Gerrit Oversluizen

Improvement of the discharge efficiency in plasma displays

The dependence of the efficacy of an alternating current surface-discharge plasma display panel on the gas pressure is investigated for several Xe–Ne gas mixtures. In monochrome green 4 in. test panels the efficacy trends and emission spectra are examined for increasing gas pressure and/or Xe concentration. The measured panel efficacy and emission characteristics are compared with the results of a numerical discharge model. It is found that the discharge efficiency for the cell geometry used in present-day commercial products can be increased significantly by using a larger Xe partial pressure. An increase of the electron heating efficiency and of the Xe excitation efficiency contribute about equally to the efficacy increase. The contribution of the increasing Xe dimer radiation fraction to the efficacy improvement is relatively small. These findings are applied in a 4 in. color test display with a design that resembles the one used in present-day commercial products and contains a gas mixture of 13.5% Xe...

Influence of the noble gas mixture composition on the performance of a plasma display panel

The influence of the noble gas mixture composition on the plasma display panel performance is investigated in test panels with a design which resembles the one used in commercial panels. Single gases and binary and ternary mixtures of He, Ne, Ar, Kr, and Xe are applied, where the Xe concentration is varied from 0% to 100%. The performance is characterized in terms of the panel luminance, efficacy, and discharge voltages. It is found that while an increase in efficacy and luminance can be achieved in several multicomponent mixtures it is necessary to examine the associated increase in the firing voltage, Vf. If one considers the luminance versus Vf dependence, then binary NexXe1−x mixtures are optimal to achieve the highest efficacy values at the lowest Vf. The maximum efficacy gain factor in high Xe partial pressure mixtures is about a factor of 3 with respect to the mixture applied in default commercial panels.The influence of the noble gas mixture composition on the plasma display panel performance is investigated in test panels with a design which resembles the one used in commercial panels. Single gases and binary and ternary mixtures of He, Ne, Ar, Kr, and Xe are applied, where the Xe concentration is varied from 0% to 100%. The performance is characterized in terms of the panel luminance, efficacy, and discharge voltages. It is found that while an increase in efficacy and luminance can be achieved in several multicomponent mixtures it is necessary to examine the associated increase in the firing voltage, Vf. If one considers the luminance versus Vf dependence, then binary NexXe1−x mixtures are optimal to achieve the highest efficacy values at the lowest Vf. The maximum efficacy gain factor in high Xe partial pressure mixtures is about a factor of 3 with respect to the mixture applied in default commercial panels.

High-Xe-content high-efficacy PDPs

The trade-off between PDP efficacy improvement and driving voltages was investigated for several design factors. It was found that for a proper combination of an increased Xe content, cell design, and the use of a TiO 2 layer combined with non-saturating phosphors, a large increase in both efficacy and luminance can be realized at moderately increased drive voltages. In a 4-in. color test panel, a white efficacy of 5 lm/W and a luminance of 5000 cd/m 2 was obtained for sustaining at 260 V in addressed condition.

Plasma display panel design for simultaneous high efficacy and high luminance

The plasma display panel efficacy is known to decrease at high luminance, due to both phosphor and plasma saturation. Especially the default green phosphor Willemite is sensitive to saturation. It is shown that an alternative green phosphor, Y1−xGdxBO3:Tb3+, is less sensitive to saturation than Willemite. Also plasma saturation is decreased in a “high efficiency discharge mode,” for design and driving conditions that govern a fast and spatially distributed discharge development. High Xe-content panels, with somewhat higher drive voltages, are especially suited for operation in this discharge mode. Further, in the high efficiency discharge mode a high luminance is obtained, enabling high resolution designs with a relatively small emissive area. For proper designs, operating in the high efficiency discharge mode and using less saturating phosphors, the combination of a high efficacy and a high luminance is achieved. For VGA resolution 5 lm/W and 5000 cd/m2 and for XGA resolution 4 lm/W concurrent with a lum...

5.1: Invited Paper: High Efficacy PDP

The trade-off between PDP panel efficacy improvement and driving voltages is investigated for several design factors. It is found that for a proper combination of an increased Xecontent, cell design, and the use of a TiO2-layer combined with “non-saturating” phosphors, a large increase of both efficacy and luminance can be realized at moderately increased drive voltages. In a 4-inch color test panel a white efficacy of 4.4 lm/W and a luminance of 5000 cd/m2 is obtained for sustaining at 250 V in addressed conditions.

