Sangwook
    • Progress in Medical Physics
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    • v.25 no.4
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    • pp.193-198
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    • 2014
  • The purpose of this study is to see the feasibility of the newly developed 2D dosimetry system using phosphor screen for helical tomotherapy. The cylindrical water phantom was fabricated with phosphor screen to emit the visible light during irradiation. There are three types of virtual target, one is one spot target, another is C-shaped target, and the other is multiple targets. Each target was planned to be treated at 10 Gy by treatment planning system (TPS) of tomotherapy. The cylindrical phantom was placed on the tomotherapy table and irradiated as calculations of the TPS. Every frame which acquired by CCD camera was integrated and the doses were calculated in pixel by pixel. The dose distributions from the fluorescent images were compared with the calculated dose distribution from the TPS. The discrepancies were evaluated as gamma index for each treatment. The curve for dose rate versus pixel value was not saturated until 900 MU/min. The 2D dosimetry using the phosphor screen and the CCD camera is respected to be useful to verify the dose distribution of the tomotherapy if the linearity correction of the phosphor screen improved.

Field Emission Properties of Screen Printed Carbon Nanotubes (스크린 프린팅된 탄소나노튜브의 전계방출 특성)

  • Lee, Yang-Doo;Lee, Jung-Ah;Moon, Seung-Il;Park, Jeung-Hoon;Han, Jong-Hun;Yoo, Jae-Eun;Lee, Yun-Hi;Nahm, Sahn;Ju, Byeong-Kwon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.5
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    • pp.541-544
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    • 2004
  • Multi- wall carbon nanotubes(MWNTs) were synthesized by thermal chemical vapor deposition. The paste for screen printing was composed of MWNTs, organic vehicle and glass frit. Carton nanotube paste was screen-printed on ITO(indium tin oxide) deposited soda lim을 glass, and then heat treatment was performed. Before the surface treatment, turn on field of derive was 2.6 V/$\mu\textrm{m}$. After the surface treatment, the value was changed into 1.8 V/$\mu\textrm{m}$. The anode current of the derive with 2.83 V/$\mu\textrm{m}$(turn on field) was changed 4 $\mu\textrm{A}$ into 390 $\mu\textrm{A}$ at 1,700 V. Adsorption effect of MWNTs onto phosphor of anode plate was observed by the field emission measurement and resulted in bad effects on properties of devices lifetime and emission lighting.

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 $600^{\circ}C$.

Production and Operating Characteristics for Inorganic EL Phosphor (무기EL용 형광체 제작 및 구동특성)

  • Chansri, Pakpoom;Lee, Don-Kyu;Gwak, Dong-Joo;Sung, Youl-Moon
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.1132-1133
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    • 2015
  • In this paper, we are presents production and operation characteristics for inorganic EL phosphors device using screen printed. The EL device is composed as ITO PET / EL phosphors dielectric $(2{\times}2cm^2)/TiO^2$ paste/Ag electrode. At 100Vac 400Hz, the luminescence of inorganic EL phosphors were $60.33cd/m^2$ of red phosphor, $42.12cd/m^2$ of green phosphor and $58.45cd/m^2$ of blue phosphor. The output current was 12.57 mA, 17.11 mA and 11.98 mA, respectively. The inorganic EL phosphors of EL device are increasing efficiency EL device.

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Calculation of the Quantum Efficiency of Phosphor Screens in CRTs and FL Tubes

  • Ozawa, Lyuji;Tian, Yakui
    • Journal of Information Display
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    • v.11 no.3
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    • pp.128-133
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    • 2010
  • The quantum efficiencies of CRT and FL tubes that use a phosphor screen as transducer of invisible particles to light in visible spectrum wavelengths were calculated in this study. The phosphor screens in CRT tubes have quantum efficiencies greater than 3,000, which give the luminance of comfortable images on phosphor devices for the observation by the eyes. The established FL tubes have the amazing quantum efficiency of $3{\times}10^{10}$ photons per moving electron per FL tube, which allows the illumination of a $5{\times}5\;m^2$ room by three FL tubes, with heating at $40^{\circ}C$. Thus, FL tubes, including for backlighting of LCD displays, have a superior over other illumination sources.

Low-voltage cathodoluminescent Characteristics of ZnGa$_2$O$_4$ : Mn phosphors

  • 조성희;유재수;이종덕;이중환
    • Journal of the Korean institute of surface engineering
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    • v.30 no.1
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    • pp.57-62
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    • 1997
  • Green-emitting $ZnGa_2O_4$ : Mn phosphors were synthesized by a thermal method and their low-voltage cathodoluminescent characteristics were examined for the field emitter display (FED) application. Low efficiency of $ZnGa_2O_4$ : Mn phosphors could be ascribed to the low penetration depth of into phosphors, which might results in charge accumulation on the phosphors screen. For increasing cathodoluminescent of $ZnGa_2O_4$ : Mn under low voltage excitation, wide band-gap oxide materials were added to the $ZnGa_2O_4$: Mn powder. It is found that the luminance can be increased by 20%. Measurement of leakage current on the phosphor screen shows that the enhancement of low-voltage cathodoluminescent by additive materials is mainly due to the consumption of surface charges on the phosphor.

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New design and its characteristics of full color anode panel for field emission display

  • Han, J.I.;Park, S.K.;Kim, W.K.;Kwak, M.G.
    • Journal of Korean Vacuum Science & Technology
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    • v.3 no.1
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    • pp.90-94
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    • 1999
  • Field Emission display (FEDs) require enhancement in both driving methods and process techniques to improve the display image quality. However, from the point of view of manufacturing, it is difficult to find methods and techniques to realize low cost manufacturing. New and simple color phosphor screen designs were suggested with non-crossed electrode lines and full color anode panels for small area displays were demonstrated. To avoid unwanted reaction with gases produced from phosphors in a high vacuum glass container, a very thin polyimide layer was coated on the phosphor screen. Moreover, to improve the display image quality, black matrix composed of inorganic materials was fabricated. This paper describes the performance and characteristics of the new full color anode panels.

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Powder EL device with 7-segment type and Driving Circuit (7-segment형 후막 EL소자와 구동회로)

  • 이종찬;박대희
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2000.11a
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    • pp.60-63
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    • 2000
  • In this paper, 7-segment was implemented using AC powder EL. ZnS:Cu and BaTiO3 was used as a phosphor and dielectric respectively. The preparation of phosphor and dielectric layer was performed with screen printing. The implemented system of 7-segment was divided as following; EL display, driving circuit, software for driving. The properties of fabricated devices was measured with EL spectrum and brightness.

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