• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.314-320
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• 2016

The glass thermal forming process provides a high volume, low cost approach to producing aspherical reflectors for x-ray optics. Thin glass sheets are shaped into mirror segments by replicating the mold shape at high temperature. Heating parameters in the glass thermal slumping process are crucial to improve surface quality of the formed glass. In this research, the heating process of a thermal slumping glass sheet on a concave parabolic mold was simulated with the finite-element method (FEM) to investigate the effects of heating rate and soaking temperature. Based on the optimized heating conditions, glass samples 0.5 mm thick were formed in a furnace with a steel concave parabolic mold. The figure errors of the formed glass were measured and discussed in detail. It was found that the formed glass was not fully slumped at the edges, and should be trimmed to achieve better surface deviation. The root-mean-square (RMS) deviation and peak-valley (PV) deviation between formed glass and mold along the axial direction were 2.3 μm and 4.7 μm respectively.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1962-1963
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• 2002

The hand-piece fiber optics is applied to medical appliances such as glaucoma theraphy to focus semiconductor laser on the affected parts efficiently. In this paper, we evaluate optical properties such as beam power and radius of a hand-piece probe by experiments and we also simulate the hand-piece optics by ray tracing method in order to study major parameters to optimize focalization ability. As results, we show experimental and simulation results of the hand-piece optics and also summarize several requirements that have to be considered in optimizing the hand-piece optics.

• Journal of Information Display
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• v.3 no.3
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• pp.30-34
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• 2002

CRTs can be improved by means of magnetic quadrupoles. Areas of improvement are convergence, spot shape, image-flatness and space charge compensation.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.68-68
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• 2000

In this paper a very brief review of historical development of optical science and technology in China is presented. More attention has been pain on Modem Optics, which developed since 1950s. The recent development of optical science and technology in following fields are introduced. 1. Optical engineering and instrumentation (tracking theodolites, high speed cameras, satellite laser ranging systems, satellite flying attitude control, cameras for remote sensing, astronomical optical instrument) 2. Applied optics (adaptive optics, optical metrology, infrared optics, optical processing, optical holography) 3. Laser science and technology (ultrashort pulse lasers, UV-X ray lasers, high power laser facilities and laser fusion, laser isotope separation) 4. Laser and nonlinear materials (rare earth elements doped laser glasses and crystals, tunable laser crystals, borate series and organic nonlinear crystals) 5. Optoelectronic science and technology (Optical communication, optical data storage, optical computing) The current situation and developing prospect of optical and optoelectronic industry in China are presented. Furthermore it points out that the optical industry could be developed vigorously only if products development capacity is enhanced and new products industrialization is heightened. The main research and education institutions in the optics field in China, as well as the Chinese Optical Society (COS) are introduced.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.13-14
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• 2007

• Korean Journal of Optics and Photonics
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• v.24 no.1
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• pp.17-22
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• 2013

High performance plastic optical fiber (POF) $N{\times}N$ star couplers are implemented based on fusing and combining technology. A set of cladding-removed POFs are fused into a solid body by heating and pressing them together to form the transition region between the input and output sides. The operation principle of the proposed star coupler is explained based on ray optics. To demonstrate the performance of the device, $2{\times}2$, $4{\times}4$ and $6{\times}6$ type POF couplers were fabricated and characterized. Performances of the POF star couplers were evaluated in terms of the flatness of the coupling ratios and excess losses.

• Particle and aerosol research
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• v.14 no.1
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• pp.1-8
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• 2018

The optical force on a perfectly reflecting sphere in a ray-optics regime is considered. With the assumption of geometric optics and a sphere smaller than the minimum waist of the illuminating beam, closed-form analytic expressions of the optical force are derived. Both axial and radial forces are expressed by a modified Bessel function of the first kind. The derived analytic expressions are compared to precise numerical computations of the exact optical force equations derived previously. In addition the error due to the small sphere assumption is estimated analytically.

• Journal of Astronomy and Space Sciences
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• v.23 no.4
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• pp.327-336
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• 2006

In this paper, gain loss of KVN (Korean VLBI Network) 21-m shaped Cassegrain antenna due to misalignment of antenna optics is calculated using ray-tracing method. It enables us to estimate alignment tolerances of feed and sub-reflector positioning. According to numerical results, KVN 21-m shaped Cassegrain antenna's gain loss is more sensitive to positions of feed and sub-reflector than in case of the equivalent classical Cassegrain antenna. The result of calculation is believed to be utilized as a possible guideline when checking the performance of the antenna system.

• Laser Solutions
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• v.17 no.1
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• pp.17-21
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• 2014

Head up display is in increasing demand for advanced devices in the modern luxury vehicles. It helps drivers focus on driving environment on the road. While HUD technology with LED has advanced, the brightness in daylight can be still an issue to be resolved. Laser light source is a possible solution to overcome the brightness problem and optimal optics design is required for the best performance. Sample design of optics is proposed and detail procedure of lens design evaluation is presented in this paper. The results were characterized by using a ray tracing method and qualitative analysis for spot and DEE is also presented. The overall error or image distortion remained in the target range of $25{\mu}m$ and the simulated image demonstrated possible use in the automotive applications.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.108.1-108.1
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• 2012

Previously we introduced ray-tracing based 3D optical earth system model for specular and scattering properties of all components of the system (i.e. clear-sky atmosphere, land surfaces and an ocean surface). In this study, we enhanced 3-dimensional atmospheric structure with vertical atmospheric profiles for multiple layer and cloud layers using Lambertian and Mie theory. Then the phase dependent disk averaged spectra are calculated. The main results, simulated phase dependent disk averaged spectra and light curves, are compared with the 7 bands(300~1000nm) light curves data of the Earth obtained from High Resolution Instrument(HRI) in Deep Impact spacecraft during Earth flyby in 2008. We note that the results are comparable with the observation.