Optical performance of in-plane electrophoretic color e-paper

— Several e-paper technologies are currently under development with the ultimate goal of replacing printed ink on paper. Here, optical performance measurements on monochrome in-plane electrophoretic e-paper devices with unsurpassed brightness, contrast, and viewing-angle performance are reported. The measurement results are captured in a straightforward optical model that allows extrapolation to full-color performance. It demonstrates that in-plane electrophoretic color e-paper technology has the unique potential to deliver on the high standards required by digital-signage applications.

High-frequency drive of high-Xe-content PDPs for high efficiency and low-voltage performance

— It has been well known that the luminous efficiency of PDPs can be improved by increasing the Xe content in the panel. For instance, the efficiency is improved by a factor 1.7 when the Xe content is increased from 3.5% to 30%. The sustain pulse voltage, however, increases from 180 to 230 V by a factor 1.3. It was found that the increase in the sustain pulse voltage can be suppressed by increasing the sustain pulse frequency. The high-frequency operation further increases the luminous efficiency. If the Xe content is increased from 3.5% to 30% and the drive pulse frequency is increased from 147 to 313 kHz, the luminous efficiency becomes 2.7 times higher and the luminance 4.5 times higher. Furthermore, the increase in the sustain pulse voltage is suppressed 1.1 times, from 180 to 200 V. A mechanism of attaining high efficiency and low-voltage performance can be considered as follows. A train of pulses is applied during a sustain period. As the sustain pulse frequency is increased, the pulse repetition rate becomes faster and a percentage of the space charge created by the previous pulse remains until the following pulse is applied. Due to the priming effect of these space charge, the discharge current build-up becomes faster, the width of the discharge current becomes narrower, ion-heating loss is reduced, and the effective electron temperature is optimized so that Xe atoms are excited more efficiently. The intensity of Xe 147-nm radiation, dominant in low-pressure Xe dis-charges, saturates with respect to electron density due to plasma saturation. This determines the high end of the sustain pulse frequency.

High-efficiency PDP micro-discharges

— High-efficiency plasma-display-panel micro-discharge characteristics will be discussed. An increase in the discharge efficiency for a higher-Xe-content gas mixture is well known. In this article, the interdependency of the capacitive design, the sustain voltage, and the Xe content will be discussed. A high panel efficacy was obtained, especially for the design and driving conditions that govern the development of a fast discharge. A fast discharge was observed for a higher discharge field at sustain voltages higher than 200 V. A +C-buffer design, where the extra capacitance acts as a local on the panel power source that lowers the voltage decrease inherent to the discharge of the discharge capacitance upon firing, and efficient priming of the discharge at higher sustain frequency, also stimulates a fast-discharge development. Apparently, a “high-efficiency fast-discharge mode” exists. It is proposed that in this mode the cathode sheath is not, or incompletely, formed during the increase in the discharge current, and the electric field in the discharge cell is dominated not by the space charges but by the externally applied voltage. The effective discharge field is lowered, resulting in a lower effective electron temperature and more efficient Xe excitation. Also, under a fast discharge build-up condition, the electron-heating efficiency increases, due to a decrease in the ion heating losses in the cathode sheath. In a 4-in. color plasma-display test panel, operating in a high-efficiency discharge mode and containing a 50%Xe in Ne gas mixture, a panel efficacy of 5 lm/W concurrent with a luminance of 5000 cd/m2 was realized. This result was obtained at a sustain voltage of 260 V. These data compare favorably with alternative high-efficacy panel design approaches.

The route towards a high efficacy PDP; influence of Xe partial pressure, protective layer, and phosphor saturation

PDP efficacy improvement factors are investigated. It is found that key elements for a high discharge efficiency are: a high Xe partial pressure combined with phosphor materials which show little saturation at high VUV load. In a color test panel a white luminance of 3500 cd/m 2 and an efficacy of 4 lm/W is realized for sustaining at 225 V. q 2003 Published by Elsevier Ltd.

Xe-excitation efficiency and plasma saturation in plasma display microdischarges

Plasma display panel (PDP) efficiency data are correlated with panel emission measurements. A large visible/infrared (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 PDP efficiency 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 to low Xe-content panels in default operation conditions and that plasma saturation decreases with the high voltage high frequency operation of high Xe-content panels. 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, increased Xe-excitation efficiency, and decreased plasma saturation.