Xe Content Research Articles

Discharge characteristics of He–Ne–Xe gas mixture with varying Xe contents and at varying sustain electrode gap lengths in the plasma display panel

The discharge characteristics of He–Ne–Xe gas mixture in the plasma display panel were investigated using a two-dimensional numerical simulation to understand the effects of adding He and varying the Xe contents in the gas mixture, and also varying sustain electrode gap. With 5% Xe content and 60 μm sustain electrode gap, decreased ionization led to the improvement of the vacuum ultraviolet (vuv) efficacy at increasing He mixing ratios. However, at 20% Xe content and 60 μm sustain electrode gap, increased electron heating improved the vuv efficacy until the He mixing ratio reached 0.7, but the efficacy decreased beyond the ratio of 0.7 due to the increased ionization of Xe atoms. At 5% Xe content and 200 μm sustain electrode gap, the vuv efficacy increased as a result of increased electron heating at the gap space at increasing He mixing ratios.

Solutions to remove a boundary image sticking in an ac plasma display panel

When displaying a square-type image with peak luminance for approximately 500 h in a 42 in. plasma display panel TV with high Xe (15%) content, halo-type boundary image sticking was observed in the nondischarge region adjacent to the discharge region. The halo-type boundary image sticking phenomenon is due mainly to the redeposit of the Mg species on the MgO layer in the nondischarge region adjacent to the discharge region, which is verified by measuring the redeposited Mg species in the boundary image sticking region using a cross-sectional scanning electron microscope. Based on this result, three kinds of solution to remove the boundary image sticking of an ac plasma display panel are introduced. First, we completely recover the boundary image sticking cells by using a full-white aging process. Second, we prohibit the inherent production of boundary image sticking by sealing the plasma display panel under vacuum. The final solution is to prohibit the inherent production of boundary image sticking by use of lower gas pressure.

Flexible, Lightweight Arrays of Microcavity Plasma Devices: Control of Cavity Geometry in Thin Substrates

Adaptation of wet chemical processing or replica molding techniques to microcavity plasma device technology has yielded lightweight and flexible arrays in the Al/Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> materials system and plastic substrates, respectively. Microplasma arrays fabricated from two bonded sections of Al mesh with an integral dielectric barrier of nanoporous alumina have an overall thickness of <100 mum, resulting in lamps that are flexible and conformable to a variety of surfaces. Operating these arrays in both flat and curved configurations reveals few changes to the voltage-current characteristics but a reduction of a factor of two in the luminance of curved or bent structures relative to that for a flat array. Truncated paraboloid cavities have also been formed in 30-70-mum-thick Al foil by a sequence of wet chemical processes. Microcavities with an emitting aperture diameter as small as 50 mum have been realized, and arrays comprising 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> cavities exhibit ignition voltages of ~140-150 V (rms) for Ne pressures between 400 and 700 torr and a 20-kHz sinusoidal voltage waveform. Mixtures of Ne and Xe with Xe content up to 67% have been operated successfully. Ignition voltages of only 70-90 V (rms) have been measured for 30 times 30 arrays of 200 times 200-mum <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> microcavities formed in ultraviolet curable polymer by replica molding and operating in 400-600 torr of Ne. For 3% N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Ar mixtures at total pressures of 400-700 torr, the ignition voltages rise to ~150-220 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</sub> for a driving frequency of 20 kHz, the array emission is spatially uniform, and rms currents above 85 mA can be drawn in the steady state by these plastic-based arrays.

26.4: Enhancement of Discharge Characteristics Using RF‐Plasma Treatment on MgO Layer in 50‐In. Full‐HD AC‐PDPs

AbstractThe characteristics of the MgO layer are known to be an important parameter that affects both the address and sustain discharge characteristics in an ac‐PDP. In this paper, to improve the discharge characteristics of 50‐in. full‐HD ac‐PDP with He (35%) ‐ Xe (11%) contents, RF‐plasma treatments on the MgO layer are examined under various gases for plasma treatment. The resulting changes in the address and sustain discharge characteristics, including the firing voltage, Vt closed curve, power consumption, luminance, luminous efficiency, and secondary electron coefficient, are then compared for both cases with and without plasma treatment on MgO layer. It is concluded that the Ar plasma treatment can enhance the discharge characteristics, such as the firing voltage and power consumption, which are caused by an increase in the secondary electron coefficient.

