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ABSTRACT: In this paper, we investigate the mechanism of low efficacy of a 200-μm-gap structure in a high driving frequency and suggest a new driving waveform for improving the efficacy. The detailed role of the address electrode during the surface discharge is discussed by measuring the discharge current flowing to each electrode. Our observation reveals that the current flowing to the address electrode increases with driving frequency and it makes the surface discharge be weakened. A new sustain waveform with the floating time has been suggested which can enhance the surface discharge by suppressing the opposite discharge. As a result of adopting the proposed sustain waveform, the luminous efficacy has been improved to around 30% compared with the conventional sustain waveform at the driving frequency of 200 kHz.
IEEE Transactions on Plasma Science 03/2011; · 1.17 Impact Factor
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ABSTRACT: The influence of plasma display panel (PDP) cell size on discharge characteristics is investigated in 50-in high-definition (HD) and full-HD (FHD) ac-PDPs using experiments and a 2-D simulation. When increasing the resolution of the 50-in PDP from HD to FHD, the discharge volume in a cell was reduced, yet the phosphor area per unit area was not reduced. The comparative experimental results showed a decreased luminous efficacy and IR efficiency for the FHD test panel of about 25%-29% and 26%-29%, respectively, indicating that the decreased luminous efficacy was mainly due to a decreased discharge efficiency, rather than the phosphor area. Meanwhile, the simulation results revealed that the degradation of the vacuum ultraviolet efficiency in the FHD cells was due to a decrease in the electron heating efficiency and Xe-excitation efficiency of the electrons. Specifically, the decrease in the electron heating efficiency was more critical, which was related to a smaller discharge space and shorter discharge path.
IEEE Transactions on Plasma Science 12/2010; · 1.17 Impact Factor
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ABSTRACT: The discharge characteristics, particularly the address discharge characteristics, were examined relative to an ambient temperature from -5°C to +65°C in an ac plasma display panel. As the ambient temperature increased, the statistical delay time decreased due to an increase in the exoelectron emission from the MgO surface by thermal activation. In contrast, the formative delay time increased due to an increase in the wall voltage variation during an address period. It was also found that the wall voltage variation during an address period depended on the level of the scan high voltage. Therefore, a temperature-adaptive driving waveform with multiscan high voltages is proposed to produce a stable address discharge irrespective of a variable ambient temperature.
IEEE Transactions on Electron Devices 12/2010; · 2.32 Impact Factor
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ABSTRACT: The influence of ion bombardment during a sustain discharge on the electron emission of the MgO surface and related driving characteristics of an ac plasma display panel were examined using the cathodoluminescence technique and SIMS analysis. The experimental results showed that severe ion bombardment predominantly sputtered Mg species from the MgO surface, thereby lowering the intensity of the F<sup>+</sup> center peak to 3.2 eV due to the elimination of the oxygen vacancy and finally increasing the formative address delay time ( Tf ) due to an aggravated electron emission capability. Meanwhile, severe ion bombardment also destroyed the shallow trap level, thereby lowering the intensity of the shallow peak to 1.85 eV and eventually increasing the statistical address delay time ( Ts ) due to a poor electron emission capability from the shallow level. Finally, the aggravated electron emission capability from the shallow level resulted in a reduced wall voltage variation during the address period.
IEEE Transactions on Plasma Science 10/2010; · 1.17 Impact Factor
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ABSTRACT: A new reset waveform for a large-sustain-gap structure in an ac plasma display panel is proposed. In the driving of a large-sustain-gap structure with a conventional ramp reset waveform, we cannot avoid the condition of an address electrode being a cathode, which causes lots of trouble in stabilizing the reset discharge. To resolve these problems, a square pulse instead of the conventional rising-ramp pulse is used. In order to stabilize the strong discharge in which the address electrode becomes a cathode, a priming discharge between the address (anode) and scan (cathode) electrodes is made prior to making a strong discharge between the address (cathode) and scan (anode) electrodes. With this scheme, a minimum address voltage of 60 V when the sustain gaps are 250 and 350 mum, respectively, is obtained. However, the contrast ratio using the square reset pulse is lower than that using the conventional ramp pulse. To improve the contrast ratio, the reset waveforms in each subfield are replaced by selective erase waveforms except for the first subfield. In the case of nonselective reset waveform, the background luminance is 19.4 cd/m<sup>2</sup>, whereas the background luminance of 2.4 cd/m<sup>2</sup> is obtained with selective reset waveform.
