AC Plasma Display Panel Research Articles

교류형 플라즈마 디스플레이에서 배경광을 줄이기 위한 계단형 경사파형

교류형 플라즈마 디스플레이에서 배경광을 줄이기 위한 계단형 경사파형

Voltage Margin and Luminous Efficiency by Changing Positive and Negative Sustain Voltage in AC Plasma Display Panel

In the AC PDP, drive waveforms are applied to three electrodes, respectively, and positive voltages are alternately used for the two electrodes during the sustain period. When the driving waveforms of two electrodes are corrected in the state where one of the three electrodes is grounded for the low cost of the driving circuit, positive and negative voltages are alternately applied to only one electrode during the sustain period, and an asymmetric discharge is generated differently from the conventional case. An asymmetric discharge indicates a strong discharge once, followed by a weak discharge. It was observed that a strong discharge occurred when negative voltage was applied and a weak discharge occurred when positive voltage was applied. When a positive voltage is applied, the potential difference between the three electrodes is the same as in the conventional case. However, when a negative voltage is applied, the voltage also affects the write electrode, so that the discharge becomes strong. Asymmetric discharges decrease the margin and efficiency of the sustain voltage, so that a symmetrical discharge must be generated. In order to generate the symmetric discharge, we proposed a method of applying positive and negative voltage heights and slopes of the waveform differently, and obtained voltage margin and efficiency similar to the conventional one.

교류형 플라즈마 디스플레이 패널에서 기입 전압을 낮추기 위한 중첩 주사파형

교류형 플라즈마 디스플레이 패널에서 기입 전압을 낮추기 위하여 주사 전극들이 겹치게 인가되는 중첩 주사 파형이 제안되었고 기입 방전의 특성이 연구된다. 기입 기간에는 주사 및 기입 펄스가 동시에 인가될 때 선택된 셀에서 방전이 발생한다. 일반적으로 기입 전압을 낮추면 방전의 지연 시간이 길어지기 때문에 기입기간에 인가되는 펄스의 폭을 늘여야한다. 그러나 1 TV 프레임 시간이 제한되어 있으므로 기입 펄스의 폭은 무한정 늘일 수 없다. 한편, 주사 전극에 인가되는 펄스는 주사 선에 의해 순차적으로 펄스가 인가되므로 펄스의 폭을 중첩시켜서 늘일 수 있다. 즉 기입 펄스의 폭은 종래의 시간과 동일하고 주사 펄스의 폭들만 각각 늘여서 주사 라인들이 중첩된 파형이 제안되었다. 낮은 기입 전압의 인가에 의해 방전 지연시간은 당연히 늦어질 것이나 길어진 주사 펄스의 폭에 의해 기입 방전은 펄스의 폭 안에서 안정적으로 발생하였고 기입 전압을 종래보다 약 13V 낮출 수 있었다.

Analysis on electron emission characteristics of MgO layer with MgO crystal powder under various panel temperatures in ac-plasma display panels

ABSTRACTThis paper examines the electron emission characteristics of the MgO layer in the case of spraying the MgO crystal powders based on the two monitoring parameters such as the electric field strength and the panel temperature. In particular, in order to analyze the effects of the electric field strength on the electron emission characteristics of the MgO layer with MgO crystal powders, the variations in the wall voltage induced by the electron emission are measured relative to the electric field strength between the address-sustain electrodes during an address period under various panel temperature conditions ranging from −5 to 65°C. As a result, it is observed that the electron emission characteristics of the MgO layer with MgO crystal powder strongly depend on the electric field strength rather than the thermal effect of exo-electron emission, which is confirmed by the measurement result of the wall voltage variation relative to the electric field strength under the low panel temperature of −5°C.

선형 계조를 갖는 교류형 플라즈마 디스플레이에서 방전 지연시간의 연구

선형 계조를 갖는 교류형 플라즈마 디스플레이에서 방전 지연시간의 연구

상판 전극들 사이에 먼 거리를 갖는 교류형 플라즈마 디스플레이에서 휘도효율의 향상

높은 Xe 가스 혼합하에서 상판의 두 개의 전극의 간격이 먼 교류형 플라즈마 디스플레이 구조에 제안된 구동 파형이 적용되었을 때 휘도 및 휘도효율이 조사되었다. 종래의 구조와 달리 상판의 두 전극 사이의 거리가 멀기 때문에 초기화 및 유지기간에서의 구동 파형이 수정되어야 한다. 초기화 기간에는 상판에 있는 주사와 유지 전극 사이에 면방전을 발생시키기 위하여 유지 전극에 음의 전압이 인가되었다. 그리고 유지기간 동안에는 상판과 하판의 전극 사이에 트리거링을 먼저 발생시킨 후에 상판사이에 면방전을 유도하기 위하여 구동 파형이 수정되었다. 패널 내부에 사용된 Xe 가스 함량은 15%이고 상판의 전극 간격이 500μm인 패널 조건하에서 유지기간 중에 양의 유지전압 140V와 음의 트리거링 전압 -110V 조건의 수정된 구동 파형을 적용한 결과, 휘도 340cd/㎡와 휘도효율 3.26lm/W를 얻을 수 있었다.