7.2: Address Discharge Characteristics of High Luminous Efficacy PDP with SrO Protecting Layer

AbstractWe have achieved low voltage driving and high luminous efficacy by applying SrO protecting layer in PDP. Especially its low voltage characteristics can make it possible to use very high Xe content such as 30% gas at the voltage levels which currently commercialized PDP use. The use of SrO protecting layer can reduce the firing voltage not only between sustain electrodes but also between address and scan electrodes, so that the threshold voltage VAY as well as the address delay in the SrO panel with Xe 30% could be made comparable to those in the MgO panel with Xe 10% with the appropriate modifications in the ramp reset waveform.

P‐94: Discharge Efficiency Study in SMPDP

AbstractThe relationship between IR and VUV emission was investigated in an opposed PDP discharge at high Xe content and high voltage levels. The ratio of VIS/IR and the ratio of Efficacy/VIS/IR were determined to analyze the behavior of the xenon excitation efficiency and the electron excitation efficiency as a function of driving voltage and xenon content. We see that the xenon excitation efficiency is almost independent from the driving voltage, and is increasing approximately linearly with the xenon partial pressure.

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.

Secondary electron emission characteristics of MgO–ZnO alloy thin film layer for AC PDP

In this study, we attempted to reduce firing voltage of ac-PDPs by alloying MgO electron emission material with ZnO. This approach was aimed to reduce band gap energy of MgO by the alloying and thereby promote the Auger neutralization reaction of Xe + ions on MgO surface. Pellets were prepared by sintering MgO and ZnO powder mixture at 1300 °C for 8 h under nitrogen atmosphere. Test panels with such alloyed MgO films showed significantly reduced firing voltages, especially when the discharge gas is of high Xe content. These results represent a new way of approaching in the development of electron emission materials for ac-PDPs.

Upper limit concentrations of trapped xenon in individual interplanetary dust particles from the stratosphere

Abstract— The Xe contents in 25 individual stratospheric interplanetary dust particles were measured in two different laboratories using focused laser micro‐gas extraction and (1) a conventional low‐blank magnetic sector mass spectrometer (Washington University), and (2) a resonance ionization time of flight mass spectrometer (RELAX‐University of Manchester). Data from both laboratories yielded a remarkably similar upper‐limit 132Xe concentration in the IDPs (&gt;2.7, 6.8 and 2.2 × 10−8ccSTP/g for Washington University Run 1, Washington University Run 2 and University of Manchester analyses, respectively), which is up to a factor of five smaller than previous estimates. The upper‐limit 132Xe/36Ar ratio in the IDPs (132Xe/36Ar &gt; ˜8 × 10−4for Run 1 and 132Xe/36Ar &gt; ˜19 × 10−4for Run 2), computed using 36Ar concentration data reported elsewhere is consistent with a mixture between implanted solar wind, primordial, and atmospheric noble gases. Most significantly, there is no evidence that IDPs are particularly enriched in primordial noble gases compared to chondritic meteorites, as implied by previous work.

A Study on Temporal Dark Image Sticking in AC-PDP Using Vacuum-Sealing Method

Minimizing the residual impurity gases is a key factor for reducing temporal dark image sticking. Therefore, this paper uses a vacuum-sealing method that minimizes the residual impurity gases by enhancing the base vacuum level, and the resultant change in temporal dark image sticking is then examined in comparison to that with the conventional sealing method using 42-in. ac-PDPs with a high Xe (11%) content. As a result of monitoring the difference in the display luminance, infrared emission, and perceived luminance between the cells with and without temporal dark image sticking, the vacuum-sealing method is demonstrated to reduce temporal dark image sticking by decreasing the residual impurity gases and increasing the oxygen vacancy in the MgO layer. Furthermore, the use of a modified driving waveform along with the vacuum-sealing method is even more effective in reducing temporal dark image sticking.

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.

