Chunliang Liu

Influence of ZrO2 addition on the microstructure and discharge properties of Mg–Zr–O protective layers in alternating current plasma display panels

Mg–Zr–O protective layers for alternating current plasma display panels were deposited by e-beam evaporation. The effect of the ZrO2 addition on both the discharge properties [firing voltage Vf, minimum sustaining voltage Vs, and memory coefficient (MC)] and the microstructure of deposited Mg–Zr–O films were investigated. The results show that the film microstructure changes and the electron emission enhancement due to the ZrO2 addition are the main reasons for the improvements of the discharge properties of Mg–Zr–O films. A small amount of Zr solution in MgO under its solid solubility can effectively increase the outer-shell valence electron emission yield so as to decrease Vf and Vs compared with using a pure MgO protective layer. The ZrO2∕(MgO+ZrO2) ratio has a great effect on the film surface conditions. Proper surface morphologies make a good contribution to obtain large MC in accordance with lower firing voltage.

A Line Array of Microplasma Devices With Coplanar Electrodes Operating in Argon

A line array of microplasma devices with coplanar electrodes has been fabricated, and the discharge characteristics of the microplasma devices under different argon pressures were investigated in experiments which were driven by sinusoidal voltage and alternating pulse voltage, respectively. The microcavities of the proposed device are composed of two coplanar electrodes instead of dielectric or single cathode. The voltage-current characteristics of the device driven by sinusoidal voltage show that the power loading of each microcavity could reach several kilowatts per cubic centimeter. Driven by alternating pulse voltage, the device performed a trend that the discharge current grows up first and then goes down gradually with the increase of operation pressure. Moreover, with the increase of driven frequency, the device operated with high discharge stability on both time and intensity. The proposed device possesses the advantages of simple structure and simple fabrication processes.

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.

Microplasma mode transition and corresponding propagation characteristics controlled by manipulating electric field strength in a microchannel-cavity hybrid structure device

Plasma redistribution in a symmetric microchannel-cavity hybrid structure device has been investigated by modulating the applied electric field strength. The device array has been operated in 200 Torr of argon, driven by a 20 kHz bipolar waveform. With the existence of the intervening microchannel between microcavities, several stable modes of operation of the microplasma have been observed, including cavity mode, hybrid mode and channel mode. Transition between the modes occurs with modulation of the applied voltage from 800 to 1100 V. The characteristics of microplasma propagation in different modes are investigated and the propagation speed along diagonal direction of the device in cavity mode, hybrid and channel mode are calculated to be ~48, ~29 and ~32 km s−1, respectively. Nonhomogeneous electric field strength distribution and plasma interaction have been discussed to explain these experimental results. Emission intensity and propagation speed differences in the cavity mode between the polarities of the applied voltage are interpreted through spatially resolved measurements of the emission profile in a partial channel-cavity array.

Perturbation and coupling of microcavity plasmas through charge injected into an intervening microchannel

Coupling between two microcavity plasmas in a symmetric, microfabricated dielectric barrier structure has been observed by injecting charge from one of the plasmas into an intervening microchannel. Periodic modulation of the electric field strength in the injector (or electron “donor”) cavity has the effect of deforming the acceptor microplasma which exhibits two distinct and stable spatiotemporal modes. Throughout the time interval in which the two microplasmas are coupled electrostatically, the acceptor plasma is elongated and displaced by 75–100 μm (∼30% of its diameter) in the direction of the microchannel. The depletion of charge in the microchannel results in an immediate transition of the second (acceptor) microplasma to an equilibrium state in which the plasma is azimuthally symmetric and centered within its microcavity. Switching between these two spatial modes requires a shift (in the plasma centroid) of ∼80 μm in <50 ns which corresponds to a velocity of 1.6 km/s. Precise control of this plasma...

