Byung-Gwon Cho

Modified Driving Waveform for Ridged Dielectric Structure Based on Vt Closed Curve Analysis in AC PDP

The discharge characteristics of an AC plasma display panel (PDP) with the ridged dielectric structure were investigated. In particular, characteristics such as firing voltage and related wall voltage based on the Vt closed curve measurement were compared in the ridged and conventional dielectric structures. The front plate of the AC PDP with the conventional panel structure is composed of glass, electrodes and dielectric. In the ridged dielectric structure, the middle part of the dielectric layer is eliminated to allow for light to pass through more easily. This structural modification causes the plasma discharge between the two front electrodes to occur at a lower voltage. Meanwhile, as the ridged dielectric structure differs from the conventional dielectric structure, various problems arise if the conventional driving waveform is used. Especially, as the discharge firing voltage characteristics between the scan and sustain electrodes of the ridged dielectric structure is different, it is necessary to modify the reset and address waveforms accordingly. In this study, the Vt closed curves are investigated to compare the discharge firing voltages in the conventional and ridged dielectric structures. Based on the investigation, a modified driving waveform for the ridged dielectric structure was proposed. Using the proposed waveforms, the address discharge time of the ridged dielectric structure was reduced by approximately 200 ns.

P-120: Comparison of Discharge Characteristics between Coplanar- and Plate-Gap Structures in Xe-Backlight Unit

The discharge characteristics between the coplanar-gap and plate-gap structures in the 6-in. Xe backlight units (BLU) are examined and compared. The discharge characteristics including the firing/sustaining voltages, capacitances of lamps, luminance and luminous efficiencies are measured for two different discharge structures, such as the coplanar-gap and plate-gap structures. In particular, the voltage, current, and infrared waveforms are observed are compared for two different structures.

Experimental study on atmospheric pressure plasma polymerized conducting polymer under coupling and remote conditions

ABSTRACT This article has analyzed conducting polymer from the viewpoint of material properties, which is polymerized under atmospheric pressure condition for coupling and remote conditions, respectively. The experimental results show that the atmospheric pressure plasma polymerized pyrrole (pPPy) exhibits similar characteristics from the viewpoint of crystallinity, but the shapes and roughness of the particles are significantly distinguished. In the case of coupling condition, a uniform and flat layer like a thin film was obtained. However, in the case of remote condition, the deposited layer had more rough nanoparticles compared to that of coupling condition. The pPPy surface characteristic and morphology changes are discussed by using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD) results. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analysis are used to determine the chemical changes introduced by the atmospheric pressure plasma for coupling and remote conditions. The both pPPy materials, which were obtained by coupling and remote conditions, are expected to be applied to various fields, especially for designing the thin conducting electrode layer of polymer light emitting diode (P-LED) or for improving the efficiency by inserting conducting polymer powder on hole injection layer.

Modified driving waveform for improving write discharge characteristics in open dielectric structure of AC PDP

ABSTRACT The modified driving waveform is proposed to improve the characteristic of the write discharge in the open dielectric structure of the AC type plasma display panel. An open dielectric is a structure in which the sustain discharge is more easily generated by removing the dielectric layer between the electrodes of the upper plate in order to increase the luminance of the AC PDP. Though the sustain discharge easily occurs when the conventional driving method was used for the open dielectric, the characteristic of the writing discharge was relatively poor. Previous studies have suggested a method to improve the characteristics of the write discharge, but it has been disadvantageous in that an excessive reset discharge due to a high voltage causes a low contrast ratio and a high voltage was applied in the negative direction. In this study, threshold voltage (Vt) closed curves of conventional and open dielectric structures were measured and the wall voltage vector inside the cell was analyzed by the applied driving waveform. Based on these results, the modified driving waveform is proposed to improve the write discharge characteristics. Compared with the conventional driving waveform, the write discharge delay time is shortened by about 0.3 µm in each write pulse.

Study on overlap scan waveform for low write voltage in AC plasma display panel

ABSTRACT Discharge characteristics in overlap scan waveforms are studied for lowering the write voltage in AC type plasma displays panel. The write discharge during the write period of the AC PDP occurs when negative pulses are applied to several hundreds of scan lines in time and a positive pulse is selectively applied to the write electrode. As the scan and write pulse widths during the write period are determined by the delay time of the write discharge, a high write voltage is typically used to stably generate the discharge within the pulse width. However, a high write voltage induces the high power consumption and causes the low efficiency of the AC PDP. Meanwhile, when the applied write voltage is decreased for the low power consumption, the discharge delay time will surely increase. If the pulse width of the scan electrode is increased so that the discharge occurs within the pulse width, the wall charge will be stably accumulated in a cell. Therefore, the widths of the write pulses are equal to the conventional time to make the same total write time, and overlapped waveforms in the scan lines are proposed by extending only the widths of the scanning pulses. Even if a low write voltage is applied, the discharge delay time will naturally be delayed, but the write discharge stably is occurred within the pulse width due to the long width of the scan pulse.

