• 한국응용과학기술학회지
• /
• 제23권3호
• /
• pp.243-251
• /
• 2006

Field emission display(FED) is actively investigated in view of the development of full color flat-panel display, which can replace some cathode-ray tube(CRT). Thus, the development of new phosphors appropriate for FED is urgently needed and has been actively investigated. In this work, $SrTiO_3:Pr^{3+}$ phosphor was prepared by sol-gel method and the coating was applied by sol-gel method combined with sonication on these phosphor's surface into diluted precursor solution. It was found that very fine particles of coating material were formed on phosphor's surface. The luminescent intensity of $SrTiO_3:Pr^{3+}$ phosphor coated with $SiO_2$ and $Al_2O_3$ was considerably increased without any noticeable change in color chromaticity. The optimum concentration of coating material was found to be 1wt% and the optimum pH value of the solution was 10.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.594-597
• /
• 2002

We studied the effect of secondary electron emission from the back plate of AC-PDP, on the ramp waveform driving of the system, using two-dimensional PDP cell discharge simulator. It is found that the secondary electron emission from back plate plays a significant role in getting a stable weak discharge during the ramping up of X-Y electrode voltage. This is because grounded address electrode acts as a cathode during the setup of surface charge, and the secondary electron emission from phosphor in the back plate must be large enough to accumulate surface charges on the dielectric layers without strong plasma discharge. We have concluded that the secondary electron emission coefficient(${\gamma}$) of phosphor, besides MgO, must be known to understand the characteristics of the PDP system. A few suggestions for improvement of the system is also made and tested.

• 한국세라믹학회지
• /
• 제47권2호
• /
• pp.146-150
• /
• 2010

Because the plasma display panel has used red, green and blue(RGB) phosphors, it has suffer from two intrinsic problems; 1) the cell defect due to the lack of binding force between phosphor particles and 2) mis-discharge because of difference of electrical characteristics among RGB phosphors. In order to control the mechanical and electrical properties of RGB phosphors, frit with $ZnOB_2O_3-SiO_2-Al_2O_3$ system was added to RGB phosphor as sintering additive. The mechanical properties were increased by the amount of frit. The amount of frit under 5 wt% rarely affected dielectric constant. However, there was the limit of amount because of decreasing optical properties seriously; over 3 wt% in red, over 10 wt% in green and blue.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
• /
• pp.33-38
• /
• 2006

An evolutionary optimization process involving genetic algorithm and combinatorial chemistry was employed in an attempt to develop titanate-based red phosphors suitable for tri-color white light emitting diodes We screened a eight-cation oxide system including $(K,Li,Na)_x(Y,Gd,La,Eu)_yTi_zO_{\delta}$ in terms of luminescent efficiency. The combination of genetic algorithm and combinatorial chemistry was proven to enhance the searching efficiency when applied for phosphor screening. As a result, the composition was optimized to be $(Na_{0.92}Li_{0.08})(Y_{0.8}Gd_{0.2})TiO_4:Eu^{3+}$, The luminance of this phosphor was 110 % of that of well-known scheelite variant phosphor at an excitation of 400 nm.

• Transactions on Electrical and Electronic Materials
• /
• 제8권3호
• /
• pp.121-124
• /
• 2007

The $Zn_2SiO_4:Mn$ phosphors were prepared using polymer matrix technique in order to improve the performance of green emitting phosphors for plasma display panel(PDP). $Zn_2SiO_4:Mn$ phosphor exhibits a strong green emission around 520-530 nm. The emission intensity and particle size of powders were controlled by sintering temperature and raw material composition. The zinc silicate $Zn_2SiO_4:Mn$ single phase were obtained at lower temperature than prepared by solid-state reaction method. PL luminance of $Zn_2SiO_4:Mn$ phosphor was similar to the commercial material.

• 한국진공학회지
• /
• 제10권1호
• /
• pp.98-103
• /
• 2001

차세대 평판 디스플레이로서 플라즈마표시기(Plasma Display Pannel, PDP)는 현재 350 $\textrm{cd/cm}^2$의 휘도와 l lm/W 정도의 효율을 갖는 AC형 PDP가 개발되어 있으나, 음극선관(CRT)의 피크 휘도가 700 $\textrm{cd/cm}^2$, 효율이 수 1 m/W인 것을 감안하면 음극선관을 대체할 수 있는 표시기가 되기 위해서는 PDP의 휘도와 효율을 더욱 개선시킬 필요가 있다. 반사형 AC-PDP셀 내에서 가스 방전으로 발생된 진공 자외선(Vacuum Utraviolet, VUV) 중 배면판 쪽으로 진행되는 부분은 형광체를 여기시켜 가시광을 발생시키게 되지만, 전면판 쪽으로 진행되는 부분은 발광에 사용되지 못하고 있다. 본 연구에서는 PDP 셀 전면판의 유전체와 보호막 사이에 VUV를 반사시킬 수 있는 다이크로익 미러(Dichroic mirror)를 증착함으로써 셀 내의 VUV 이용 효율을 증가시켜 휘도와 효율을 향상시킬 수 있는 방법을 제안하였다. 다이크로익 미러를 정확하게 설계하기 위해서 미러에 사용되는 $MgF_2$, $LaF_3$, MgO 박막의 VUV 영역에서의 광학 계수(Optical Constant)를 실험과 시뮬레이션을 이용한 광도 측정법(Photometric method)을 통해서 구하였다 (1). 이 값들을 이용해서 플라즈마 표시기의 패널 방전에서 방출되는 빛의 휘도를 결정짓는 가장 중요한 요소인 147nm 부근의 진공자외선을 반사시킬 수 있는 다이크로익 미러를 설계하였다. 다이크로익 미러는 전자빔 증착기 (I-beam evaporator)를 이용하여 증착되었고, 박막의 광학 계수 결정을 위한 반사도(Reflectance), 투과도(Transmittance) 측정과 다이크로익 미러의 반사도 측정은 Reflectometer를 이용해 측정하였다. 패널 실험은 동일한 패널 내에 반쪽 면에만 다이크로익 미러를 증착시켜 방전 전압에 따른 휘도와 효율을 미러가 없는 면과 동일 조건하에 비교 측정하였다. 여러 방전 조건하에서 다이크로익 미러를 AC-PDP에 적용한 경우가 그렇지 않은 경우보다 휘도와 효율이 약 20-30% 정도 증가함을 확인하였다.

