• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.380-384
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• 1993

In precision wire electrode discharge machining by CAD/CAM, it is the most important problem on machining method to determine the wire electrode offset amout from the accurate calculation of discharge gap in order to increase the machining accuracy, after fixing the main machining conditions such as machining speed, wire tension, coolant conductivity, gap vlotage. The present study shows the relationships between discharge gap and main machining conditions by means of a series of experiment concerned with the gap using the workpiece of STD 11, and suggests the experimental eguation to calculate the accurate wire electrode offset amount under the given machining conditions for spot workers.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.827-832
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• 2008

One of the most important issues in AC PDP is luminance and luminous efficacy. To improve the luminance and luminous efficacy, new sustain electrode structure which contains long discharge gap is necessary. However, it causes a rise of firing voltage. In this experiment, a new structure is proposed in order to solve this problem. To drop the firing voltage, the hump shaped electrode is inserted into the forward area of the main discharge gap. The experimental results show that proposed structures with 160um discharge gap have high firing voltage by 38V, high luminance by 30% and high luminous efficacy by 15% compared with conventional type having 60um discharge gap. In addition, the proposed structure with hump electrode shows lower firing voltage by 24V compared with the test panel with 160um discharge gap which doesn't have hump electrode though they have similar luminous efficacy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.83-89
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• 2013

In order to reduce the power consumption in international standard IEC62087, the luminance efficiency should be improved at the low discharge load rather than at the high discharge load. Thus, this paper analysed the characteristics of the discharge at the panels with ITO Gap of $65{\mu}m$, $80{\mu}m$, and $100{\mu}m$ in 50-inch PDP with FHD resolution. It was well known that the long gap panel improves the luminance and the luminous efficiency. However, it is very difficult to drive the panel due to high driving voltage. When the normal driving method was applied at the panel with ITO gap of $100{\mu}m$, the phenomenon of the double peak was generated in the sustain period. We confirmed that main factor of the double peak is the self-erasing discharge. When the CLHS driving method was applied at the panel with ITO gap of $100{\mu}m$, the self-erasing discharge was improved in the sustain period. Also, the $V_S$ and $V_A$ minimum voltage of the CLHS driving method decreased about 9V and 12V compared with those of the normal driving method. Moreover, when the CLHS driving method was applied to the panel with ITO gap of $100{\mu}m$, the luminance and the luminous efficiency increased compared with those of the normal driving method. The luminance and the luminous efficiency greatly increased at the low discharge load. The less discharge load, the higher increase rate of the luminance and the luminous efficiency. Especially, the luminous efficiency at ITO gap of $100{\mu}m$ increased about 26.3% at the discharge load of 4% compared with that at ITO gap of $65{\mu}m$.

• 전기의세계
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• v.17 no.3
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• pp.7-28
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• 1968

When a insulator plate is inserted to the discharge path of a space discharge gap in which the field strength is not uniform, the spark voltage under the atmospheric pressure between the electrodes decreases or rises according to the position of the insulating plate. Also it is reported that if a metallic barrier plate is inserted to the discharge path of the same space discharge gap, similar variations of spark voltage are found. Speaking briefly, mensioned above are the spark voltage characteristics when an insulator or metallic barrier is inserted to the space discharge gap. Also some experimental results, concerning to the surface creepage flash over characteristics at the case when an insulator barrier is inserted to the discharge path of a surface creepage discharge gap, were reported by Peek. But up to now there are no reports on surface flash over voltage characteristics at the case when a metallic barrier is inserted to the surface creepage gap. In this study the effects of a conducting metallic barrier inserted to the path of a surface creepage discharge gap on the flash over voltage characteristics are investigated theoretically and experimentally, and got some important results, clearing the effects of the position and width of a conducting barrier is inserted, the surface flash over voltage characteristics appear as an Inverse N or W Characteristics. Such theoretical or experimental results may have some relation not only with the effects of dry belt and snow on suspension insulators, but also with the effects of dirty zone or water drops on the surface creepage flash over voltage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.155-159
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• 2009

