A Mini-Neck electron gun with a 22.5mm neck diameter has been developed for color display tubes applicable to the power-saving monitors. In order to restrain the disadvantage of its small gun diameter, minimized 0.35mm dia. apertures have been introduced to its G1 and G2 electrodes in the beam forming region. Furthermore, the mignification and the aberration are compromised, and the optimized astigmatiss is applied in the main focusing lens configuration. The attained focus characteristics is almost similar to that of the conventional guns with 29.1mm neck diameters.

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In order to reduce the Alternating Electric Field (AEF) leakage from Color Display Tubes (CDT), the most convenient and suitable method is to lower the surface resistivity of the face plate of CDT. On the other hand, the low reflectance coating also needs for CDT to reduce the reflectance of ambient light. Now, we have developed a low cost coating technology for CDT with so low a surface resistivity as 1×10^5Ω/□ or less against AEF leakage and with a low luminous reflectivity.

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Factors inducing the cut-off voltage drift during CRT life, have been analyzed in the case with oxide cathodes. The displacement of the emission surface against other electrodes as one of the factors, is difficult of direct measurement. We have obtained it by analyzing current-voltage characteristics with diode tubes, to translate it into the voltage drift. In conclusion, it has been found that the drift is dominated by only the emission surface displacement which is caused by both the shrinkage of emitter and the displacement of the cathode base-cap. Actual measurements of the shrinkage have allowed us to estimate the percentage of these factors.

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Radiation characteristics of the mercury-rare gases discharges were investigated by means of their spectral intensities and radiation waveforms. In the negative glows, all the gases filled in are excited and radiate their spectrals. When the Hg-Ar tubes are discharged by the voltage in the sine-waveform, the continuous spectral bands which are emitted by the reconbinations appear in the wave length range from 530nm to 600nm. In the double pulse discharges, the spectral intensities of the second pulse decrease as increasing the interval of two pulses.

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Mgo protecting layer for ac-PDPs was prepared by rfmagnetron sputtering method with and measured aging characteristics of testing panel. Sputtered MgO is excellent in point of low sustaining voltage and stability of sustaining voltage. We analyzed sputtered MgO by x-ray diffraction and Scanning electron microscope.

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With the objectives of enlarging the panel, reducing cost and improving the uniformity, we studied the fabrication of the protective MgO layer by means of screen-printing. The mixure of 1000A(75%) and 500A(25%) showed the highest luminous efficiency and the lowest discharge voltage. Moreover, for the high density, we prepared the MgO protective layer by the repeated screen-printing of thin film. The film showed 16% higher density, moreover, the repeated firing process after every screen-printing showed the 30% higher than single-phase film. The screen-printed protective film with high density showed the same Vf, 97 cd m^<-2> higher luminance and 50% higher luminous efficiency than those of single-phase film.

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We have developed a screen-printing process using Mg-Alkoxide solution to make a protecting film for AC-PDP. This process has made it easy to get a large and transparent protecting film inexpensively. As the film is transparent enough, so we can apply the film for AC-PDP whose structure is reflective. The characteristics of discharge voltage and life of AC-PDP provided the protecting film are satisfactory.

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For the purpose of realizing the very fine barrier electrode ac plasma displays, we fabricated the testing panels with a cell pitch of 0.5mm by sandblasting method. We investigated the materials and fabricating method. As a result, we were able to obtain the excellent results of very high luminance of 570 cd/m^2 and luminous efficiency of 1.0 lm/W for the panel with a cell pitch of 0.5mm.

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Color plasma displays realize gray levels using sub-field method. In this method, the flame time is divided into sub-field. each of which includes different number of gas discharges to attain necessary brightness. However, in this technique, the brightness saturates when increasing the number of gas discharges. This phenomenon originates from the phosphor decay time related phosphor luminescence saturatmon. The panel brightness saturation is explained analytically using simple exponential phosphors luminous decay model. Using the same model, 256 gray level brightness values are calculated. The results explain discontinuous brightness jump between consecutive brightness level signals, and countermeasures are proposed.

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Wall charges play an important role in determining the discharge characteristics of AC discharges in plasma display panels (PDPs). In AC/DC hybrid PDPs, DC discharges produce wall charges, while AC discharges produce light emission for displaying images. The separation of these two functions makes it easy to provide various conditions for measuring the wall charge effects. This report presents the measured results on the wall charge effects using the AC/DC hybrid PDP. It was found that an application of a (DC) voltage to the AC electrodes during the presence of the DC discharges is essential in production and diffusion processes of the wall charges. By using the experimental results, a new method of driving the AC/DC hybrid PDP is proposed in which both write-address and erase-address DC pulse are applied to the discharge cells.

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When moving images are displayed on matrix displays which utilize a pulse-width (or pulse-number)-modulation-within-a-field technique for gray scale expression, new category contour noise is often observed. It was found that the noise appears at positions where the gray scale jumps from, e.g., the 127th level (combination of bits 0-6) to 128th level (bit 7). The noise originates from a transfer of a temporal nonuniformity of a light-emission scheme into a spatial non-uniformity due to the image motion. The noise can be reduced by sub-dividing the light-emitting periods of the major bits.

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