• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.5
• /
• pp.349-353
• /
• 1999

In this paper, to fabricate the AC power electroluminescent device (PELD) with high brightness, new structure that constructed single emissive layer between electrodes was proposed. Dielectric and phosphor material structure that constructed single emissive layer between electrodes was proposed. Dielectric and phosphor material were BaTiO3 and ZnS:Cu respectively. Fabricated AC power EL devices were estimated by optical and electrical properties of EL spectrum, brightness, CIE coordinate system, transferred charge density and EL emission wave in time domain. With above results, we found that brightness of newly proposed AC powder EL power EL device was 2754 cd/m2 at 100V, 400 Hz and compared with conventional device structure.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2007.11a
• /
• pp.112-113
• /
• 2007

ZnS:Cn,Cl phosphor was coated by solid-gel reaction with $SiO_2$ outside layer. The effect of $Cu^{2+}$ -doping concentration has been investigated on the luminescence characteristics of ZnS:Cn,Cl blue-green phosphors for inorganic electro luminescent device. Also, SiO2 coated layers' effect on luminescence characteristics. Evaluation of luminescence characteristics dependent on the synthesis conditions is important to get high-performance phosphors properties. EL and PL properties such as luminescence intensity and chromaticity of ZnS:Cn,Cl phosphors synthesized with different concentration of activator, $Cu^{2+}$, were analysed separately

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.271-274
• /
• 1999

In this paper, we studied the matrix type Powder AC Electroluminescence using ZnS:Cu,Cl Phosphor. Previously, Powder AC EL was used in Backlighting of LCD. Rescently, organic Thin Film EL was rapidly developed because of high Luminescence and low applied voltage. But Powder AC EL has Superior features that include sheet like flexibility thickness, low weight, self-emission, a wide viewing angle and a fast response time. We tried to change of phosphor thickness and binder mixture rate in order to obtain the good condition of powder AC EL and we obtained the very low breakdown voltage that was just 15V. Till now, we measured the current-voltage(V-I), luminance-voltage(V-L), Luminance-current (L-I), color coordinate (CIE), and phosphor Intensity of variable thickness. In experiment result, the devices has the luminance of 840 cd/$m^2$ and improved color coordinate, x=0.1557, y=0.2145, using a 10kHz drive frequency.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07b
• /
• pp.1323-1326
• /
• 2005

The photoluminescence, electroluminescence and surface properties of ZnS:Cu,Cl phosphor coated by sol-gel process were studies. Na-silicate was used as precursor coating material. pH of solution and the concentration of Na-silicate are the important conditions to obtain the uniform coating on the phosphors. Also, the electroluminescent devices were made with Na-silicate coated phosphor. The spectroscopic characterization is performed by photospectrometer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.396-399
• /
• 2003

In this paper, the purpose is to develop imaging technique of synchrotron radiation using CMOS image sensor. The detector using hybrid method to be research in this lab was used, in order to increase image signal. We made experiments with 1B2 Whitebeam/microprobe beamline in PAL (Pohang Accelerator Laboratory). Phosphor materials such as ZnS:(Ag,Li), ZnS:(Cu,Al), $Y_2O_2S:Eu$ were produced by spin coating on glass. Synchrotron radiation images were acquired and evaluated from monochromatic light from monochromoator in PAL 1B2line. From obtained object and phantom, MTF was 0.15 in ZnS:(Ag,Li) phosphor, and 0.178 in ZnS:( Cu,Al) at 151p/mm. MTFs were unsystematic because thickness of phosphor and uniformity of surface were not optimized. It's expected to improve MTF and the qualify of images as uniformity's optimized.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.29 no.1
• /
• pp.23-33
• /
• 2011

