AC PDP Research Articles

High Luminous Efficacy Characteristics of Long Gap Structure AC Plasma Display Panel With Self-Ignition Electrodes

A long gap structure alternating current plasma display panel (ac PDP) with ignition electrodes is suggested, and its luminous characteristics are investigated. The operation voltages of the long gap structure PDP can be reduced with the help of ignition electrodes. Luminance and luminous efficacy are improved compared with those of an ac PDP with electrodes having the conventional short discharge gap. The luminance and luminous efficacy of the suggested structure can be further improved by applying address auxiliary pulses synchronized with the sustain pulses. The detailed current waveform analysis suggests that the application of address auxiliary pulse changes the discharge current ratio between the long gap electrodes to the ignition electrodes. By increasing the address auxiliary pulse voltage to a certain extent, the luminous efficacy increased along with the discharge current ratio. It has been also observed that when the width of the long gap discharge electrode is increased, the dynamic voltage margin increased accordingly.

A Study of False Contour Noise in Moving Images through Consideration of the Phosphor Decay Time of AC PDP

The dynamic false contour noise was analyzed with consideration for the phosphor decay time of an ac PDP by computer simulation based on the measurement of the 1/10 phosphor decay times of the primary colors red green and blue at the main wavelengths of each phosphor. The noise level of dynamic false contour is strongly dependent on phosphor decay time. The noise level decreases incrementally with the phosphor decay time whereas the noise width increases. The moving velocity of an object does not affect the noise level. The entire experiment was performed under the condition of 8 subfields ADS driving scheme, 2.5[μsec] scan speed, and 5 [μsec] sustain period with VGA grade panel.

Wall Voltage and Priming Effect Due to Auxiliary Electrode in AC PDP With Auxiliary Electrode

Variation of wall voltage and priming effect due to an auxiliary electrode are investigated with the aim of attaining a better understanding of the discharge phenomenon in an ac plasma display panel with an auxiliary electrode. A periodic positive pulse, which is applied to the auxiliary electrode during afterglow, reduced wall charges accumulated on the auxiliary and sustain electrodes so that discharge current decreased with an increase of auxiliary-pulse voltage. In addition, the auxiliary pulse influenced on the priming particles so that the optical output was not changed as much as the reduced current and sustain voltage was lowered. Based on these results, modified auxiliary-pulse waveforms, i.e., dual auxiliary pulses, were applied to the auxiliary electrode to utilize more priming particles to improve luminous efficacy. The proposed auxiliary waveforms improved IR efficiency by 10%-15% as compared to that obtained with a single auxiliary pulse.

Equivalent circuit model and characteristic parameters for AC PDP discharge cells

In this paper, an equivalent circuit model for discharge cells of alternating current plasma display panel (AC PDP) is developed. In this model, a voltage controlled switch is introduced to describe the breakdown process of the gas discharge. And two zener diodes are introduced to describe the sustain process of the gas discharge. Three internal discharge characteristic parameters, the breakdown voltage of discharge gap, the minimum sustain voltage of discharge gap and the discharge cell capacitance ratio, are proposed. The formulas for expressing external discharge characteristic parameters by internal discharge characteristic parameters are derived. The experimental method for measuring internal characteristic parameters is developed and the measurement results for a macro discharge cell are presented.

Gd2O3첨가에 따른 AC PDP 보호막용 MgO 박막의 광학적.전기적 특성

The effects of <TEX>$Gd_2O_3$</TEX> addition and sintering condition on optical and electrical properties of MgO films as a protective layer for AC plasma display panels were investigated. Doped MgO films prepared by the e-beam evaporation have a higher <TEX>${\Upsilon}$</TEX> (secondary electron emission coefficient) than pure MgO protective layer. Relative density and grain size increased with amount of <TEX>$Gd_2O_3$</TEX> up to 100 ppm and then decreased further addition. These results showed that discharge properties and optical properties of MgO protective layers seemed to be closely related with microstructure factors such as relative density and grain size. Good optical and electrical properties of <TEX>${\Upsilon}$</TEX> of 0.138, surface roughness of 5.77 nm and optical transmittance of 95.76 % were obtained for the MgO+100 ppm <TEX>$Gd_2O_3$</TEX> protective layer sintered at <TEX>$1700^{\circ}C$</TEX> for 5 hrs.

