In this paper, we describe the principles of operation of a plasma display panel (PDP) and the physical mechanisms controlling the performances of a PDP in terms of light emission efficiency, lifetime and image quality Emphasis is put on the physics of the plasma occurring in a PDP cell, on the discharge optimization, and on the analysis of recent results provided by experimental and numerical diagnostic tools We focus on alternative current PDPs, where the plasma is generated by a dielectric barrier discharge, the configuration adopted by most PDP companies The recent improvements and the remaining research issues are discussed

http://plasmapanel.grid.umich.edu/articles/0022-3727_36_6_201.pdf

Plasma display panels: physics, recent developments and key issues

In this paper, we give a detailed review of recent work carried out on the numerical characterization of non-thermal gas discharge plasmas in air at atmospheric pressure. First, we briefly describe the theory of discharge development for dielectric barrier discharges, which is central to the production of non-equilibrium plasma, and we present a hydrodynamic model to approximate the evolution of charge densities. The model consists of the continuity equations for electrons, positive and negative ions coupled to Poisson's equation for the electric field. We then describe features of the finite element flux corrected transport algorithm, which has been developed to specifically aim for accuracy (no spurious diffusion or oscillations), efficiency (through the use of unstructured grids) and ease of extension to complex 3D geometries in the framework of the hydrodynamic model in gas discharges. We summarize the numerical work done by other authors who have applied different methods to various models and then we present highlights of our own work, which includes code validation, comparisons with existing results and modelling of radio frequency systems, dc discharges, secondary effects such as photoionization and plasma production in the presence of dielectrics. The extension of the code to 3D for more realistic simulations is demonstrated together with the adaptive meshing technique, which serves to achieve higher efficiency. Finally, we illustrate the versatility of our scheme by using it to simulate the transition from non-thermal to thermal discharges.We conclude that numerical modelling and, in particular, the extension to 3D can be used to shed new light on the processes involved with the production and control of atmospheric plasma, which plays an important role in a host of emerging technologies.

https://iopscience.iop.org/article/10.1088/0022-3727/38/20/R01/pdf

Numerical modelling of atmospheric pressure gas discharges leading to plasma production

Fluid, particle-in-cell and hybrid models are the numerical simulation techniques commonly used for simulating low-temperature plasma discharges. Despite the complexity of plasma systems and the challenges in describing and modelling them, well-organized simulation methods can provide physical information often difficult to obtain from experiments. Simulation results can also be used to identify research guidelines, find optimum operating conditions or propose novel designs for performance improvements. In this paper, we present an overview of the principles, strengths and limitations of the three simulation models, including a brief history and the recent status of their development. The three modelling techniques are benchmarked by comparing simulation results in different plasma systems (plasma display panels, capacitively coupled plasmas and inductively coupled plasmas) with experimentally measured data. In addition, different aspects of the electron and ion kinetics in these systems are discussed based upon simulation results.

https://www3.nd.edu/~sst/teaching/AME60637/reading/2005_JPDAP_Kim_Iza_Yang_particle_fluid_modeling.pdf

Particle and fluid simulations of low-temperature plasma discharges: benchmarks and kinetic effects

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.

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

This paper compares the performance and limitations of different models of the cathode region of cold-cathode low-pressure dc glow discharges: (i) we review known modelling approaches, (ii) develop our own simulation codes based on these approaches, (iii) perform calculations using these codes for reference sets of discharge conditions, which allows a critical comparison of the models and (iv) for a further check of the simulation results we carry out Langmuir probe measurements of electron densities in abnormal Ar glow discharges. The theoretical approaches include fluid models both neglecting and including the electron energy balance equation, as well as hybrid models, which combine the fluid treatment of slow plasma species with the kinetic simulation of fast electrons. We also test the effect of the choice of the ionization source term in fluid models. We find that the electron densities calculated from the fluid models are far (several orders of magnitude) below the experimental values even if the electron energy equation is considered in the calculations. This weakness of fluid models clearly points out the importance of an accurate calculation of the ionization source term, which can only be accomplished by a kinetic approach under the conditions of highly nonlocal electron transport in the cathode region of glow discharges. In hybrid models Monte Carlo simulation is used for this purpose, and indeed, this approach gives electron densities comparable to our experimental data.

/pdf/on-the-accuracy-and-limitations-of-fluid-models-of-the-y2p4qoi2wh.pdf

On the accuracy and limitations of fluid models of the cathode region of dc glow discharges

In order to understand the discharge characteristics in an alternating current plasma display panel (ac PDP) and optimize it further, a three-dimensional fluid code (FL3P) has been developed. Using this simulator, various three-dimensional features of discharges are investigated in the sustain mode of PDP. First, the striations of wall charge are observed at both the anode and cathode side. Second, the local efficiency is obtained as a function of position. It is mainly divided into the anode region and the cathode region and highest near the anode center. Finally, the effects of various three-dimensional parameters are studied. As one of the examples showing the effect of electrode shaping, the discharge characteristics of a T-shaped electrode cell are compared with those of a conventional cell. The phosphor on barrier ribs contributes to over 44% of the total luminance, but barrier ribs themselves do not play an important role in the overall discharge efficiency. Address electrode width is not always pr...

