Influence of wall charge on image sticking phenomena in AC plasma display panels

This paper investigates the image sticking phenomenon in an AC plasma display panel (PDP), which appears when the PDP is subjected to a strong sustain discharge for an extended time and leaves a residual image on the display. This problem is very difficult to resolve using a conventional reset. Image sticking was investigated by observing the light emission from the reset, indicating that the wall charges accumulated on the sustain electrodes were the major cause. A few face (plate-gap) discharges equated the wall voltages on the sustain electrodes and set all cells of the PDP at the same external voltage for firing a surface discharge. The image sticking phenomenon disappeared after the face discharges.     

Radio‐frequency plasma‐display cell

Abstract— This paper demonstrates that it is possible to improve the basic parameters of plasma displays (efficiency, primarily) using AC voltages with frequencies so high that the amplitude of the electron‐drift oscillations is smaller than the inter‐electrode gap. In this case, the voltage drop on sheaths is much smaller than that in the low frequency or DC discharge and, correspondingly, the energy losses in ion heating are also small. Electron losses in the RF discharge are of the diffusion character and sufficiently lower than the losses in a typical AC plasma‐display panel (AC PDP), in which the electron drift to the electrodes is predominant. Hence, the energy cost of gas ionization in the cells of radio‐frequency PDPs (RF PDPs) is also rather low. In the long run, about 80% of the energy absorbed in the RF discharge goes into excitation of the energy level of a Xe atom, yielding UV radiation. The experiments performed show that efficiency of a RF PDP is five times higher than the efficiency of existing AC PDPs and DC PDPs and can exceed 5 lm/W.     

Space and time evolution of the plasma in a PDP cell: Comparisons between simulations and experiments

We have used a macroscopic discharge cell to study the space and time evolution of the plasma in geometry similar to real matrix and coplanar PDP cells with a scaling factor of around 100 (dimensions 100 times larger, pressure 100 times smaller, i.e., 1‐cm gap length, 5‐torr pressure). Discharges in pure neon and in a xenon‐neon mixture with 10% xenon have been investigated. The measurements have been compared with results from a two‐dimensional fluid model of the discharge.     

Laser Thomson scattering and optical emission studies of striated PDP micro‐discharge plasmas

Abstract— Properties of a plasma‐display‐panel (PDP) like discharge were examined by emission and laser Thomson scattering (LTS) measurements. Emission measurements were performed using an intensified CCD camera. By varying several external parameters such as the amplitude of the input voltage, gas composition, and pressure, the influence of these parameters on the discharge behavior was studied. Results of emission measurements showed that they were in good agreement with similar emission measurements on real PDP cells. LTS measurements were performed for the striated PDP‐like discharge at a pressure of 100 Torr and the results showed clear modulations in both profiles of electron density and electron temperature.     

Improved discharge characteristics using MgO single‐crystal particles and advanced CEL structure

Abstract— Pioneer Corporation introduced plasma‐display‐panel (PDP) TVs in 2005, which achieved the highest dark‐room contrast ratio of 4000:1 at the time. These PDPs had a novel discharge cell structure consisting of a crystal emissive layer (CEL) on a MgO protective thin film. This cell structure is refered to as a CEL structure. Magnesium‐oxide single‐crystal particles, which have a unique luminance peak around 230–250 nm and a good exo‐electron‐emission property, were found to be an excellent material for CEL and were utilized in CEL panels. In 2007, newly developed PDP TVs in which CEL was formed on a phosphor layer, in addition to the previous CEL structure, were introduced, and this discharge cell structure is refered to as advanced CEL structure. By using the new cell structure, the opposed discharge characteristics have been drastically improved, and a stable reset discharge has been realized with only a weak opposed discharge. As a result, black luminance has been drastically reduced, and a dark‐room contrast ratio of over 20,000:1, the highest ever reported, has been achieved.     

Investigation of the firing voltage in a shadow‐mask PDP

Abstract— A numerical method was used to investigate the firing characteristics of the discharge cell in an AC shadow‐mask PDP (SM‐PDP). The firing voltages for the various discharge paths in the addressing and sustaining periods were calculated, and the effects of the metal barrier rib and the dielectric layer in the discharge cell on the firing characteristics were studied. Furthermore, the advantages of the SM‐PDP in terms of the firing characteristics will be discussed.     

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.     

High‐efficacy drive of spatial positive‐column‐discharge PDP with delayed D pulses

Abstract— A thick‐film ceramic‐sheet PDP provides a long sustain discharge gap of 0.45 mm, enabling the use of positive column discharges. The discharges are established in the middle of the discharge space and are completely free from touching the surface of substrates. This allows for the reduction in diffusion losses of the charged particles. To further improve the efficacy, delayed D pulses are applied to the address electrodes during the sustain period. Although the pulses only draw a little current, they perturb the electric field, reducing the peak discharge current and hence resulting in higher efficacy and luminance. The efficacy and luminance increase by 35% and 38%, respectively, with the delayed D pulses. These pulses are incorporated into the contiguous‐subfield erase‐addressing drive scheme for TV application. A short gap of 70 μm between the sustain and data electrodes generates a fast‐rising discharge and allows a high‐speed addressing of 0.25 μsec. This provides 18 contiguous subfields for the full‐HD single‐scan mode, with 70% light emission duty. A luminous efficacy of 6.0 lm/W can been attained using Ne + 30% Xe 47 kPa, a sustain voltage of 320 V, and a sustain frequency of 3.3 kHz, when the luminance is 157 cd/m². Alternatively, the panel can achieve 4.2 lm/W and 1260 cd/m² by increasing the sustain frequency to 33 kHz.     

