• Title/Summary/Keyword: Ion beam exposure

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Liquid Crystal Alignment Effect on Polyimide Surface by Ion-beam Irradiation (이온빔을 이용한 폴리이미드 표면의 액정배향효과)

  • Park, Hong-Gyu;Oh, Byeong-Yun;Kim, Young-Hwan;Kim, Byoung-Yong;Han, Jeong-Min;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.330-330
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    • 2008
  • It is widely investigated to liquid crystal (LC) alignment using non-contact alignment method such as ion-beam (IB) irradiation, UV alignment, and oblique deposition. Because conventional rubbing method has some drawbacks. These include defects from dust and electrostatic charges and rubbing scratch during rubbing process. In addition, rubbing method needs additional process to remove these defects. Therefore rubbing-free methods like ion-beam irradiation are strongly required. We studied LC alignment effect on poly imide surface by IB irradiation and electro-optical (EO) characteristics of twisted nematic liquid crystal display (TN-LCD). In this experiment, a good uniform alignment of the nematic liquid crystal (NLC) with the ion-beam exposure on the polyimide (PI) (SE-150 from Nissan Chemical) surface was observed. We also achieved low pretilt angle as a function of ion-beam irradiation intensity. In addition, it can be obtained the good EO properties of the IB-aligned TN-LCD on PI surface. Some other experiments results and discussion will be included in the poster.

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Tilted Homeotropic Alignment using Ion Beam Process; Development of Novel Inorganic thin films

  • Hwang, Byoung-Har;Kim, Kyung-Chan;Ahn, Han-Jin;Kim, Jong-Bok;Baik, Hong-Koo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.450-452
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    • 2005
  • The ion beam alignment technique is one of the potential and fascinating methods. However, there are merely a few reports about aligning nematic liquid crystals (NLCs) horizontally for in-plane switching mode (IPS) by means of low energy ion beam exposure on inorganic materials such as DLC. In this study, we have investigated the tilted vertical alignment of NLC by the ion beam technique on the thin films of various amorphous silicon compounds as new inorganic alignment materials. Appropriate pretilt angles of NLC with preferred orientation on these thin films were achieved. And the electro-optic property of vertically aligned single domain cells has been investigated.

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A Study on Electro-optical Characteristics of the Ion Beam Aligned FFS Cell on a Inorganic Thin Film (무기 박막을 이용한 이온빔 배향 FFS 셀의 전기광학특성에 관한 연구)

  • Hwang, Jeoung-Yeon;Park, Chang-Joon;Jeong, Youn-Hak;Kim, Kyung-Chan;Ahn, Han-Jin;Baik, Hong-Koo;Seo, Dae-Shik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.10
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    • pp.1100-1106
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    • 2004
  • In this paper, we intend to make fringe-field switching (FFS) mode cell by the ion beam (IB) alignment method on the a-C:H thin film, to analyze electro-optical characteristics in this cell. We studied on the suitable inorganic thin film for fringe-field switching (FFS) cell and the aligning capabilities of nematic liquid crystal (NLC) using the alignment material of a-C:H thin film as working gas at 30 W rf bias condition. A high pretilt angle of about 5 $^{\circ}C$ by ion beam (IB) exposure on the a-C:H thin film surface was measured. Consequently, the high pretilt angle and the good thermal stability of LC alignment by the IB alignment method on the a-C:H thin film surface as working gas at 30 W rf bias condition can be achieved. An excellent voltage-transmittance (V -T) and response time curve of the IE-aligned FFS-LCD was observed with oblique IB exposure on the a-C:H thin films. Also, AC V-T hysteresis characteristics of the IB-aligned FFS-LCD with IE exposure on the a-C:H thin films is almost the same as that of the rubbing-aligned FFS cell on a polyimide (PI) surface.

Homeotropic Alignment Effect for Nematic Liquid Crystal on the SiOx Thin Film Layer by New Ion Beam Exposure

  • Han, Jeong-Min;Choi, Sung-Ho;Kim, Byoung-Yong;Han, Jin-Woo;Hwang, Jeoung-Yeon;Ok, Chul-Ho;Seo, Dae-Shik
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.6
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    • pp.293-296
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    • 2006
  • We studied homeotropic alignment effect for a nematic liquid crystal (NLC) on the $SiO_{x}$ thin film irradiated by the new ion beam method. $SiO_{x}$ thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) and were treated by the DuoPIGatron ion source. A uniform liquid crystal alignment effect was achieved over 2100 eV ion beam energy. Tilt angle were about $90^{\circ}$ and were not affected by various ion beam energy.

Alignment of Nematic Liquid Crystals on Polyimide Surface Bombarded by $Ar^+$ Beam

  • Gwag, Jin-Seog;Lee, Seo-Hern;Park, Kyoung-Ho;Park, Won-Sang;Han, Kwan-Yougn;Yoon, Tae-Hoon;Kim, Jae-Chang;Kim, Hee;Cho, Seong-Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.409-412
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    • 2002
  • We found that polyimide surfaces bombarded by a low energy argon ion beam align liquid crystals. The pretilt angle of the liquid crystals is controlled by ion beam parameters, such as the energy of the incident ions, the angle of incidence, exposure time and current density. The alignment direction of liquid crystal on substrates corresponded to ion beam direction. By argon ion beam the pretilt angle of the liquid crystals was controlled between $0.5^{\circ}$ and $4^{\circ}$for SE-3140 under the proper conditons. By the atomic force microscope (AFM), polyimide surfaces before and after bombarded by ion beam are compared.

