AC Plasma Display Research Articles

Study on Pulse Waveforms for Improving Voltage Margin and Luminous Efficacy in an AC Plasma Display Panel Having Auxiliary Electrodes

New pulse waveforms applied to an alternating-current plasma display panel (ac PDP) with an auxiliary electrode are investigated for the purpose of improving the panel's operating voltage margin and luminous efficacy. In the proposed pulse waveforms with reciprocal sustain pulses, a pair of positive and negative sustain pulses is applied to the sustain electrodes simultaneously and alternately. A positive auxiliary pulse is applied to the auxiliary electrode immediately after reciprocal sustain pulses. The voltage margin becomes wider, and the luminous efficacy is improved because of the suppression of the discharge toward the address electrode. In the another proposed pulse waveforms with reciprocal sustain and auxiliary pulses, a negative pulse, which is the same as the negative pulse of reciprocal sustain pulses, is additionally applied to the auxiliary electrode when reciprocal sustain pulses are applied. This negative auxiliary pulse can maintain a high level of luminous efficacy because it supports the effect of the auxiliary pulses. The measurement results show that the operating voltage margin is about twice wider than that of the typical pulse waveforms for an ac PDP with an auxiliary electrode; furthermore, the maximum luminous efficacy is able to reach 3.14 lm/W in terms of the measurement of the discharge in a 50-in XGA resolution (0.27 mm × 0.81 mm) panel with a white cell and a gas mixture of Ne+20%Xe.

Analysis of Sustaining Waveforms for Improving Luminance and Luminous Efficacy in AC Plasma Display Panels

Wall voltage and priming particles are the main parameters to enable the improvement of luminance and luminous efficacy in AC plasma display panels. By moderately controlling the sustaining pulsewidth ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> ) and the time interval between successive sustaining pulses ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ), the wall voltage and the amount of priming particles in the discharge space can be manipulated. In this brief, two types of sustaining waveforms, namely, negative- and positive-going pulses (which have different potential distributions during the off period), are investigated to analyze their effect on luminance and luminous efficacy. In both waveforms, the sustaining pulsewidths and the time intervals between the pulses have been varied to control the wall voltage and priming particles. Each sustaining waveform showed different trends in the resulting luminance and luminous efficacy with the sustaining pulsewidth and time intervals used. The <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> time was a dominant factor in the negative-going pulse waveform, while the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> time was more important in the positive-going pulse waveform.

Cost-effective sustain driver employing a new four-quadrant switch cell for AC plasma display

A new energy-recovery circuit (ERC) for the plasma display panel (PDP) using a switched transformer is proposed. The proposed ERC is very cost effective due to the reduction of device count and circuit complexity such as highside gate drivers and diodes in the resonant path. Also, the leakage inductances of the transformers are used as resonant inductors for soft-switching operation of the main switches. The operation and performance of the proposed energy recovery circuit were validated through waveform and power efficiency measurement tests with prototype hardware in 200 kHz switching frequency.

P‐92: Driving Waveforms for Improving Temporal Bright Image Sticking in AC Plasma Display Panel

AbstractThe iterant strong sustain discharge during a sustain period was known to induce an image sticking problem, but its detailed mechanism is not still fully understood. It is found that the rising slope of the sustain waveform has a significant influence on the recovery time of temporal bright image sticking. As a result, the recovery time of temporal bright image sticking is shortened considerably by properly controlling the rising slope of the sustain waveform.

Improvement of Luminance and Luminous Efficiency Using New Electrode Structures in AC Plasma Display

Two new electrode structures, namely, fence electrode (Fen) and combination of coplanar and fence electrodes (CoFen), employing an elevated bus electrode in the conventional surface discharge structure with three electrodes are suggested. In this paper, various comparisons between the conventional and two new structures are made to validate the effectiveness of the proposed structures. The firing and sustain voltages, displacement and discharge currents, cell capacitance, luminance, and luminous efficiency for three electrode structures are measured for various pressure ranges used in the conventional plasma displays. Consequently, the experimental results show that the CoFen structure has lower firing and sustain voltages than the conventional and Fen structures for all pressure ranges from 100 to 700 torr. In addition, the Fen structure realizes over 80% brighter and approximately 18% higher luminous efficiency than the conventional one.

