The voltage-pulsing effects in AC plasma display panel

The effect of the voltage pulsing is simulated in AC plasma display panel using various two-dimensional simulation codes. The volume-averaged density increases rapidly because of the large electric field in the AC-plasma display panel cell as the peak voltage is raised. The ignition time and the decaying time of the discharge are related to the external voltage. The space and time variations of the charged particle densities and the potential profile are described for various voltage forms. The ion energy distribution near the cathode-side dielectric which plays an important role in the MgO lifetime and the secondary electron emission coefficient is concentrated to much lower energies than the applied voltage     

New color-enhancing discharge mode using self-erasing discharge in AC plasma display panel

A new color-enhancing discharge mode using a self-erasing discharge is proposed based on an analysis of the Ne emission mechanism in a Ne-Xe gas mixture. The effects of the new color-enhancing discharge mode produced by a ramped-square sustain waveform on improving the color reproducibility are examined in an alternate current plasma display panel (ac-PDP) filled with a Ne-Xe gas mixture. When the ramped-square sustain pulses are applied at 150 kHz, the color purities of the blue and green visible emissions are both improved, thereby expanding the color gamut area by about 5.4% without reducing the luminance.     

Simulation study of ghost image phenomenon induced by contrast enhancement film in plasma display panels

We have performed simulations of the ghost image phenomenon induced by a contrast enhancement film used for plasma display panels (PDPs). An optical imaging system was designed in order to investigate the ghost image qualitatively and quantitatively. We report on and discuss the effects of the material parameters and film orientation on the relative illuminance of the ghost image for a conventional louver-type contrast enhancement film adopting a trapezoidal black-stripe structure. The ghost image phenomenon is strongly affected by the film orientation relative to the PDP module and the difference between the refractive index of the ultraviolet curable urethane acrylate layer and that of the black stripes. We show that when the top side of the black stripes faces the PDP module and the refractive index difference is small, the ghost image phenomenon is weakened.     

Operation of a coplanar-electrode plasma display panel cell

Plasma display panels (PDPs) are composed of miniature gas discharge devices sustained in noble gas mixtures. In this paper, the dynamics of a coplanar-electrode PDP cell are described using results from a two-dimensional computer simulation. During the first voltage pulse, the discharge takes place between the top and bottom electrodes. Due to charging of the bottom dielectric during the first discharge pulse, a surface discharge takes place between the top coplanar electrodes on successive pulses     

Microstructure and discharge properties of Mg-Zr-O protective films in plasma display panel

Mg-Zr-O protective films for plasma display panels (PDPs) were deposited on soda-lime glass substrates by magnetron sputtering method. The effects of Zr doping on both the discharge properties (firing voltage, V_f and the minimum sustaining voltage, V_s) and the microstructure of the Mg-Zr-O films were investigated. The results show that the deposited Mg-Zr-O films retain the NaCl-type structure as the pure MgO crystal. The doped Zr exists in the form of Zr⁴⁺ substitution solution in MgO crystal and an appropriate amount of Zr can improve the surface characteristics of the Mg-Zr-O films effectively. When the Zr atomic concentration is about 2%, the Mg-Zr-O films have the strongest (2 0 0) preferred orientation and the minimum surface roughness. The firing voltage and the minimum sustaining voltage of Mg-Zr-O protective layer are reduced at most by about 25 V and 15 V, respectively, compared with those of the pure MgO film. Mg-Zr-O protective layers with an appropriate amount of Zr are promising to meet the demands of advanced high-vision PDPs.     

Characteristics of charged and metastable species in micro-discharges of AC- plasma display panel

The temporal effects of charged and metastable particles in the micro-discharges of an AC plasma display panel (AC-PDP) were investigated under actual driving conditions. The discharge gas used in the 4-in PDP was Neon + 4% Xenon. The discharge characteristics in terms of the time scale related to the space-charge decay, wall charge decay, metastable decay, and charge accumulation were investigated using a pulse technique. For Neon + 4% Xenon gas-mixture discharges of 500 torr, 4 /spl mu/s was related to the time scale of the space-charge decay and wall-charge accumulation time. The minimum sustain voltage started to dramatically increase at 20 /spl mu/s, which was related to the time scale of the metastable particles. Whereas, after 40 /spl mu/s, the minimum sustain voltage slowly increased with a slope of 0.01581, which was related to the inverse of the time scale of the wall charge decay.     

Design and development of driving waveforms for AC plasma display panels

This paper presents design and development of driving waveforms to improve efficacy, contrast, and resolution for ac plasma display panels (PDPs). In the paper, the conventional driving waveforms are first reviewed, and the proposed driving waveforms are then discussed. The driving of PDPs in each subframe is divided into three periods: the reset period, scan period, and sustain period. During the reset period, the proposed ramp-like reset waveforms can enhance the contrast and resolution, and can lower the scan voltage while still sustaining a reliable wall-charge control. Additionally, a square sustain waveform stacked with the ramp-like waveform can induce self-erasing discharges which will improve efficacy during the sustain period. Operation of a PDP and comparison among various driving waveforms are also presented. Experimental results measured from a 46-in PDP system have verified the feasibility of the proposed driving waveforms.     

