• Title/Summary/Keyword: Liquid prism

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Design and Fabrication of Pattern Structures of the Light Guide Plate for Enhanced Brightness of Backlight Unit (고휘도 BLU 구현을 위한 도광판 패턴 설계 및 특성 평가)

  • Bae, Chang-Hwan;Heo, Kyung Chan;Jhun, Chul Gyu;Rvu, Bong Jo;Koo, Kyung Wan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.2
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    • pp.310-314
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    • 2015
  • To improve the optical performance of the backlight unit with light guide plate(LGP), we investigated the effects of LGP patterns on the brightness and viewing angles properties of the backlight unit. We designed several patterns of LGP and calculated their optical properties by the optical simulation. The results reveal that the highest brightness and wide viewing angle was achieved with the extended-closed-polygon diffusion pattern and upper triangle prism pattern of the LGP.

Experimental Investigation on Machining Feasibility of Micro Patterns using a Single Crystal Diamond Tool (단결정 다이아몬드 공구를 이용한 미세 패턴 가공성에 대한 실험적 분석)

  • Kim, Hyun-Chul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.5
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    • pp.76-81
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    • 2012
  • The continuing demand for increasingly slimmer and brighter liquid crystal display(LCD) panels has led to an increased focus on the role of the light guide panels(LGPs) or optical films that are used to obtain diffuse, uniform light from the backlight unit(BLU). And the most basic process in the production of such BLU components is the micromachining. LCD BLUs comprise various optical elements such as a LGP, diffuser sheet, prism sheet, and protector sheet with micro patterns. High aspect ratio patterns are required to reduce the number of sheets and enhance light efficiency, but there is a limit to the aspect ratio achievable for a given material and cutting tool. Therefore, this study comprised a series of experimental evaluations conducted to determine the machining feasibility in microcutting various aspect ratio patterns on electroless nickel plated die materials when using single-crystal diamond tools. Cutting performance was evaluated at various cutting speeds and depths of cut using different machining methods and machine tools.

Tandem Light Deflector Operated by Electrowetting (전기습윤으로 구동하는 이중 광원 조향장치)

  • Song, Hyeonseok;Won, Jung Min;Chung, Sang Kug
    • Journal of the Korean Society of Visualization
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    • v.18 no.1
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    • pp.38-43
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    • 2020
  • This paper presents a new type of electrowetting driven tandem light deflector for high performance optical application. To steer an incident light, the proposed light deflector deforms the fluid interface using electrowetting actuation. The performance of the light deflector was experimentally verified by using a prototype of the proposed light deflector. Single and tandem light deflectors were separately prepared using microfabrication processes. The optical tests of the deflectors were conducted using a laser light. The proposed tandem light deflector obtained a 45° beam steering angle with a 5.3° deflection angle while a single light deflector was required for a 10.9° deflection angle to obtain the same beam steering angle. The proposed tandem light deflector with high optical capability can be applied to various optical applications from camera modules in mobile smart devices to advanced future optical systems.

Optical Simulation Study on the Performances of Collimating Films for LCD Backlight Applications (액정표시장치 백라이트용 집광필름의 광학특성 분석을 위한 시뮬레이션 기법 연구)

  • Park, Ji-Hee;Lee, Jung-Ho;Jeong, Jin-Ha;Nahm, Kie-Bong;Ko, Jae-Hyeon;Kim, Joong-Hyun
    • Korean Journal of Optics and Photonics
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    • v.18 no.6
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    • pp.432-440
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    • 2007
  • Optical simulation methods such as a ray tracing technique have been widely used to predict the optical performances of collimating films for LCD backlight applications. It is necessary to optimize simulation conditions which have substantial effect on the simulation result in order to predict accurate performances of collimating films. We have set up a very simple backlight model consisting of a reflection film, a virtual flat light-source, and a prism film, which is a representative collimating film for backlight, in order to analyze the simulation conditions which are strongly correlated with the on-axis luminance gain and the viewing-angle characteristics of prism films. It was found that the dependence of the relative change in the on-axis luminance on the structure and material properties of collimating films can be derived from the above-mentioned simple BLU model and from simulation using it. However, the exact reflection property of the reflection film and the distribution of the incident light onto the optical film were found to be very important for revealing exact viewing-angle characteristics of collimating films.

