• Title/Summary/Keyword: Reflective light

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Preparation and characterization of TiO2 anti-reflective layer for textured Si (100)

  • Choe, Jin-U;Nam, Sang-Hun;Jo, Sang-Jin;Bu, Jin-Hyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.322-322
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    • 2010
  • Recently, anti-reflective films (AR) are one of the most studied parts of a solar cell since these films improve the efficiency of photovoltaic devices. Also, anti-reflection films on the textured silicon solar cells reduce the amount of reflection of the incident light, which improves the device performance due to light trapping of incident light into the cell. Therefore, we preformed two step processes to get textured Si (100) substrate in this experiment. Pyramid size of textured silicon had approximately $2{\sim}9\;{\mu}m$. A well-textured silicon surface can lower the reflectance to 10%. For more reduced reflection, TiO2 anti-reflection films on the textured silicon were deposited at $600^{\circ}C$ using titanium tetra-isopropoxide (TTIP) as a precursor by metal-organic chemical vapor deposition (MOCVD), and the deposited TiO2 layers were then treated by annealing for 2 h in air at 600 and $1000^{\circ}C$, respectively. In this process, the treated samples by annealing showed anatase and rutile phases, respectively. The thickness of TiO2 films was about $75{\pm}5\;nm$. The reflectance at specific wavelength can be reduced to 3% in optimum layer.

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A Study on the Transmittance, Heat-Resistance, and Mechanical Properties of SiO2, TiO2 Anti-Reflective Single Layers Deposited on Sapphire Substrate by MOCVD (금속유기화학증착법으로 사파이어 기판에 증착된 단층 SiO2, TiO2 저반사막의 광 투과율, 내열성, 기계적 특성에 관한 연구)

  • Shim, Gyu-In;Eom, Hyengwoo;Kang, Hyung;Choi, Se-Young
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.5
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    • pp.672-679
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    • 2014
  • To improve sensing capability of infrared, heat-resistance and mechanical properties, the $SiO_2$ and $TiO_2$ anti-reflective layers were coated on sapphire substrate by MOCVD. The standard wavelength was 4,600nm, and the thickness of anti-reflective layers were 379 and 758nm in case of ${\lambda}/4$ and ${\lambda}/2$ of incident angle($65^{\circ}$), respectively. The $SiO_2$ and $TiO_2$ anti-reflective layers were coated 12.6 and 9.7nm/min of deposition rates by increasing oxygen pressure to set the ideal refractive index of 1.283. In case of $SiO_2({\lambda}/2)$ coating, the transmittance increased from 55.0 to 62.7%. The transmittance of $TiO_2({\lambda}/2)$ anti-reflective layer also increased from 55.0 to 64.8%. The flexural strength of $SiO_2({\lambda}/2)$ and $TiO_2({\lambda}/2)$ layer coated sapphire increased from 337.8 to 362.9 and 371.8MPa, respectively. The flexural strength at $500^{\circ}C$ of these materials also increased respectively to 304.5, 358.2MPa from 265.9MPa. From these results, we confirmed these materials can be used as transmission window of infrared light.

A Study on the Injection Molding for the tight Guide Plate of a Small Sized LCD (1) : finite Element Analysis and Mold Design (소형 LCD 도광판의 사출성형에 관한 연구 (1) : 유한요소해석 및 금형설계)

  • 이호상
    • Transactions of Materials Processing
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    • v.11 no.4
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    • pp.332-340
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    • 2002
  • The light guide plate of the TFT-LCD reflects the light originated from the light source, and guides the light to the front side of LCD so that we can see images vividly. This paper is concerned with tile injection molding of the light guide plate for the reflective typed LCD related to IMT-2000. The finite element analysis has been carried out based on the pine stress theory to predict both the thermal stresses of the products in the post-filling stage and the in-plane deformation behavior of the products after ejection process. Based on the simulation results, the mold for the light guide plate of a 2inch sized LCD has been designed.

