Seong-eui Lee

Study of various coplanar gaps discharges in ac plasma display panel

To achieve a high luminous efficacy in a plasma display panel, the display characteristics, including the luminance, discharge current, and luminous efficacy, were investigated with various coplanar gaps. The temporal behavior of the infrared emission from 80-, 150-, 200-, and 300-/spl mu/m coplanar gap discharges was also studied. The luminance and luminous efficacy increased as the coplanar gap increased until 200 /spl mu/m. However, when the coplanar gap was 300 /spl mu/m with a fixed barrier rib height of 150 /spl mu/m, the luminous and luminous efficacy suddenly decreased. This phenomenon can be explained by the results of the infrared emission observation, as the discharge shape of the 300-/spl mu/m coplanar gap became narrow when the height of barrier rib was fixed at 150 /spl mu/m. The luminous efficacy of the 200-/spl mu/m coplanar gap discharge was about 3.2 lm/W (green cells) when an Ne+4%Xe gas mixture was used as the discharge gas in the alternating current plasma display panel.

Effect of dual coplanar electrodes on Mercury-free flat fluorescent lamps for liquid crystal display

The effects of dual coplanar electrodes on a Hg-free flat fluorescent lamp were studied. For a dual coplanar lamp, brightness and efficacy were improved by 80% compared to a conventional coplanar lamp. The improvement is regarded as the result of reduced diffusion loss and the effective usage of the discharge volume in the dual coplanar lamps. An efficacy of 35.9 lm/w (14900 cd/m/sup 2/) was achieved for 250 torr of a Xe(30%)/Ne(70%) gas mixture, by a 20-kHz ac pulse driving.

The Effect of the Auxiliary Electrode on the Microplasma Generated in a Plasma Display With a Coplanar Gap

The microplasma modes generated in a plasma display with a coplanar gap and an auxiliary electrode were investigated using the discharge current peak time (discharge delay) and discharge current. Three types of modes were classified as follows: mode 1) showed a decrease in both the discharge current and the discharge delay, mode 2) showed a decrease in the discharge current and an increase in the discharge delay, and mode 3) showed an increase in the discharge current and a decrease in the discharge delay. The infrared efficiency increased in modes 1) and 2) with an increase in the auxiliary pulse voltage. However, in mode 3), the IR efficiency started to decrease. According to the measurement results, modes 1) and 2) are suitable for microplasma generated in a coplanar gap with an auxiliary electrode to obtain high efficacy.

Effect of helium addition on discharge characteristics in a flat fluorescent lamp

The discharge characteristics of a multielectrode dual coplanar in a mercury-free flat fluorescent lamp were investigated using brightness-efficiency measurement and the infrared (IR) spectrum and intensified charge coupled device (ICCD) characteristics. The level of brightness was above 14900cd∕m2 under the conditions of neon-–50% xenon–8% He gas composition, 150Torr pressure, and 20kHz alternating current pulse. The ICCD results revealed a faster and wider discharge with a Ne–50% Xe–8% He gas composition. The effect of adding helium (He) to Ne–50% Xe revealed a faster peak emission, as confirmed by ICCD images. From the gated IR emission spectrum, the intensity ratio of I823nm∕I828nm was ∼8% higher with Ne–50% Xe–8% He than with Ne–50% Xe under the same pressure and applied voltage conditions.

8.2: New Electrode Structure to Improve Discharge Characteristics in AC PDPs

A new structure including igniter electrode is proposed to achieve a low sustaining voltage and high luminous efficacy. By measuring minimum sustaining voltage(Vsm), discharge current(Ion), displacement current(Ioff) and brightness of the light from a 6-inch AC PDP, performances of the conventional structure and the igniter structure are compared. When compared with the conventional structure, the igniter structure showed 10% Vsm improvement at the Ne-Xe(10%) gas mixture of 600 mbar. Therefore, we could apply the higher partial pressure of Ne-Xe(12%) to the igniter structure, which results in 42% luminous efficacy improvement at the similar sustaining voltage range.

Passivation Layers for Organic Thin-film-transistors

Inorganic layers, such as SiOxNy and SiOx deposited using plasma sublimation method, were tested as passivation layer for organic thin-film-transistors (OTFTs). OTFTs with bottom-gate and bottom-contact structure were fabricated using pentacene as organic semiconductor and an organic gate insulator. SiOxNy layer gave little change in characteristics of OTFTs, but SiOx layer degraded the performance of OTFTs severely. Inferior barrier properties related to its lower film density, higher water vapor transmission rate (WVTR) and damage due to process environment of oxygen of SiOx film could explain these results. Polyurea and polyvinyl acetates (PVA) were tested as organic passivation layers also. PVA showed good properties as a buffer layer to reduce the damage come from the vacuum deposition process of upper passivation layers. From these results, a multilayer structure with upper SiOxNy film and lower PVA film is expected to be a superior passivation layer for OTFTs.

Effects of diamond and AlN layers inserted beneath the phosphor layer on the discharge characteristics of PDPs

— In this study, the effects of diamond and AlN layers inserted beneath the phosphor layer of the rear plate of a PDP were investigated. The layers were formed via an osmotic-pressure coating process. Macrocells and test panels were prepared to examine their effects on luminance and luminous efficacy. The results indicate that the layers primarily affect the glow-discharge behavior and eventually enhance the luminous efficacy of the PDP, suggesting the possibile improvement in the performance of PDPs.

P-87: Effects of Temporal Spreader Layers on Discharge Characteristics of PDP

In this study, thermal spreader and/or reflection layers with materials of high thermal conductivity were applied in-between the surface of rear plate of PDP and phosphor layer via osmotic pressure coating process.[1] The coating materials include diamond, AlN, and zeolite. The results demonstrated that the layers not only reflects the visible light within the cell but also affects the discharge characteristics of glow discharge in the cells, resulting increased the luminance and luminous efficacy of the panels.