A Study on Optimization for Separation of Phenols and Preconcentration-Separation of Trace Phenols in Reversed-Phase Liquid Chromatography (역상 액체 크로마토그래피에서 페놀류의 분리 최적화 및 미량 페놀류의 농축-분리에 관한 연구)

  • Lee Dai Woon;Lee Sung Won;So, Min Jeong;Cho Byung Yun
    • Journal of the Korean Chemical Society
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    • v.37 no.5
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    • pp.513-522
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    • 1993
  • The purpose of this study is to optimize the selectivity of mobile phase solvents for separation of 25 phenols in reversed phase liquid chromatography and to accomplish the simultaneous preconcentration and separation of trace phenols from water samples. Phenols used in this study were classified into three groups, chloro-, methyl-, and nitrophenols. Quaternary solvent mobile phases were employed to improve the selectivity. Overlapping resolution maps(ORM) as a statistical simplex techniques was used to predict the optimum solvent system. Additional criterion such as pH and temperature were also investigated. In order to improve the resolution and decrease the analysis time, isoselective multisolvent gradient elution system was employed with ORM-Prism method. The simultaneous preconcentration and separation of trace phenols from water samples were performed by using XAD-2/Dowex 1-X8 tandem column. When the extraction efficiency was evaluated by sampling up to 1 L of distilled water, recovery of the phenols, except phenol, was above 90% and the limit of detection of the phenols was 5 ppb. The XAD-2/Dowex 1-X8 method was superior to C18 cartridge in terms of recovery and selectivity.

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Micro-patterning of light guide panel in a LCD-BLU by using on silicon crystals (실리콘 결정면을 이용한 LCD-BLU용 도광판의 미세산란구조 형성)

  • lChoi Kau;Lee, Joon-Seob;Song, Seok-Ho;Oh Cha-Hwan;Kim, Pill-Soo
    • Korean Journal of Optics and Photonics
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    • v.16 no.2
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    • pp.113-120
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    • 2005
  • Luminous efficiency and uniformity in a LCD-BLU are mainly determined by fine scattering patterns formed on the light guide panel. We propose a novel fabrication method of 3-dimensional scattered patterns based on anisotropic etching of silicon wafers. Micro-pyramid patterns with 70.5 degree apex-angle and micro-prism patterns with 109.4 degree apex-angle can be self-constructed by the wet, anisotropic etching of (100) and (110) silicon wafers, respectively, and those patterns are easily duplicated by the PDMS replica process. Experimental results on spatial and angular distributions of irradiation from the light guide panel with the micro-pyramid patterns were very consistent with the calculation results. Surface roughness of the silicon-based micro-patterns is free from any artificial defects since the micro-patterns are inherently formed with silicon crystal surfaces. Therefore, we expect that the silicon based micro-patterning process makes it possible to fabricate perfect 3-dimensional micro-structures with crystal surface and apex angles, which may guarantee mass-reproduction of the light guide panels in LCD-BLU.

Study on the gate cutting of light guiding plate for mobile using quenching element (박형 도광판의 음각, 양각 마이크로 패턴 성형성에 관한 연구)

  • Hwang, Chul-Jin;Kim, Jong-Sun;Min, In-Gi;Kim, Jong-Dug;Yoon, Kyung-Hwan
    • Design & Manufacturing
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    • v.2 no.5
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    • pp.1-4
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    • 2008
  • LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LCP (Light Guide Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50-200{\mu}m$ in diameter on it by erosion method. But the surface of the erosion dots of LGP is very rough due to the characteristics of the erosion process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. Especially, the negative and positive micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP.

