• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.273-277
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• 2003

A general process of electronic assembly is composed of a series of geometric alignments and bonding/screwing processes. After assembly, the function is tested in a following process of inspection. However, assembly of micro-optic devices requires both processes to be performed in equipment. Coarse geometric alignment is made by using vision and optical function is improved by the following fine motion based on feedback of tunable laser interferometer. The general system is composed of a precision robot system for 3D assembly, a 3D vision guided system for geometric alignment and an optical feedback system with a tunable laser. In this study, we propose a new fast alignment algorithm of micro-optic devices for both of visual and optical alignments. The main goal is to find a fastest alignment process and algorithms with state-of-the-art technology. We propose a new approach with an optimal sequence of processes, a visual alignment algorithm and a search algorithm for an optimal optical alignment. A system is designed to show the effectiveness and efficiency of the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• 제35권4호
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• pp.500-505
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• 2011

본 논문에서는 콜리메이터를 이용한 투과형과 반사형의 마이크로 광학형 누수감지 센서 시스템을 제안하고 실험하였다. 센서는 빛을 송신하고 수신하는 두 개의 콜리메이터가 10 mm 정도 떨어져서 마주보는 형태로 구현되어졌다. 센서가 공기 중에 노출된 경우 송신 콜리메이터에 나온 빛은 공기를 투과하여 수신 콜리메이터로 전송되어 일정한 출력 광 전력을 유지한다. 그러나 액체속에서는 송신된 빛이 산란되어 수신단으로 전달되지 못하므로 침수를 감지한다. 반사형의 경우 광섬유형 격자를 센서 끝단에 설치함으로서 센서에서 반응한 광 출력 정보가 입력단으로 다시 되돌아 올 수 있게 하여 시스템의 모니터링 구조를 단순화 하였다. 또한 두 시스템의 동작 특성을 비교하여 제시하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.623-624
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• 2005

Micro injection molding is a branch of micro system technology and has been under development for the mass manufacture of micro parts. Enhanced technological products like micro optical devices are entering the market. This paper presents fundamental research on the injection molding technique in micro fabrication. In order to successful manufacturing of micro plastic parts, it is necessary to research for development of micro-injection machine, machining of micro mold, decision of optimum injection conditions and the research for polymer material. Therefore in this study, in order to machining of micro mold, a mold core with microscopic V-shaped groove was tooled by ultra-precise tooling machine. The transcription experiments with a polymer, PMMA resin on the surface of core with Ni plating were carried out and surface profile of injected parts was measured with AFM.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.1080-1083
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• 1997

Micro-stereolithography is a newly proposed technology as a means that can fabricate 3D micro-structures of free form. It makes a 3D structure by dividing the shape into many slices of relevant thickness along honzontal surfaces, hardening each layer of slice with a laser, and stacking them up to a des~red shape. Scale effect becomes important in this micro-fabrication process, d~fferently from the conventional stereolithography. To realize this micro-stereolithography technology, we developed an equipment using Ar+ laser, xyz stages, controllers and all the optic devices. Using the equipment, a number of micro-structures were successfully fabricated including a winecup of several tens of micrometers.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.20-21
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• 2003

Erbium doped fiber (EDF) sources are useful devices for characterization of optical components for wavelength division multiplexing (WDM) fiber optic communication system. Therefore, there are many efforts to extend the bandwidth and to increase the power of the light source. Especially, L-band ASE source uses the low inversion state of EDF. It makes the power efficiency very low and needs a lot of fiber as several times as the fiber needed in C-band ASE generation. (omitted)

• Journal of Information Display
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• 제7권2호
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• pp.12-15
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• 2006

We propose a patterning method of liquid crystal (LC) alignment layer for producing multi-domain LC structures. By controlling thermal conditions during micro-contact printing procedures and facilitating wetting properties of patterning materials, patterned LC orientation can be easily obtained on a bare ITO surface or other polymer films. The newly proposed patterning method is expected to be a very useful tool for fabricating multi-domain LC structures to enhance or design electro-optic properties of LC-based devices.

• Journal of Magnetics
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• 제8권1호
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• pp.50-59
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• 2003

Spatial light modulators (SLMs) are centrally important devices in volumetric recording, data Processing, Pattern recognition and other optical systems. Various types of reusable SLMs with two-dimensional pixel arrays have been intensively developed. Of these, magneto-optic spatial light modulators (MOSLMs) have advantages of high switching speed, robustness, nonvolatility, and radioactive resistance. In this article, we review recent development work on MOSLMs, mainly in relation to our own studies.

• Steel and Composite Structures
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• 제38권3호
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• pp.337-353
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• 2021

Micro-electro-mechanical systems (MEMS) are widely employed in sensors, biomedical devices, optic sectors, and micro-accelerometers. New reinforcement materials such as carbon nanotubes as well as graphene platelets provide stiffer structures with controllable mechanical specifications by changing the graphene platelet features. This paper deals with buckling analyses of functionally graded graphene platelets micro plates with two piezoelectric layers subjected to external applied voltage. Governing equations are based on Kirchhoff plate theory assumptions beside the modified couple stress theory to incorporate the micro scale influences. A uniform temperature change and external electric field are regarded along the micro plate thickness. Moreover, an external in-plane mechanical load is uniformly distributed along the micro plate edges. The Hamilton's principle is employed to extract the governing equations. The material properties of each composite layer reinforced with graphene platelets of the considered micro plate are evaluated by the Halpin-Tsai micromechanical model. The governing equations are solved by the Navier's approach for the case of simply-supported boundary condition. The effects of the external applied voltage, the material length scale parameter, the thickness of the piezoelectric layers, the side, the length and the weight fraction of the graphene platelets as well as the graphene platelets distribution pattern on the critical buckling temperature change and on the critical buckling in-plane load are investigated. The outcomes illustrate the reduction of the thermal buckling strength independent of the graphene platelets distribution pattern while meanwhile the mechanical buckling strength is promoted. Furthermore, a negative voltage, -50 Volt, strengthens the micro plate stability against the thermal buckling occurrence about 9% while a positive voltage, 50 Volt, decreases the critical buckling load about 9% independent of the graphene platelet distribution pattern.

• Journal of the Optical Society of Korea
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• 제13권1호
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• pp.33-36
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• 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.

• ETRI Journal
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• 제41권1호
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• pp.32-41
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• 2019

We propose a speckle reduction technique in electronic holographic display systems, where digital micro-mirror array devices are used as spatial light modulators. By adopting a programmable filtration in a general 4-f optic configuration, it is shown that the signal spectrum components in the frequency domain of a viewing-window-based holographic display system can be selectively filtered. Compared to the widely utilized single-sideband filtration techniques in electronic holographic display systems, our proposed programmable filtration can be utilized to effectively reduce the speckles in the reconstruction of point-cloud-based computer-generated holograms. Experimental results are presented to verify our proposed concept.