• Journal of Information Display
• /
• v.9 no.3
• /
• pp.28-32
• /
• 2008

Low sustained voltage $(V_s)$ and high luminous efficiency (lumen/Watts) are required for the enhanced performance of an AC PDP. Both are not realized in the same condition, however, because luminous efficiency decreases when the sustained voltage is lowered in most cases. In this study, the three design factors in the front panel of a PDP, i.e., the thickness and position of the bus electrode and the thickness of the dielectric layer, were chosen to investigate how they affect the sustained voltage and the luminous efficiency, and to find a way to optimize them. Two values were given to each of the three design factors, and experiments were done via full factorial design, i.e., with a total of eight conditions, using a 3-in.diagonal test panel. The changes in the sustained voltage and the luminous characteristics were explained in connection with the discharge characteristics of the PDP cells.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.2
• /
• pp.261-267
• /
• 2008

One of the most important issues in fence-type PDP is low luminance and luminous efficiency. To improve luminance and luminous efficiency, new sustain electrode structure which contains long discharge gap is necessary. However, it causes rise of firing voltage. In this paper, a new fence electrode structure is proposed in order to solve these problems. To drop the firing voltage, tow hump shaped electrodes is added on the main discharge electrode, and distance between two humps is controlled. The experimental results show that the test panel with the narrow horizontal gap(40um) between two humps shows low firing voltage by 17V compared with 80um gap in spit of similar luminance and luminous efficiency.

• Korean Journal of Materials Research
• /
• v.21 no.10
• /
• pp.532-541
• /
• 2011

The Xe plasma flat lamp, considered to be a new eco-friendly LCD backlight, requires a further improvement of its luminance and luminous efficiency. To improve the performance of this type of lamp, it is necessary to understand the effects of the discharge variables on the luminous characteristics of the lamp. In this study, the luminous characteristics of a coplanartype Xe plasma flat lamp with a teeth-type electrode pattern were analyzed while varying the gas composition, gas pressure and input voltage. The effects of the phosphor layer on the discharge and the luminous characteristics of the lamp were also studied. The luminous efficiency of the coplanar-type Xe plasma flat lamp improved as the Xe input ratio and gas pressure increased. Higher luminous efficiency was also obtained when helium (He) was used as a buffer gas and when a phosphor layer was fabricated on the electrode region. In contrast, the luminous efficiency was reduced with increasing the input voltage. It was found that the infrared emissions from the lamp were affected by the Xe excitation rate in the plasma, the Xe gas density, the collisional quenching of excited Xe species by gas molecules, and the recombination rate between the Xe ions and electrons.

• 전기의세계
• /
• v.22 no.2
• /
• pp.57-69
• /
• 1973

The aim of this study was to investigate the behaviors of plasma jet under coaxial magnetic field in paralled with it for controlling optical characteristics and input power of plasma jet without impurity and instability of arc plasma column. Because the discharge characteristics of plasma jet were so distinctively different according to the existence or non-existence of magnetic field, the input power, luminous intensity of plasma jet and thermal efficiency were comparatively studied in respect of such variables as arc current, gap of electrode, quantity of argon flow, magnetic flux density, diameter and length of nozzle, with the use of several materials which were different in diameter and length of nozzel. The results were as follows; 1) The voltage tends to show a drooping characteristic at law current and then rises gradually. The luminous intensity of plasma jet increases exponentially with arc current. 2) Arc voltage increases and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity increase in accordance with the quantity of argon flow. 4) At first step, arc voltage increases to maximum value with the growth of flux density and then tends to show a gradual decrease. Luminous intensity decreases with the growth flux density. 5) Arc voltage decreases as the constriction length of nozzle increases, maximum decrease is shown at the constriction length of 20(mm) and it increases beyond that value. The luminous intensity decreases as the constriction length grows. 6) Arc voltage and luminous in tensity increase with the growth of diameters of nozzle. 7) Thermal efficiency has values between 50% and 75%, being influenced by arc current, the quantity of argon flow, flux density, the length of electrode gap and the constriction length of nozzle.

