• 폴리머
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• 제25권4호
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• pp.545-557
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• 2001

Hydroxypropyl cellulose (HPC)를 이용하여 제조한 메탄올의 유방성 용액에 두 종류의 aliphatic dicarboxylic acid chlorides (succinyl chloride 와 suberoyl chloride)를 첨가하여 주형시킴에 의해 cholesteric 질서를 지닌 가교필름들을 제조하였다. 가교필름의 cholesteric pitch의 온도의존성과 물과 메탄올중에서의 가교필름의 팽윤거동을 검토하였다. 필름들은 cholesteric 액정상의 특징적인 지문조직을 나타내었으며 이들의 pitch는 HPC 자체와 동일하게 온도가 상승함에 따라 증가하였다. 그러나 모든 가교시료들은 주어진 온도하에서 HPC가 나타내는 pitch에 비해 대단히 크며 가교제의 농도 및 길이의 증가에 의해 증가하였다. 가교시료들은 두 용매중에서 이방성 팽윤을 나타냈다. 이방성 팽윤의 정도는 용매와 가교제의 종류에 다소 의존하나 검토된 가교제의 농도에는 거의 의존하지 않았다.

• Journal of Photoscience
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• 제12권1호
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• pp.41-46
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• 2005

We synthesized chiral choleseric liquid crystalline monomer p-phenylene bis-(p-3-acryloxy-2(S)-methylpropoxy)benzoate (1) and achiral nematic liquid crystalline monomer, p-phenylene p-acryloxy-6-hexyloxy-p-octyloxybenzoate (2) for the construction of cholesteric polymer network with a pitch gradient. In this research we attempted to synthesize cholesteric polymer film which have a wide reflection bandwidth in the region of visible wavelength with the synthesized chiral cholesteric monomer 1 and nematic monomer 2 under various photopoly merization conditions. We succeeded to construct cholesteric polymer film network with a pitch gradient covering more than 200 nm bandwidth in the visible wavelength by diffusion controlled photostructuring method.

• Journal of Information Display
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• 제11권2호
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• pp.91-93
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• 2010

The shearing effects on the electro-optical properties of a stressed cholesteric liquid crystal were investigated. A photopolymer was dispersed in the cholesteric liquid crystal cell. By carefully choosing the mixing ratio between the liquid crystal and the photoreactive monomer, and by applying suitable mechanical shearing on the substrates, a cholesteric liquid crystal display with a low threshold voltage and no alignment layer was demonstrated.

• Transactions on Electrical and Electronic Materials
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• 제16권3호
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• pp.117-123
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• 2015

Cholesteric liquid crystals are one dimensional photonic band-gap materials due to their birefringence and periodic structure. Dye doped cholesteric liquid crystals are self-assembling, mirror-less, low threshold laser structures that exhibit distributed feedback. In this review paper, we have presented the development in the field of lasing characteristics of dye doped cholesteric liquid crystals.

• Journal of Information Display
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• 제4권3호
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• pp.26-28
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• 2003

In the paper, we investigated the Bragg reflective cholesteric display based on polymer stabilization. We studied the bistability in the polymer stabilized cholesteric texture (PSCT) films and baused on which we achieved wider viewing angle though imperfect planar texture.

• 한국전기전자재료학회논문지
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• 제21권5호
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• pp.474-480
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• 2008

In order to make full color cholesteric displays, color filter-less R, G, B sub-pixel structured cholesteric LC cells have been studied. To make R, G, B colors, UV induced pitch variant chiral dopant was added to cholesteric LC mixtures. The concentration of the photo-sensitive chiral dopant was adjusted so that the initial state showed blue color and the color was changed from blue to green and red with increase of UV irradiation to the cholesteric cells. To prevent the mixing of R, G, B reflective sub-pixel liquid crystals, separation walls were formed using negative photo resister in boundary area between sub-pixels, Through the optimization of the material concentrations and UV irradiation condition, vivid R, G, B colors were achieved.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1236-1239
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• 2004

We developed a new cholesteric material for bistable LCDs. The material consists of dispersion of sub-micron ferroelectric particles in cholesteric host. We found that the doping of the cholesteric with ferroelectric particles in small concentration (< 1% by weight) strongly improved basic characteristics of the transition between poly-domain planar texture and focal conic texture. Decrease of the driving voltage, increase of the reflection contrast and the steepness of the transition is associated with giant steady dipole and dielectric constant of the ferroelectric particles.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.982-985
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• 2007

The authors report methods of fabrication singlelayer color cholesteric liquid crystal displays (CLCDs). A single-layer CLCD has been prepared from a polymerstabilized cholesteric liquid crystal. The unique feature of the polymer stabilization is in that the electrically switched colors preserve high reflectivity. A bistable single-layer CLCD has been prepared by the formation of polymer barrier walls and light-tuned cholesteric pitches to reflect blue, green and red color sub-pixels.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.608-610
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• 2003

In the paper, we have investigated the reflective cholesteric display based on the polymer stabilization. The bistability in the polymer stabilized cholesteric texture(PSCT) films was observed and wider viewing angle was achieved due to imperfect planar texture.

• 폴리머
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• 제34권3호
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• pp.242-246
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• 2010

선택 반사를 보이는 콜레스테릭 액정의 planar 배열과 선택적 반사 효율과의 연관성에 대하여 FTIR spectroscopy를 이용하여 정량적으로 조사하였다. Cholesteric liquid crystal(CLC) 내 planar 배열이 잘 유도될수록 선택 반사율이 높아짐을 알 수 있었고, 배향막을 사용하지 않고 shear force 효과에 의해서만 planar 배열을 유도할 수 있었지만 완전한 planar 배열을 유도하기 위해서는 배향막을 사용하는 것이 효과적이었다.