IEEE Transactions on Electron Devices 01/2009; · 2.32 Impact Factor
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JCSE. 01/2009; 3:165-180.
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ABSTRACT: When displaying the square-type image with peak luminance for about 500 hours in 42-in. PDP-TV with high Xe (15 %) content, the halo-type boundary image sticking was observed in the non-discharge region adjacent to the discharge region. The halo-type boundary image sticking phenomenon is due to the re-deposition of the Mg species on both the MgO and phosphor layers in the non-discharge region adjacent to the discharge region. In this paper, the two kinds of solutions to remove a boundary image sticking of an ac plasma display panel are introduced. One solution is to completely recover the boundary image sticking cells by means of full white-aging process. The other solution is to prohibit inherently the production of the boundary image sticking by sealing the PDP panel under a vacuum condition.
Optical Fiber Communication & Optoelectronic Exposition & Conference, 2008. AOE 2008. Asia; 12/2008
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Chang-Hoo Jeong,
Yunsoo Choi,
Du-Seok Jin,
Minho Lee,
Sung-Pil Choi,
Kwangyoung Kim,
Min-Hee Cho,
Won-Kyun Joo,
Hwa-Mook Yoon, Jeong-Hyun Seo,
Jinsuk Kim
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ABSTRACT: Vast amount of XML documents raise interests in how they will be used and how far their usage can be expanded. This paper has two central goals: 1) easy and fast retrieval of XML documents or relevant elements; and 2) efficient and stable management of large-size XML documents. The keys to develop such a practical system are how to segment a large XML document to smaller fragments and how to store them. In order to achieve these goals, we designed SCOF model (service-centric object fragmentation model), which is a semi- decomposition method based on conversion rules provided by XML database managers. Keyword-based search using SCOF model then retrieves the specific elements or attributes of XML documents, just as typical XML query language does. Even though this approach needs the wisdom of experts in XML document collection, SCOF model makes it efficient both retrieval and management of massive XML documents.
Parallel and Distributed Computing, Applications and Technologies, 2007. PDCAT '07. Eighth International Conference on; 01/2008
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Jinsuk Kim,
Du-Seok Jin,
Yunsoo Choi,
Chang-Hoo Jeong,
Kwangyoung Kim,
Sung-Pil Choi,
Minho Lee,
Min-Hee Cho,
Ho-Seop Choe,
Hwa-Mook Yoon, Jeong-Hyun Seo
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ABSTRACT: While information retrieval(IR) and databases(DB) have been developed independently, there have been emerging requirements that both data management and efficient text retrieval should be supported simultaneously in an information system such as health care systems, bulletin boards, XML data management, and digital libraries. Recently DB-IR integration issue has been budded in the research field. The great divide between DB and IR has caused different manners in index maintenance for newly arriving documents. While DB has extended its SQL layer to cope with text fields due to lack of intact mechanism to build IR-like index, IR usually treats a block of new documents as a logical unit of index maintenance since it has no concept of integrity constraint. However, towards DB-IR integration, a transaction on adding or updating a document should include maintenance of the postings lists accompanied by the document - hence per-document basis transactional index maintenance. In this paper, performance of a few strategies for per-document basis transaction for inserting documents -- direct index update, stand-alone auxiliary index and pulsing auxiliary index - will be evaluated. The result tested on the KRISTAL-IRMS shows that the pulsing auxiliary strategy, where long postings lists in the auxiliary index are in-place updated to the main index whereas short lists are directly updated in the auxiliary index, can be a challenging candidate for text field indexing in DB-IR integration.
