• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.919-922
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• 2000

A robust optical security technique using ortho-gonally polarized lights in the interferometer is proposed. We use orthogonally polarized lights in order to minimize the noise generated by the refractive index change due to vibration, flow of air, change of temperature etc. To make orthogonally polarized lights the first beam splitter in the Mach-Zehnder interferometer is substituted by a polarizing beam splitter(PBS). Because of incoherence of orthogonally polarized lights, the noise generated by the change of refractive index is minimized. To encrypt an image we use the random partition and the diffusing of pixel. Finally we make Phase-only-filters of each image which is randomly partitioned and diffused pixel by pixel. Simulation results show the proposed system has the ability of encryption and decryption of an image.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.4
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• pp.1-12
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• 2015

This research analyzes the current state of the semiconductor industry delivering the prediction for the future development of the semiconductor industry along with some semiconductor memory's responsive strategies. In the 2014, top 10 semiconductor companies were targeted and studied its growth based on its profitability and growth indications in perspective during three years. The system semiconductor industry with the increase in Hyper-scale customers, proactive actions in the technology consortium, is polarizing caused by increased R&D expense to ensure process scaling limits and high performance, and some results have shown: PC and Mobile slowdown and growth recession phenomenon due to IoT's unclear direction. The leading company is to secure new growth engines through 'Acquiring'. While as the subordinated companies following this consecutive survival through the 'Acquired', the future of system semiconductor industry is to strengthen the market dominance and its techniques by concentrating on the reorganization of the market by few large companies. Accordingly, the semiconductor memory industry is expected to reach the limit of its expansion to domain of system semiconductor, and it is highly suggesting the need of the 'Memory Life Extension' growth strategy.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.71-79
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• 1994

In this paper, $As_{40}Se_{50-x}S_[x}Ge_{10}$(x=0, 25, 35, at.%) bulk and thin films, to develope device of reversible hologram, proved amorphous by X-RD analysis. On the thin films with composition rate, as Se-doped-quantity increased, absorption edge shifted to long wavelength, and we found that reversible photodarkening effect occurred when thin films are exposed and annealed. Optical energy gap was larger when thin films are annealed than exposed. In this effect thin films structurally stabilized by annealing. It is to formed grating hologram by the bragg method on the $As_{40}Se_{15}S_[35}Ge_{10}$ thisn films with the best transmittance properties As polariging angle grew larger, we found that maximum diffraction efficiency became smaller, and obtained it of 4.5% on the thin fim thicknesss of 0.6 m, polarizing angle of 40$^[\circ}$ and exposing for 20sec.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.5
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• pp.438-443
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• 2008

In this paper, segmenting and classifying low contrast defects on flat panel display is one of the key problems for automatic inspection system in practice. Problems become more complicated when the quality of acquired image is degraded by the illumination irregularity. Many algorithms are developed and implemented successfully for the defects segmentation. However, vision algorithms are inherently prone to be dependent on parameters to be set manually. In this paper, one morphological segmentation algorithm is chosen and a technique using frequency domain analysis of input images is developed for automatically selection the morphological parameter. An extensive statistical performance analysis is performed to compare the developed algorithms.

• Journal of the Korean Society of Visualization
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• v.2 no.1
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• pp.32-38
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• 2004

A new PIV technique was developed for decreasing optical error which was created during simultaneous measurements of velocity fields at a wall-normal plane and wall-parallel plane by a plane PIV and a Stereo-PIV systems. For experimental study, two different Reynolds number based on momentum thickness, Re$_{ =514 and 934 were generated in a blowing type wind tunnel under the condition of zero pressure gradient. The two Nd:Yag laser systems and three CCD cameras were synchronized. to obtain instantaneous velocity fields at the same time. To avoid optical noise at the crossing line by the two laser light sheets, a new optical arrangement using polarization was applied. The obtained velocity fields show the existence of hairpin packet structure vividly and the idealized hairpin vortex signature is confirmed by experiment.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.104-107
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• 2003

Poly(vinyl alcohol) (PVA) obtained by the saponification of poly(vinyl ester) like poly(vinyl acetate) o. poly(vinyl pivalate) is a linear semicrystalline polymer, which has been widely used as fibers for clothes and industries, films, membranes, medicines for drug delivery system, and cancer cell-killing embolic materials[1-3]. PVA fibers and films have high tensile and compressive strengths, high tensile modulus, and good abrasion resistance due to its highest crystalline lattice modulus. (omitted)

• Current Optics and Photonics
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• v.2 no.2
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• pp.172-178
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• 2018

We propose a precise 3D endoscopic technique for medical and industrial applications. As the 3D measuring principle, the continuously scanning structured illumination microscopy (CSSIM), which enables to obtain 3D sectional images by the synchronous axial scanning of the target with the lateral scanning of the sinusoidal pattern, is adopted. In order to reduce the size of the probe end, the illumination and detection paths of light are designed as coaxial and a coherent imaging fiber bundle is used for transferring the illumination pattern to the target and vice versa. We constructed and experimentally verified the proposed system with a gauge block specimen. As the result, it was confirmed that the 3D surface profile was successfully measured with $16.1{\mu}m$ repeatability for a gauge block specimen. In order to improve the contrast of the sinusoidal illumination pattern reflected off on the target, we used polarizing optical components and confirmed that the visibility of the pattern was suitable in CSSIM.

• Journal of Sensor Science and Technology
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• v.26 no.4
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• pp.274-279
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• 2017

LCD(Liquid Crystal Display) panel cutting problem is a sort of two dimensional cutting stock problem. A cutting stock problem is problem that it minimizes the loss of the stock when a stock is cut into various parts. In the most research of the two dimensional cutting stock problem, it is supposed that the relative angle of a stock and parts is not important. Usually the angle is regarded as horizontal or perpendicular. In the manufacturing of polarizing film of LCD, the relative angle should be maintained at some specific angle because of the physical and/or chemical characteristics of raw material. We propose a mathematical model for solving this problem, a two-dimensional non-Guillotine cutting stock problem that is restricted by an arranged angle. Some example problems are solved by the C++ program using ILOG CPLEX classes. We could get the verification and validation of the suggested model based on the solutions.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.421-425
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• 2007

A new 3D rear projection display system using double-layer polarization-selective screen systems, one stacked in front of the other, has been developed. The front and rear screens are made of scattering polarizer films, and they either diffuse-scatter or transmit the incident light depending on the polarization state of the light. The near and for images are projected onto the front and rear screens, respectively, using light waves with mutually orthogonal polarization states. The new display system produces clear high-resolution images, which are visible over a wide range of viewing angle. It was found that the impression of depth is pronounced and eyestrain is only comparable to that by 2D display systems.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1273-1274
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• 2007

In this paper, a Optical Voltage Transformer has been designed and fabricated to improve temperature stability caused by materials properties and insulation in measuring system, using single crystal $Bi_{12}SiO_{20}$ as Pockels effect cells for Gas Insulated Switchgear[GIS] System. LD[wavelength: 850nm] was used as optical source, InGaAs as optical detector to measure optical power, Polarizing Beam Splitter as Polarizer and Analyzer, and Multi-mode Optical-fiber[62.5/$125{\mu}m$] as Light transmission line. OPT was assembled in order to pockels effect, and adopted direct electric field type. The linearity of OPT maintains variation for applied voltage range from 100V - 3000V during the test of electric property, As the temperature was changed from $25^{\circ}C$ to $60^{\circ}C$. the result of this study shows that characteristics of OPT are good, and it can be reflected for practical optical sensors in GIS system.