A Study on MgO Characteristics of AC Plasma Display Panel Fabricated by Vacuum Sealing Method

In this paper, the vacuum sealing method to enhance a base vacuum level was adopted, and the resultant changes in the MgO characteristics, such as firing voltage, MgO sputtering rate, MgO hardness, and photoluminescence, were examined in comparison with those in the conventional sealing method in the 42-in. AC-PDP with a high Xe (15%) content. The 42-in. panel fabricated by the vacuum sealing method caused the changes in the MgO characteristics, such as firing voltage, MgO sputtering rate, MgO hardness, and photoluminescence, which are caused by an increase in the oxygen vacancy of the MgO layer.

An in-situ Study on Discharging Characteristics of an Alternative Current Plasma Display Panel Varied with Discharging Space

An in-situ experimental was carried out to analyze how the gap between a front and rear panel influenced on the discharging properties of an AC Plasma Display Panel (PDP). Initial firing voltages showed almost constant values except at the position of near the barrier rib as the gap increased. The fluctuations of sustain voltages became smaller dependent on the gap, and seemed to have a linear relation to the filtered IR at 828 nm. Observation on the Infra-red indicated the excited or the metastable species could be greatly affected by the rear panel regardless of the gap. Based on these results, we discussed a new method to evaluate dimensional fluctuation of an AC PDP.

Effects of Address-on-Time on Wall Voltage Variation during Address-Period in AC Plasma Display Panel

To explain the variation of the address discharge during an address period, the wall voltage variation during an address period was investigated as a function of the address-on-time by using the Vt closed curves. It was observed that the wall voltage between the scan and address electrodes was decreased with an increase in the address-on-time. It was also observed that the wall voltage variation during an address period strongly depended on the voltage difference between the scan and address electrodes. Based on this result, the modified driving waveform to raise the level of Vscanw, was proposed to minimize the voltage difference between the scan and address electrodes. However, the modified driving waveform resulted in the increase in the falling time of scan pulse. Finally, the overlapped double scan waveform was proposed to reduce a falling time of scan pulse under the raised voltage level of Vscanw, also.

ICCD Observation on Discharge Characteristics in AC Plasma Display Panel Prepared by Vacuum Sealing Process

The vacuum sealing process with a base vacuum of 10-5 Torr is adopted to minimize the residual impurity gas. The address and sustain discharges in the 42-in PDP prepared by the vacuum-sealing process are observed by using the ICCD. As a result, the ICCD observation illustrates that thanks to the reduction of the impurity level by the vacuum-sealing process, the surface and plate-gap discharges are initiated and extinguished very fast and the corresponding IR emissions are also intensified.

A new circular waveform for the three-electrode shadow mask PDP

A new type of ac-plasma display panel (PDP) with shadow mask (SMPDP) is presented with a cost effective structure. The standard SMPDP only includes two electrodes: a scan electrode and an address electrode, and the discharge is a vertical discharge between these two electrodes. A three-electrode SMPDP is described with increased design freedom to improved performance. A special circular waveform has been designed for the three-electrode SMPDP which is expected to result in a higher efficiency by combining the vertical discharge and the surface discharge.

Analysis of the Discharge Characteristics for Kr Gas Mixtures in an ac Plasma Display Panel

We investigated the discharge characteristics of a Kr gas mixture in an ac plasma display panel through two-dimensional numerical simulations. In a Ne-Kr gas mixture, the VUV output and the e cacy increase with higher Kr content due to an increase in the VUV source. In order to analyze the e ect of Kr content on the luminous characteristics for various gas mixtures, we compared the results for Ne-Kr, Ne-Kr-Xe and Ne-Xe mixtures. As the Kr content was decreased and the Xe content increased, the VUV generation e cacy increased because the lower energy level of the Xe excited state caused the generation of excited species to be more e ective than that of Kr gas.

