• 전기학회논문지
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• 제58권5호
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• pp.982-988
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• 2009

In a surface type ac PDP having $200{\mu}m$ gap between the surface electrodes, the luminous efficacy has a reciprocal dependence on the sustaining frequency. The discharge current flowing to the address electrodes are measured to investigate the phenomena and spectral intensity from visible light to infra red is measured to verify phosphor saturation with the frequency. Experiments show the discharge between the address and surface electrodes deteriorates the efficacy in high sustaining frequencies. Pulse width modulation is introduced to improve the efficacy. In optimum conditions, we obtained 1.99lm/w and 1.79lm/w at 200kHz and 250kHz, respectively.

• 한국정보통신학회논문지
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• 제9권8호
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• pp.1793-1798
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• 2005

액정 디스플레이 소자의 디렉터 내에서 결점을 모델링 할 수 있는 fast Q-텐서법을 이용하여 불균일한 표면에서 발생할 수 있는 결점의 발생과 움직임에 대한 모델링을 하였다. 결점을 모델링하기 위하여 $1{\mu}m$ 단차의 전극을 가진 수직배향셀을 이용하였다. 모델링을 통하여 단차에서 발생하는 액정 디렉터 내에서의 결점의 발생과 결점선을 확인할 수 있었으며 이러한 결과는 실험을 통하여 확인하였다.

• 한국전기전자재료학회논문지
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• 제11권4호
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• pp.306-313
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• 1998

To elucidate the liquid crystal(LC) molecules alignment mechanism, it is important to determine the molecular orientation of the rubbed polymer surface molecules that directly contact with LC molecules. In this work, the molecular orientation on a rubbed surface of polyimide (SE-3310, Nissan) film has been studied by polarized FTIR absorption spectroscopy. It has been found that molecular chain on the rubbed surface of polymide film are oriented along the rubbing direction and are tilted up on an average by 5.0$^{\circ}$. In the SHG(Second Harmonic Generation) measurement, the pretilt angle of molecular chain on the poylmide fim was 4.6$^{\circ}$ fro, the surface plane. And the pedit angle of liquid crystal (ZLI-2293, Merck) molecules measured by crystal rotation method was 5.4$^{\circ}$in the same rubbing condition.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.404-405
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• 2007

Tin-doped indium thin film is outstanding material among transparent Conductive Oxide (TCO) materials. ITO thin films show a low electrical resistance(<$10^{-4}\;[{\Omega}{\cdot}m]$) and high transmittance(>80%) in the visible range. ITO thin films usually have been deposited on the glass substrate. In order to apply flexible display, the substrate should have the ability to bend and be deposited without substrate heat. Also properties of ITO thin film depend on what kind of substrate. In this study, we prepared ITO thin film on the polycarbonate (PC) substrate by using Facing Target Sputtering (FTS) system. Before deposition of ITO thin film, PC substrate took plasma surface treatment. The electrical and surface properties of as-deposited thin films were investigated by Hall Effect measurement, UV/VIS spectrometer and the surface property of substrate is investigated by Contact angle measurement.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.541-544
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• 1999

We synthesised a novel photo-alignment material of PCEMA (poly(cinnamolyethyl methacrylate)) on photo-dimerization reaction. Next we investigated the electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-liquid crystal display (LCD) with linearly polarized ultraviolet (UV) light irradiation on PCEHA surface. The excellent voltage-transmittance characteristics of photo-aligned TN-LCD on PCEMA surface were obtained. The threshold voltage of photo-aligned TN-LCD decreases with increasing the UV light irradiation time on PCEMA surface. Also, the response time of photo-aligned TN-LCD on PCEMA surface is almost the same as rubbing-aligned TN-LCD.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.498-501
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• 2003

We investigated response characteristics of twisted nematic (TN) cell with different nematic liquid crystals (NLCs) and cell gap d on a rubbed polyimide (PI) surface. High transmittance and fast response time of the TN cell on the rubbed PI surface were achieved by using high birefringence (${\Delta}n$) and low cell gap d. The transmittance and response time of the TN cell on the rubbed PI surface decreased with decreasing ${\Delta}nd$. The fast response time of TN cell using high birefringence with ${\Delta}nd=0.363$ on the rubbed PI surface was measured 5.1 ms.

• 소성∙가공
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• 제7권6호
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• pp.575-585
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• 1998

An automated surface-strain measuring system using the image processing technique is developed in the present study which consists of the hardware to capture and to display digital images. and the software to calculate the 3-D informations of grid points from two views. New or improved algorithms for the mapping and establishing correspondence of grid points and elements the camera calibration and the subpixel measurement of grid points are implemented. As an application of the present system the surface-strains of deformed blanks in the limitting dome height test the square cup deep-drawing and punch stretching to obtain the forming limit diagram are measured. The results are com-pared with those obtained by conventional manual methods.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.220-228
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• 2018

In this study, we found a simple surface biofunctionalization of biphasic calcium phosphate (BCP) based on the high affinity between alendronate and the calcium ions of BCP, and the strong interaction between heparin and bone morphogenic protein-2 (BMP-2). The biofunctionalized BCP did not be precipitated well and display a remarkable enhancement of osteogenic activity of human adipose-derived stem cells by showing increased alkaline phosphatase (ALP), calcium deposition and osteogenic-related genes (i.e., Runx-2, ALP, osteocalcin, and osteopontin), and bone regeneration in the calvarial defect model. Therefore, this simple surface technique can be used to easily functionalize various calcium phosphates.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2003년도 춘계학술대회 발표 논문집
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• pp.18-22
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• 2003

The sapphire wafers for blue light emitting devices were manufactured by the implementation of the surface machining technology based on micro-tribology. This process has been performed by grinding, lapping and polishing. The surfaces of sapphire wafers were mechanically affected by residual stress and surface default. This mechanical stress and strain can be cured by thermal anneal ing process. The sapphire crystalline wafers were annealed at $1100~1400^{\circ}C$ and then characterized by double crystal X-ray diffraction. The sample showed good quality of crystalline wafer surface wi th full width at hal f maximum of 16 arcsec for the 4-hour heat-treatment at $1300^{\circ}C$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.132-132
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• 2015

Virtual metrology (VM) model based on plasma information (PI) parameter for C4F8 plasma-assisted oxide etching processes is developed to predict and monitor the process results such as an etching rate with improved performance. To apply fault detection and classification (FDC) or advanced process control (APC) models on to the real mass production lines efficiently, high performance VM model is certainly required and principal component regression (PCR) is preferred technique for VM modeling despite this method requires many number of data set to obtain statistically guaranteed accuracy. In this study, as an effective method to include the 'good information' representing parameter into the VM model, PI parameters are introduced and applied for the etch rate prediction. By the adoption of PI parameters of b-, q-factors and surface passivation parameters as PCs into the PCR based VM model, information about the reactions in the plasma volume, surface, and sheath regions can be efficiently included into the VM model; thus, the performance of VM is secured even for insufficient data set provided cases. For mass production data of 350 wafers, developed PI based VM (PI-VM) model was satisfied required prediction accuracy of industry in C4F8 plasma-assisted oxide etching process.