49.3:Invited Paper: High Efficient Discharge Mode in an AC PDP with an Auxiliary Electrode

AbstractA high efficacy AC PDP with an auxiliary electrode was investigated with the aim of attaining a better understanding of the discharge mechanism in a display cell. There are three types of discharge modes in an AC PDP with an auxiliary electrode; however, only two discharge modes that can decrease the discharge current are recommended for use in a high efficacy AC PDP. The discharge current decreased as the auxiliary pulse voltage increased because the wall charges on the sustain electrode were erased. However, the IR intensity did not decrease as the auxiliary pulse was applied. It was also found that the auxiliary pulse provides priming particles for the following periodic sustain pulse discharge. Consequently, there is a decrease in the discharge current without a reduction of the luminance and priming particles due to the auxiliary pulse. This can enhance the excitation rate of the discharges generated in the display cell of an AC PDP with an auxiliary electrode.

P‐98: The Effects of Si Doped MgO Protecting Layer in AC PDP

AbstractIn order to improve the material characteristics of the protective layer for ac‐PDPs, a small amount of Si was added to the MgO films. Both the surface characteristics of the protecting layer and the electro‐optical properties were investigated, such as discharge voltages, luminance, luminous efficacy, addressing jitter, and image sticking.

49.2: Invited Paper: Realization of High Luminous Efficacy with Full HD AC PDP

AbstractWe have investigated the effect of cell resolution change on the luminous efficacy of AC PDP with the 3‐dimensional computer simulation and experiment. The luminous efficacy decreased and the minimum sustain voltage increased as the resolution increased from VGA to full HD resolution, due to increased particle loss. A simple increase of the Xe content to realize the high luminous efficacy resulted in a much enhanced luminous efficacy decremental ratio as the cell resolution increases, because of the increased plasma loss and decreased electron heating efficacy.The increase of the sustain electrode gap from the commonly used value of 60μm to 140μm in the 50″ full HD cell with Ne‐Xe [20%] gas resulted in the luminous efficacy value comparable to that of the XGA cell with 60μm gap which indicates that a large electrode gap with a high Xe content gas is an effective way of realizing high luminous efficacies.However the excessive increase of driving voltage and the discharge time lag with the large electrode gap and high Xe content gas should be compromised in order to be used in the commercial product and increase the luminous efficacy further. A new cell structure with an auxiliary electrode (DIDE: Dual Ignition Discharge Electrode), optimized thickness of dielectric and phosphor layer, driving waveform, is demonstrated to show a luminous efficacy of 5.8 lm / W (Green, 25 kHz) with the address minimum voltage as low as 50V as an example of high luminous efficacy cell with low driving voltage.

AC PDP의 전기 광학적 특성과 동작 가스 Xe+Ne+Kr의 구성비와의 상관관계에 관한 연구

Plasma display panel(PDP)의 동작전압, 밝기, 방전 늦음 시간, 광 효율, 수명, 잔상 등의 방전특성은 PDP내부의 동작가스의 혼합비율에 영향을 많이 받기 때문에, 높은 비율의 Xe 가스가 첨가된 PDP의 연구가 최근에 활발히 진행되고 있다. 그러나 high Xe이 패널에 주입되더라도 방전 개시전압과 유지전압의 상승 등의 문제점 들이 발생하고 있다. 본 연구에서는 이러한 문제를 해결하기 위한 방법으로 Ne+Xe+Kr 3원 가스에서의 가스혼합비율에 따른 방전 전압과 마진, 휘도, 광 효율을 연구하였다.