Series resonant sustain driver for AC plasma display

A new series resonant sustainer is presented to reduce the cost and power consumption of PDP TV, which employs address-and-display-period-separated (ADS) driving method. The proposed sustain driver can reduce the number of components compared with the prior approaches. It also improves the energy recovery efficiency about 3%. The operational principle and its features are illustrated and compared with the conventional approaches. The high-performance of the proposed sustain driver is verified by computer-aided simulations and experiments using a prototype equipped with a 7.5-inch diagonal panel, which is operated at 200 kHz switching frequency.

Effects of Operating Frequency on Luminance Characteristics of Wide-Gap AC Plasma Display Panel

The three-electrode microdischarge characteristics of ac plasma display panels are analyzed with a wide-sustain-discharge gap of 180 mum. In particular, the luminance and consumed-power variations are examined as parameters of the operating frequency. It is found that the luminance per unit pulse decreases, and simultaneously, the consumed power per unit pulse increases with an increase in the operating frequency. For the wide-gap structure, the sustain voltage increases when increasing the operating frequency, thus causing the power consumption per unit pulse to be increased. However, the luminance per unit pulse decreases when increasing the sustain voltage, even though the power consumption per unit pulse increases with the sustain-voltage increase. As a result, it is observed that the self-erasing discharge between the sustain and address electrodes caused by the short pulsewidth under high frequency affects the luminance and consumed power. Due to the self-erasing discharge, the sustain voltage increases, and the discharge shrinkage phenomenon affecting the luminance characteristics occurs under high frequency that is up to 200 kHz with a wide-sustain-discharge gap of 180 mum.

Prevention of Boundary Image Sticking in an AC Plasma Display Panel Using a Vacuum Sealing Process

Boundary image sticking can be inherently prevented in an ac plasma display panel fabricated using a vacuum sealing process. The results indicate that residual impurities, such as nitrogen or oxygen, are essentially related to the production of boundary image sticking. When checking the production of boundary image sticking in a test panel fabricated using a or an flow during the vacuum sealing process, no boundary image sticking appeared in the case of a flow, whereas boundary image sticking was produced with an flow, although the test panel was fabricated using a vacuum sealing process. Consequently, reducing the residual impurity, particularly oxygen, based on a vacuum sealing process can inherently prevent boundary image sticking.

A Study on the Measurement Technique of Image Retention in AC Plasma Display Panels

A technique for quantitatively measuring the image retention is suggested. This work focuses on dark image retention, which occurs during the reset period. To investigate the dark image retention phenomenon, characteristics of reset discharge were observed in accordance with the slope of the reset pulse. The temporal behaviors of luminance, chromatistic values, and infra red emission were observed with the black-level image after a five-minute repeatedly strong discharge. The image retention time of the luminance and chromatistic values increased with a decrease in the rising time of the reset ramp pulse. For the case of infrared (IR) emission, there was no clear tendency, in contrast with the image retention or temporal image sticking phenomenon. The results indicate that measurement of the temporal behaviors of luminance and chromatistic values provide suitable measurement for investigating the image retention in AC plasma display panels (PDPs), whereas the IR emission does not provide a useful guide in this regard.

P‐134: Dependency of Auxiliary Pulse Width on Luminous Efficacy in AC Plasma Display Panel

AbstractThe width of the pulse applied to an auxiliary electrode was varied to investigate the characteristics of luminous efficacy of an AC plasma display with an auxiliary electrode in accordance with the frequency and duty factor of the sustain pulse. The auxiliary voltage margin increased with an increase in the sustain pulse width and a decrease in the auxiliary pulse width. In addition, the luminous efficacy increased with a decrease in the sustain pulse width and an increase in the auxiliary pulse width, except when the time interval between the auxiliary pulse and the subsequent sustain pulse is zero.

