• Title/Summary/Keyword: Light Uniformity

검색결과 358건 처리시간 0.023초

Effect of H2 Addition on the Properties of Transparent Conducting Oxide Films Deposited by Co-sputtering of ITO and AZO (동시 스퍼터링으로 제조한 AZO-ITO 혼합박막의 증착 중 수소 혼입 영향 분석)

  • Kim, Hye-Ri;Kim, Dong-Ho;Lee, Sung-Hun;Lee, Gun-Hwan
    • Journal of the Korean institute of surface engineering
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    • 제42권6호
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    • pp.267-271
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    • 2009
  • Multicomponent transparent conducting oxide films were deposited on glass substrates at 150 by dual magnetron sputtering of AZO and ITO targets. In the case of mixing a limited amount of ITO (10W), resistivity of TCO films was significantly increased compared to the AZO film; from $3.5{\times}10^{-3}$ to $9.7{\times}10^{-3}{\Omega}{\cdot}cm$. Deterioration of the electrical conductivity is attributed to the decreases in carrier concentration and Hall mobility. Improvement of the conductivity could be obtained for the films prepared with ITO powers larger than 40 W. The lowest resistivity ($\rho$) of $7.3{\times}10^{-4}{\Omega}{\cdot}cm$ was achieved when ITO power was 100 W. Effects of $H_2$ incorporation on the electrical and optical properties of AZO-ITO films were investigated in this work. Addition of small amount of hydrogen resulted in the increase of carrier concentration and the improvement of electrical conductivity. It is apparent that the roughness of AZO-ITO films decreases dramatically after the transition of microstructure from polycrystalline to amorphous phase, which gives practical advantages such as an excellent uniformity of surface and a high etching rate. AZO-ITO films grown at sputtering ambient with hydrogen gas are expected to be applicable to optoelectronic devices such as organic light emitting diodes and flexible displays due to their sufficient electrical and structural properties.

A Review : Improvement of Operation Current for Realization of High Mobility Oxide Semiconductor Thin-film Transistors (고이동도 산화물 반도체 박막 트랜지스터 구현을 위한 구동전류 향상)

  • Jang, Kyungsoo;Raja, Jayapal;Kim, Taeyong;Kang, Seungmin;Lee, Sojin;Nguyen, Thi Cam Phu;Than, Thuy Trinh;Lee, Youn-Jung;Yi, Junsin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제28권6호
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    • pp.351-359
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    • 2015
  • Next-generation displays should be transparent and flexible as well as having high resolution and frame number. The main factor for active matrix organic light emitting diode and next-generation displays is the development of TFTs (thin-film transistors) with high mobility and large area uniformity. The TFTs used for transparent displays are mainly oxide TFT that has oxide semiconductor as channel layer. Zinc-oxide based substances such as indium-gallium-zinc-oxide has attracted attention in the display industry. In this paper, the mobility improvement of low cost oxide TFT is studied for fast operating next-generation displays by overcoming disadvantages of amorphous silicon TFT that has low mobility and poly silicon TFT that requires expensive equipment for complex process and doping process.

Physical Properties of Polypropylene Blended Yarns with Yarn Counts and Blended Ratio (Polypropylene 복합방적사의 섬도와 혼용율에 따른 물성)

  • Kim, Jeong-Hwa;Lee, Jung-soon
    • Fashion & Textile Research Journal
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    • 제20권5호
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    • pp.600-607
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    • 2018
  • Polypropylene fibers, while having many advantages such as light weight, sweat fast drying, water-repellent, drainage, thermal insulation, anti-static property has a drawback in dyeing. In recent years, the development of dyeable polypropylene fibers has expanded its value in the textile market. The purpose of this study is to fabricate composite spun yarns using polypropylene, acrylic, rayon and wool and to analyze tensile properties, uniformity characteristics, bending properties, hairiness, and surface shape according to the degree of fineness and blended ratio. The specimens consisted of 100% polypropylene spun yarn pp30, pp40 and ppa(pp/acrylic), ppr(pp/rayon), ppw(pp/wool), 5 altogether sed in this study. The results of the study are as follows. The breaking strength of polypropylene spun yarn blended with rayon and acrylic was higher than that of 100% polypropylene spun yarn. The polypropylene spun yarn is higher the fineness been shown to decrease the breaking strength and elongation. The bending properties of polypropylene spun yarns were in the order of ppa>ppr>pp40>pp30>ppw. The unevenness of ppw, ppr, and ppa was higher than pp40 and pp30. With the exception of ppw with crimp properties, pp30 and pp40 were found to have a hairiness index greater than ppr, ppa. In the microscopic photographs of polypropylene spun yarn, pp30, which had the highest hairiness index, was found to have a thick yarn and a large number of hairs, and ppw had hairs of 3 mm or more protruding elongated outwardly.