To increase the luminance and luminous efficacy in the discharge for alternating current plasma display panel (ac PDP), the increment of Xe contents and long discharge gap are necessary. However, the driving voltage and the cost of driving circuit increases in the high Xe contents and long discharge path condition. In this paper, a long gap ITO hump electrode (LGH) model for discharge cells of ac PDP is evaluated in the various Xe contents($5{\sim}20%$). The discharge voltage of LGH structure is lower about 30V than that of ITa reference structure with same main discharge gap. The LGH structure has lower power consumption and higher luminance than those of reference structure, respectively. Also, the luminous efficacy of LGH structure is higher about 20% than that of ITO reference structure in the 20% Xe contents.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.993-998
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• 2011

In this paper we suggest new criteria for the classification of the electrode gap between common and scan electrodes. The electrode gap is categorized as a short, middle, and long gap according to the criteria. Among these structures, we focus on the erase waveform of a mid-gap structure. we report an unstable discharge arising from the erase ramp period in a mid-gap structure. Based on the Vt close curve, we analyze the unstable discharge at various conditions. Our analysis reveals that the unstable discharge is ignited between surface electrodes and caused by un-erased wall charges accumulated on the outer edges of electrodes. By reducing the voltage level of the last sustain pulse, the problem is solved.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.11
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• pp.529-535
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• 2003

In this paper, we presents the characteristics of the new electrode structure in an AC Plasma Display Panel(PDP) that can generate dual mode discharges with a combination of short-gap and long-gap discharges. The experiment results show that the discharge voltage of the new electrode structure is mainly determined by short-gap discharge and the luminous efficiency is improved by 20% compared with the conventional electrode structure. The improvement of luminous efficiency is mainly caused by higher VUV generation and broader distribution from Ole ICCD camera measurements.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.22-28
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• 1996

From the experimental study of Wire-Cut Electric Discharge Machining of STD-11 alloy steel and P-20 tungsten carbide, the characteristics such as hand drum form and discharge gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap voltage and spark cycle become smaller, thickness become thinner, wire tension become larger and the no of cutting increases. When 60mm thickness tungsten carbide is cut in normal condition, hand drum form becomes larger due to the low conductivity machining allowance become slightly larger when peak discharge current and gap voltage become larger, or wire tension becomes smaller. Under the same condition, machining allowance of tungsten carbide is larger than alloyed steel by 1/100mm.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.585-588
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• 2007

We studied the effect of self-erase discharge on the luminous efficacy of ac PDPs. We observed through discharge current analysis to confirm that the selferase discharge occurred mainly between sustain cathode and address electrode, which have an influence on the luminous efficacy. The amount and timing of the self-erase discharge was varied to observe its effect on the luminous efficacy. It has been found that the luminous efficacy could be improved by the self-erase discharge when it is adjusted to occur right before the main discharge in the small gap structure. In the long gap structure, on the contrary, the luminous efficacy could be increased when the self-erase discharge is suppressed. Also, various waveforms to control self-erase discharge are suggested and tested in the panel experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1422-1428
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• 2008

In the current PDP technology, one of the most important issues in AC PDP is improvement of luminance and luminous efficacy. To improve luminance and luminous efficacy, new cell structure of PDP containing long discharge path is necessary. However, it causes an increment of firing voltage. In order to decrease firing voltage of AC PDP having long discharge gap, the protrusion electrode is proposed. To drop the firing voltage, the protrusion electrode is inserted into the forward area of the main discharge gap. This paper presents measurements of detailed optical and electrical characteristics of AC PDP with protrusion electrodes. The experimental results show that the proposed structure with gap 80um has lower firing voltage to 27V than that of the conventional long gap structure. Moreover, the ICCD(Intensified Charge Coupled Device) images of the proposed structure show quick discharge generation by 0.07usec and longer continuation by 0.05usec than that of the conventional long gap structure. Therefore, the proposed protrusion electrodes have higher luminance by 12.5% than that of the conventional structure, as having no decrement of Luminous efficacy.