Improvement of PDP discharge efficiency based on macro‐cell studies

Abstract— In this paper we explain how macro‐cells (real PDP cells scaled‐up a hundred times) with external and removable electrodes have been validated by comparison with real panels and modeling and used to optimize the luminous efficacy of real PDPs. We illustrate the application of the macroscopic PDP tool to optimize the electrode configuration of short‐gap discharges towards higher luminous efficacy, as well as its use in conjunction with 2D and 3D modeling to lower the operating voltages of high‐efficacy long‐gap discharges triggered by auxiliary electrodes.     

Effect of single crystalline MgO powder treatment of phosphor surface on discharge property of high-Xe AC plasma display panels

This paper presents a method of surface treatment of phosphor using a single crystalline MgO powder, and investigates effect of the surface treatment on discharge property of a plasma display panel (PDP). The discharge gas of the PDP was a 88% Ne–12% Xe gas mixture at a pressure of 400 Torr. For the surface treatment, a single crystalline MgO powder was mixed in methanol, sprayed on the phosphor surface, and annealed at 400 °C. This treatment suppressed glow discharge, which was observed very often in the weak discharges for reset of PDP if the phosphor works as a cathode, and provided a favorable condition for the PDP reset operation. When an experimental PDP fabricated using the surface treatment was driven by the twin reset waveform, the measured time delay for 99.9% cumulative probability of address discharge was 830 ns, which meets the timing requirement for addressing a Full HD (1920 × 1080 resolution) PDP with the 10 sub-field single scan method.     

High‐performance MgO thin films for PDPs with a high‐rate sputtering‐deposition process

Abstract— A high‐rate sputtering‐deposition process for MgO thin films for PDP fabrication was recently developed. The deposition rate of the MgO thin film was about 300 nm/min which shows the possibility of production‐line application. The MgO film deposited in this work has a higher density than that of other deposition processes such as electron‐beam deposition and shows good discharge characteristics including firing voltage and discharge formation. These were achieved by controlling the stoichiometry and/or the impurity doping during the sputtering process.     

Use of self‐erase discharges for high‐speed and low‐voltage addressing of PDPs

Abstract— A technique called “self‐erase‐discharge addressing” has been incorporated with a address‐while‐display driving scheme, contiguous subfield, and erase addressing to obtain high‐speed and low‐voltage addressing of PDPs. The technique uses a relatively high X‐sustain pulse voltage VXsus, which produces a weak self‐erase discharge at its trailing edge. An application of a data pulse Vdata synchronous to a weak self‐erase discharge results in full erase discharge and eliminates all the wall charges. The technique assures a wider operating‐voltage margin since it provides identical amounts of priming charges as well as wall charges to all the horizontal scan lines just prior to addressing. The priming charges are generated by the weak self‐erase discharges, resulting in low Vdata of 30 V and a high addressing speed of 0.66 μsec for a Ne + 10% Xe PDP. V_Xsus = 245 V, and the voltage margins of Vdata and VXsus were 35 and 16 V, respectively. For a 30% Xe PDP, Vdata and VXsus were 30 and 335 V, respectively, with an addressing speed of 1.0 μsec. In order to obtain high dark‐room contrast, it is essential to use ramp reset pulses, with which erase addressing cannot be achieved. By adopting the write addressing only to the first subfield and the self‐erase‐discharge addressing to the subsequent subfields, a peak and background luminance in green of 3100 and 0.22 cd/m², respectively, were obtained with a dark‐room contrast of 14,000:1. The number of subfields was 28, and the light emission duty was 83%. The number of ramp reset pulse drivers could be reduced to 12 by adopting the common reset pulse technique.     

A 25‐in. SMPDP with fine pitch and high resolution

Abstract— A 25‐in. SMPDP with fine pitch and high resolution has recently been developed as a succession of the 34‐in. SMPDP, which had been exhibited at ASID '04. SMPDP was regarded as a hopeful low‐cost PDP solution. The new pitch size of 0.66 mm realized an SVGA resolution on this 25‐in. SMPDP, and it also promises HDTV‐resolution compatibility for a 42‐in. SMPDP. The discharge cell has been re‐designed and the delta‐type arrangement of discharge cells has been applied, which provides more display area and facilitates the panel fabrication as well. Other modifications, such as the bus‐electrode structure and the alternatives of the glass material for substrates, have been tested. A peak luminance of 500 cd/m² and a total power consumption of 100 W has been achieved for the 25‐in. SMPDP sample.     