Development of Daylighting System with Modified Light Pipe for Longer Transmission Distance and Higher Illuminance

  • Vu, Hoang;Kim, Youngil;Park, Chaehwan;Park, Jongbin;Bae, Hojune;Shin, Seoyong
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.2
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    • pp.93-102
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    • 2021
  • In this research, we present a natural lighting system with transmission distance of 30m and lighting efficiency of 35% (30m standard) for operating hours of 7h/day (based on clear sky). The system is composed of parabolic reflective mirror and modified light pipe that can secure more than 88% of light concentration efficiency. The light loss rate of newly designed light pipe transmission system is demonstrated to 0.8 %/m in the straight-line part and 2%/m in the curved part. Modified light pipe daylighting system shows better performance over fiber optic daylighting system in terms of transmission distance (1.5 times longer) and illuminance (3.05 times higher).

Highly Efficient Top-Emitting Electrophosphorescent Organic Light-Emitting Devices

  • Lu, Min-Hao M.;Weaver, Michael S.;Zhou, Theodore X.;Rothman, Mark;Kwong, Raymond C.;Hack, Mike;Brown, Julie J.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.90-93
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    • 2002
  • We present both a theoretical analysis and experimental data to show that electrophosphorescent top-emitting organic light emitting-devices (TOLEDs) with a reflective anode and a transparent cathode can be more efficient than the equivalent state-of-the-art bottom-emitting electrophosphorescent OLEDs (PHOLEDs$^{TM}$). The lifetime of devices with transparent cathodes are shown to approach that of the corresponding bottom-emitting devices.

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Evaluating the Efficacy of Whitening Products by Using Luminescence Measurement and Revealing Correlation between Luminescence and Other Parameters (투명감 측정을 통한 제형의 미백 효능 평가와 투명감에 관여하는 요소들에 대한 분석)

  • Jeong, Choon-Bok;Kim, Han-Kon;Nam, Gae-Won
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.36 no.4
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    • pp.253-258
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    • 2010
  • Until now, evaluating the efficacy of brightening mainly depends on total reflective light measurement. For example, SHV (Saturation, Hue, Value), $L^*$ $a^*$ $b^*$ (CIELAB color space system) color space system was used and lightness and saturation changes were chosen as major parameters for evaluating brightening effect. However, those parameters were calculated from total reflective light on the skin and it is hard to evaluate perceptive efficacy such as luminescence, and glossy. In this research, we applied new method for estimating change of luminescence of skin by using 'Lumiscan' which uses polarized light for detecting surface and inside reflective light independently. We also tested 15 different parameters for finding correlations between luminescence and those parameters. As a results, our 2 different brightening products showed 5 ~ 9 % increase of luminescence at 4 and 8 weeks. And we also found that skin roughness (-28 %), melanin index (-17 %), redness (-7 %), hydration (15 %), and lightness (6 %) were related to luminescence of skin.

High Resolution System on Glass Displays

  • Okumura, Fujio
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.119-123
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    • 2004
  • This paper describes low temperature poly-Si (LTPS) TFT system on glass (SOG) technology developed in NEC. High resolution SOG-LCDs such as a 230 ppi reflective type LCD, a 2.5", 333 ppi 2D/3D autostereoscopic LCD, and a 2.1" single voltage driven full integration LCD for mobile applications and a 0.9", XGA light valve for projectors are reviewed from the perspective of the high resolution technologies

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3D shape reconstruction using laser slit beam and image block (레이저슬릿광과 이미지블럭을 이용한 경면물체 형상측정알고리즘)

  • 곽동식;조형석;권동수
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.93-96
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    • 1996
  • Structured laser light is a widely used method for obtaining 3D range information in Machine Vision. However, The structured laser light method is based on assumption that the surface of objects is Lambertian. When the observed surfaces are highly specularly reflective, the laser light can be detected in various parts on the image due to a specular reflection and secondary reflection. This makes wrong range data and the image sensor unusable for the specular objects. To discriminate wrong range data from obtained image data, we have proposed a new algorithm by using the cross section of image block. To show the performance of the proposed method, a series of experiments was, carried out on: the simple geometric shaped objects. The proposed method shows a dramatic improvement of 3D range data better than the typical structured laser light method.

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