• 한국전기전자재료학회논문지
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• 제13권7호
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• pp.625-629
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• 2000

We synthesized a new copoly (PM4Ch-ChMA) copoly(poly(4-methacryloyloxy) chalcone-cholesteryl methacrylate) having chalconyl and cholesteryl moiety for homeotropic liquid crystal(LC) alignment. Pretilt angles of nematic(N) LC generated by linearly polarized UV exposure on the copolymer surfaces were investigated. Good thermal stabilities of the synthesized copolymer were obtained by TGA (Thermogravimetric Analysis) measurement. Pretilt angles of the NLC decreased with increasing UV exposure time on the copolymer surfaces. We consider that the pretilt angle of the NLC is attributed to increased chalcone by increased UV exposure time. High pretilt angle of the NLC is attributed to increased chalcone by increased UV exposure time. High pretilt angle of 81$^{\circ}$was observed after the UV exposure for 3 min.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.477-480
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• 2003

We investigated the electro-optical (EO) performances of the super twisted nematic liquid crystal display (STN-LCD) on the polyimide (PI) surface using polymer film. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance (V-T) curve of the plastic STN-LCD was observed on the polyimide (PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide (PI) surfaces using polymer film can be achieved. However, the transmittance of the plastic STN-LCD on the polyimide (PI) surfaces using polymer film decreased greatly as cell gap decreases.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.426-427
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• 2006

In this paper, the neural network model of the pretilt angle in the nematic liquid crystal on the homogeneous polyimide surface with different surface treatments is investigated. The pretilt angle is one of the main factors to determine the alignment of the liquid crystal display. The pretilt angle is measured to analyze the variation of the characteristics on the various process conditions. The rubbing strength and the hard baking temperature are considered as input factors. Latin hypercube sampling was used to generate initial weights and biases.

• 한국광학회지
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• 제9권2호
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• pp.117-122
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• 1998

쌍안정 TN LCD의 스위칭 특성을 Berreman에 의해 제시된 backflow를 고려한 이론적 모델을 적용하여 해석하였다. 그리고 이 모델을 적용하여 $180^{\circ}$ 쌍안정 TN 액정셀이 쌍안정 특성을 갖기 위해서는 두 유리기판을 서로 반대 방향으로 러빙해야 하고 d/p도 중요한 요소임을 확인하였다.

• 한국재난정보학회:학술대회논문집
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• 한국재난정보학회 2023년 정기학술대회 논문집
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• pp.215-216
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• 2023

본 논문에서는 액정 디스플레이 산업에서 발생하는 공정별 유해요인 및 연구동향에 대해 조사하였다. 액정 디스플레이는 컴퓨터, 텔레비전, 태블릿, 스마트폰 등에서 사용되는 주요 디스플레이 기술로, 빠른 응답속도와 저전력 운영, 높은 해상도 등을 제공한다. 액정 디스플레이 제조에서 중요한 역할을 하는 액정 배향 기술은 러빙 천을 사용하는 물리적 배향법과 같은 기존 방법의 단점을 극복하기 위해 비접촉식 액정 배향법과 같은 연구가 진행 중이다. 액정 디스플레이 제조과정은 TFT, 컬러필터, 액정, 모듈 단계로 이루어져 있으며 이 과정에서 사용되는 다양한 화학물질은 작업자에게 노출 될 수 있다. 그러므로 유해요인의 관리와 분석, 공정의 개선, 그리고 화학 물질 사용 최소화와 같은 기술에 대한 연구가 중요하다. 최근에는 비접촉식 액정 배향법 및 박막 제작 기술에 대한 연구가 활발히 진행 중이며, 소자 오염 및 배향 공정 등에서 발생하는 유해요인을 최소화하기 위한 노력이 계속되고 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.120-122
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• 1997

In this paper, the viewing angle characteristics of amorphous (a) - twisted nematic (TN) - liquid crystal display (LCD) on poly(viny)cirmamate (PVC) alignment surfaces were investigated. It was found that the threshold voltage is increased with increasing the polymerization on PVC surfaces. We suggest that the threshold voltage is affected to the surface anchoring strength with increasing the polymerization of the alignment film. Also, we obtained that the viewing angle of a-TN-LCD is increased with increasing the polymerization on PVC surfaces. Finally, we considered that the viewing angle of a-TN-LCD on PVC surfaces is large compared to TN-LCD on rubbed polyimide (Pl) surface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.369-372
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• 2001

We studied the electro-optical (EO) performance in the vertical-alignment (VA) - l/4$\pi$ cell photoaligned with polarized UV exposure on a homeotropic photopolymer surfaces. Excellent voltage-transmittance curve in the VA - l/4$\pi$ cell photoaligned with polarized UV exposure for 3 min on the photopolymer containing cholesterol group of 8% can be achieved. The V-T characteristics in the VA-l/4$\pi$ cell photoaligned on the photopolymer surface can be improved by increasing cholesteryl group. For response time measurement, the transmittance characteristics of the VA-l/4$\pi$ cell photoaligned on the photopolymer surface was better than that of the VA-l/4$\pi$ cell rubbingaligned on a polyimide(Pl) surface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.43-44
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• 2006

We have studied electro-optical characteristics and stability of liquid crystal director depending on electrode patterning of common electrode on top substrate in patterned vertical alignment (PVA) mode. In the present studies, new type of common electrode pattern was suggested to enhance a dark state by reducing interference area due to data signal. According to the simulation result, PVA device with new common electrode pattern contributed to Improvement of an aperture ratio.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1395-1397
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• 1998

In this paper, we studied the liquid crystal(LC) alignment and generation of pretilt angle in nematic (N) LC with oblique p-wave polarized ultraviolet (UV) light irradiation on the two kinds of the polyimide (PI) surface. The monodomain alignment of NLC is obtained with oblique p-wave polarized UV light irradiated on PI surface at 5$\sim$60min. We obtained that the pretilt angles of the NLC is generated about $2.1^{\circ}$ with angle of incidence of $30^{\circ}$ at 20min. Also, the pretilt angle of NLC decreases with increasing the imidization temperature on PI surface.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.9-10
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• 2000

The wide viewing angle and fast response time characteristics of negative dielectric anisotropy nematic liquid crystal (NLC) using a novel vertical-alignment (VA) - 1/4 ${\pi}$ cell mode on a homeotropic alignment layer were investigated. Good voltage-transmittance curves and low driving voltage using the novel VA - 1/4 ${\pi}$ cell mode without a negative compensation film were obtained. The iso-viewing angle characteristics of NLC using the novel VA - 1/4 ${\pi}$ cell mode without a negative compensation film can be achieved. The fast response time of 24.4 ms in NLC was successfully measured. The iso-viewing angle, fast response time, and low driving voltage characteristics using the novel VA - 1/4 ${\pi}$ cell mode can be achieved.