Surface aging mechanisms of AC plasma display panels

Excellent life performance is being achieved for ac plasma display panels through understanding of the causes of voltage changes, surface overcoat material research, and adjustment of the manufacturing process to eliminate contaminants. It has been found that surface aging phenomena are dominant in many practical cases. Because of prefereutial operation patterns (i.e., alpha numerics), a differential aging pattern may evolve. The differential pattern is the result of voltage changes which are different for heavily operated and lightly or nonoperated cells. It is shown that the nature and extent of surface changes are dependent on overcoat material selection and the presence (or absence) of contaminants introduced during manufacture. With the use of thin overcoat layers in contact with the gas, it is necessary to be aware of the possibility of surface film removal by sputtering. The effects of significant variables: gas pressure and composition surface material, and operating voltage 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.     

Write and erase waveforms for high-resolution AC plasma display panels

The successful operation of ac plasma display panels (PDP) depends on the optimization of panel parameters such as chamber gap, gas pressure, line width, and the use of half or full-select cancellation techniques. As resolution increases, however, so does the importance of the write and erase waveforms. A unique set of write and erase waveforms which are specifically designed to optimize the performance of high-resolution PDP's are discussed.     

Thermal characteristics of glass-metal composition plasma display panels

Plasma display panels use gas plasma to produce light, with a technique very similar to that used for fluorescent tubes. This is currently the only flat panel technology available for very large flat-panel televisions. A newly developed plasma display panel utilizes a composition of glass, metal and frit glass sealing material, in addition to functional thin and thick film glass-powder-based laminate composites. This paper focuses on this new plasma display technology and discusses its structure and thermal reliability characteristics and challenges.     

Spatial distribution of wall charge density in AC plasma display panels

Experimental results are given for the spatial and temporal variation of both the wall charge density and the light intensity along the electrode lines of an ac plasma display panel. The results show that the major part of the luminous spreading is along the cathode line, and it does not accurately reflect the spreading of the wall charge. The wall charge density distribution is approximately symmetrical along both the cathode and anode lines, and it is fairly constant up to about a linewidth away from the edge of the electrode line. A qualitative explanation is proposed for this extended uniformity of the spatial profile of the density of wall charge.     

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

The firing voltage Vfof ac operated plasma display panels can be reduced by coating the dielectric materials with (Ca, Sr)oxides. The reasons for the reduction of Vfare explained in this paper. The secondary electron emission yield, γi(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 γi(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⁺s(H) color centers and F⁺scolor centers) were found in the sample of the preceding composition. (F⁺s(H) and F⁺scolor center are considered as a direct source of emission. As a result of the increase of (F⁺s(H) and F⁺scolor centers, reduction of the work function and increase of γi(Ar⁺) occur. The theoretical calculation of γi(Ar⁺), using the theory of Parilis et al., was carried out to clarify the influence of the work function upon γi(Ar⁺). The theoretical results are in good agreement with the measurement of γi(Ar⁺). From the discussion based on the potential ejection process in ae-plasma display panels, it is shown that the reduction mechanism of Vfis caused by the increase of F⁺scolor centers.     

A new sustainer by using clamping RC components for AC plasma display panels

A new sustain driver with an energy recovery circuit for ac plasma display panels is proposed. The proposed driver uses not expensive clamping diodes but relatively cheap RC components in the Y and X main boards without degrading the performance. Consequently, it features fewer power devices and lower cost because of no clamping diodes. To demonstrate the validity of the proposed driver, various experimental results with a prototype 42-inch HD PDP module are presented.     

Cost-effective driving system for AC plasma display panels without employing voltage separation switches

Proposed is a low-cost driving system for AC plasma display panels. To achieve it, a new driving circuit that eliminates voltage separation switches (path switches) is presented. It has additional merits of higher reliability, lower power consumption, and simpler structure owing to fewer switching components     

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.     

Three-electrode-per-pel AC plasma display panel

A new ac plasma display technique is described in which the alternating sustain function is achieved on the back or substrate glass surface and thex-yselected write-addressing uses a transparent front cover electrode and a substrate electrode. The three-electrode-per-pel structure achieves high overall emission efficiency as a result of nonshielded sustain discharges and low electrode capacitances.     

Two-frequency drive for AC-refresh plasma display panels

A new drive scheme, with mixed low- and high-frequency drives, has been developed for large-capacity (large number of dots) ac-refresh plasma display panels. Its usefulness for suppressing both firing-voltage increase and luminance-level decrease in a large-capacity panel was confirmed using a practical-size plasma panel. This drive technique can produce a large display panel ( > 400-600 scan lines) with about 50-percent lower power dissipation and higher luminance level than a conventional drive technique. It has been clarified experimentally that these results are due to the sufficient formation of the wall charge at an initial discharge period.     