Modified Driving Waveform for Stable High-Speed Address Discharge in AC PDP under High Xe Gas Mixture

For the fast and stable address under the high Xe gas condition of plasma display panels (PDPs), the weak and strong discharge characteristics in both surface-gap and plate-gap discharges were examined for two different Xe gas contents (7 and 20%). It is observed that it is very difficult to produce the strong plate-gap discharge required for the address discharge as the Xe gas content increases from 7 to 20%, thus requiring an additional voltage increase for the strong plate-gap discharge. Based on these experimental observations, the modified driving waveform, featuring being able to produce an intensified address discharge in the plate-gap discharge without a misfiring discharge in the surface-gap discharge, is proposed for the successful high speed address of the high Xe PDP.

Effect of gold nanorods in an MgO protective layer of AC plasma display panels.

We propose a modified MgO protective layer for alternating current plasma display panels. The modified MgO protective layer of the panel tested here has a structure that incorporates silica-coated Au nanorods (NRs), leading to localized surface plasmon resonance (LSPR) in the near-infrared (IR) region. The silica-coated Au NRs were synthesized by a simple chemical method and inserted into an MgO protective layer using an air-spray method. The operating voltage of the proposed structure was decreased by 10 V. The luminance and luminous efficacy of the test panel part with the silica-coated Au NRs both increased by about 15%. According to the measured results of the IR response time, the sustain discharge time lag was reduced. In addition, by inserting the silica-coated Au NRs into the MgO protective layer, a decrease of the IR emission proceeding from the plasma discharge was acquired. Finally, we investigated the LSPR effect of the silica-coated Au NRs in a simulation with a finite-difference time domain method.

Modified Driving Waveform for Ridged Dielectric Structure Based on Vt Closed Curve Analysis in AC PDP

The discharge characteristics of an AC plasma display panel (PDP) with the ridged dielectric structure were investigated. In particular, characteristics such as firing voltage and related wall voltage based on the Vt closed curve measurement were compared in the ridged and conventional dielectric structures. The front plate of the AC PDP with the conventional panel structure is composed of glass, electrodes and dielectric. In the ridged dielectric structure, the middle part of the dielectric layer is eliminated to allow for light to pass through more easily. This structural modification causes the plasma discharge between the two front electrodes to occur at a lower voltage. Meanwhile, as the ridged dielectric structure differs from the conventional dielectric structure, various problems arise if the conventional driving waveform is used. Especially, as the discharge firing voltage characteristics between the scan and sustain electrodes of the ridged dielectric structure is different, it is necessary to modify the reset and address waveforms accordingly. In this study, the Vt closed curves are investigated to compare the discharge firing voltages in the conventional and ridged dielectric structures. Based on the investigation, a modified driving waveform for the ridged dielectric structure was proposed. Using the proposed waveforms, the address discharge time of the ridged dielectric structure was reduced by approximately 200 ns.

플라즈마 디스플레이 패널에서 선형적 계조 표현을 위한 유지 구동파형의 연구

교류형 플라즈마 디스플레이(AC PDP)의 유지기간 동안 강방전과 약방전을 발생시킬 수 있는 파형을 인가하여 계조의 선형성을 향상시키기 위한 새로운 유지 구동파형과 그의 구현 방법이 제안된다. AC PDP의 계조를 표현하기 위한 구동방법은 하나의 TV 프레임 내에 여러 개의 서브필드를 조합하는 것이며 각 서브필드 내의 휘도는 유지 펄스 개수의 차이에 의해 결정된다. 유지기간 동안 유지 펄스들이 인가되면 똑같은 크기의 강한 플라즈마 방전만 발생하므로 이상적으로 선형적 계조 표현이 용이해 보이지만, 각 서브필드 내에는 계조 표현과 상관없는 기입 방전과 첫 번째 유지 방전이 매번 발생하기 때문에 사실상 선형적 계조 표현이 어려워진다. 그러므로 유지기간 동안 유지 파형의 모양을 변형시켜서 강방전 대신 일부분 약방전도 발생시키는 새로운 유지 구동 파형을 적용하여 계조 표현을 선형에 가깝도록 개선하였다.

