Heiju Uchiike

Secondary electron emission characteristics of dielectric materials in AC-operated plasma display panels

From the measurement of the ion-induced secondary electron emission yield γiit was shown that with increasing γiof the dielectric panel material the firing voltage of an ac gas discharge display panel decreased. The measurement of the energy distributflon of the secondary electrons showed that the dielectric material with higher γihas lower most-probable energy (MPE), and half-width (HW) values. The energy distribution introduced by Stolz in the ease of secondary electrons emitted from a metal was applied to the dielectric panel material and solved by using a computer. From this result, it was shown that the lower the electron affinity of the dielectric panel material, the higher is the γi. Under the condition when γibecame greater than unity, unstable self-sustained emission was observed even though the primary ion beam was cut off.

Study on the generation process of the discharge for color plasma displays based on observation by using an ultra-high-speed electronic camera

Instead of the direct observation of ultraviolet rays of 147 nm emitted from Xe, light emission of 828 nm was observed first by using ultra-high-speed electronic camera system. The experimental results show that the ultraviolet rays of 147 nm emit above both cathodes and anodes simultaneously. The striation phenomena observed on anodes were analyzed.

24.2: Direct Observation of VUV Rays for Surface-Discharge ac Plasma Displays by Using an Ultra-High-Speed Electronic Camera

VUV rays for surface-dischaqge ac PDPs were observed directly by using a newly developed ultra-high speed electronic camera with a wave length of 120nm to 330nm. It is first confirmed that 147nm, 152nm and 173nm WV rays are emitted from both cathodes and anodes.

Optimum composition of CaO, SrO dielectric materials in AC plasma display panels

The firing voltage V<inf>f</inf>of ac operated plasma display panels can be reduced by coating the dielectric materials with (Ca, Sr)oxides. The reasons for the reduction of V<inf>f</inf>are explained in this paper. The secondary electron emission yield, γ<inf>i</inf>(Ar⁺), resulting from Ar ion bombardment, was directly measured for the compound oxides having various ratios of Ca to Sr. Also, the work function was obtained from the measurement of thermionic emission. The results show that γ<inf>i</inf>(Ar⁺) reaches a maximum for a weight ratio of CaO to SrO of 1:3 while the work function reaches a minimum. From the results of Auger analysis and the measurement of optical absorption, it was confirmed that the most anion vacancies of SrO (F⁺<inf>s</inf>(H) color centers and F⁺<inf>s</inf>color centers) were found in the sample of the preceding composition. (F⁺<inf>s</inf>(H) and F⁺<inf>s</inf>color center are considered as a direct source of emission. As a result of the increase of (F⁺<inf>s</inf>(H) and F⁺<inf>s</inf>color centers, reduction of the work function and increase of γ<inf>i</inf>(Ar⁺) occur. The theoretical calculation of γ<inf>i</inf>(Ar⁺), using the theory of Parilis et al., was carried out to clarify the influence of the work function upon γ<inf>i</inf>(Ar⁺). The theoretical results are in good agreement with the measurement of γ<inf>i</inf>(Ar⁺). From the discussion based on the potential ejection process in ae-plasma display panels, it is shown that the reduction mechanism of V<inf>f</inf>is caused by the increase of F⁺<inf>s</inf>color centers.

Direct observations of vacuum ultraviolet rays for surface‐discharge ac plasma displays by using an ultra‐high‐speed electronic camera

— Vacuum ultraviolet (VUV) rays emitted from Xe during the operation of surface-discharge ac plasma-display panels (PDPs) were observed directly by using a recently developed ultra-high-speed electronic camera. It is confirmed that 147- and 173-nm VUV rays are emitted from both the cathode and the anode simultaneously. The direct observation shows that the emitting area for 147- and 173-nm emissions above the cathode and the anode extends outward from the edge of the gap. These emission extensions are considered to be caused by a lowering of the electric field above the area due to the accumulation of wall charges. The intensity of the 147- and 173-nm emissions above the anode decays faster than those above the cathode. It is clarified that the difference in the decay characteristics of VUV rays above the cathode and the anode is caused by the difference in the wall-charge-accumulation rates above the cathode and the anode. The major reactions concerning the generation of Xe(1s4), a xenon resonant state, which is related to 147-nm emission, and that of Xe2Y*, a xenon molecule state, which is related to 173-nm emission, are discussed.

Characteristics of discharge pattern in surface-discharge AC plasma display panels

A two-dimensional computer simulation for the surface-discharge ac plasma display panel shows that the suppression electrodes perform the function of confining the discharge area within a unit cell. This is due to the effect of the suppression on the surface potential caused by the ion or electron accumulation on the dielectric protecting layer rather than the pinch effect on the electric field. The investigation of the effects of various panel dimensions on the discharge pattern resulted in discovery of an analytical relationship that can be used to determine whether the discharge pattern is a criss-cross or single-sided one for given panel dimensions. The formation mechanism of the crisscross discharge pattern was clarified from the consideration of the computer simulation and the computer-aided image processing of the discharge pattern from an experimental surface-discharge ac plasma display panel.

Optimum composition of dielectric materials, (Ca, Sr) oxides, in AC-operated plasma display panels

From the measurements of the secondary electron emission and an Auger analysis, the firing voltage, 65 V, was obtained at the composition of mixtures of CaO and SrO in the ratio of 25 : 75 wt%. From the half-width value of the energy distribution curve of the secondary electrons and Richardson plot, it was obtained that the electron affinity and the work function has the minimum value at the optimum composition. The excess Sr layer was observed at the optimum composition from an Auger analysis. From the experimental results, we propose that the donor like states formed by the excess Sr increase the yield and the firing voltage is decreased consequently.

Laser‐induced fluorescence study of discharge plasma in He+Xe mixture gas

This paper contains experimental results on the population of the 21S atom of HeI in the discharge plasma of a He+Xe gas mixture. The population measurement was made by the laser‐induced fluorescence method with the laser light tuned to the HeI line of 5016 A(21S‐31P). The fluorescence intensity of HeI lines was measured as a function of the mixture ratio of Xe to He gas. As the Xe gas was mixed, the fluorescence intensity was significantly reduced at pressures ranging from 0.2 to 1 Torr. Further, an increment of the discharge current made the population of the 21S atom increase more remarkably in the Xe‐mixed gas than in the pure He. These behaviors were considered using the measured temperature and density of the electrons, and it was concluded that at 1‐Torr the Penning collision of the 21S atom with Xe was effective and dominated the behavior of the 21S atom.

Laser‐induced fluorescence study of Penning collision of Hei 23S atom with Xe in He+Xe gas discharge plasma

This paper presents an experimental result on the population of the 23S of Hei in He+Xe gas discharge. The laser‐induced fluorescence method was used to find the behavior of the 23S population, and a strong coupling of the 23S with 23P state enabled us to determine the 23S population from the measurement of Hei 5876 A (23P–33D). The discharge condition considered ranged from 0.2 to 5 Torr in pressure and 20 to 260 mA in discharge current. The measured population of the 23S state in the Xe‐mixed condition showed a significant reduction at the pressure of 3 and 5 Torr, but not when the pressure became as low as 0.2 Torr. It was demonstrated that the overall behavior of the observed population was quantitatively explainable with an inclusion of the Penning collision of the 23S with the Xe atom.