Recent developments in three-color plasma display panels

This paper describes recent developments in the fabrication of three-color-phosphor plasma display panels that improve both electrical and optical performance. The electro-optical characteristics of panels incorporating a phosphor bar pattern are presented, including the properties of panels fabricated with a black, UV-absorbing material surrounding the phosphors. In addition, processes developed to produce 20 × 20 in plasma panels with 512 × 512 three-color resolution elements at a total line density of 60 per inch are described.     

等离子显示器用滤光膜的研制

等离子显示器(PDP)图像的颜色和亮度由经过调制的脉冲电流控制,该脉冲电流会产生电磁波、近红外线以及氖黄光干扰,影响其效果,需安装滤光膜。通过对不同种类、不同厚度的涂层进行对比研究,开发了一种PDP用滤光膜,其EMI屏蔽效能大于45 dB,比进口的略低,但透光率达到43%、高于进口值。氖黄光透光率为15%,近红外透光率低于10%,成本不到进口膜的1/3,完全可以取代进口产品,用于PDP显示面板。     

A highly stabilized AC plasma display

Achieving overall stability of the ac plasma display/ memory device is vital to solving major problems to secure maintenance-free operation in its practical use. The stability improvement reported in this paper has been achieved by improving driving waveforms for the panel. The main improvements were: finding an address-pulse shape suitable for the panel characteristics, applying a proper address sequence, and the use of an addressing method free from half-select failure. These techniques have enabled us to obtain a wide operating margin in character-display application.     

A planar single-substrate AC plasma display

A novel method is described for constructing an acsustained gas-discharge display (plasma panel). Electrodes and insulating layers are applied alternatively on a single base substrate to produce a matrix of insulated crossovers. A second clear substrate is used to contain gas on the electrode side of the base substrate where glow discharge occurs. As in conventional two-substrate panels, internal memory is obtained by charge storage on the dielectric. The pulsed write and the sustain mechanisms of single- and twin-substrate display elements are discussed with regard to the effects of cell and field geometries. In the sustain mode, glow-propagation effects are observed, especially in the nonhomogeneous fields of the single-substrate design. Here cathode-type glows which form a narrow band are observed with a high-speed photomultiplier and shown to sweep across the dielectric surfaces. Luminance, intensity distributions, and luminous efficiency data are compared on small 10 × 10-line panels using single-substrate and conventional designs. A three- to four-fold improvement in luminance is achieved with the single-substrate geometry.     

Optical readout from plasma display/memory panels

Techniques for extracting stored information from an array of plasma display elements using optical detection systems are presented. Two specific electronic drive schemes and several experimental area photodetector systems used in realizing readout capability in display systems are described. Limitations of optical read-out systems due to optical noise generated by the display panel and by incident ambient light are discussed.     

Preparation and characteristics of white EL display panels

Two methods for preparing white emitting EL panels are well known in principle: (1) blending a blue and an orange emitting EL phosphor and (2) partially cascading of green EL emission with a red photoluminescent material, typically an organic fluorescent dye. Both methods have their advantages and shortcomings. Panels containing phosphor blends are readily viewed even in moderately bright ambient light but the “ white” color is reasonably stable only over limited times because the blue phosphor comnonent deteriorates faster than the orange. Cascading panels show very long lives, depending on the green EL phosphor involved, without any visible color change but these panels can be used only under restricted ambient light conditions. Brightnesses and efficiencies of both kinds of panels are about comparable     

EXPERIMENTAL RESEARCH OF ELECTRO-OPTICAL CHARACTERISTICS OF NOBLE GASES IN AC PLASMA DISPLAY PANEL

Luminous spectra and electric characteristics of gas mixtures:Ar+He,Kr+He,He+Ne,He+Xe,Kr+Ar and Ar+Hg are investigated in order to find out a kind of gas mixture radiatingblue-green light.It was shown in the investigation that the gas mixture of Ar+Hg,which radiates blue-greenlight,and has higher brightness and lower firing voltage,is more satisfactory.     

Nondestructive graphic cursors and light-pen tracking on AC gas-discharge display panels

Interactive graphic displays need a displayed cursor such as a cross-hair to provide the system user with feedback of the system's point of attention. It has proven difficult to provide a movable cursor on ac gas-discharge displays without regenerating the original image each time the cursor is moved. This paper presents a new technique for displaying nondestructive cursors of various forms on gas panels and for high-speed automatic light-pen detection and tracking.