• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.744-747
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• 2005

The exploitable efficiency of UHP is very important in a projection system. We always use lens array for light shaping and energy distribution transformation in conventional projection system. Because of the limitation of arc gap and F/# of elements, the utilize efficiency is always dismal. In this paper we try to bring out a new method to reduce the sparkle formed on the PS converter and enhance the system efficiency.

• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.45-54
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• 2015

In this study, a novel parallel wavefront correction system architecture is proposed, and a model-based tabu search (MBTS) algorithm is introduced for this new system to compensate wavefront aberration caused by atmospheric turbulence in a free-space optical (FSO) communication system. The algorithm flowchart is presented, and a simple hypothetical design for the parallel correction system with multiple adaptive optical (AO) subsystems is given. The simulated performance of MBTS for an AO-FSO system is analyzed. The results indicate that the proposed algorithm offers better performance in wavefront aberration compensation, coupling efficiency, and convergence speed than a stochastic parallel gradient descent (SPGD) algorithm.

• Journal of the Optical Society of Korea
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• v.16 no.1
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• pp.42-46
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• 2012

We have developed a fluorescence optical detection system using a digital micromirror device (DMD) for monitoring 3D cell culture matrices in situ. Full 3D imaging with fast scanning speed was implemented by the combined action of a DMD and a motorized stage. Imaging results with fluorescent microbeads measure the minimum axial resolution of the system as $6.3{\mu}m$, while full 1-mm scanning through 3D alginate-based matrix was demonstrated. For cell imaging, improved images were obtained by removing background fluorescence although the scanning distance was reduced because of low intracellular fluorescence efficiency. The system is expected to be useful to study various dynamics and behaviors of 3-dimensionally cultured cells in microfluidic systems.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.4
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• pp.460-466
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• 1988

In this paper, the theory and experiments on the one-way optical image transmission through optical fiber by using degenerate four wave mixing in BSO single crystal are demonstrated. From the theoretical analysis, the diffraction efficiency of phase conjugate wave in BSO single crystal is greatly dependent on applied electric field intensity, diffraction grating period formed in the crystal and incident beam ratio, those are also in good agreement with the experimental results. Based on the experimental results, we have arranged the typical degenerate four wave mixing system in the optimal conditions (applied electric field, E. = 5kV/cm` diffraction grating period, 3\ulcorner` beam ratio of backward pump wave versus signal wave, 2.7) and realized one-way optical image transmission system through optical fiber using BSO single crystal.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.266-269
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• 2003

TFT LCD mode has some well-documented performance limitations, namely limited viewing angle, inversion of the gray scale levels and poor luminance efficiency because of the necessity of using crossed polarisers attached to the display cell. During the last few years many initiatives have been undertaken to solve these problems by incorporation birefringent films of various designs into the LCD module. Controlling the optical performance of LCDs often requires combination of liquid crystal material properties, cell parameters and optical films. Such optical films have traditionally been made with stretched polymer materials such as polycarbonate, but recently coated liquid crystalline materials have been used to give improved optical films which can greatly enhance the performance of LCDs. We have now developed reactive mesogen materials to add ultra-thin optical layers into the display structure, and these allow the potential for many new applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.160-163
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• 2002

Silica waveguide for an integrated diffractive optical head system was designed and fabricated. The waveguide was designed to optimize the optical efficiency of red and/or blue laser source, and a lab-made RF magnetron sputter was adopted to deposit silica cladding and core layers on SiO$_2$/Si substrates. The cladding and core layers were formed using commercial targets, and the former was done with ＃7740 and the latter with BK7 and BAK4, respectively The surface roughness of the waveguide layers was measured to be 30.3${\AA}$ for BK7 and 17.8${\AA}$ for BAK4, and the difference of refractive indices between core and cladding layers was 0.9% and 2.5%, respectively. The waveguide fabricated with the core layer of BK7 showed better optical properties when the final diffractive optical probe heads were measured with red laser(650nm) source.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.529-532
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• 2003

Machining technique for optical crystals with single point diamond turning tool is reported in this paper. The main factors influencing the machined surface quality are discovered and regularities of machining process are drawn. Optical crystals have found more and more important applications in the field of modern optics. Optical crystals are mostly brittle materials of poor machinability. The traditional machining method is polishing which has many shortcomings such as low production efficiency. poor ability to be automatically controlled and edge effect of the workpiece. The purpose of our research is to find the optimum machining conditions for ductile cutting of optical crystals and apply the SPDT technique to the manufacturing of ultra precision optical components of brittle materials. As a result. the surface roughness is good when spindle speed is 200m/min. and teed rate is small. The influence of depth of cut is very small.

• Journal of the Semiconductor & Display Technology
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• v.6 no.2 s.19
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• pp.41-44
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• 2007

Optical simulation of the rear and front panel geometries were needed to improve the luminance and efficiency in PDP cells. The 3-dimensional optical code can be used to analyze the variation of geometries and changing of optical properties. In order to improve the accuracy of simulated results, a new UV source, called a multi-cubes UV source, was designed. To design the source, at first UV distribution was calculated with the plasma fluid code and then the UV distribution was transformed to the multi-cube structures in the optical code. Compared to the results from existing UV source, called a planar UV source, could be improved the accuracy of visible light distribution. Simulated results were also compared to the visible distribution measured with the ICCD in a real PDP cell.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.739-744
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• 2016

We have designed a new TIR(Total Internal Reflection) structure for generating an LED lens which can produce a rectangular beam with small divergence angle in two perpendicular directions for an optical guidance system. The lens can control the divergence angle in the horizontal direction to be a small value of about $8^{\circ}$ with a $1mm{\times}1mm$ LED source, also in the vertical direction it can be about $7^{\circ}$, with optical collection efficiency higher than 0.83. After the lens is manufactured, the work demonstrates that the lens is suitable for an optical guidance system.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.128-132
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• 2013

L-Arginine semi-oxalate (LASO) single crystal has been grown by solution growth technique at room temperature. The crystal structure and lattice parameters were determined for the grown crystal by single crystal X-ray diffraction studies. Photoluminescence studies confirm the violet fluorescence emission peak at 395 nm. Optical constants like band gap, refractive index, reflectance, extinction coefficient and electric susceptibility were determined from UV-VIS-NIR spectrum. The dielectric constant, dielectric loss and ac conductivity of the compound were calculated at different temperatures and frequencies to analyze the electrical properties. The solid state parameters such as plasma energy, Penn gap, Fermi energy and polarizability were calculated to analyze second harmonic generation (SHG). Nonlinear optical property was discussed to confirm the SHG efficiency of the grown crystal.