Advanced Language Processing and Web Information Technology, 2007. ALPIT 2007. Sixth International Conference on; 09/2007
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iiWAS'2007 - The Ninth International Conference on Information Integration and Web-based Applications Services, 3-5 December 2007, Jakarta, Indonesia; 01/2007
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ABSTRACT: Although the selective ramp reset waveform having one reset period during one television (TV)-field has a higher contrast ratio than the conventional ramp reset waveform with eight reset periods, the address discharge using the selective ramp reset waveform in a stripe barrier rib is severely influenced by the crosstalk. This problem of crosstalk among the cells constitutes the main obstacle to the development of high-resolution alternating current plasma display panels (AC-PDPs). In this paper, a new driving waveform is proposed, which renders the address discharge stable by decreasing the crosstalk, in addition to reducing the background luminance. In order to compare the address discharge stability of the proposed waveform with that of the conventional ramp reset waveform, we investigated the address discharge time lag through the photo-waveform measurement of address discharge for three waveforms and measured the dark room contrast ratio. As shown in the results, without decreasing the contrast ratio or the change of the panel structure, the address discharge time lag was considerably improved by the proposed waveform
IEEE Transactions on Plasma Science 07/2006; · 1.17 Impact Factor
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ABSTRACT: The temperature-dependent characteristics of ac plasma display panels (PDPs) are investigated, based on various case studies using a conventional driving scheme with reset pulses. Though the main factor of the thermal effects is caused by strong sustain discharges, it is not only caused by the panel characteristics, but also by the temperature-dependent characteristics of the driving system. One important thermal effect is a decreased breakdown voltage due to an increase in the panel temperature. Therefore, these results may be helpful in solving image-sticking and temperature-related phenomena.
IEEE Transactions on Plasma Science 03/2005; · 1.17 Impact Factor
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ABSTRACT: A new plasma display panel driving method was proposed to reduce the address period. The scan time of the address method using overlapping scan time overlaps with the next scan time during the formative lag time of the discharge. Thus, without reducing the address pulsewidth and the scan pulsewidth, the driving method can reduce the address period. We could overlap the scan time of about 100 ∼300 ns. However, the driving method has a narrow address voltage margin compared with a conventional method. In order to improve the address voltage margin of the driving method, the scan direction is set to the opposite direction compared with the conventional direction. As shown in experimental results, the address voltage margin of the new driving method is increased by 7∼10 V when the opposite scan direction is used.
IEEE Transactions on Electron Devices 02/2005; · 2.32 Impact Factor
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ABSTRACT: The basic characteristics of reset discharges related to a wall voltage and a priming effect were investigated under a conventional ramp driving scheme. The reset discharges could be minimized by controlling the wall voltage which is determined by pre-reset conditions. Accordingly, the current study presents a simple pre-reset condition for minimizing the reset discharge. Essentially, it is not only to reduce the duration of reset discharges but also to reduce the intensity of light emissions when the wall voltage polarity is opposite to the external voltage polarity.
IEEE Transactions on Electron Devices 02/2005; · 2.32 Impact Factor
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ABSTRACT: In this paper, a new gray scale expression method that divides scan lines into multiple blocks is suggested. The proposed method can drive 16 sub-fields per 1 TV field in the panel with XGA (1366×768) resolution. Because reset pulse is applied every 2 sub-fields, both the contrast ratio and the dynamic voltage margin are sufficiently obtained in comparison with previous AWD (address while display) methods. In realizing 16 subfields, shortening the scan time in the erase address period was important. The X bias voltage in the erase address period affected the minimum address voltage but did not the delay time of address discharge. The delay time of address discharge was affected by the address voltage and the time interval between the last sustain discharge and the scanning time. We also evaluated the dynamic false contour. The new method shows an improved image quality in horizontal moving, but discontinuous lines were observed at the boundaries of each block in vertical moving.