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A Study on the Flow Field Characteristics of Air Induction System for Reducing the Signal-to-Noise in the MAFS Output

  • Yoo, Seoung-Chool
    • Journal of ILASS-Korea
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    • v.5 no.1
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    • pp.49-57
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    • 2000
  • This study presents the flow visualization results, velocity and turbulence intensity measurements made within an air filter cover and entry region of a mass air flow sensor (MAFS) which is used in an induction system of 3.8L engine. Flow structure in two air filter cover assemblies were examined. The first was a clear plastic replica of the production cover while the second was a modified clear plastic cover with a geometry configured to reduce fluctuations. High speed flow visualization and laser doppler velocimetry (LDV) systems were used to reveal and analyze the flow field characteristics encountered in the sensor design process under steady flow conditions. A 40-watt copper vapor laser was used as a light source. Its beam is focused down to a sheet of light approximately 1.5mm thick. The light scattered off the particles was recorded by a 16mm high speed rotating prism camera at 5000 frames per second. A comparison of the flow patterns and LDV measurements in the original and modified air filter covers is presented to illustrate the controlling effect of the cover design on the turbulence structure formation near the bypass and on the sensor output signal. In both axial and radial planes of the main passage it was found that the turbulence flow pattern is remarkably influenced by the air filter cover and main passage configuration.

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Optical holographic interconnection method for free-space-division-multiplexed photonic switching (자유공간분할 광교환을 위한 홀로그램 광연결 방법)

  • 장주석;박진상;지창환;정신일
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.5
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    • pp.60-70
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    • 1995
  • As a Basic study to implement a wide-band photonic switching sysetm, we proposed a scheme of free-space-division-multiplexed photonic switching based on a holographic interconnectio method and carried out simple experiments on it. First, we recorded holgraphic interconnection element array for nonblocking optical interconnections. Just a single stage of the array realizes full optical interconnections between NN${\times}$NN input prots and NN${\times}$NN output ports in 3-D space. Next, in reading of the array for optical internnections, we showed that the zeroth-order diffacted beam could be eliminated in the output port by introducing a right angle prism. The elimination of the zeroth-order diffracted beam reduces optical noise in the output ports and provides conveniences of interconnection control in our scheme. Finally, from the experiments on ON-OFF switching of the optical interconnection paths one by one using a spatial (display of the liquid crystal telecision), we showed the feasibility of photonic wsitching based on the holographic interconnection method. We also estimated approximately the maximum interconnectio scale that can be realized without difficulty with current optical devices.

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Effect of ground granulated blast furnace slag on time-dependent tensile strength of concrete

  • Shariq, M.;Prasad, J.
    • Computers and Concrete
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    • v.23 no.2
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    • pp.133-143
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    • 2019
  • The paper presents the experimental investigations into the effect of ground granulated blast furnace slag (GGBFS) on the time-dependent tensile strength of concrete. The splitting and flexural tensile strength of concrete was determined at the ages of 3, 7, 28, 56, 90, 150 and 180 days using the cylindrical and prism specimens respectively for plain and GGBFS concrete. The amount of cement replacement by GGBFS was 0%, 40% and 60% on the weight basis. The maximum curing age was kept as 28 days. The results showed that the splitting and flexural tensile strength of concrete containing GGBFS has been found lower than the plain concrete at all ages and for all mixes. The tensile strength of 40 percent replacement has been found higher than the 60 percent at all ages and for all mixes. The rate of gain of splitting and flexural tensile strength of 40 percent GGBFS concrete is found higher than the plain concrete and 60 percent GGBFS concrete at the ages varying from 28 to 180 days. The experimental results of time-dependent tensile strength of concrete are compared with the available models. New models for the prediction of time-dependent splitting and flexural tensile strength of concrete containing GGBFS are proposed. The present experimental and analytical study will be helpful for the designers to know the time-dependent tensile properties of GGBFS concrete to meet the design requirements of liquid retaining reinforced and pre-stressed concrete structures.