Discharge Characteristics of AC Plasma Display Panel Prepared Using Vacuum Sealing Method

The base vacuum level achieved before loading the discharge gas is known to be an important parameter that affects both the address and sustain discharge characteristics in an AC plasma display panel (PDP), as a higher base vacuum level improves the discharge characteristics. Accordingly, the vacuum sealing method, which can enhance the base vacuum level, is adopted to enhance the MgO characteristics by reducing any residual gas impurity. The resulting changes in the address and sustain discharge characteristics, including the secondary electron coefficient, firing voltage, and dynamic voltage margin, are then compared with the results when using conventional atmospheric-pressure sealing for a 42-in ac PDP with a high Xe (11%) content. The vacuum sealing method was found to improve the secondary electron emission coefficient, lower the firing voltage, particularly under MgO cathode conditions, and increase the dynamic voltage margin. However, the vacuum sealing was also found to deteriorate the visible transmittance of the dielectric layer in the front panel. Nonetheless, the vacuum sealing process enabled the use of a higher Xe content, which is up to 17%, under a stable dynamic margin voltage, thereby improving both the luminance and luminous efficiencies of the AC PDP.

Effect of reduced pressure on the polarization of 129Xe in the production of hyperpolarized 129Xe gas: Development of a simple continuous flow mode hyperpolarizing system working at pressures as low as 0.15 atm

AbstractThe effect of reduced pressure on the polarization of 129Xe has been examined in batch and continuous flow modes aiming at developing a simple and convenient hyperpolarizing system. The effect of foreign gases was found to show a different tendency at reduced pressure as low as 0.15 atm compared to that near atmospheric pressure. For example, 129Xe polarization in binary mixtures of Xe and N2 was larger than that observed in ternary mixtures of Xe, N2, and 4He when compared with the same Xe content, and the highest polarization of 63.6% was given by the 5% Xe + 95% N2 mixture in the batch mode. The most noticeable result in the flow mode was that 129Xe polarization reached a plateau at 0.15 atm when cell pressure was reduced from atmospheric pressure, being enhanced to about twice of that observed near atmospheric pressure. Also demonstrated is the use of isotopically enriched 129Xe gas at reduced partial pressure. This will be devoid of the anesthetic side effects of Xe while making use of enhanced polarization at reduced pressure, leading to the development of a simple and convenient hyperpolarizing system for medical use. © 2008 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 33B: 192–200, 2008

27.2: Analysis of Discharges in High Luminous Efficacy PDP with 5lm/W

AbstractDischarge mechanism concerning the width of the display electrodes in high Xe content conditions has been researched for improving the luminous efficacy of PDPs. It was found that 5lm/W is realized under high Xe content and narrower display electrode conditions. In this paper, discharge phenomena in high Xe content conditions will be discussed as compared with that in low Xe content conditions.

P‐128: Experimental Study on Reduction of Temporal Bright Image Sticking in AC‐PDP Using Vacuum‐Sealing Method

AbstractThe base vacuum level before filling a discharge gas is an important parameter to affect both the temporal dark and bright image stickings in an AC‐PDP. In this paper, the vacuum‐sealing method is adopted to minimize the residual impurity gas by enhancing a base vacuum level, and the resultant change in the temporal bright image sticking was examined in comparison with that of the conventional sealing method in the 42‐in. ac‐PDP with a high Xe (11 %) content. As a result of monitoring the difference in the display luminance and infrared emission between the cells with and without temporal bright image sticking, the vacuum‐sealing method can reduce the temporal bright image sticking which is caused by decrease in the residual impurity gases and an increase in the oxygen vacancy of the MgO layer. In particular, in the vacuum‐sealing method, the modified driving waveform enabled the effective reduction of temporal bright image sticking.

27.1: Invited Paper: High Efficiency Plasma Display Discharges

AbstractPlasma display panel efficacy data are correlated with panel emission measurements. A large (VIS/IR)‐ratio, of the phosphor emission in the visible to the Xe emission in the infrared, indicates a high Xe‐excitation efficiency. Monitoring the changes in the (VIS/IR)‐ratio allows a decomposition of the discharge efficiency into Xe‐excitation efficiency and electron‐heating efficiency contributions. for several different panel efficacy dependencies on sustain voltage and frequency, consistent trends in Xe‐excitation efficiency and electron‐heating efficiency are found. In addition, in order to follow the discharge development, the time dependence and the spatial distribution of the Xe emission are monitored. The combined results show that plasma saturation is significant for low Xe content panels in default operation conditions, and that plasma saturation decreases for high voltage, high frequency operation of high Xe‐content panels. Finally, it is found that the Xe‐excitation efficiency increases for increasing sustain voltage and frequency. These driving conditions, which are especially suited for high Xe‐content panels, govern a fast and spatially distributed discharge development, with a lower effective electron temperature and decreased plasma saturation.

