• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.12 s.255
• /
• pp.1557-1563
• /
• 2006

A scanning electron microscope (SEM) is well known as a measurement and analysis equipment in nano technology, being widely used as a crucial one in measuring objects or analyzing chemical components. It is equipped with an electron optical system that consists of an electron beam source, electromagnetic lenses, and a detector. The present work concerns numerical analysis for the electron optical system so as to facilitate design of each component. Through the numerical analysis, we investigate trajectories of electron beams emitted from a nano-scale field emission tip, and compare the result with that of experimental observations. Effects of various components such as electromagnetic lenses and an aperture are also discussed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1066-1067
• /
• 2004

New diffuser film for LCD backlight is developed. A diffuser film was manufactured through coating UV curable monomer on a plastic film. The diffuser layer coated on plastic film showed excellent optical transmittance.

• ETRI Journal
• /
• v.29 no.6
• /
• pp.779-784
• /
• 2007

In this paper, we report the experimental results of a hybrid wideband fiber amplifier. The amplifying medium is a concatenated hybrid fiber consisting of Er-doped fiber (EDF) and dispersion compensating fiber (DCF). The gain mechanisms are based on stimulated emission in the EDF and stimulated Raman scattering (SRS) in the DCF. Since we simultaneously use optical amplification by the two processes, the gain bandwidth is easily expanded over 105 nm by a two-tone pumping scheme. Using an experimental setup constructed with a hybrid structure of EDF-DCF-EDF, we analyzed the spectral behavior of amplified spontaneous emission for pumping powers. We achieved an optical gain of over 20 dB in the wavelength range from 1,500 to 1,600 nm under optimized pumping conditions to make the spectral gain shape flat.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.5
• /
• pp.9-18
• /
• 1998

The components with J-lead. which are more integrated and smaller than ones with Gull-wing. are rapidly being used in electronic board such as the PCB, for they have the advantage of occupying a small space compared to the other components. However, the development of inspection system for these new components is not so rapid as component development. Component-inspection with J-lead using vision system is difficult because they are hidden from camera optical axis. X-ray inspection, which has the advantage of inspecting the inside of solder state, is used to J-lead inspection. However. it is high cost and dangerous by leaking out X-ray compared to vision system. Therefore, in this paper, we design vision system suited to J-lead inspection and then propose algorithm which have flexibility in mount and rand error.

• Journal of the Optical Society of Korea
• /
• v.19 no.6
• /
• pp.649-657
• /
• 2015

We present a surface color measurement including quantities of surface color, methods, and uncertainty evaluation. Based on a relation between spectral reflectance and surface color, we study how an uncertainty of spectral reflectance propagates to surface color. In analyzing the uncertainty propagation, we divide the uncertainty into uncorrelated components, fully correlated components, and correlated components with spectrally varying correlations. As an experimental example, we perform spectro-reflectometric measurements for ceramic color plates. With measured spectral reflectance and its uncertainty evaluation, we determine surface color and analyze uncertainties of the ceramic color plates.

• 연구논문집
• /
• s.32
• /
• pp.23-34
• /
• 2002

Up to now, collimators have teen generally produced by handwork and only a few companies have produced by semi-automatic system. Under this situation, automatic system for assembly of optical collimators has risen as a mast essential technique in the development of optical communication components. In this study, it was constructed to develop optical collimators with high functionality and we manufactured optical collimators with a GRIN rod lens and spherical lens using automatic system. Therefore, we worked a performance test through a comparison of collimators made by automatic system and handwork with angle augment, bean size. Also we selected a optimum assembly condition of GRIN rod lens and spherical lens. As a result, it brought a reduction of the tact time and an improvement of an efficiency and a productivity of optical collimators, therefore it was found that automatic system was indispensable for materialization of optical collimators with high functionality.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.119-122
• /
• 2002

Collimators were mostly produced by handwork and semi-automatic system in some companies. Under this situation, automatic manufacturing system for optical collimators is on the rise most essential technique in the development of optical communication components. In this study, automatic manufacturing system was designed and constructed to develop optical collimators with high functionality. Also optical collimators were manufactured using a developed automatic system. We have compared collimators made by automatic system and handwork fer performance test with a measured values of angle alignment, beam size and TIL. As a result, it brought a reduction of the tact time fur manufacturing and improvement of an efficiency of optical collimators, and then it was found that automatic system was indispensable for materialization of optical collimators with high functionality.

• Current Optics and Photonics
• /
• v.1 no.4
• /
• pp.396-401
• /
• 2017

In this article, we proposed hybrid polarization singularity configurations, based on the superposition of two orthogonal circularly polarized components, one of which is a light beam with two optical vortices. The topological configurations are the hybridization of lowest-order polarization singularities, but are different from high-order polarization singularities. Our numerical simulation may provide a theoretical basis for expanding the variety of polarization singularity configuration.

• Transactions of Materials Processing
• /
• v.11 no.7
• /
• pp.589-595
• /
• 2002

Up to now, Collimators have been generally produced by handwork and only a few companies have produced by semi-automatic system. Under this situation, automatic system for assembly of optical collimator has risen as a most essential technique in the development of optical communication components. In this study, it was constructed to develop optical collimators with high functionality and We manufactured optical collimators with a GRIN rod lens using automatic system. Therefore, we worked a performance test through a comparison of collimators made by automatic system and handwork with angle alignment, beam size. Also we compared common product with auto-manufactured sample. As a result, it brought a reduction of the tact time and an improvement of an efficiency and a productivity of optical collimators. therefore it was found that automatic system was indispensable for materialization of optical collimators with high functionality.

• Journal of the Optical Society of Korea
• /
• v.13 no.1
• /
• pp.33-36
• /
• 2009

Laser ablation with femtosecond lasers is highly promising for microfabrication of materials. Also, the high peak power of femtosecond lasers could induce a multiphoton absorption to ablate transparent materials. Similar results have also been were obtained in the case of optical fibers. In this paper, we present our experimental results of femtosecond laser microstructuring of optical fiber and its applications to microelectronic components and fiber optic devices. Finally, we directly produced micro holes with femtosecond laser pulses in a single step by moving an optical fiber in a preprogrammed structure. When water was introduced into a hole drilled from the bottom surface of the optical fiber, the effects of blocking and redeposition of ablated material were greatly reduced and the aspect ratio of the depth of the hole was increased. We have presented circular and rectangular-shaped holes in optical fiber.