Modification of a Driving Waveform in an AC Plasma Display Panel With Sc-doped MgO Protecting Layer

In this paper, the change in addressing characteristics of an AC Plasma display panel with Sc-doped MgO protecting layer are investigated with the variation of operation temperature, addressing waiting time, and scan voltage level during address period using ramp addressing pulse. The addressing voltage in the cell which is addressed long time after reset period is higher but showed narrower distribution of addressing discharge event than other cell. This phenomenon is assumed as a result of the increased wall voltage loss and the enhancement of priming effect due to the electron emission from the Sc-doped MgO protecting layer. A modification of driving waveform for scan electrode is suggested to minimize the wall voltage loss and utilize the priming effect due to the electron emission from the protecting layer, and the improvement in addressing characteristics is presented.

Study on the Addressing Characteristics of an ac PDP With Sc-Doped MgO-Protecting Layer

In this paper, the addressing characteristics of an ac plasma display panel (PDP) with Sc-doped MgO-protecting layer are investigated. The characteristics of addressing voltage and temporal distribution of addressing discharge event in Sc-doped MgO panel are different from those in a conventional MgO panel. In particular, the characteristics depending on the operation temperature are changed drastically in Sc-doped MgO panel. The formative discharge time lag increases as the addressing pulse application time and operation temperature increase regardless of protecting layers. The statistical time lag shows the contrary trend compared to the formative discharge time lag except for the MgO when operated in room temperature. The variation of addressing voltage and temporal distribution of addressing discharge event in different protecting layers can be understood through the survey of previous research result on the exoelectron emission characteristics from protecting layers in an ac PDP. It is assumed that the emission of electrons from a protecting layer results in the decrease of wall voltage but increase of priming effect for the addressing discharge. Also, the possibility for the control of addressing characteristics is suggested by changing scan voltage level during address period.

Improvement of Luminous Efficacy Using Short Sustain Pulsewidth and Long Off-Time Between Sustain Pulses in AC Plasma Display Panel

This paper investigated the discharge characteristics driven by a short sustain pulsewidth according to the sustain pulsewidth and the off-time between the sustain pulses in an ac plasma display panel. As a result, the luminous efficacy was found to increase when decreasing the sustain pulsewidth due to a reduced ion heating loss. Furthermore, it was shown that the sustain discharge mode could be controlled by adjusting both the sustain pulsewidth and the off-time. It should be noted that the luminous efficacy was significantly improved when the sustain discharge was made to occur outside the sustain pulsewidth due to the minimized ion heating loss. Consequently, under this experimental condition, a sustain pulsewidth of 0.4 μs and an off-time of 10 μs produced the maximum luminous efficacy of 3 lm/W, which was almost double the value obtained with the conventional sustain pulsewidth of 2 μs and the off-time of 10 μs.

Optimization of sustain pulses in the single-sustainer driving of an AC plasma display panel

It was reported that the discharge characteristics of an AC plasma display panel (PDP) with a single sustainer, which is sustained by the successive application of bipolar pulses, are different from those with a conventional driver. The luminous efficacy of an AC PDP with a single sustainer increases with increased sustain voltage, whereas the conventional PDP shows the opposite trend, resulting from the dependence of the luminous efficacy on the polarity of the sustain pulse. In this study, the IR emission efficiency was analyzed to determine the dependence on the polarities of the sustain pulses. The IR emission efficiency showed dependence on the amplitude of the sustain pulse with opposite polarities, which provided a motive to optimize the sustain pulse amplitude in each polarity of the sustain pulse. The luminous efficacy in an AC PDP with a single sustainer increased with increasing positive-going pulse amplitude, and decreased as the negative-going pulse amplitude increased. The optimal sustain can be obtained under the condition where the positive-going pulse amplitude is high and the negative-going pulse amplitude is low. As a result, a 5% higher luminous efficacy can be achieved when the maximum positive and minimum negative sustain voltages are used than when equal positive and minimum negative sustain voltages are used.

Effects of Operating Frequency on Panel-Aging and Discharge Characteristics in AC Plasma Display Panel

This paper investigates the changes in the optical and discharge characteristics during the panel-aging process in ac plasma display panel as a parameter of the operating frequency. The resulting changes in the optical and discharge characteristics, including the firing voltage, dynamic voltage margin, three-dimensional IR emission, and SEM image, are then compared for the three different operating frequencies (10, 25, and 50 kHz) during the panel-aging process. Our experimental results confirm that the 50 kHz operating frequency is very effective in obtaining the uniform surface morphology of the MgO thin film during the panel-aging process.