Discharge striations on a coplanar AC‐PDP

Abstract— Observations suggest that the discharge striations in a coplanar AC‐PDP are related to the ion wall‐charge waves generated by the self‐sustained perturbations during the force‐balancing between the ion and the electron wall charge accumulated on the dielectric layer over the electrodes.     

Effects of diamond and AlN layers inserted beneath the phosphor layer on the discharge characteristics of PDPs

Abstract— In this study, the effects of diamond and AlN layers inserted beneath the phosphor layer of the rear plate of a PDP were investigated. The layers were formed via an osmotic‐pressure coating process. Macrocells and test panels were prepared to examine their effects on luminance and luminous efficacy. The results indicate that the layers primarily affect the glow‐discharge behavior and eventually enhance the luminous efficacy of the PDP, suggesting the possibile improvement in the performance of PDPs.     

New electrode structure for reducing power consumption of PDPs

Abstract— A new electrode structure for plasma‐display panels (PDPs) is proposed, which decreases the panel capacitance by effectively decreasing the electrode area and increasing the discharge efficacy. Although the electrode area is decreased, the proposed structure does not require an increase in operating voltage and can improve the discharge efficacy by limiting the discharge current. The effect of panel capacitance reduction of the suggested electrode structure contributes to power‐consumption reduction in the entire PDP system by reducing the dissipative power due to the charging current of the panel capacitance. The effects of panel‐capacitance reduction by using the new electrode structure were confirmed by comparing the charging‐current waveforms and directly measuring the capacitances of various panels with conventional and new electrode structures.     

Discharge efficiency of a 25‐in. high‐resolution SMPDP

Abstract— A novel round subpixel and triangle‐arrangement shadow‐mask plasma‐display panel (SMPDP) suitable for high‐resolution displays has been investigated. The discharge efficiency of this high‐resolution SMPDP and the AC coplanar PDP (ACCPDP) has been calculated separately. The variance of the discharge efficiency with pressure and xenon content will be reported. Results indicate that the SMPDP can reach a higher efficiency for high‐resolution displays than conventional ACCPDPs.     

Improvement in luminance,luminous efficiency,driving margin,and operational lifetime of HD PDPs by using discharge deactivation film

Abstract— We have improved our 116‐cm HD PDP in many respects by using DDF formed on MgO around the display line boundaries. The DDF allows an extremely narrow inter‐pixel gap even for a stripe‐rib structure because it prohibits vertical crosstalk discharge. The DDF combined with a stripe‐rib structure results in the best address discharge response. Thus, a very wide driving margin area is achieved, allowing for a high percentage of Xe. The preferable sustain electrode shape follows the CAPABLE DDF style, where the principal discharge portion is separated from the bus via a slim bridge. This cell configuration proved to be excellent in operational life testing with respect to DDF as well as in manufacturing process margin. By employing both a thinner dielectric layer and a TiO₂reflective underlayer for phosphor, the address response is further improved so that Xe15% vol. is available from the viewpoint of the driving margin. Thus, we achieved a white peak luminance of 1220 cd/m² and a luminous efficiency of 2.16 lm/W simultaneously despite of an applied sustain voltage as low as 185 V. We foresee that they will be soon as high as 1400 cd/m² and 2.5 lm/W by modifying the sustain electrode style.     

Effects of shadow‐mask voltage on the discharge in shadow‐mask PDPs

Abstract— A new type of ACPDP with a shadow mask (shadow‐mask PDP, SMPDP) has been developed, featuring an effective structure and lower cost. The distinct difference between an SMPDP and a conventional ACPDP is that the dielectric barrier ribs are replaced by a single metal shadow mask. A three‐dimensional self‐consistent fluid model was used to analyze the effects of the shadow‐mask voltage on the discharge for a simplified driving scheme. The simulation results indicate that by selecting the appropriate shadow‐mask voltage, the addressing speed can be improved due to the local strong electric field. The steady discharge in the sustaining period will not be affected by changes in the shadow‐mask voltages in the addressing period. While in the sustaining period, the shadow‐mask‐voltage variation can directly affect the sustaining discharge. The floating shadow mask in the sustaining period is beneficial in achieving a stable sustaining discharge.     

Power-efficient drive circuit for plasma display panel

This paper proposes a power-efficient drive circuit for plasma display panels (PDPs). The proposed circuit reduces reactive power consumption by varying the inductance for energy recovery and by separating the grounds of the sustain and data drivers. Power consumption due to discharge current is reduced by using two soft-switching inductors for the pull-up switches in the bridge circuit. Power consumption for data addressing is reduced by using a dc voltage source to bias the ground for the sustain driver. The proposed circuit was tested on a 50″ full-HD single-scan PDP which had a sustain discharge gap of 80 μm; total power consumption to display the dynamic broadcasting content of IEC 62087 was ∼40 W (14.5%) less than that required by the conventional drive circuit, and the EMI level for 2 < f < 9 MHz was reduced significantly. The experimental results demonstrate that a high performance power-efficient PDP drive circuit can be built using the proposed method.