Discharge dynamics of self-oriented microplasma coupling between cross adjacent cavities in micro-structure device driven by a bipolar pulse waveform

The excitation dynamics and self-oriented plasma coupling of a micro-structure plasma device with a rectangular cross-section are investigated. The device consists of 7 × 7 microcavity arrays, which are blended into a unity by a 50 μm-thick bulk area above them. The device is operated in argon with a pressure of 200 Torr, driven by a bipolar pulse waveform of 20 kHz. The discharge evolution is characterized by means of electrical measurements and optical emission profiles. It has been found that different emission patterns are observed within microcavities. The formation of these patterns induced by the combined action between the applied electric field and surface deactivation is discussed. The microplasma distribution in some specific regions along the diagonal direction of cavities in the bulk area is observed, and self-oriented microplasma coupling is explored, while the plasma interaction occurred between cross adjacent cavities, contributed by the ionization wave propagation. The velocity of ionization wave propagation is measured to be 1.2 km/s to 3.5 km/s. The exploration of this plasma interaction in the bulk area is of value to applications in electromagnetics and signal processing.The excitation dynamics and self-oriented plasma coupling of a micro-structure plasma device with a rectangular cross-section are investigated. The device consists of 7 × 7 microcavity arrays, which are blended into a unity by a 50 μm-thick bulk area above them. The device is operated in argon with a pressure of 200 Torr, driven by a bipolar pulse waveform of 20 kHz. The discharge evolution is characterized by means of electrical measurements and optical emission profiles. It has been found that different emission patterns are observed within microcavities. The formation of these patterns induced by the combined action between the applied electric field and surface deactivation is discussed. The microplasma distribution in some specific regions along the diagonal direction of cavities in the bulk area is observed, and self-oriented microplasma coupling is explored, while the plasma interaction occurred between cross adjacent cavities, contributed by the ionization wave propagation. The velocity of ionizat...

Two-stage dither to enhance gray scales based on real-time motion detection in plasma display panel

Abstract In order to reduce gray scale loss in low and middle-high gray scale ranges which are caused by inverse gamma conversion and limited gray scale method for dynamic false contour (DFC) improvement, respectively, and enhance gray scales both in static and moving regions of an image, two-stage dither based on real-time motion detection method is proposed. Firstly, the image is divided into blocks, and the motion state of each image block is detected according to real-time motion detection method. So limited gray scale method to improve DFC can only be used in moving image blocks. Then, ordered dither and random dither combined with minor pixel separation (MPS) are used to improve gray scale loss caused by inverse gamma conversion and limited gray scale method, respectively. The experimental results show that motion detection can be implemented easily and the detection accuracy is more than 99.3%. The gray scales in moving and static image regions are all expressed smoothly while DFC is markedly improved.

Multiple Voltage Driving Method for Reducing Invalid Power Caused by Unlighted Lines in PDPs

Sustain power consumed by unlighted lines in displayed image in each subfield is totally wasted. To improve the power efficiency, multiple sustain voltages applied to lighted and unlighted lines separately are proposed, which can reduce invalid power by decreasing the sustain voltage in unlighted lines. Different sustain voltages are used to testify the proposed method. The instance circuit operation mode is analyzed. The experimental results show that power saving efficiency can be improved by 4.5% when 10-min-long standard video supplied by the International Electrotechnical Commission displays in 50-in plasma display panel. The proposed method is easy implemented and the additional cost is very low compared with conventional circuit.

Self-sustaining discharge condition of Penning gases mixture in plasma display panels

Discharging characteristics of Penning gases mixture in plasma display panels can not be described correctly with the self-sustaining discharge conditions which did not consider the influence of Penning ionization. On the basis of Townsend breakdown criteria and the chemical kinetics analysis of Penning gases mixture discharging in plasma display panels, empirical equation of self-sustaining discharge condition for Penning gases mixture was given. The firing voltage Uf and effective secondary electron emission coefficient /spl Upsi//sub eff/ values of Ne-Xe/MgO and Ne-Ar/MgO in testing macroscopic discharge cell of AC-PDP were calculated by this empirical equation. In comparison with the voltage characteristics calculated by Paschen law and the equation which did not consider the influence of Penning ionization on electron ionization coefficient a, the results calculated by the empirical equation had better conformity with experimental data. The empirical equation gave a new approach to research discharge characteristics of penning gases mixture and the secondary electron emission behaviors in plasma display panels.