Process Development of Self-Assembled Monolayers(SAMs) of Colloidal Particles (콜로이드 입자의 자기 배열성을 이용한 Monolayer 형성에 관한 연구)

  • Ko, Hwa-Young;Lee, Hae-Weon;Kim, Joo-Sun;Moon, Joo-Ho
    • Journal of the Korean Ceramic Society
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    • 제39권10호
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    • pp.981-987
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    • 2002
  • Monodispersed colloidal silica was prepared by Stober process. We have synthesized monodispersed colloidal silica of carious sizes (100 nm, 200 nm, 300 nm) by controlling volume ratios of TEOS(Tetraethylorthosilicate), $NH_4OH$, Ethanol and D. I. water. Shape and monodispersity of the synthesized colloidal particles were observed by Scanning Electron Microscopy(SEM) and laser light scattering particle analyzer. Self-assembled monolayer of monodispersed colloids was achieved by dipping Si substrate into a well-dispersed silica suspension. It was determined that uniformity and spatial extent of the self-assemble monolayer of monodispersed colloids are significantly influenced by the experimental parameters such as concentration, pH and surface tension of the colloidal suspension. We have observed a hexagonally well-ordered packing colloidal monolayer in a relatively large area (1.5 mm ${\times}$ 1.5 mm) as confirmed by SEM.

Ageless Trend and the Fashionable Style of Korean Middle-Aged Men (한국 중년 남성의 젊음 추구와 유행 스타일 변화)

  • Lee, Na Hyun;Ha, Ji Soo
    • Journal of the Korean Society of Clothing and Textiles
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    • 제39권5호
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    • pp.745-754
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    • 2015
  • This study analyzed Korean middle-aged men's fashionable styles according to ageless trends as their representative characteristic and deriving their special features from men's magazines. Literature and case studies were conducted together. The research findings are as follows. First, it showed uniformity, conformity, passive clothing selection and consumption in 1990s as characteristics of middle-aged men's wear by period. However, clothing became an expressive way to pursue individuality and an ageless trend gradually, and middle-aged men positioned themselves as subjects of a consumer market for men's wear after 2010 through active clothing selection and consumption. Second, along with a trend change preferring a comfortable and active to formal atmosphere, it showed that casual style became diversified and segmented gradually in Korean middle-aged men's ageless trend and fashionable style. Third, as for formative characteristic changes in middle-aged men's fashionable style by period, it contained a slim silhouette, bright and splendid colors and patterns, increase of light, active and functional materials, generalization of casual items and pursuit of individuality by various mix & match styles. Fourth, in Korean men's ageless trend and changing fashionable style, four kinds of special characteristics were derived that included a change of the traditional clothing symbolism, weakened conformity & pursuit of personality, obscured boundaries between age and wearing style, and active embracing of a trend.

Actual Conditions on the Illumination Environment of the Study Rooms in the Youth of an Agriculture Village (농촌 청소년 공부방의 조명환경 실태조사)

  • Kim, Hyun-Ji;Jun, Kyoung-Sun;Lee, In-Hyo;An, Ok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • 제23권4호
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    • pp.1-7
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    • 2009
  • This study investigated the actual conditions of the illumination environment from agricultural youth study room. The result, average space of the study room was 11.42[$m^2$]. The illuminant uses the fluorescent lamp mainly, Method of using illumination was only general illumination the case which uses 73.8[%]. Method of light distribution was a direct lighting mainly. The house which has a stand illumination was also 45.7[%], The percentage using the stand illumination which was a local illumination was nothing but in 20[%] of the whole subject of investigation, therefore eye work could not effective. The internal illuminance was average 131.82[lx], the desk illuminance was 253.64[lx] which was the minimum permitted limit and poor. Uniformity ratio of illuminance appeared with average 35.61[%]. The satisfaction with 3.93 points to be high for illumination environment, therefore it was thought that the recognition of illumination was very insufficient.

Characterization of Atomic-Layer Deposited ZnSnO Buffer Layer for 18%- Efficiency Cu(In,Ga)Se2 Solar Cells (18% 효율 Cu(In,Ga)Se2 박막태양전지용 ZnSnO 버퍼층의 원자층 증착법 및 분석)

  • Kim, Sun Cheul;Kim, Seung Tae;Ahn, Byung Tae
    • Current Photovoltaic Research
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    • 제3권2호
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    • pp.54-60
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    • 2015
  • ZnSnO thin films were deposited by atomic layer deposition (ALD) process using diethyl zinc ($Zn(C_2H_5)_2$) and tetrakis (dimethylamino) tin ($Sn(C_2H_6N)_4$) as metal precursors and water vapor as a reactant. ALD process has several advantages over other deposition methods such as precise thickness control, good conformality, and good uniformity for large area. The composition of ZnSnO thin films was controlled by varying the ratio of ZnO and $SnO_2$ ALD cycles. The ALD ZnSnO film was an amorphous state. The band gap of ZnSnO thin films increased as the Sn content increased. The CIGS solar cell using ZnSnO buffer layer showed about 18% energy conversion efficiency. With such a high efficiency with the ALD ZnSnO buffer and no light soaking effect, AlD ZnSnO buffer mighty be a good candidate to replace Zn(S,O) buffer in CIGSsolar cells.