/pdf/three-dimensional-fluid-simulation-of-a-plasma-display-panel-1x7z0j06ln.pdf

Three-dimensional fluid simulation of a plasma display panel cell

After three years of upgrading work, the Pohang Light Source-II (PLS-II) is now successfully operating. The final quantitative goal of PLS-II is a top-up user-service operation with beam current of 400 mA to be completed by the end of 2014. During the beam store test up to 400 mA in the storage ring (SR), it was observed that the vacuum pressure around the radio frequency (RF) window of the superconducting cavity rapidly increases over the interlock level limiting the availability of the maximum beam current storing. Although available beam current is enhanced by setting a higher RF accelerating voltage, it is better to keep the RF accelerating voltage as low as possible in the long time top-up operation. We investigated the cause of the window vacuum pressure increment by studying the changes in the electric field distribution at the superconducting cavity and waveguide according to the beam current. In our simulation, an equivalent physical modeling was developed using a finite-difference time-domain code. The simulation revealed that the electric field amplitude at the RF window is exponentially increased as the beam current increases, thus this high electric field amplitude causes a RF breakdown at the RF window, which comes with the rapid increase of window vacuum pressure. The RF accelerating voltage of PLS-II RF system was set to 4.95 MV, which was estimated using the maximum available beam current that works as a function of RF voltage, and the top-up operation test with the beam current of 400 mA was successfully carried out.

Studies and optimization of Pohang Light Source-II superconducting radio frequency system at stable top-up operation with beam current of 400 mA

Design of a Low-Q S-Band Cavity Beam Position Monitor

A new light source based on the electron storage ring, dubbed the “diffraction-limited storage ring” (DLSR) to keep the full intrinsic wave nature of X-rays had been proposed since the early stage of storage ring history and has finally been developed successfully, and an upgrade and a new construction programs have now chosen in the worldwide synchrotron facilities. The construction of the so-called “4th generation storage ring” (4GSR), which is a newly-coined term aiming in the same direction, was decided in Korea. The Korean 4GSR is expected to be 10–100 times brighter than the Pohang Light Source-II (PLS-II). Hard X-ray undulator beamlines will benefit from the 4GSR due to its low emittance approaching the diffraction limit. In the PLS-II, more than 10 hard X-ray undulator beamlines are currently in operation. We present a comparative study of the representative hard X-ray undulator beamlines by using the cutting-edge diffraction-spectroscopy techniques in the PLS-II and the 4GSR for better understanding the upcoming light source in Korea. The figures-of-merit of the two specific experimental techniques, resonant inelastic X-ray scattering (RIXS) and resonant X-ray emission spectroscopy (RXES), are discussed for comparison of the two light sources. Both RIXS and RXES are sometimes referred to as a “renaissance” in X-ray science and are, therefore, strongly expected to be adopted in the 4GSR beamlines.

/pdf/comparative-study-of-hard-x-ray-undulator-beamline-58ano4ee5u.pdf

Comparative study of hard X-ray undulator beamline performance in the Korean 4GSR and the PLS-II

The beam stability is one of the most important issues for the user service of the synchrotron radiation facility. After the upgrade of the Pohang Light Source (PLS-II), the electron-beam orbit is maintained within a root-mean-squred (rms) 1-μm range by using an orbit feedback system. However, that does not guarantee the radiation stability at the end of the beamline because unknown factors, such as focusing mirrors and double-crystal monocrometers, are present in the beamline. As a first step to solve this problem, photon-beam-position monitors (PBPMs) are installed in the front ends of the beamline to monitor the radiation stability. If the radiation is stable at the starting point of the beamline, we can move to the other components downstream that make the radiation unstable. In this paper, a correlation study will be presented between the beam-position monitor (BPM) and the PBPM. In addition, the effect of the orbit feedback system on the correlation will be described.

Seunghwan Shin

Papers

Three-dimensional fluid simulation of a plasma display panel cell

Studies and optimization of Pohang Light Source-II superconducting radio frequency system at stable top-up operation with beam current of 400 mA

Design of a Low-Q S-Band Cavity Beam Position Monitor

Comparative study of hard X-ray undulator beamline performance in the Korean 4GSR and the PLS-II

Correlation study of a beam-position monitor and a photon-beam-position monitor in the PLS-II