A two-dimensional multispecies fluid model of the plasma in an ACplasma display panel

A time dependent, two-dimensional model for simulating the plasma evolution in an AC plasma display panel (AC-PDP) is described. Reaction-convection (mobility)-diffusion equations for charged particles and excited heavy neutral species are solved along with Poisson's equation, a radiation transport equation, a surface charge buildup equation, and an external L-R-C circuit equation using a fully implicit numerical method. Electron-driven rate coefficients are computed with a 0-D Boltzmann solver in the local field approximation. For studying the particle dynamics in pure helium, we consider a reduced model in which radiation transport is ignored and the excited species manifold is collapsed to composite metastable and excited states. The model predictions of breakdown voltage are quite sensitive to the value of the secondary electron emission coefficient assumed and the uncertainties in the electron-driven reaction rates. An initial comparison between the model predictions and I-V measurements from a specially constructed helium-filled panel is made with qualitatively similar behavior. The lack of quantitative agreement can be explained by a combination of uncertainties in the model input data and uncertainty in the initial surface charge state in the experiments     

Large-gap AC coplanar plasma display cells: macro-cell experiments and 3-D simulations

We present experimental and simulation studies of the plasma in a macroscopic AC plasma display panel discharge cell operating with a large coplanar gap. We find that the xenon excitation efficiency is much larger than that in the conventional, small-gap electrode configuration but with larger sustaining voltage. We discuss the discharge mode and efficiency in such large gap configurations, with the help of time resolved optical diagnostics and simulations.     

Experimental observation of dust circulation in unmagnetized cogenerated dusty plasma

The vortex motion of a dust cloud was experimentally observed in unmagnetized cogenerated dusty plasma in different experimental parameters. Particle image velocimetry analysis demonstrated that several vortex zones exist in the dust cloud at relatively low pressures (0.06 mbar (or 6 Pa)–0.08 mbar (or 8 Pa)) and low discharge voltages (peak‐to‐peak voltage 540–560 V), whereas in relatively high pressure (0.4 mbar (or 40 Pa)–0.7 mbar (or 70 Pa)) and high discharge voltage (peak‐to‐peak voltage 690–740 V), dust vortices formed in dense dust cloud with background plasma fluctuation.     

Influence of charge deposition in a field-emission display panel

Field-emission displays (FEDs) have been studied intensively in recent years as a candidate for flat-display panels in the future. In a FED, electrons emit from field emitters. Some electrons may impinge on the insulator surface between cathode and gate electrodes and cause charging of that surface because the yield of secondary electron emission is usually not equal to one. The charging of the insulator walls between cathode and gate electrodes is one of the important factors influencing the performance of a FED. In this paper, a simulation program is used to calculate this charge deposition, electric field distribution and electron trajectories. From the change of the electric field upon charge deposition in the triode region, it is shown that the insulator surface is negatively charged at a low gate voltage, e.g. 20 V. However, positive charge is deposited when the gate voltage is high, e.g. 100 V. The simulations also show that the emission current will increase even further after coating the dielectric with a thin film of a material with a high-secondary emission coefficient such as MgO. If a cone-shaped dielectric aperture is used in a triode, the emission current will decrease after charge deposition. However, the focus performance of the electron beam is improving in this case.     

Experimental observation of radiation from cherenkov wakes in a magnetized plasma

A proof-of-principle experiment demonstrates the generation of radiation from the Cherenkov wake excited by an ultrashort- and ultrahigh-power pulse laser in a perpendicularly magnetized plasma. The frequency of the radiation is in the millimeter range (up to 200 GHz). The intensity of the radiation is proportional to the magnetic field intensity as expected by theory. Polarization of the emitted radiation is also detected. The difference in the frequency of the emitted radiation between these experiments and previous theory can be explained by the electrons' oscillation in the electric field of a narrow column of ions in the focal region.     

Experimental observation of nonlinear ion - acoustic resonances in bounded plasma

The response of well matched Nb point-contract junctions, with a relatively small ratio of barrier and noise energy, has been measured at 35 GHz and is compared with theories on Josephson tunneling in the presence of strong fluctuations.     

Experimental observation of enhanced stopping of heavy ions in a hydrogen plasma

Zeitschrift für Physik A Hadrons and nuclei - Enhanced energy loss of 333 MeV 238Uions in a hydrogen discharge plasma with a high degree of ionization has been observed. The ion stopping in a...