• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.31.4-32
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• 2011

The previous KRISS profilometer design used an aluminum profile structure to which a bar-type reference mirror subsystem and the measurement subsystem are mounted. The earlier design suffers from low stiffness as shown from the first resonance mode of 45.1 Hz. The improved mechanical design we describe in this study replaces the aluminium profile structure with a granite structure of $1340{\times}220{\times}230$ in dimension. The finite element analysis results for the revised design show 0.001 degree in probe contact angle variation. The first resonance mode was computed to 91.2 Hz that is much better than 45.1 Hz from the previous design. We describe the improved design, structural analysis results and how these results would satisfy the form accuracy requirement of 1 ${\mu}m$ PV.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.391-403
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• 2005

Vision is the most important sense of the five senses in our body. This represents that an eye is for the mysterious organ playing the essential role in our body. Alain Mikli known as a famous spectacle designer in France said that glasses exists for seeing and for being seen. This saying is one of the philosophically well-organized definition of the most fundamental function of eye-glasses described in and out of itself. Today, in the world, there are a number of works of glasses design and lots of glasses designers are designing hard in order to convey the goods with the best value and philosophy to customers. They work for the goal that glasses is used as seeing and try to give customers satisfaction and enjoyment of it. And they think that glasses should play the role of the interface. At this point, we need to catch hold of the interface of glasses. That means that glasses has to have the communication between eyes and objects and be the mediation of the connection between the image of oneself and that of one by others. For the character of the interface of glasses, glasses designers should plan and investigate this character at the being of design. This study of optical art has been researched for the necessary and sufficient condition between consumers and products.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.333-334
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.65-65
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• 2000

Although it is difficult to predict the future engineers, including optical engineers, must do it on a regular basis. After all, what is the generation of a new optical design, but an attempt to predict what will be needed next year\ulcorner But optical engineers do not consult oracles or look into crystal balls, instead they look at past history, new research, and the trends in technology. This talk will use this approach to look at where optics will take us in this new century. (omitted)

• Current Optics and Photonics
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• v.6 no.6
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• pp.576-582
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• 2022

Plasmonic high-order harmonic generation (HHG) is used in nanoscale optical applications because it can help in realizing a compact coherent ultrashort pulse generator on the nanoscale, using plasmonic field enhancement. The plasmonic amplification of nanostructures induces nonlinear optical phenomena such as second-order harmonic generation, third-order harmonic generation, frequency mixing, and HHG. This amplification also causes damage to the structure itself. In this study, the plasmonic amplification according to the design of a metal-coated sapphire conical structure is theoretically calculated, and we analyze the effects of this optical amplification on HHG and damage to the sample.

• Journal of the Optical Society of Korea
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• v.10 no.3
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• pp.105-111
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• 2006

A novel image quality evaluation method, which is based on combination of the rigorous grating diffraction theory and the ray-optic method, is proposed. It is applied for design optimization and, tolerance analysis of optical imaging systems implementing diffractive optical elements (DOE). The evaluation method can predict the quality and resolution of the image on the image sensor plane through the optical imaging system. Especially, we can simulate the effect of diffraction efficiencies of DOE in the camera lenses module, which is very effective for predicting different color sense and MTF performance. Using this method, we can effectively determine the fabrication tolerances of diffractive and refractive optical elements such as the variations' in profile thickness, and the shoulder of the DOE, as well as conventional parameters such as decenter and tilt in optical-surface alignments. A DOE-based 2M-resolution camera lens module designed by the optimization process based on the proposed image quality evaluation method shows ${\sim}15%$ MTF improvement compared with a design without such an optimization.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.41-48
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• 2010

Non-contacting, laser-based resonant ultrasound spectroscopy (L-RUS) was applied to characterize the microstructure of a material. L-RUS is widely used by virtue of its many features. Firstly, L-RUS can be used to measure mechanical damping which related to the microstructural variations (grain boundary, grain size, precipitation, defects, dislocations etc). Secondly, L-RUS technology can be applied to various areas, such as the noncontact and nondestructive quality test for precision components as well as noncontact and nondestructive materials characterization. In addition, L-RUS technology can measure the whole field resonant frequency at once. In this paper, we evaluated material characteristics such as resonant frequency, nonlinear propagation characteristic through the development of Laser-Based Resonant Ultrasound spectroscopy (Laser-RUS) System for the detection of Micro Crack in Materials.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.93-97
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• 2005

We have developed the FDSS (Fine Digital Sun Sensor) for the space technology of the STSAT-2 (Seience & Technology Satellite 2). The FDSS is firstly developed by using CMOS image sensor(CIS) in South Korea. The FDSS consists of the optics part, FPGA(Field Programable Gate Array) part, and MCU(Micro controller unit)part. This paper will focus on the optical characteristics of the optics part and describe the configuration of FDSS with the design of aperture. We also analyze the characteristic of optics about the pixel of the CMOS image sensor.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.1
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• pp.101-108
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• 2016

The RCS characteristics of stealth modified three-surface aircraft are analyzed in this paper. Prototype A is built with CATIA software and the three-dimensional digital models of modified stealth three-surface B and C are also designed based on carrier-based aircraft Su-33; the numerical simulation of RCS characteristics of three-surface aircraft is conducted with RCSAnsys software based on physical optics method and the method of equivalent currents; The following results are obtained by comparative analysis and mathematical statistics: (1) by the use of physical optics method and equivalent electromagnetic current method, the scattering intensity for each part of the model and RCS characteristic of the aircraft can be analyzed efficiently and accurately; (2) compared with model A, the mean RCS value of model B is reduced to 14.1% in forward direction and 48.1% in lateral direction; (3) compared with model A, the mean RCS value of model C decreases to 11.4% in forward direction and 21.6% in lateral direction. The results are expected to provide theoretical basis and technical support to the conceptual design of aircraft and stealth technology research.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.30.2-30.2
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• 2011

In this report, we present in-orbit radiometric performance prediction for the Amon-Ra (Albedo Monitor and Radiometer) energy channel instrument. The Integrated Ray Tracing (IRT) computational technique uses the ray sets arriving at the Amon-Ra instrument aperture orbiting around the L1 halo orbit. Using this, the variation of flux arriving at the energy channel detector was obtained when the Amon-Ra instrument including the energy channel design observes the Sun and Earth alternately. The flux detectability was verified at the energy channel detector (LME-500-A, InfraTecTM). The detector time response and RMS signal voltage were then derived from the simulated flux variation results. The computation results demonstrate that the designed energy channel optical system satisfies the in-orbit detectability requirement. The technical details of energy channel instrument design, IRT model construction, radiative transfer simulation and output signal computation results are presented together with future development plan.