• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.67-72
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• 2000

A lot of varIOUS studies are taking advantage of annular masks or various pupil filters to design optical systems such as a digital versatile disc (DVD) pick up head and precise scanning microscopy that have the superresolution beyond the diffraction limit. We considered both annular mask and pupil filter for the superresolution system. Since image quality is a function of annular width, position and modulation amount, we computel'lzed the optimized condition for the phase modulation and mvestigated the variation of lhe center peak: intensity for the phase modulated system From tills result, we were able to detenrune the best conditions for the annular apodizer, wluch give the maximum value of the center peak intensity_ We made especially sure that the phase modulated system have an excellent compensation for spherical aberration as it lllcreases. eases.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.165-171
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• 2001

We discuss the influence of annular binary filters on the axial PSF of imaging systems which are apodized by a radiallysymmetric filter and have spherical aberration and coma. In this paper we consider a whole family of annular binary fIlters in two cases. First, the binary filters are composed of two transparent annuli of the same area. Second, the binary filters are composed of a central clear circle and a concentric annular aperture with area bigger than that of the inner circle. In order to investigate the influence of the proposed filters on the axial PSF, we may use the axial resolution gains, which evaluate in terms of the FWHM of the intensity in the focal region of an apodized imaging system in comparison with that corresponding to a nonapodized one. We evaluate the PSF for the conventional and confocal systems having an aberration. ation.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.491-497
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• 2016

This study aims to develop a vision inspection system for screw threads. To inspect external defects in screw threads, the vision inspection system was developed using front light illumination from which bright images can be obtained. The front light system, however, requires multiple side images for inspection of the entire thread surface, which can be performed by omnidirectional optics. In this study, an omnidirectional optical system was designed to obtain annular images of screw threads using an image sensor and two reflection mirrors; one large concave mirror and one small convex mirror. Optical simulations using backward and forward ray tracing were performed to determine the dimensional parameters of the proposed optical system, so that an annular image of the screw threads could be obtained with high quality and resolution. Microscale surface defects on the screw threads could be successfully detected using the developed annular inspection system.

• Korean Journal of Optics and Photonics
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• v.10 no.6
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• pp.453-461
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• 1999

In this paper, we have studied on the effects of annular and quadrupole illuminations by changing their conditions for enhancing the pattern resolution and depth of focus (OaF) in the optical lithography system using KrF Eximer laser 0.248$\mu$m and 0.65 NA. As a result, it is revealed that each illumination condition to optimize the resolution and the OaF for the mask containing the assistance pattern is different under the annular illumination. And in case of quadrupole illumination, we could ascertain that the resolution and the OaF would be enhanced through changing the arrangement of each pole from the conventional X type (45 degrees) to some proper type according to the main pattern direction. ction.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.28-29
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• 2000

최근, 통신, PC등의 보급과 함께, 메모리기기의 발전이 급속히 이루어 지고있다. 이 중에서 광기억장치는 기록 및 재생용량을 증가시키는 기술이 활발히 연구되어 왔다. 본고에서는 대용량기기의 대표적인 DVD(Digital Versatile Disc)에 있어서, 핵심광학기술로 각광을 받고있는 CD호환을 위한 환형(annular type) lens의 특성을 고찰하였다. 그리고, 반도체 메모리, Hard disk등도 고밀도연구가 지속적으로 연구되고있으며, 이에 대응되는 광기억장치의 기술로서 근접장 광학이 최근 활발히 연구되고있다. 근접장에 의한 고개구수를 달성하기 위한 효율적인 대물렌즈로서 종래의 굴절렌즈만이 아닌 반사광학계도 사용한 굴절-반사광학계 (Cata-dioptric Optics)를 응용한 Solid Immersion Mirror (SIM)에 관한 특성을 살펴보았다. (중략)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.460-464
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• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, the advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours and is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. In this paper, maxwell 3D finite element analysis program (Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by D simulation software operated at 250KHz and some specific conditions. Photometric characteristic of the ring-shaped electrodeless fluorescent lamp were investigated using LS-100 lightmeter and TA-0510 thermometer respectively.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.161-163
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• 2003

Ring-shaped electrodeless fluorescent lamp is removed the internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. The ring-shaped electrodeless lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. In this paper, maxwell 3D finite element analysis program (Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250[㎑]and some specific conditions. The optical measurement measured luminance and a temperature and an optical spectrum distribution for 10 minutes in a one minute interval at the same time.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.190-199
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• 2001

In this paper, we have researched the depth of focus (DOF) and cutoff intensity of the $0.1{\mu}m$rule dense line'||'&'||'space pattern according to the various off-axis illumination (OAl) conditions in the optical system of 0.65 NA using ArF excimer laser (193 nm). We have also studied the variation of the DOF and cutoff intensity according to the sub-resolution pattern (hammer head type) size for optical proximity correction (OPC) applied to the capacitor pattern and the various OAl conditions in the same optical system. As a result, it is revealed that the cross type quadrupole or annular illumination is preferred to the conventional X type quadrupole for printing the $0.1{\mu}m$ rule dense pattern. Also, we can investigate the optimal illumination condition and the size of ope sub-resolution pattern to keep a consistent DGF and cutoff intensity trends.

• Polymer(Korea)
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• v.38 no.6
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• pp.752-759
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• 2014

Crosslinked polyimides (PIs) were synthesized by reacting 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) and 2,2'-bis(trifluoromethyl)benzidine (TFDB) with various ratios of the cross-linkable, end-capping agent cis-1,2,3,6-tetrahydrophthalic anhydride (CDBA) via ring-opening metathesis polymerization. Residual stress behaviors were investigated in-situ during thermal imidization of the crosslinked PI precursors using a thin film stress analyzer (TFSA) by wafer bending method. The thermal properties were investigated via differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and thermogravimetric analysis (TGA). The optical properties were measured by ultraviolet-visible spectrophotometer (UV-vis) and spectrophotometry. All properties were interpreted with respect to their morphology of crosslinked networks. With increasing the amounts of the end-capping agent, the residual stress decreased from 27.9 to -1.3 MPa, exhibited ultra-low stress and high thermal properties. The minimized residual stress and enhanced thermal properties of the crosslinked PI makes them potential candidates for versatile high-density multi-layer structure applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.552-559
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• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, the advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. The ring-shaped electrodeless lamp is intended as a high efficiency replacement for the incandescent reflector lamp in many applications. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, maxwell 3D finite element analysis program(Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250 KHz and some specific conditions. The optical characteristics were measured luminance and a temperature and an optical spectrum distribution for 10 min in a one minute interval at the same time. With a goal of finding alternative materials, we show measurement results of electrical characteristics of a ring-shaped electrodeless fluorescent lamp as a function of frequency and the number of coil turns using a highly permeable($\mu$$_{r}$(equation omitted) 2,000) Mn-Zn ferrite. These results are compared with those of conventional ring-shaped electrodeless fluorescent lamp. It is found that the resistance, inductance and impedance are increased while the quality factor decreases as frequency increases.s.