TOF-SIMS study on nano size conducting polymer prepared by simple atmospheric pressure plasma polymerization technique for display applications

ABSTRACT We had previously reported on a surface analysis investigation of newly atmospheric pressure plasma (APP) polymerized conducting polymers films, both plasma-polymerized polyaniline and polypyrrole (pPPy). In this study, time of flight secondary ion mass spectrometry (ToF-SIMS) has been used to characterize nano size conducting polypyrrole films between the conventional and novel APP source under room temperature. Specific negative and positive ions from pPPy were effective in monitoring the change in the pPPy content at the surface of the composites. This ToF-SIMS analysis clearly demonstrates that novel APP polymerization source is effective in increasing the surface polymer content and thus confirms previously published X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS) data based on some necessary assumptions. To check the suitability of the conductive layer for the display application, the resistance variations of the pPPy grown on the interdigitated electrode substrates are examined by doping with iodine.

Study on luminous efficiency of AC plasma display panel with large gap between sustain electrode

ABSTRACT The luminance and luminous efficiency was investigated in new structure of AC plasma display panel with the large gap between the front electrodes under a high Xe gas mixture when adopting the proposed driving waveform. As an electrode was far from the other on the front plate comparing to the conventional structure, the driving waveform, especially in the reset and sustain period, should be modified. Therefore, during the reset period, the negative voltage was applied to the sustain electrode to produce the surface discharge between the scan and sustain electrodes. In addition, the sustain waveform was also modified to induce the surface discharge between the front plates after the triggering was made between the front and rear plates. As a result, when the modified driving waveform with the positive sustain voltage of 140 V and negative triggering voltage of −110 V during a sustain period applied to the panel with Xe gas mixture of 15% and the sustain gap of 500 um, the luminance of 340 cd/m2 and luminous efficiency of 3.26 lm/W were obtained in the 42-inch AC PDP.

Improvement on Address Discharge Characteristics for Overall Subfield Time Using Additional Scan Voltage in AC PDP

The address discharge time lags are investigated in each subfield time in AC PDP and shortened by changes in the amplitude of the additional scan voltage during total subfield time under the stable address voltage margin range. During the reset period, the reset discharge is produced by applying the high positive-going ramp voltage and the wall charge in a cell is generated. That wall charge plus the external address voltage induce the address discharge. In the first subfield time, the address discharge is fast produced than the other subfield times because the wall charge are much remained by the high positive-going ramp voltage during the reset period. Meanwhile, from the second to last subfield, the address discharge production time is gradually delayed due to the dissipation of the wall charge in a cell. In this study, the address discharge time lags are measured in each subfield time and the modified driving method to shorten the total address discharge time is proposed by applying the different additional scan voltages in each the subfield time.

Address Discharge Simulation of Additional Pulse Application to Common Electrode in AC PDP

The address discharge simulation and the light waveform are investigated when the additional pulses are applied to the common electrode during an address period in AC plasma display panel. The wall charges in a cell are accumulated on three electrodes during a reset period and those are utilized to produce the address discharge triggering in addition to the externally applied voltage between the scan and address electrodes during an address period. As the accumulated wall charges should be utilized on the overall electrodes to improve the address discharge triggering, the additional pulses are applied to the common sustain electrodes when the scan and address pulses are driven. In this study, the Xe 3P2 energy state to generate the vacuum ultraviolet are simulated when the scan and address pulses on two electrode are applied including the additional pulses on the common electrodes. In addition, the address discharge light waveforms in the conventional and the proposed driving method are measured and compared.

Study on Address Discharge Characteristics Using Wall Charge on Three Electrodes during an Address Period in AC PDP

A modified driving waveform in AC plasma display panel is proposed to improve the address discharge characteristics applying the additional pulses on the sustain electrode during an address period. After a reset period in the driving scheme of an AC PDP, the electrons are accumulated on two front electrodes and the ions are accumulated on the address electrode. Among the accumulated wall charge on three electrodes, the electrons on the scan electrode and the ions on the address electrode are mainly used for the address discharge triggering when the scan and address pulses are applied simultaneously during an address period. Meanwhile, since the constant bias voltage on the sustain electrode is only maintained during an address period, the wall charge on the sustain electrode a little contribute to an address discharge triggering. In this sense, if the electrons on the sustain electrode during an address period are utilized, the improvement of the address discharge characteristics is expected. Therefore, in this study, the additional negative going pulses are applied to the sustain electrode while the scan and address voltages are changed during an address period. In addition, the address discharge characteristics are investigated in accordance with the various voltage height and pulse applying time. Consequently, the production time of an address discharge can be reduced approximately 200 ns under the optimal driving condition compared with the conventional driving waveform.