Development of a new design simulator for poly‐Si TFTs to optimize the lightly doped drain structure

A new design simulator to simulate the characteristics of poly‐Si TFTs taking into account its physical structure was developed. By using the simulator, we can optimize the length and the sheet resistance of the LDD region in order to obtain sufficient ON currents and to suppress OFF currents under both dark and illuminated conditions.     

Surface‐discharge electrode design methods for ACPDPs

Abstract— In order to lower development costs and to shorten development time, small panels, under 10‐in on the diagonal, are used for the experiments to improve the luminous efficiency of plasma‐display panels. However, it is difficult to show the same results as those of large panels, over 40 in. on the diagonal. In this paper, first, we show that the luminous efficiency and the voltage margin of mini‐panels are not obtained with large panels by using an actual 46‐in. PDP. The reason is that the resistance in the large panels is larger than that in the mini panels and the voltage drop in the large panels are larger than in mini‐panels. Therefore, we conclude that the bus electrode width and the transparent electrode width are important factors in the design of large PDPs. Next, we show the technique of designing large panels by using a database obtained from mini‐panels. The estimated cell‐design results show good agreement with an actual 46‐in. PDP in luminous efficiency and minimum sustain voltage. We show that a desired large PDP can be obtained by using the cell design proposed in the present paper.     

A study on the chromaticity shifts of blue phosphor for color plasma displays

The dependency of the chromaticity shifts on the concentration of Eu²⁺ doped in BaMgAl₁₀O₁₇ (BAM) was investigated under heat‐treatment and vacuum ultraviolet (VUV) irradiation. The Eu²⁺ ions in BAM show an asymmetrical broad emission band with a maximum at ～452 nm under excitation of VUV light at room temperature, showing that multiple crystalline cationic sites exist in the host. It was found that the chromaticity shifts greatly decrease with increasing heat‐treatment temperature. Regardless of the Eu²⁺ concentration, the chromaticity shifts caused by heat‐treatment are greater than that caused by VUV irradiation. Compared with conventional BAM, a solid solution of BAM with barium aluminate as a powder and film was also studied, and very few chromacity shifts were observed. It is suggested that the distribution of Eu²⁺ ions in different sites in a BAM lattice results in different chromaticity coordinates. By increasing the Eu²⁺ concentration in BAM, or under heat‐treatment and VUV irradiation, the emission band shifts towards longer wavelengths.     

Study on the generation process of the discharge for color plasmadisplays based on observation by using an ultra-high-speed electroniccamera

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     

Color plasma displays

After decades of research and development, plasma displays are finally beginning to appear in the commercial and consumer markets. Following a short review on the basic principles of direct and alternating current plasma displays, we present a summary of the status of color plasma displays. Plasma display panels (PDPs) have finally achieved luminance and efficiency values on par with hi-definition cathode ray tube monitors. Additional improvements in performance will open up a new world of large PDP displays. Ultimately, what will drive the PDP market will be continued improvements in the performance of color PDPs themselves. PDP makers are working on reducing power consumption through improved luminous efficiency and improved component materials and manufacturing methods of color PDPs. With improvements in the cell structure and driving methods, there is a good prospect of achieving a luminous efficiency of 2-3 lm/W and a power consumption of about 200 W for 50-in diagonal size     

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

Abstract— 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 Xe^2Y*, a xenon molecule state, which is related to 173‐nm emission, are discussed.     

A study on the secondary electron emission from Na-ion-doped MgO films in relation to the discharge characteristics of plasma display panels

Using a sol-gel precursor, Na-ion-doped MgO was prepared and applied to alternative current plasma display panels (ac-PDP). The cathodoluminescence spectra showed that the F⁺ center was increased as the concentration of Na⁺ was increased. Numerous pores were found on the printed MgO surface and seemed to give higher memory margin of ac-PDP compared to an electron beam-evaporated MgO film. All doped MgO showed higher secondary electron emission than printed pure MgO, likely owing to the O defect states of MgO. In addition, this result indicated the operational memory margin of the ac-PDP was directly proportional to the grade of surface charging.