Tim Dekker

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...

Discharge efficiency in plasma displays

The dependence of the panel efficacy of an alternating current-surface-discharge plasma display on the input power is investigated. Test panels with a design resembling the one used in main stream commercial products are used. The input power is varied in two ways: namely by changing the dielectric layer capacitance (thickness) and by changing the sustain voltage. An interesting different behavior is found: for increasing capacitance the efficacy decreases markedly, whereas for increasing sustain voltage the efficacy increases slightly. The different behavior is attributed to changes in the ion heating losses. It is found that plasma saturation, which implies a fundamental trade-off between luminance and efficacy, is not significant at practical input power values. A high luminance and a high efficacy are concurrent for a plasma panel design with a low dielectric layer capacitance and a high sustain voltage.

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.

7.4: Design of 2D/3D Switchable Displays

Recently we presented a robust and economic concept for an auto-stereoscopic switchable 2D/3D display, [5]. This concept is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. A general issue of lenticular-based multi-view displays is the uniformity. In this paper we present the solutions for the uniformity issue that we use in our switchable displays and we compare computational and experimental results for a test panel.

Improvement of luminance and luminous efficacy in PDPs

The dependence of PDP luminance and efficacy on the input power was investigated for several Xe-Ne gas mixtures. The input power was varied in two ways: namely, by changing the dielectric-layer capacitance (thickness) and by changing the sustain voltage. A distinctly different behavior was found; for increasing capacitance the efficacy decreases markedly, whereas for increasing sustain voltage the efficacy increases. A design window comprising the combination of a high Xe concentration and a high sustain voltage was suggested. In this window, a high luminance and a high efficacy are concurrent. A 4-in, test panel with 10% Xe in Ne has been realized showing a white luminance of 2040 cd/m 2 and an efficacy of 2.3 lm/W for continuous sustaining at 50 kHz with a sustain voltage of 225 V.

20.1: Locally Switchable 3D Displays

3D displays will drastically enhance the viewing experience of future displays for many applications. Unfortunately, 3D displays generally have a lower resolution since the pixels are divided over more views. Therefore, some 3D displays have the opportunity to switch between 2D and 3D mode such that either natural 3D images or high-resolution 2D images can be displayed. However, especially for mobile applications it is advantageous to be able to display 3D and 2D at the same time. In this paper we will discuss the design and driving of locally switchable lenticulars, which combines perfect high-resolution 2D with natural 3D areas.

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.

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.