• Title/Summary/Keyword: photo

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A Study of Fabrication Techniques of Thin film Photo-Electric Energy Conversion Elements (박막 광전에너지 변환소자의 개발에 관한 연구)

  • 성영권;민남기;성만영;김승배
    • 전기의세계
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    • v.25 no.5
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    • pp.63-69
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    • 1976
  • Among various types of photo-electric energy conversion element which can transfer solar energy into electric energy through the photo voltaic effect, Si solar cells were investigated on photoelectric characteristics, improvements of its efficiency and economical evaluation for its production cost. To study the above subjects, we decided best conditions on fabricating of thin film Si solar cell by epitaxial growth and knew that the thin solar cell by epitaxial growth was more efficient than that by diffusion process. And also higher photo voltaic output was obtained as a effect of SiO as antireflection coating by several methods, i.e. vacuum evaporating techniques of electrode to decrease the contact resistance and to form best ohmic contact, and concentration techniques of sun's ray by lenz or both-sided illumination through special structure for reflection using mirrors.

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Micro Patterning Using Near-Field Coupled Nano Probe Laser Photo Patterning Of Chloromethylated Polyimide Thin Film (클로로메틸 폴리이미드(CMPI) 박막과 근접장 나노 프로브 레이저 패터닝을 이용한 미세 형상 가공 기술)

  • 최무진;장원석;김재구;조성학;황경현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.369-372
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    • 2004
  • Photo-induced surface alignment is charming as a non-contact photo-patternable alignment technology which can be used in the next generation of displays, such as large area, multi-domain. For decades, many polymer film have been investigated and developed to be used in the photo alignment. Among these photoreactive materials, recently developed polyimide, Chloromethylated Polyimide(CMPI) now became the focus of interests in this area because of its high photosensitivity and superior thermal stability. In this report, we present micro patterning method to form the nanoscale structure by Mask-Less laser patterning using this CMPI film and NSOM probe.

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A Study on the Effects of the Optical Characteristics of backlight Sources on the Photo Leakage Currents of a-Si:H Thin Film Transistor (비정질 실리콘 TFT의 광누설 전류에 Backlight 광원의 광학적 특성이 미치는 영향에 대한 연구)

  • Im, S.H.;Kwon, S.J.;Cho, E.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04a
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    • pp.55-56
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    • 2008
  • The photo leakage currents of a conventional hydrogenated amorphous silicon(a-Si:H) thin film transistor(TFT) were investigated and analyzed in the case of illumination from various lightsources such as halogen lamp, cold cathode fluorescent lamp(CCFL) backlight, and white light emitting diode(LED) backlight The photo leakage characteristics showed the apparent differences in the leakage level and in the $I_{on}/I_{off}$ ratio in spite of the similar luminances of light sources. This leakage level is expected to be related to the wavelength of the lowest intensity peak from spectral analysis of light sources.

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Preparation of the Polymers Containing Phenylamide and Dimethylaminoethyl Groups and their Properties as a Nagative Photoresist

  • Chae, Kyu-Ho;Kang, Jin-Koo;Kim, Su-Kyung;Chough, Sung-Hyo
    • Journal of Photoscience
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    • v.7 no.2
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    • pp.47-52
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    • 2000
  • The copolymmers of N, N-dimethylaminoethyl methacrylate(DAEM) and N-arylmethacrylamide (AMA) were prepared, and their photochemical properties as a negative photoresist were studied by the measurements of insoluble fraction, and by UV and IR absorption spectral changes. These copolymers are soluble in DMF, actone, methanol, of acidic buffer solutions. Solubility of these copolymer films in the vuffer solutions increased with the amount of DAEM units in the copolymer and decreased with the pH value. The insoluble fraction of the copolymer films in the buffer solution of pH 4 of in methanol increased with irradiation time and the amount of AMA units in the copolymer. UV and IR spectral changes indicated that not only photo-crosslinking but also the photo-Fries rearrangement took place upon irradiation with a 254nm UV light.