• Transactions on Electrical and Electronic Materials
• /
• v.6 no.6
• /
• pp.276-279
• /
• 2005

Influences of sustain pulse-width on electrical characteristics and luminous efficiency are experimentally investigated for surface discharge of AC-PDP. A square pulse with variable duty ratio and fixed rising time of 300 ns has been used in the experiment. It is found that the memory coefficient is significantly increased at the critical pulse-width. And the wall charges and wall voltages as well as capacitances are experimentally measured by Q- V analysis method along with the voltage margin relation, in terms of the sustain pulse-width in the range of $1{\mu}s$ to $5{\mu}s$ under driving frequency of 10 kHz to 180 kHz. And the luminous efficiency is also experimentally investigated in above range of sustain pulse-width with driving frequency of 10 kHz to 180 kHz. It is noted that the luminous efficiency for 10 kHz and 180 kHz are 1.29 1m/W and 0.68 1m/W respectively, since the power consumption for 10 kHz is much less than that for 180 kHz. It has been concluded that the optimal sustain pulse-width is in the range of $2.5 {\~}4.5{\mu}s$ under driving frequency range of 10 kHz and 60 kHz, and in the range of $1.5 {\~} 2.5{\mu}s$ under driving frequency range of 120 kHz and 180 kHz based on observation of memory coefficient, and wall voltage as well as luminous efficiency.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.2C no.5
• /
• pp.253-257
• /
• 2002

A new Current-Controlled Driving Method that can drive AC PDPs with low voltage and high luminous efficiency for the sustaining period is presented. In this driving method, the voltage source is connected to a storage capacitor and the stored voltage is delivered to the panel through LC resonance. Thus, this driving method can drive the panel with a voltage source as low as about half of the voltage necessary in the conventional driving methods. The discharge current flowing into the AC PDP is limited in this method. Thus, the power consumption for the discharge is reduced and the discharge input power to output luminance efficiency is improved. Experimental results using this driving method showed that we could drive an AC PDP with a voltage source as low as 146V and that high luminous efficiency of 1.33 1m／W can be achieved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.10
• /
• pp.822-833
• /
• 2011

A Xe plasma flat lamp, which has been noticed as a new eco-friendly LCD (liquid crystal display) backlight, requires the improvement of the luminance and the luminous efficiency although it has several advantages. To improve the performance of a lamp, it is necessary to understand the effects of discharge variables on the luminous characteristics of the lamp. Since it is difficult to diagnose a lamp discharge experimentally, the numerical analysis can be used instead. In this study, the luminous characteristics of a planar type Xe plasma flat lamp were analyzed with the variation of an input voltage and a pulse frequency. The numerical analysis of a lamp discharge was then performed using a RCT (relaxation continuum) model and a LFA (local field approximation) model. The comparison with the experimental results showed that the RCT model is valid for the numerical analysis of the flat lamp. The numerical analysis also showed that the modifications of a high frequency component and a voltage falling rate in the input voltage waveform could improve the luminous characteristics of the lamp.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.5
• /
• pp.409-417
• /
• 2003

We have studied electrical properties and luminous efficiency of organic light-emitting diodes(OLEDs) with different buffer layer and cathodes in a temperature range of 10 K and 300 K. Four different device structures were made. The OLEDs are based on the molecular compounds, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole transport, tris(8-hydroxyquinolinato) aluminum(III) (Alq$_3$) as an electron transport and omissive layer, and poly(3,4-ethylenedioxythiophene) :poly (styrenesulfonate) (PEDOT:PSS ) as a buffer layer. And LiAl was used as a cathode. Among the devices, the ITO/PEDOT:PSS/TPD/Alq$_3$/LiAl structure has a low energy-barrier height for charge injection and show a good luminous efficiency. We have got a highly efficient and low-voltage operating device using the conductive PEDOT:PSS and low work-function LiAl. From current-voltage characteristics with temperature variation, conduction mechanisms are explained SCLC (space charge limited current) and tunneling one. We have also studied energy barrier height and luminous efficiency at various temperature.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.11C no.2
• /
• pp.37-41
• /
• 2001

In this study, organic electroluminescent devices with the ITO/TPD/Alq$_3$/cathode structure, using various materials of Al, Mg:Ag, Al:Li, MgF$_2$/Al, and LiF/Al as cathodes, were fabricated. We investigated the electrical and optical properties of the devices as follow: current density-voltage(J-V), luminance-voltage(L-V) and luminous efficiency-voltage curves. The bilayer cathodes with LiF/Al and MgF$_2$/Al exhibited better device performance than the other cathodes. It is considered that the improved performance of the organic electroluminescent devices is attributable to the lowering of driving voltage caused by the enhanced electron injection. The alkaline-earth fluorides are desirable materials to improve the performance of the EL devices with the Al cathode, and high luminous efficiency was achieved.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.740-743
• /
• 2009

In this paper we proposed a new electrode design to get an enhanced luminous efficiency in AC PDP. The width and shape of the TTO electrode were varied, and the electro-optical properties such as luminance, power consumption, luminous efficiency were estimated with the variation of frequency, duty ratio and applied voltage. The discharge characteristics were investigated to explain the effect of the new electrode structure on the electro-optical properties.