• Journal of Information Display
• /
• 제7권1호
• /
• pp.25-29
• /
• 2006

By the voltage threshold (Vt) close-curve measurement method, the changes in the discharge characteristics such as a firing voltage and IR emission among the three electrodes were examined relative to the low or high panel temperature ranging from -10 to $80^{\circ}$. The variation in the panel temperature was found significantly influence the surface discharge between the MgO surfaces rather than the plate gap discharge between the MgO and phosphor layers. Based on this experimental observation, a modified reset waveform that alleviates the surface discharge during a ramp-up and -down period was deeloped. By adopting the proposed reset waveform, a stable address discharge could be obtained irrespective of the panel temperature variation.

• 한국전기전자재료학회논문지
• /
• 제15권1호
• /
• pp.67-74
• /
• 2002

A phosphor for Plasma Display Panel, BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$, showing a blue emission band at about 450nm was prepared by a solid-state reaction using BaCO$_3$, $Al_2$O$_3$, MgO, Eu$_2$O$_3$ as starting materials wish flux AlF$_3$. The study of the behaviour of Eu in BAM phosphor was carried out by the photoluminescence spectra and the Rietveld method with X-ray and neutron powder diffraction data to refine the structural parameters such as lattice constants, the valence state of Eu, the preferential site of Mg atom and the site fraction of each atom. The phenomenon of the concentration quenching was abound 2.25~2.3wt% of Eu due to a decrease in the critical distance for energy transfer of inter-atomic Eu. Through the combined Rietveld refinement, R-factor, R$_{wp}$, was 8.11%, and the occupancy of Eu and Mg was 0.0882 and 0.526 at critical concentration. The critical distance of Eu$^{2+}$ in BAM was 18.8$\AA$ at 2.25% Eu of the concentration quenching. Furthermore, c/a ratio was decreased to 3.0wt% and no more change was observed over that concentration. The maximum entropy electron density was found that the modeling of $\beta$-alumina structure in BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$correct coincided showing Ba, Eu, O atoms of z= 1/4 mirror plane.e.ane.e.

• 조명전기설비학회논문지
• /
• 제14권6호
• /
• pp.1-5
• /
• 2000

최근 디지털 텔레비젼전 및 고해상도(High Definition) 텔레비전용 표시장치로 교류형 풀랴즈마 디스플레이가 각광 받고 있다. 상용화되고 있는 교류형 플라즈마 디스플레이의 구조를 보면 3전극행 면방전형(three electrodes surface discharge type)이 주류이다. 재의 효율은 11m/W의 수준으로 본격적인 상용화를 위해서는 효율의 향상이 관건이다. 효율 향상올 위해서는 패널 구조(Panel structure)의 개선도 필요하지만 주어진 구조에서 최대한의 효율을 갖도록하는 구동방법의 최적화가 선결 과제이다. 교류형 플라즈마 디스플레이의 방전 이미지는 연속되는 방전 발광에 의해 이루어 진다. 대부분의 전략 소모는 연속되논 발광을 위한 유지 방전에서 소모되기 때운에 유지방전의 파형의 최적화는 고 방전 효율을 위한 중요한 과제이다. 구동 방식으로서는 ADS(Address and Display period Separated) 구동이라는 방식이 일반적으로 널리 쓰이고 있다. 이 구동법의 평균 유지방전 주파수는 수십 [kHz]이지만 실제 주파수는 100[kHz]에서 200[kHz] 사이의 상당히 높은 값이다. 본 연구 결과에 따르면 형광체가 가시광을 방출시킬 때 형광체 재료의 특성상 감쇄시간(Decay Time)이 수 ms에 이른다. 만약 감쇄 시간이 유지방전 펄스으 주기보다 길다면 방전에서 만들어진 진공자외선(Vacuum Ultra Violet Rav)이 가시광으로 변환애 효과적으로 이용되지 못한다. 결국 발광 효율은 유지방전 주파수에 비례하여 감소한다. 결론적으로 말해 저 주파수 유지 방전으로 발광효율을 크게 개선할 수 있다.

• 한국분말재료학회지
• /
• 제22권1호
• /
• pp.27-31
• /
• 2015

Flat panel display devices are mainly used as information display devices in the 21st century. The worldwide waste flat panel displays are expected at 2-3 million units but most of them are land-filled for want of a proper recycling technology More specifically, rare earth metals of La and Eu are used as fluorescent materials of Cold Cathode Flourscent Lamp(CCFL)s in the waste flat panel displays and they are critically vulnerable and irreplaceable strategic mineral resources. At present, most of the waste CCFLs are disposed of by land-filling and incineration and proper recovery of 80-plus tons per annum of the rare earth fluorescent materials will significantly contribute to steady supply of them. A dearth of Korean domestic research results on recovery and recycling of rare earth elements in the CCFLs prompts to initiate this status report on overseas research trends and noteworthy research results in related fields.