3-3 高精細AC型PDPにおける放電開始電圧の検討(第3部門 情報ディスプレイ2)

3-3 高精細AC型PDPにおける放電開始電圧の検討(第3部門 情報ディスプレイ2)

Microdischarge using priming particles for reducing neon emission in AC plasma display panel with Ne-Xe-He gas mixture

This study uses neon, xenon, and helium gas mixture microdischarge to determine the effects of priming particles on the neon emission characteristics in an alternate current plasma display panel (AC PDP). The infrared (823 nm) and neon emission (585 nm) intensities are measured and compared in the blue cells in the case of new discharge with priming particles or conventional discharge without priming particles, respectively. It is found that the priming particles can produce a plasma discharge effectively even under the weak electric field condition, thereby resulting in reducing the neon emission intensity remarkably without sacrificing the IR emission intensity. As a result, it is found that the Ne emission intensity is reduced by about 46.4 % but the blue visible emission intensity is increased by about 15.2 % when compared with the conventional discharge without priming particles.

Effects of Linear Falling Ramp Reset Pulse on Addressing Operation in AC PDP

The effects of linear falling ramp reset pulse related to addressing operation in an alternating current plasma display panel (AC PDP) were studied. The wall charge waveforms were measured by the electrode balance method in a 12-inch coplanar AC PDP. The wall charge waveforms show the relationship between the slope ratio of the falling ramp reset pulse and the wall charges at the end of the falling ramp reset pulse which influences the addressing stability. Then the effects of the slope ratio of the linear falling ramp reset pulse on the addressing voltage and addressing time were investigated. The experimental results show that the minimum addressing voltage increases with the increase of the slope ratio of the falling ramp reset pulse, and so does the minimum addressing time. Based on the experimental results, the optimization of the addressing time and the slope ratio of the falling ramp pulse is discussed.

Characteristics of an address discharge time lag in terms of a wall voltage in an AC PDP

The characteristics of an address discharge have been investigated in terms of a wall voltage, which plays an important role in achieving a high-speed address discharge in an ac plasma display panel. The wall-voltage conditions generated in a reset period are a considerable factor to reduce the address-discharge time lag. Based on the experimental results, the reset driving scheme in which an address bias voltage is applied to the address electrode in a reset period is proposed to enhance the characteristics of an address-discharge time lag.

The effect of an atmospheric pressure plasma treated MgO layer on the discharge performance of an AC plasma display panel

The effect of an atmospheric pressure plasma treated MgO layer on the discharge performance of an alternating current plasma display panel (AC PDP) was investigated by measuring the contact angle, the surface roughness, the composition, the breakdown and sustaining voltages. The plasma cleaning was performed using the He/O2/Ar gas mixture. Higher contact angle (35°) of water droplet on the MgO surface and the MgO surface roughness (90 nm, Rmax) after one day duration in the air was significantly reduced to 4° and 54 nm (Rmax) after the plasma cleaning. After the plasma treatment, the adsorbed CO2, CO, H2O impurities on the MgO surface are effectively removed. The breakdown and sustaining voltages were reduced probably due to the increase of secondary electron emission coefficient of MgO, implying that the plasma cleaning process of the MgO layer is beneficial for the improvement of the discharge performance of the AC PDPs.

High luminous efficiency characteristics of alternating current plasma display panel with delta color arrayed, enclosed barrier rib structure

The luminous efficiency characteristics of a new alternating current plasma display panel (ac PDP) structure with the segmented electrodes in delta color arrayed subpixels with enclosed barrier ribs (SDE) are investigated. The SDE structure which has a 4:3 horizontal to vertical cell dimension ratio showed higher luminance and luminous efficiency increment characteristics as the Xe partial pressure increased compared to those of the conventional stripe type with 1:3 ratio for a given resolution. The luminance and luminous efficiency increases with the electrode width, which provides a means to change the color temperature for the full color panel without using other method such as the subpixel size change. The driving feasibility of SDE structure panel with various electrode widths is confirmed by demonstrating the existence of sufficient driving voltage margin

Mechanism of high luminous efficiency in delta color arrayed, enclosed subpixel structured AC PDP with high Xe content