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Study on Electro-Optical Specific of Polyimide and Organic Overcoat (PI와 유기 절연막 과의 전기광학 특성 비교에 관한 연구)

  • Kim, Byoung-Yong;Kim, Jong-Hwan;Han, Jeong-Min;Kim, Young-Hwan;Kang, Dong-Hoon;Kim, Jong-Yeon;Ok, Chul-Ho;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.376-376
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    • 2007
  • In Liquid Crystal Display (LCD) manufacturing, the organic over coat materials over coat materials for insulation layer of color filter with acryl ate was widely used. Therefore, we approach that the organic overcoat material can use to insulation layer for color filter and liquid crystal (LC) alignment layer in this research. The LC aligning capabilities was successful stuided for the first time. The organic overcoat layer and polymer layer was coated by spin-coating. In order to characterize the LC alignment, electric optic and residual DC and atomic force microscopy (AFM) image was used. The good LCD aligning capabilities treated on the organic overcoat thin film surfaces with ion beam exposure of $45^{\circ}$ above ion beam energy density of 1200 eV can be achieved. Also the good LCD alignment capabilities treated polymer on surfaces with ion beam exposure of $45^{\circ}$ above ion beam energy density of 1800 eV can be achieved. Comparing electro-optical characteristics between the Polyimide (PI) and the overcoat, the resultant transmittance of the overcoat considerably matched that of the PI and the residual DC also exhibited similar features with the PI.

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Chemically modulated polystyrene surface using various ion beam exposure time for liquid crystal alignment of high brightness mobile display (고휘도 휴대용 디스플레이를 위한 액정소자의 폴리스타일렌 배향막에 관한 연구)

  • Cho, Myung-Hyun;Lee, Ho-Young
    • Journal of Satellite, Information and Communications
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    • v.9 no.3
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    • pp.22-26
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    • 2014
  • This paper introduces homogeneous liquid crystal (LC) orientations on chemically modulated polystyrene (PS) surfaces using various ion beam (IB) exposure time. Transparent PS was replaced with conventional polyimde material. Especially, PS has higher transparent property than conventional polyimide thin film and it means PS is more suitable material for producing high brightness mobile LCD. As a non-contact process, IB bombardment process induced LC orientation in the direction parallel to the IB process. Through x-ray photoelectron spectroscopy, it was shown that the chemical compositional changes of the IB-irradiated PS surfaces were determined as a function of IB exposure time. Using this analysis, the optimal IB bombardment condition was determined at IB exposure time of up to 15 s. Moreover, thermal stability on IB-irradiated PS surfaces were carried out which showed that a relatively high IB exposure time induced a thermally stable LC alignment property. And it has a highly potential of mobile high transparent mobile LCD such as smart phone display and mobile information device.

Ion-Induced Changes in a $Se_{75}Ge_{25}$ Inoaganic Resist for Focused Ion Beam Microlithgraphy (집속 이온빔 마이크로리소그라피를 위한 비정질 $Se_{75}Ge_{25}$ 무기질 레지스터의 이온 유기 변화)

  • 이현용;박태성;정홍배;강승언;김종빈
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1992.05a
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    • pp.30-33
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    • 1992
  • This thesis was investigated on ion-induced characteristics in a-$Se_{75}Ge_{25}$ positive and negative resists for focused-ion-beam microlithogaphy. The exposed a-$Se_{75}Ge_{25}$ inorganic thin film shows an increase in optical absorption after exposure to~$10_{16}$ dose of Ga+. The observed shift in the absorption edge toward longer wavelengths is consistent with that in films exposed to band-gap photons(~$10^{21}$photons/cm2). This result may be related with microstructural rearrangements with in the short range of SeGe network. Due to changes in the short range order, the chemical bonding may be affected, which results in increased chemical dissolution in ion-induced film. Also, this resist exhibits good thermal stability because of its high Tg(~$220^{\circ}C$). When focused ion beams are used for direct exposure of resist over a substrate, unwanted implantation of the substrate may be an issue. A possible way to avoid this is to match the thickness of the resist to the range of ions in the resist. Thin aspect is currently under investigation.

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Statistical modeling of pretilt angle control for NLC using ion beam alignment (이온빔 배향을 이용한 네마틱 액정의 프리틸트각 제어를 위한 통계적 모델링)

  • Kang, Hee-Jin;Kang, Dong-Hun;Lee, Jung-Hwan;Yun, Il-Gu;Oh, Yong-Cheul;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.302-303
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    • 2006
  • The response surface modeling of the pretilt angle control using ion-beam (IB) alignment on nitrogen doped diamond-like carbon (NDLC) thin film layer is investigated. The response surface model is used to analyze the variation of the pretilt angle under various process conditions IB exposure angle and IB exposure time are considered as Input factors. The analysis of variance technique is used to analyze the statistical significance, and effect plots are also investigated to examine the relationships betweenthe process parameters and the response. The model can allow us to reliably predict the pretilt angle with respect to the varying process conditions.

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Liquid Crystal Alignment Effects Using a SiO Thin Film (SiO 박막을 이용한 액정배향 효과)

  • Kang, Hyung-Ku;Hwang, Jeong-Yeon;Park, Chang-Joon;Seo, Dae-Shik;Ahn, Han-Jin;Kim, Kyung-Chan;Kim, Jong-Bok;Baik, Hong-Koo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05a
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    • pp.198-201
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    • 2004
  • We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a SiO thin film. The homogenous alignment can be obtain어 using ion beam (IB) exposure on the SIO thin film, when positive type NLC ($Delta\varepsilon$>0) was injected However, the homeotropic alignment can be obtained using ion beam (IB) exposure on the SiO thin film, when negative type NLC ($\Delta\varepsilon$>0) was injected The LC aligning ability on the SiO thin film depends on the dielectric anisotropy type of LC. It will be discussed.

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