Hidekazu Hatanaka

Laser Thomson scattering measurements of electron density and temperature profiles of a striated plasma in a plasma display panel (PDP)-like discharge

A laser Thomson scattering technique has been used to directly measure the electron density (ne) and electron temperature (Te) profiles of a striated plasma in a plasma display panel (PDP)-like discharge. A modulation in ne was observed only on the anode side of an electrode substrate; this corresponds to a feature similar to that of the emission images obtained using an intensified charge-coupled device (ICCD) camera. Also, a modulation in Te was observed and it was found to be out of phase from the modulation in ne.

Production efficiencies of Kr*(1s5,1s4) atoms leading to vacuum-ultraviolet emissions in ac plasma display panels with Kr-Ne binary mixtures measured by laser-absorption spectroscopy

Ne–Kr gas mixtures with high Kr concentrations were applied to ac plasma display panels. Spatiotemporal behaviors of excited Kr atoms in the 1s5 metastable state and the 1s4 resonance state were measured by microscopic laser-absorption spectroscopy in the binary mixtures with Kr concentrations of 20% and 40%. A systematic comparison was done between the characteristics of Ne–Kr-filled panels and those of conventional Ne–Xe panels with the same structure but with lower Xe concentrations of 5% and 10%. For example, the total number of Kr*(1s5) atoms in a unit cell ranged from 7.4×107 to 2.0×108, at the peak was apparently smaller than the value of Xe*(1s5) atoms. However, when the difference in the decay rate of the excited atoms by three-body collision processes is taken into account, the production efficiency of vacuum-ultraviolet (VUV) emission from Kr2* excimers is as large as that from Xe2* excimers in a usual panel since these processes lead directly to the formation of excimers. From the measured den...

Production efficiency of excited atoms in PDP cells with grooved dielectric structures studied by laser absorption spectroscopy

Performances of microplasmas in unit discharge cells with grooved structures in the dielectric layer covering the coplanar electrodes were investigated in alternating current (ac)-type plasma display panels filled with Ne-Xe(10%) mixture at 450 torr. The diagnostics are based on a microscopic laser-absorption spectroscopy technique for the spatiotemporally resolved measurements of absolute densities of Xe/sup */(1s/sub 5/,1s/sub 4/) atoms, from which the production rate and the efficiency of the vacuum ultraviolet photons were estimated. These results were compared with previously reported data obtained in conventional phosphor coated panels with the same structures for the dependences on the applied sustain voltages. As the result, the following conclusions were ascertained. The grooved structure does not help to improve the luminous efficiency but it helps to lower the firing and sustaining voltages by about 20 V if the electrode gap is kept constant. Therefore, it provides additional possibilities for the selection of other operating conditions such as the gas composition and pressure for the improvements of the luminance and the luminous efficiency.

P-50: Excimer Gas Discharge Characteristics for Color AC-PDPs

We present the discharge characteristics of a rare gas halide mixture in AC- Plasma Display Panels. Studies for excimer gas of plasma display panels are performed using XeF. This excimer gas is investigated as function of its pressure and different discharge condition. In this paper, the real panel using XeF excimer gas is researched for good discharge characteristics and a full-color panel is demonstrated.

8.2: New Electrode Structure to Improve Discharge Characteristics in AC PDPs

A new structure including igniter electrode is proposed to achieve a low sustaining voltage and high luminous efficacy. By measuring minimum sustaining voltage(Vsm), discharge current(Ion), displacement current(Ioff) and brightness of the light from a 6-inch AC PDP, performances of the conventional structure and the igniter structure are compared. When compared with the conventional structure, the igniter structure showed 10% Vsm improvement at the Ne-Xe(10%) gas mixture of 600 mbar. Therefore, we could apply the higher partial pressure of Ne-Xe(12%) to the igniter structure, which results in 42% luminous efficacy improvement at the similar sustaining voltage range.

25.3: Luminous Efficacy Dependence of Kr2* Excimer ACPDP on Sustain Driving Conditions

Sustain driving conditions for Kr2* excimer ACPDP are investigated with real 6-inch panels. At the optimized driving with 5 kHz, the PDP with a mixture of Kr: Ne = 50:50 (%) shows the efficacy of 1.6 lm/W, which is over 2 times higher than that of the same PDP panel with a conventional mixture (Xe: Ne = 4:96 (%), 0.7 lm/W).

40.1: Invited Paper: The Dual Coplanar Electrode Mercury Free Flat Fluorescent Lamp

The authors introduce a dual coplanar electrode flat fluorescent lamp, which is basically the sum of two coplanar electrode lamps, one having the electrodes on the front plate and the other on the bottom plate. It has the same level of discharge stability as that in a usual coplanar lamp. And the results also indicate that the brightness and luminous efficacy improve largely for a dual coplanar lamp compared to a coplanar lamp because there is less diffusion loss for the dual coplanar lamp.

LP‐7: Late‐News Poster: Development of an Infrared Laser Thomson Scattering System for Measurements of Electron Density and Electron Temperature of a PDP Micro‐discharge Plasma

An infrared laser Thomson scattering (LTS) system is newly developed so that LTS is applicable to measurements of electron density and electron temperature of PDP micro-discharge plasmas produced in Ne/Xe gas mixtures. The first experimental result shows that the performance of the system is good enough for the present purpose.

Luminous efficacy evaluation of XeI excimer for ACPDP

We demonstrate for the first time a luminous efficacy of a Xel excimer PDP comparable to that of a conventional Xe/Ne-mixture PDP using 6-in. ACPDPs. For the conventional PDP as a reference, a mixture of Xe:Ne = 4:96(%) with a total gas pressure of 60.0 kPa (450 torr) was used. For the Xel PDP, Ne-buffered mixtures with the same total gas pressure were tried, and a mixture of I 2 :Xe:Ne = 0.02:7.1:92.88 (%) showed an efficacy as high as that of the conventional Xe PDP.

14.4: Plasma Display Panel with Ridged Dielectric Layer between Sustaining Electrodes

This article presents a front panel structure for an alternating current plasma display panel (AC PDP) based on a ridged transparent dielectric layer between the sustaining electrodes. Compared to a conventional AC PDP, the suggested structure can reduce a firing voltage and sustaining voltage due to a strong electric field between the sustaining electrodes. First experiments were conducted to see the effect of ridged dielectric structure in the short electrode gap of 110 μm with various Xe contents from 10% to 50% at a gas pressure of 450 Torr, and the results confirmed that the ridged dielectric structure reduced the firing and sustaining voltages by about 74 and 79 V at 10% Xe content compared to a conventional structure with 10% Xe content, respectively. Also, the proposed structure improved the luminous efficacy and luminance by about 50.9% and 33%, respectively, with 50% Xe content when compared to a conventional structure with 10% Xe content at a similar driving voltage. Second, performances of the conventional structure and the ridged dielectric structure with the electrode gap of 140 μm were compared. Experimental results confirmed that the box shaped ridged dielectric structure could be driven at a lower voltage than conventional AC-PDPs with the same Xe content. Also, the luminous efficacy of box shaped ridged dielectric structure was higher than those of conventional structures.