We investigated the effect of Xe content variation on the luminous efficiency of two different subpixel types, i.e., segmented electrode in delta color arrayed, enclosed subpixel (SDE) and conventional stripe barrier type, in an alternating current plasma display panel through three-dimensional (3-D) numerical simulations. The simulation result agreed well with the experimental result where the SDE structure showed to have higher luminous efficiency improvement with increasing Xe content than the conventional structure did. The conventional cell type was found to have higher vacuum ultraviolet (VUV) generation efficiency at low Xe content as compared with SDE structure, but as the Xe content increased, the SDE type showed a higher improvement in efficiency due to the lower plasma loss to the enclosing surfaces. Using the ray-optics code in conjunction with the 3-D plasma simulation, the transport efficiency of visible light from phosphor through the front plate in the SDE structure, which has a higher aperture ratio, was higher than that of the conventional structure with much increased improvement with the increase of Xe content

A Real-time Image Processor with Dynamic Error Diffusion based on Edge Detection for Plasma Display Panel

In the conventional error diffusion method applied to alternating current plasma display panel (AC PDF), all directions' diffusion coefficients are fixed all the time in diffusion process, which results in the loss of image details and causes false contours. To overcome the shortcoming of the conventional error diffusion method, a dynamic error diffusion method based on edge detection is proposed. In the proposed method, error diffusion coefficients are dynamically adjusted according to the edge detection executed along four diffusion directions. The dynamic error diffusion method makes the error diffusion coefficients coincide with the characteristic of image contour, and decreases the accumulated errors generated in the conventional error diffusion process. A real-time image processor with the dynamic error diffusion was implemented and tested on a 42- inch AC PDP. Simulation and experimental results show that both the static false contours caused by lack of gray levels and the loss of image details caused by fixing diffusion coefficients are decreased effectively, which improves image quality of AC PDP greatly.

An adaptive subfield coding method for driving AC PDPs

The image quality suffers from the lack of grayscale expression capability when the simple accumulation of light emission is applied to express grayscale in alternating current plasma display panels (ac PDP). To solve the problem, an adaptive subfield coding (ASC) method for driving ac PDP is proposed, in which subfield vector is adaptively figured out based on the normalized histogram of input image every television field. The calculated subfield vector can express the most grayscale information of input image. And then the number of sustain pulses in each subfield is adjusted according to the calculated subfield vector. Simulation results show that the proposed method can eliminate the dynamic false contours in ac PDPs and overcome the lack of grayscale expression capability caused by the simple-accumulation-lighting-mode. It could provide good grayscale expression in ac PDPs.

Diagnostics of the microdischarge in an alternating current plasma display panel (AC PDP)

In this paper, we describe the experimental approaches to understand the microdischarge physics of an alternating current plasma display panel (ac PDP) cell. We discuss the experimental techniques to explore the major parameters to understand the operation of ac PDP such as the vacuum ultra violet (VUV) emission and wall charge variation. Regarding the discharge dynamics, the detailed VUV emission characteristics were measured and explained by the gas reaction modeling and the microdischarge characteristics during the ramp reset period were compared with the simulation result. The wall voltage and wall charge distribution were measured by laser induced fluorescence (LIF) and electro-optic modulation method. The slight increase of the wall voltage by Xe addition to pure He discharge gas was observed by LIF. And the existence of self-erasing discharge results in the drastic decrease of wall charge near discharge gap.

Critical aspects of the plasma display panel manufacturing process

The panel manufacturing process of the alternating current plasma display panel (AC PDP) is discussed from the viewpoint of panel performances. From this viewpoint, not only the cell structure formation, but also the inner panel environment control is important. The inner panel environment means the chemical and physical conditions of cell inner surface and gas impurities. When a good inner panel environment is established, a stable panel operation and a longer panel life are achieved. Much more effort is required in the panel manufacturing process to obtain a good inner panel environment, where the impurities are sufficiently low, the oxygen concentration keeps at an optimum level, and these conditions keep after a long-term operation.