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ListenPhoto: Automatic Music Annotated Photo Browsing System (ListenPhoto: 자동 슬라이드 쇼 배경음악 추천 시스템)

  • Seo, Jong-Hoon;Kim, Dong-Chul;Han, Tack-Don
    • Proceedings of the Korean Information Science Society Conference
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    • 2007.10c
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    • pp.267-271
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    • 2007
  • 디지털 카메라의 보급과 U.C.C. 개념의 등장으로 인하여 개인이 생산하는 사진의 양도 많아지고, 이를 감상하는 시간도 많아졌다. 사진이란 추억을 회상하는데 하나의 포인트 역할을 하는 매체이다. 따라서 인간의 감성적인 부분을 많이 자극되는데, 이 과정에서 추가적인 자극을 줌으로써 사용자의 감성을 더욱 자극할 수 있다. 하지만, 기존의 연구들은 디지털 사진을 검색하고 관리하는데 초점이 맞추어져 있었다. 본 논문에서는 사용자가 사진 앨범을 감상할 때에 개별 사진을 분석하여 전체 사진과 가장 잘 어울리는 배경음악을 추천/재생하는 ListenPhoto 시스템을 제안한다. 그리고, 시스템의 필요성에 대한 평가와 시스템 성능에 대한 평가 두 부분으로 나누어 평가를 진행하였다. 사용자들은 이 시스템을 통하여 풍부하게 디지털 사진 생활을 즐길 수 있게 될 것이다.

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Electro-optical Characteristics of the TN Cell Photo-aligned on the Blending Photopolymer Surfaces (복합 광폴리머 표면을 이용한 광배향 TN 셀의 전기 광학 특성)

  • 황정연;서대식
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.7
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    • pp.600-605
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    • 2001
  • The electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photo-aligned with polarized UV exposure on various blending photopolymer surfaces were investigated. Excellent LC alignment and voltage-transmittance (V-T) characteristics for TN-LCD photo-aligned with polarized UV exposure of normal incidence on the blending photopolymer (polyimide (PI) +PM4Ch(poly(4-methacryloyloxy chalcone))) surface containing chalcone group can be achieved. The EO performances for the TN-LCD photo-aligned on the blending photopolymer can be improved due to the photosensitivity by long side chain of the photopolymer.

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Metal-insulator Transition of VO2 Thin Films and Nanowires Induced Photo-excitation

  • Sohn, Ahrum;Kim, Haeri;Kim, Eunah;Kim, Dong-Wook
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.196.1-196.1
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    • 2014
  • VO2 exhibits metal-insulator transition (MIT), of which critical temperature (TC) is about 340 K. There have been many reports that MIT can be induced by UV light as well as heat. Clear mechanism regarding such photo-induced MIT has not been clarified. We have compared the MIT behaviors of VO2 thin film during heating-cooling cycles with and without light. We tried several light sources with different wavelengths (red, blue, and UV). Tc and hysteresis width of the resistance change were influenced by the illumination of the samples. We performed Kelvin probe force microscopy (KPFM) studies, which can reveal the evolution of the local sample work function. In this presentation, we will discuss possible physical origins for the photo-induced effects on the MIT behaviors of the VO2 samples.

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Macroscopic Nonlinear Optical Properties of Tricyanopyrrolidene Chromophore Containing Amorphous Polycarbonate: Effect of Molecular Lateral Moiety in the Conjugative Structure

  • Cho, Min-Ju;Lee, Sang-Kyu;Jin, Jung-Il;Choi, Dong-Hoon
    • Macromolecular Research
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    • v.14 no.6
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    • pp.603-609
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    • 2006
  • Tricyanopyrrolidene chromophores were prepared in order to compare their macroscopic nonlinear optical (NLO) properties with a conjugated structure through the long molecular axis. A thiophene or phenyl ring was tethered to an ethylenic bond; it may act as a lateral moiety to disrupt the planarity of a chromophore and lessen the electrostatic interaction. Thin film composites of these chromophores dissolved in amorphous polycarbonate (APC) were fabricated. Real time pole and probe method was employed to investigate the change of electro-optic (EO) signal during poling. The EO properties and their relaxation behaviors of the guest-host systems containing newly synthesized chromophores were investigated in detail.

Smart LCD using a-Si photo sensor

  • Hong, Sung-Jin;Kim, Jin-Hong;Shin, Kyung-Ju;Chai, Chong-Chul;Choi, Jung-Ye;Park, Cheol-Woo;Suk, Jun-Hyung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.280-284
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    • 2005
  • Recently, the demands of the high quality LCD display device have increased. We have developed the smart LCD that photo sensor is integrated in. Amorphous silicon TFTs have photo leakage current characteristics when the channel of TFTs are lighted on. This characteristic has applied in our device. We expect that photo sensor integrated LCDs have lots of merits in mobile display device, note PC panel and LCD TV.

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