Eun Gi Heo

Experimental Observation of Halo-Type Boundary Image Sticking in AC Plasma Display Panel

Infrared-emission observations show that the discharge characteristics related to the MgO surface are improved in both the image sticking and boundary image sticking cells, whereas luminance observations show a deterioration in the visible-conversion characteristics related to the phosphor layer in both the image sticking and boundary image sticking cells. Consequently, the image sticking phenomenon is strongly related to the Mg species sputtered from the MgO surface of the discharge cells due to an iterant strong sustain discharge. In particular, halo-type boundary image sticking is due to the redeposition of Mg species on both the MgO and phosphor layers in the nondischarge region adjacent to the discharge region, as confirmed by Vt close curve, time-of-flight secondary ion mass spectrometry, and scanning electron microscope analyses.

Prevention of Boundary Image Sticking in an AC Plasma Display Panel Using a Vacuum Sealing Process

Boundary image sticking can be inherently prevented in an ac plasma display panel fabricated using a vacuum sealing process. The results indicate that residual impurities, such as nitrogen or oxygen, are essentially related to the production of boundary image sticking. When checking the production of boundary image sticking in a test panel fabricated using a or an flow during the vacuum sealing process, no boundary image sticking appeared in the case of a flow, whereas boundary image sticking was produced with an flow, although the test panel was fabricated using a vacuum sealing process. Consequently, reducing the residual impurity, particularly oxygen, based on a vacuum sealing process can inherently prevent boundary image sticking.

Improvement of luminous efficiency using high helium content in full-HD plasma-display panels

— The influence of the Xe (15%) and He (70%) fractions on the discharge and driving characteristics was compared in 50-in. full-HD plasma-display panels. The same improvement in the luminous efficacy was obtained when increasing either the Xe or He fraction. However, the discharge current with a high He fraction was smaller than that with a high Xe fraction. While the breakdown voltage was hardly influenced by an increase in the He fraction, it was significantly changed when increasing the Xe fraction. The formative and statistical time lags were only slightly changed with a high He fraction, yet significantly increased with a high Xe fraction. In addition, the relatively low luminance and driving-margin characteristics with a high He fraction were compensated for by controlling the capacitance of the upper dielectric layer.

Discharge Characteristics of AC Plasma Display Panel Prepared Using Vacuum Sealing Method

The base vacuum level achieved before loading the discharge gas is known to be an important parameter that affects both the address and sustain discharge characteristics in an AC plasma display panel (PDP), as a higher base vacuum level improves the discharge characteristics. Accordingly, the vacuum sealing method, which can enhance the base vacuum level, is adopted to enhance the MgO characteristics by reducing any residual gas impurity. The resulting changes in the address and sustain discharge characteristics, including the secondary electron coefficient, firing voltage, and dynamic voltage margin, are then compared with the results when using conventional atmospheric-pressure sealing for a 42-in ac PDP with a high Xe (11%) content. The vacuum sealing method was found to improve the secondary electron emission coefficient, lower the firing voltage, particularly under MgO cathode conditions, and increase the dynamic voltage margin. However, the vacuum sealing was also found to deteriorate the visible transmittance of the dielectric layer in the front panel. Nonetheless, the vacuum sealing process enabled the use of a higher Xe content, which is up to 17%, under a stable dynamic margin voltage, thereby improving both the luminance and luminous efficiencies of the AC PDP.

Recovery of Boundary Image Sticking Using Aging Discharge in AC Plasma Display Panel

A full-white aging discharge process is proposed to recover permanent boundary image sticking in an AC plasma display panel. A simultaneous 100-h aging discharge in both boundary image sticking and nonimage sticking cells induced sputtering and redeposition of the MgO surfaces in both cell types, resulting in similar MgO surface morphologies. The luminance characteristics, including the infrared emission and chromaticity coordinates, of the boundary image sticking cells were also compared to those of the nonimage sticking cells. As a result, the full-white aging discharge was found to contribute to the recovery of permanent boundary image sticking cells.