P‐136: Low Cost and High Efficiency Energy Recovery Circuit for Driving AC Plasma Display Panel with Single Sustain Circuit Board

AbstractThis paper presents an energy recovery (ER) circuit which can improve the energy recovery efficiency and can drive AC PDP with a single sustain circuit board. The proposed ER circuit consists of one energy recovery inductor and two insulated‐gate bipolar transistors. To reduce power consumption in the parallel resonance mode of operation, the leading edge of the first sustain pulse and the trailing edge of the last sustain pulse are generated using a current build‐up operation. The measured energy recovery efficiencies of the proposed ER circuit were better than the conventional parallel resonance circuit. Experimental results on a 42‐inch XGA single scan PDP show that the proposed ER circuit is suitable for use in a PDP drive circuit.

P‐141: Effect of Modified Scan and Sustain Waveforms on Black Luminance and Address Voltage in an AC Plasma Display Panel

AbstractAlthough the three Electrode Surface Discharge type AC PDP is the de‐facto standard in the Plasma TV industry, one parameter which researchers and manufacturers are working hard to improve is Dark Room Contrast Ratio. Poor DRCR is a result of the high Black luminance caused by strong reset discharge. Another parameter, which has seen a lot of activity, is the Address Voltage. This paper investigates the effect of increasing the negative bias voltage applied to the Scan (Y) electrode while reducing the voltage from sustain voltage level applied to the Sustain (X) electrode during the Reset period and address period. Under the optimum voltage and ramp conditions, the Black Luminance was found to have reduced by a factor of 8 and the Address Voltage reduced to the extent of 15 – 20 Volts as compared to conventional waveform. These improvements were tested and validated in the lab on 42″ SD Plasma Display Panels. The significance of this scheme lies in the fact that the improvement in picture quality as a result of Low Black Luminance and consequent improvement in the Dark Room Contrast Ratio did not lead to an increase in the cost of electronics. In fact a reduction of electronic costs is possible due to reduction in the Address Voltage by allowing the use of cheaper Address Driver ICs.

Preparation of MgO Films by Atmospheric Metal–Organic Chemical Vapor Deposition as a Protective Layer in AC Plasma Display Panels

MgO thin films were fabricated by atmospheric metal–organic chemical vapor deposition as a protective layer of AC plasma display panels. The deposition conditions and the discharge properties of the films were evaluated. Among four Mg precursors tested, Mg(C11H19O2)2 [Mg(DPM)2] was the most suitable source material in film growth properties and discharge characteristics. The deposition rate increased with increasing vaporizing temperature and substrate temperature, and the maximum deposition rate reached 3.3 nm/s (5.1 min/µm). The films had (200) main orientations, and highly crystalline square-pyramid structures were observed in high deposition-rate films. Under the high-rate deposition condition, the firing voltage and the discharge delay of the film were comparable to those of conventional vacuum-evaporated MgO film. The discharge delay was shorter when the crystal size was larger, the work function was smaller, and the concentrations of impurities were lower.

Modified Reset Waveform to Widen Driving Margin under Low Address Voltage in AC-Plasma Display Panel

This paper proposes a new reset driving waveform to widen the driving margin under a low address voltage in AC-PDPs. The proposed reset waveform alters the wall charge distribution between the X-Y electrodes by applying an X-ramp bias prior to an address-period, thereby lowering the minimum level of the scan pulse (AVy) during an address-period without any misfiring discharge in the off-cells. When adopting the proposed reset waveform, the address discharge time delay is reduced by about 200ns at an address voltage of 35 V, while the related dynamic driving margin is wide under a low address voltage condition. The related phenomena are also examined using the V t close-curve method.