Effects of plasma loss on the luminous efficacy in a full high definition alternating current plasma display panel

We have investigated the effect of cell resolution change on the luminous efficacy of an alternating current plasma display panel with the three-dimensional plasma simulation. The luminous efficacy decreased and the minimum sustain voltage increased as the resolution increased from VGA to full high definition (HD) resolution, due to the increased particle loss to the enclosing surfaces. 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. We are proposing some effective ways of realizing high luminous efficacy in the high resolution 50-in. full HD cell, such as the increase of the sustain electrode gap, the adoption of a segmented electrode in delta color arrayed, enclosed subpixel, type cell with 4:3 aspect ratio, and the optimization of the barrier rib height. Because the adoption of those geometrical parameters causes the reduced plasma loss, the transport efficacy of visible light from phosphor through the front plate in a full HD cell resulted in much increased improvement with the increase of Xe content.

Discharge characteristics and low‐voltage driving of high‐Xe‐content PDPs

Abstract— High‐Xe‐content PDPs attain improved luminous efficiency, but with sacrifices of higher sustain and address voltages and slower discharge build‐up. By examining PDPs with 3.5–100% Xe contents, it was revealed that space‐charge priming as well as wall‐charge accumulation are effective in obtaining low‐voltage and high‐speed operation. In addition, it was found that the effectiveness is emphasized for higher‐Xe‐pressure PDPs. In this respect, erase addressing is more favorable than write addressing, especially for high‐Xe‐pressure PDPs. The formative time lag of the discharge and diffusion/drift of the space charges are shorter for high Xe contents. In this respect, high‐Xe‐content PDPs have a potential for high‐speed addressing, if driven adequately. The use of space‐charge priming, however, is limited by the duration between the priming and scan pulses. Accumulation of wall charges is limited by ignition of a self‐erase discharge with which all the wall charges are dissipated. Although the highest efficiency and luminance are attained with a 100%‐Xe panel, the optimum Xe gas content, considering the sustain pulse voltage and drive voltage margin, would be 70% Xe + Ne.

Excited xenon density and ion-induced secondary electron emission coefficient for vacuum ultraviolet luminous efficiency in alternating current plasma display panel

It is shown for Xe content ratio of 10% that the excited xenon atom density for the 1s 5 metastable state is 3.0 × 10 12 cm − 3 with a gap distance of 50 μm under a fixed gas pressure of 5.3 × 10 4 Pa in alternating current plasma display panels. It is observed that the VUV emission of 173 nm continues after its peak and lasts much longer than 147 nm emission. We also found that the time of VUV peak emission intensity for higher xenon mole fraction is longer. It is also concluded that the luminous efficiency is strongly dependent on the ion-induced secondary electron emission coefficient.

Effect of Auxiliary Address Pulses on the Luminous Efficacy in AC Plasma Display Panel With Grooved Dielectric Layer

This paper investigates the effect of applying auxiliary short pulses to an address electrode with varying Xe contents on the improvement of luminous efficacy. The luminous efficacy increases with the application of auxiliary pulse; however, as the Xe content increases in the Ne-Xe mixture discharge gas, the efficacy improvement effect by auxiliary address pulse discharge decreases. The surface discharge was hardly affected by the face ignition discharge between the address and sustain electrodes, and thus, the high-driving-voltage problem still remains when the high-Xe-content gas is used to get the high luminous efficacy. To decrease the sustain voltages of the high-Xe-content gas, we adopted locally thin dielectric layer structure near the electrode gap. The panel with the suggested grooved dielectric layer structure showed decreased driving voltage margin and improved luminous efficacy even for high-Xe-content gases. We obtained 5 lm/W and 3700 cd/m2 at 220-V, 50-kHz continuous sustaining condition from a monochrome green test panel with the Ne-Xe (16%) mixture, which was about two-and-a-half times improved luminous efficacy as compared to that of the reference structure with Ne-Xe (4%). Full driving feasibility was also checked by applying the auxiliary address pulses to the grooved structure panel. The misaddressing could occur when the auxiliary pulses are applied continuously to the address electrodes in the sustain period, which decreased the driving voltage margin. However, this demerit can be compensated by lowering the driving voltage margin with the adoption of the grooved structure. Also, the address discharge delay decreased by about 48% in the panel with the grooved structure.