43.3: Discharge Characteristics of 42‐in. AC Plasma Display Panel Fabricated by Vacuum Sealing Method

The base vacuum level before filling a discharge gas is an important parameter to affect both the address and sustain discharge characteristics in an AC-PDP. for the improvement in discharge characteristics, the vacuum sealing method is adapted. In this paper, the vacuum sealing method to enhance a base vacuum level is adopted to minimize the residual impurity gas, and the resultant changes in the address and sustain discharge characteristics, such as a dynamic voltage margin, firing voltage, statistical address delay time, and secondary electron coefficient, were examined in comparison with the conventional sealing method in the 42-in. AC-PDP with a high Xe (11 %) content. The high base vacuum level in the 42-in. panel fabricated by the vacuum sealing method can enhance the discharge characteristics, such as a dynamic voltage margin, a firing voltage, and a statistical address delay time, which are caused by a decrease in the residual impurity gases and an increase in the secondary electron coefficient. In particular, in the vacuum sealing method, the sustain voltage was decreased by about 30 V, and the address voltage was also decreased by about 7V in the Xe (11 %) condition.

Stability of Coated-Green Phosphor for Enhancing Discharge Efficiency in a Plasma Display Panel Cell

The picture quality of a plasma display panel (PDP) is very sensitive to its phosphor characteristics, including luminance, decay time, surface charge, and longevity of the phosphor material itself. In our previous work, the discharge efficiency of a green cell in a PDP was enhanced by coating Zn 2 SiO 4 :Mn 2+ phosphor with positively charged metal oxides, such as MgO or ZnO. The coated Zn 2 SiO 4 :Mn 2+ phosphors were examined for stability under PDP manufacturing as well as operating conditions. It was found that Al 2 O 3 would be the best coating material for Zn 2 SiP 4 :Mn 2+ phosphor because it gives longevity as well as a stable charging effect in green cells.

24.3: Experimental Study on Halo‐Type Boundary Image Sticking in 42‐in. AC Plasma Display Panel

When displaying the square-type image with peak luminance for about 500 hours in 42-in. PDP-TV with high Xe (15 %) content, the luminance and IR (828 nm) emission of the non-discharge region adjacent to the discharge region were observed in comparison with the discharge region and non-discharge region far away from the discharge region, under the two different image patterns, such as the dark and full white backgrounds. In particular, the halo-type boundary image sticking was observed in the non-discharge region adjacent to the discharge region. Under the dark background, the IR was initiated the fastest and the luminance was the highest in the regions adjacent to the discharge region, whereas under the full white background, the IR was initiated the fastest in the region adjacent to the discharge region but its luminance was higher than that of the discharge region and lower than that of the region far away from the discharge region. The halo-type boundary image sticking phenomenon is due to the re-deposition of the MgO on both the MgO and phosphor layers in the non-discharge region adjacent to the discharge region, which is confirmed by the Vt close curve, Mg-profile and SEM analyses.

P-139: Distinguished Student Paper: Driving Waveform with Multi-Scan High Level for Stable Address Discharge Under Variable Ambient Temperature

To explain the address discharge fail at a high temperature, the wall charge leakage phenomenon during address-period is investigated relative to the number of applied address and sustain pulses under variable ambient temperature based on the Vt closed-curve analysis. The wall charge leakages are increased with an increase in the number of the applied address and sustain pulse, and this tendency are intensified as the ambient temperature increased. It is also observed that the wall charge leakage during address period depends on the level of scan high voltage. Base on the experimental observation, the driving waveform with multi scan high level is proposed to produce the stable address discharge under variable ambient temperature.

30.3: Discharge Characteristics of High Efficiency Rib and its Optimized Electrodes (HERO) using High Xe Gas Mixture

High Efficiency Rib and its Optimized electrode (HERO) is investigated on a characteristics of the electrical-discharge with increasing Xe concentration. HERO adopts an increasing Xe concentration in discharge gas mixture, which is a recent trend for achieving high luminous efficiency in AC-PDP. HERO is uses a relatively high Xe concentration in a 42″ VGA module. It shows 2.5 lm/W of luminous efficiency that can deliver full white brightness of 200cd/m2 with power less than 200W.