Verification of the Appropriateness of the Standard for Tunnel Luminance in the Threshold Zone Through a Full-scale Tunnel Driving Test (실 규모 터널 주행실험을 통한 터널 경계부 휘도 기준의 적정성 검증)

  • Park, Won Il;Cho, Won Bum;Jeong, Jun Hwa
    • International Journal of Highway Engineering
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    • 제17권6호
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    • pp.105-115
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    • 2015
  • PURPOSES : This study aimed to evaluate the appropriateness of safety with the standard for threshold zone luminance as specified in the Recommendation for Lighting of Traffic Tunnel, which has been widely adopted worldwide. METHODS : A driving test of the subject in a full-scale road tunnel was conducted. The adaptation luminance and threshold zone luminance, which should be known for the driver to perceive an object within stopping sight distance, were obtained. These values were compared with the adaptation luminance and threshold zone luminance obtained by the existing reduced model test and tunnel lighting standard that has served as a guideline for the current threshold zone luminance standard. RESULTS : According to this study, threshold zone luminance should be increased to at least 1.8 times the value proposed in the existing studies and to twice the domestic tunnel lighting standard (KS C 3703: 2014). CONCLUSIONS : The threshold zone luminance proposed in this study differs largely from that obtained from indoor tests and from the current tunnel lighting standard used worldwide; this difference may be attributed to the fact that the indoor tests did not incorporate driving workload, non-uniformity of luminance distribution in terms of sight, and factors that reduce the visibility of the driver, such as the light reflected into the driver's eyes. Hence, it is necessary to further review the factors that reduce the visibility of drivers approaching tunnels in order to determine the rational tunnel threshold zone luminance.

A Computational Analysis on Candela Distribution Curves and Performance Prediction of a Fiber Optic Dish Daylighting System by Photopia (Photopia를 이용한 추적식 디쉬형 집광기의 배광분포 분석 및 자연채광 성능 예측)

  • Oh, Seung-Jin;Han, Hyun-Joo;Jeon, Young-Il;Chun, Won-Gee
    • Journal of the Korean Solar Energy Society
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    • 제32권3호
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    • pp.104-113
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    • 2012
  • A set of candela distribution curves(CDCs) were generated for a fiber optic dish daylighting system by Photopia under clear sky conditions at different solar altitudes. The candela distribution curves were then exported to Radiance for photometric analysis of a windowless lecture room. Observations were made on the Radiance rendered illuminance images, which provided photo realistic scenes varying with solar altitudes. If no tracking error were assumed, the daylight collection efficiency of the system remained at a constant value of 68.4% during its operation. Higher the solar altitude angle, greater in photometric quantities were observed, which are represented by candela(cd) and total lumens(lm). In all cases considered, however, the angle of light distribution remained fixed reflecting the solar tracking feature of the system. The illuminance uniformity on the workplane lingered around 0.12, which is quite low. This is quite a contrast to its average value of 0.68 of the $2.7m^2$ area directly below the terminal device (diffuser) of the system. The maximum illuminance of 1,340lux was obtained at a solar altitude of 80 degrees.

Effects of storing defocused Fourier plane holograms in three-dimensional holographic disk memories (디스크형 3차원 홀로그래피 메모리에서 비초점 Fourier 면 홀로그램의 저장 효과)

  • 장주석;신동학
    • Korean Journal of Optics and Photonics
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    • 제12권1호
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    • pp.61-66
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    • 2001
  • Defocused Fourier plane holograms are stored in disk-type holographic memories where thin recording media are used, the areal storage density per hologram and the intensity uniformity of the signal beam at the recording plane are studied. As the pixel pitch of the spatial light modulator that represents binary data increases, the storage density per hologram increases if exact Fourier holograms are stored. When defocused Fourier plane holograms are stored, however, we show that there exists an optimal pixel pitch that maximizes the area storage density per hologram in general, to increase the areal storage density per hologram, f/# of the Fourier transform lens that focuses the data image should be as small as possible. In this case, not only the intensity distribution at the recording plane but also the recording area becomes very sensitive to the degree of defocusing. Therefore, even if the exact Fourier plane holograms are stored, the defocusing effect owing to the medium thickness should be taken into account to achieve the maximal areal storage density per hologram.logram.

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