• Journal of the Korean institute of surface engineering
• /
• v.44 no.4
• /
• pp.165-171
• /
• 2011

In this work, handling of sapphire substrate for LED by using an electrostatic chuck was studied. The electrostatic chuck consisted of alumina dielectric, which was doped with 1.2 wt% $TiO_2$. As the volume resistivity of alumina dielectric was decreased, the electrostatic force was increased by Johnsen-Rahbek effect. The narrower width and gap size of electrode led to the stronger electrostatic force. When alumina dielectric with $3.20{\times}10^{11}{\Omega}{\cdot}cm$ resistivity and 3 mm width/1.5 mm gap sized electrode was used, the strongest electrostatic force in this work was obtained, which value reached to ~14.46 gf/$cm^2$ at 2.5 kV for 4-inch sapphire substrate. This results show that alumina electrostatic chuck with low resistivity and fine electrode pattern is suitable for handling of sapphire substrate for LED.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.15 no.3
• /
• pp.25-34
• /
• 2001

In this paper, discharge lamp ozonizer(DLO) of a new discharge type using superposition of gaseous electrical discharge for environment improvement was designed and manufactured. DLO is equipped with 3 electrodes(central ground electrode of discharge lamp type internal high voltage electrode of mesh type and external high voltage electrode of spiral type), and it is composed of double gap(gap between discharge lamp and internal electrode, gap between discharge lamp and external electrode). Internal and external electrodes are respectively applied AC high voltage which has 180[$^{\circ}$] phase difference. Ozone is generated by overlaying of each silent discharge which is respectively came from two gaps. At the moment discharge characteristics and ozone generation characteristics of DLO were investigated in accordance with quantity of supplied gas, discharge power and the number of DLO. When ozone generated by DLO was in contact with NO gas, removal characteristics was excellent, so it confirmed that DLO could be used as air environment improvement facility.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.795-798
• /
• 2008

The discharge characteristics of a flat plasma backlight with long electrode gap are investigated. The effect of operating voltage and repetition rate on brightness and luminance efficiency is investigated. A new high efficacy mode is found at low frequencies around 15-40 KHz; a lumen efficacy of 15.3 lm/W is achieved at a luminance of $2400\;cd/m^2$. In the high brightness mode, present at high voltage, we find a maximum luminance of $5900\;cd/m^2$ at 30KHz.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.340-343
• /
• 2008

This work reports the simple fabrication of the single cell gap transflective liquid crystal display (LCD) using wire grid polarizer. The nano sized wire grid polarizer was patterned on common electrode itself, on the reflective part of FFS (Fringe field switching) mode whereas the common electrode was unpatterned at transmissive part. However, this structure didn't show single gamma curve, so we further improved the device by patterning the common electrode at transmissive part. As a result, V-T curve of proposed structure shows single gamma curve. Such a device structure is free from in-cell retarder, compensation film and reflector and furthermore it is very thin and easy to fabricate.

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.46-48
• /
• 2004

A micro-scale discharge device has been fabricated using MEMS technology and failure mechanisms during DC discharge are investigated for the microstructure. The failure of sustaining the plasma is mainly caused by either open or short of the micro-electrodes, both resulting from the sputtered metal atoms during the DC discharge. The glow discharge lifetime of the microstructures is found to depend on bias circuit scheme as well as the electrode structure. Based on the understanding of the failure mechanism, a novel microstructure is suggested to improve discharge lifetime and the longer lifetime is experimentally demonstrated. In addition to the failure mechanism, an electric breakdown between two electrodes with microns gap are studied using micromachined metal structures. The electrode gap is able to be accurately controlled by thickness of a sacrificial layer and the electric breakdown was measured while varying the gap from $2{\mu}m$ to $20{\mu}m$. The electric breakdown behavior was found to highly depend on the electrode material, which was not considered in Paschen's law.

• 전기의세계
• /
• v.24 no.6
• /
• pp.77-84
• /
• 1975

This paper treats A.C. arc movement in a transverse A.C. magnetic field at atmospheric pressure with the purpose of selecting electrode materials and obtaining detailed data for design of A.C. air circuit breaker, plasma accelerator and plasma jet. Arc velocities in transverse magnetic field are measured by varying arc current, arc voltage, gap length, magnetic flux density and the erosion of electrode surface, which influence arc velocities. The main results are; 1)Arc velocities in transverse magnetic field have different values according to electrodes of various materials and decrease in a descending order of cold cathode, medium cathode and hot cathode. 2)Arc velocities in transverse magnetic field increases with arc current, arc voltage, gap length and magnetic flux densith and on the other hand decrease with the increase of electrode surface erosion. 3)D.C.arc velocity in D.C. magnetic field is higher than A.C. arc velocity in A.C. magnetic field of the same value.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.101-104
• /
• 2003

The real test panel with the $200{\mu}m$ discharge gap in a coplanar AC plasma display panel was investigated. The auxiliary electrode was placed between two sustain electrodes and used for providing wall charges and prime particle during sustain period. The luminous efficiency had the maximum value when the voltage of the auxiliary pulses was 20 ${\sim}$ 100[V]. The luminous efficiency of coplanar long-gap discharge with auxiliary electrode was 2.6 times as much as that of the conventional structure.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1999.11a
• /
• pp.145-148
• /
• 1999

In this paper, multi gap type ozonizer(MGO) has been designed and manufactured. The ozonizer is equipped with three electrodes(central electrode of screw shape, internal electrode and external electrode) of cylinder shape. This paper describes the following two characteristics: $\circled1$ The characteristics of discharge with variation of output voltage of AC H.V source, flux of oxygen supplied gas and discharge voltage. $\circled2$ The characteristics of ozone generation by varying flux and discharge power.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.66-67
• /
• 2007

We have developed reflective information display using opposite-charged two particles. An appropriate amount of both the yellow and the black powers are putted between the ITO patterned glass substrate separated with cell gap. The rib maintains the cell gap and prevents the interference between the pixels. When a negative voltage is applied to the upper ITO electrode, the positively charged black powder moves to the upper electrode viewing a black appearance. In case of positive voltage is applied to this electrode white particle is observed. So we analyzed the electrical and optical properties of our charged particle type display panel.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.36 no.11
• /
• pp.796-805
• /
• 1987

The flashover voltages have been investigated for spacer and unbridged-gap in SF6-N2 gas mixtures up to the value of 760(torr. cm), The gap was stressed by DC source The results obtained are as follows` 1) The flashover voltages for an unbridged gap and for a spacer in SF6, N2 and SF6-N2 gas mixtures follow the Paschen's curve. 2) The polarity effects was not observed in both unbridged gap and a spacer which had per ect contact with an electrode. The flashover voltages for negative polatity are lower than those for positive polarity in case of imperfect contact. 3) 3%flashover voltage is decreased by putting a spacer which had perfect contact with an electrode. The spacer which has a gap void shows the lowest flashover voltage. 4) The lowest spacer efficiency was obtained with higher gas pressure & large amount of N2 content. The flashover voltages depend on the gas pressure rather than the spacer efficienty at low value of pd. 5) The flashover voltages of gas mixtures of N2 with SF6 are relatively high, even though the amount of SF6 gas content is small.