IEEE Transactions on Consumer Electronics 06/2004; · 0.94 Impact Factor
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ABSTRACT: Three-dimensional fluid code was used to investigate the effects of discharge cell's geometrical parameters on the characteristics of the addressing and the sustaining discharges. The main parameters investigated in this study are the cell pitch, the address electrode width, and the barrier rib height. The investigated discharge characteristics are the sustain voltage range, the luminance and efficiency, and the minimum applied voltage needed for the successful addressing. In this study, it was found that a larger cell pitch or a higher barrier rib can lower the sustain voltage range and a wider address electrode can lower the addressing voltage. Also, we obtained that the luminance and efficiency dependence on the sustain voltage for various values of each parameter. Especially for the analysis of the barrier rib height effect, we developed a ray-optics code where the luminance and efficiency can be calculated in terms of the visible light. From this analysis, we found that although cells with a higher barrier rib generate more VUV photons, there exists an optimal barrier rib height for a given cell pitch that gives the highest visible luminance and efficiency because of the shadow effect by the barrier ribs.
IEEE Transactions on Plasma Science 11/2003; · 1.17 Impact Factor
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ABSTRACT: The mechanism of high luminous efficiency discharges with high Xe content in an AC plasma display panel was analyzed by computer simulation using a two-dimensional fluid model. The model has reproduced well the experimental results. The high luminous efficiency with high Xe content is attributed to high electron heating efficiency as well as high excitation efficiency by electron. The electron heating efficiency is increased with increasing the sustaining voltage under high Xe content and this phenomenon was analyzed by investigating the cathode sheath and secondary electron emission characteristics.
IEEE Transactions on Plasma Science 11/2003; · 1.17 Impact Factor
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ABSTRACT: In the usual two-dimensional (2-D) simulations for the analysis of the plasma discharge in a three-electrodes coplanar-type alternating current plasma display panel (AC PDP) cell, the address electrode is regarded as an infinite plane electrode and the existence of barrier ribs is ignored. We have developed a three-dimensional (3-D) fluid code for the analysis of the plasma discharge in an AC PDP cell, where the address electrode and the barrier ribs can be properly treated. Using this 3-D code, we investigated the dynamics of charged particles and excited species during the address and the sustain periods. Time evolution of the Xe**(≥6 p states) excited species density profile shows a rounded bright head due to the effect of barrier ribs, which is consistent with the infrared images observed using an image intensified charge coupled device. Sustain voltage ranges for the successful sustenance of display discharges after addressing were obtained using both the 2-D and 3-D simulations through the voltage transfer curve analysis. In addition, the UV luminance and the efficiency changes with the variation of sustain voltages were obtained and compared with those of 2-D simulation.
IEEE Transactions on Plasma Science 05/2002; · 1.17 Impact Factor
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ABSTRACT: Three-dimensional fluid code was used to investigate the effect of barrier ribs on the addressing and the sustaining discharges. The barrier rib height and the cell pitch are the main parameters used in this study. The lower barrier rib height allows the faster addressing but requires the higher sustain voltage, while the wider cell pitch allows the lower address and sustain voltages .
12/2001;
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ABSTRACT: To improve the luminance and efficiency of an alternating current
plasma display panel, the direct measurement of infrared and vacuum
ultra violet (VUV) imaging is performed to study discharge dynamics.
Images show two emission regions. One is the cathode glow and the other
is the anode glow. In the course of discharge cycle, the cathode glow
propagates toward the outer edge of the electrode, while the anode glow
does not propagate. We developed a two-dimensional model to simulate the
time evolution of the discharge dynamics. We learned from the modeling
results that the dominant role for the propagation of the cathode glow
is the ion transport and the electron transport for the anode glow. In
addition, the effects of address voltage on the luminance and efficiency
are investigated during the sustain period. When the address electrode
is floating, VUV output is larger than that of biased conditions, but
the efficiency decreases slightly. The comparison of 100 V with 0 V bias
shows that biased voltage does not affect the luminance and efficiency
at the steady state
IEEE Transactions on Plasma Science 11/2001; · 1.17 Impact Factor