Influence of Surface Contamination on the Electrical Breakdown between Ag Electrodes in AC Plasma Display Panels

In this study, the surface contamination and related electrical current were examined by TOF-SIMS and Micromanipulators in order to identify the main factors on the electrical short phenomenon between Ag electrodes in the 50-in. full HD AC-PDPs with a various contaminations. The experimental results reveals that such atoms as Na, K, and Cl were detected on both Ag electrode and glass surface as culprits causing sever surface contamination. It was also found that the more severely contaminated the samples were, the more increased the electrical current became. This result confirms that the electric breakdown on the Ag electrode is closely related with its surface contamination.

Effects of pressure and electrode resistance on AC-plasma display panels (AC-PDPs) for various panel temperatures

In this study, the effects of panel temperature on AC-plasma display panels (AC-PDPs) were investigated. Macroscopic properties, such as the luminance, discharge delay time lag, and discharge current decreased while the breakdown voltage increased with increasing panel temperature. These data implied that changes in the materials properties with the panel temperature strongly affected the macroscopic properties, including the gas-discharge characteristics of AC-PDPs. The reason can be explained by the change in the collision kinetics due to the increase in the pressure in the AC-PDPs, the voltage drop due to the increase in the resistivity of the metal electrodes, and the decrease in the effective voltage due to the decrease in the surface resistivity of a MgO protective layer. The properties of other components such as the indium-tin-oxide (ITO) transparent electrode and the dielectric layer changed little in the considered temperature range (0 ∼ 80 °C), and, thus, are not thought to affect the macroscopic properties of AC-PDPs with changing panel temperature.

Effects of Gas Pressure on Temporal Image Sticking in AC Plasma Display Panel

The temporal dark and bright image sticking phenomenon was examined under various gas pressures in a 42-in. ac-PDP with an He(35%)-Xe(11%)-Ne gas composition. To study the temporal dark and bright image sticking phenomena for various gas pressures, the displayed luminance, IR emission profile, disappearing time, color temperature, panel temperature, and Xe and Ne ions density of temporal dark and bright image sticking were measured relative to the gas pressure. With a decrease in the gas pressure, the temporal bright image sticking was observed to be reduced due to the reduction of the ion bombardments onto the phosphor layer.

Influences of He Contents and Panel Working Gas Pressures in Ternary Gas Mixture on Discharge Characteristics in AC Plasma Display Panel

The discharge characteristics, particularly the address and sustain discharge characteristics, were examined relative to the He contents and panel working gas pressures under 11% Xe content in the 50-in. full HD AC-PDPs with a ternary gas mixture (Xe-He-Ne). The Xe content in this study was fixed at 11%. As the helium gas increases from 0 to 50%, the formative address delay becomes shortened by about 60 ns. In addition, the luminance are increased by about 15 cd/m2 because of enlarging the Xe2* excimer emission (823 nm) with an increase with the He gas. Also, the power consumption is reduced by about 30 W since the addition of He gas induces a reduction of cathode fall potential. The decrease in the gas pressure from 600 to 300 Torr causes a lower firing voltage, thereby resulting in reducing both the formative and statistical address delay times by about 71 ns and by about 65 ns, respectively. As a consequence, the pressure below 400 Torr and He content above 50% are the best panel factors suitable for high speed and low voltage driving of micro-discharge cells with the 50 in full HD cell size.

Numerical Analysis and Experiment on Discharge Characteristics Under Various Address Electrode Widths in AC Plasma Display Panel

The address-electrode width is an important parameter to affect both the address and sustain discharge characteristics in an ac-plasma display panels (ac-PDPs). It was numerically founded that as the address-electrode width was wider, the capacitance between the sustain and address electrodes (=CAY) increased, but the capacitance between the two sustain electrodes (=CXY) decreased. The resultant changes in the sustain and address discharge characteristics, such as a firing voltage, discharge delay time, and luminance, were examined in the 50 in ac-PDP with a high Xe (>11%) content. The increase in the address-electrode width caused an increase in the firing voltage between the sustain electrodes, which was mainly due to the decrease in the capacitance between two sustain electrodes and the increase in the wall charges accumulation toward the address electrode. In particular, the luminance was observed to increase with an increase in the address-electrode width. As the address-electrode width became broaden, the sustain discharge path was longer toward the address electrode, thereby enlarging the discharge volume. Therefore, it was observed that the IR (VUV) and Ne emissions were increased considerably. Furthermore, these experimental results were confirmed by simulating the electric field strength and Xe ion distribution in discharge cell with respect to the address-electrode width.