This experimental focus to characterize luminescence properties related to CNT (Carbon Nano Tube) element dispersedly implanted in ZnS-based phosphor thin film panel fabricated by a screen printing method. More specifically FE-SEM measurements, L-V(Luminescence vs. Voltage) and photo luminescence were carried out to determine an optimum value of CNT concentration and film thickness for the thin film structure of CNT-ZnS:(Cu, Al) by the screen printing method. We confirmed that an optimum value of CNT concentration in the ZnS:(Cu, Al) film panel is about 0.75 wt% resulting that the electric conductivity is 1.6 times higher than that of pure CNT sample and showing that the luminescence intensity is increasing until the optimum concentration. Clearly, CNT is presenting in the luminescence process providing a pathway for the creation of hot electron and a channel for the electron-hole recombination but overly inserted CNT may hinder to produce the hot electron for making an avalanching process. In case of the overly doped CNT 1.0 wt% in the ZnS-based phosphor, the luminescence intensity is decreasing although the electric conductivity is exponentially increasing. Based on these results, we realized that hot electron occurred by the external electric field or exciton arose by the external photon source are reduced dramatically over the critical value of CNT concentration because CNT element provide various isolated residues in the composites of ZnS based phosphor rather than pathway or channel for the D-A(Donnor to Acceptor) pair transition or the radiative recombination of electron-hole.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.1030-1033
• /
• 2003

ZnS:Mn has been studied as a yellow phosphor for the application to fluorescent displays operated at low voltage. It was found that luminescence of $Mn^{2+}$ ion from hexagonal phase of ZnS was suitable for the display applications. The main emission peak was shifted to shorter wavelength when Cu ions were doped. The luminescence color of ZnS:Mn phosphor could be changed with decrease of its brightness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.04b
• /
• pp.81-84
• /
• 2004

본 논문은 스크린 프린트 방식을 이용하여 두께 $18{\mu}m$의 ZnS:(Cu,Al) 필름을 제조하여 미세구조와 결정성을 분석하고 형광체로써의 특성을 평가하였다. 영상획득에는 포항 가속기 연구소의 싱크로트론을 이용하였으며 CMOS 영상 센서를 사용하여 DR의 간접방식을 구현하였다. 특성 평가를 위해 SEM 측정, 발광 강도 측정을 하였고, 단색광(Beam size $5mm{\times}2mm$)을 사용하여 test phantom 영상과 물고기 영상을 획득하였다. 획득한 영상의 평가를 위해서 test phantom 영상의 MTF 측정을 하였다 제조된 ZnS:(Cu,Al) 필름의 표면은 육방정계 구조를 가졌으며, 5lp/mm는 73.8%, 10lp/mm는 38.9%, 15lp/mm는 15.4%, 20lp/mm는 12.2%의 MTF를 가졌다. 물고기 영상을 통하여 ZnS:(Cu,Al) 필름을 이용한 고해상도 미세구조영상 획득의 가능성을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.576-577
• /
• 2008

ZnS:Cu,Cl blue-green phosphors were prepared by conventional solid state reaction. Copper activator of different concentrations was doped into ZnS structure at two firing steps. The luminescence characteristics dependent on $Cu^{2+}$ doping concentration of the phosphors has been investigated for inorganic electroluminescent device.

• Journal of the Semiconductor & Display Technology
• /
• v.5 no.3 s.16
• /
• pp.1-4
• /
• 2006

White-light-emitting ZnS:Mn, Cu, Cl phosphors with spherical shape and the size of $20\;{\mu}m$ are successfully synthesized. They have the double phases of cubic and hexagonal structures. They are applied to electroluminescent (EL) devices by silk screen method with the following structure: $electrode/BaTiO_3$ insulator layer ($50{\sim}60\;{\mu}m$)/ ZnS:Mn, Cu, Cl phosphor layer ($30{\sim}50\;{\mu}m$)/ITO glass. The EL devices are driven with the voltage of 100 V and the frequency of 400 Hz. The EL devices show the three emission peaks. The blue and green emission bands are originated from $CICu^{2+}$ transition and $ClCu^+$ transition, respectively. The yellow emission band results from $^4T^6A$ transition of $Mn^{2+}$ ion. As an increase of Cu concentrations, the blue and green emission intensities decrease whereas the yellow emission intensity increases; the quality becomes warm white. It is due to the energy transfer from the blue and green bands to the yellow band.