• Journal of the Semiconductor & Display Technology
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• v.12 no.3
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• pp.35-39
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• 2013

In this paper, we developed an optical sheet for LED lighting with integrated $CO_2$ gas and temperature sensor which can monitor at the indoor environment. The optical sheet for LED lighting is fabricated through PMMA(Polymethyl methacrylate) injection process using mold. This research enables to fabricate the reflective sheet, light-guide plate and the prism sheet in a optical sheet. The fabricated sheet demonstrates higher intensity of optical efficiency compared with single-sided sheets. The $CO_2$ sensor was fabricated using NDIR(NON-Dispersive Infrared) method and it has $0.0235mV/V{\cdot}PPM$ sensitivity. The temperature sensor was fabricated using RTD(Resistance temperature detector) method and it has $0.563{\Omega}/^{\circ}C $sensitivity.

• Journal of Intelligence and Information Systems
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• v.2 no.1
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• pp.27-44
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• 1996

컴퓨터통합생산 시스템의 실현을 위한 중요한 분야의 하나의 부품설계도면으로부터 최종제품을 생산 하는데 필요한 공정계획의 자동화, 즉 컴퓨터지원 자동공정계획(Computer Aided Process Planning ; CAPP) 시스템 기술의 개발이다. 국내외적으로 금형가공 부품을 대상으로 한 CAPP 시스템의 개발은 비교적 저조하므로, 본 연구에서는 사출금형 부품을 대상으로 하여 실용성이 있는 공정계획 전문가시스템 개발을 목적으로 한다. 본 연구에서 금형 공정계획전문가의 경험적 지식을 기반으로 한 사출금형부품의 공정계획 전문가시스템인 MOLDCAPP을 개발하였다. MOLDCAPP 시스템은 도면정보로부터 형상정보를 자동적으로 인식하여 공정계획의 기능 중에서 가동공정, 가공공정 순서, 공작기계 및 절삭공구를 자동적으로 결정한다. 개발된 MOLDCAPP 시스템은 실제 사례연구를 통하여 그 타당성을 분석하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.100-101
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• 2011

사출금형은 자동차의 경량화 요구에 따라 일반 엔지니어링 플라스틱에서 고강도 플라스틱 성형을 위한 사용 환경으로 변해가고 있다. 이에, 사출금형의 표면은 마모에 대한 내력을 갖는 고경도 특성과 수지의 유동성을 양호하게 하기 위한 저마찰 특성의 요구가 점차 증가하고 있다. 본 연구는 사출금형 소재 표면의 고경도 저마찰 특성 부여를 위하여 대형 플라즈마 표면처리 공정을 이용하여 각각 질화처리와 비정질 탄소 코팅 공정기술에 관한 연구를 수행하였다. 각각의 플라즈마 처리된 샘플은 표면처리 공정 변수에 따른 경도 및 마찰계수 평가를 통하여 사출금형 소재 표면의 물리적 특성 변화를 관찰하였다.

• Proceedings of the KIEE Conference
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• 2005.11c
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• pp.107-109
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• 2005

Temperature distribution measured to estimate condition of an electrical apparatus is an absolute reference for the apparatus conditions and the difference between the reference temperature and the current one. Because a passive thermography without the external thermal stimulation shows the difference in surface temperature between the object and back ground, the results can apply only to the estimation or the monitoring for the condition of terminal loose and the overload pertaining to the rise in temperature. However, a thermal flow in the active thermography is differently generated by the structure and condition of the surface and subsurface. This paper presents the nondestructive testing using the behavior and deals with the results by heat injection and cooling to the apparatus. The buried discontinuity of subsurface could be detected by these techniques.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.46-52
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• 2000

3D Welding and Milling is a solid freeform fabrication process which is based on the combination of welding as additive and conventional milling as subtractive technique. This hybrid approach enables direct building of metallic parts with high accuracy and surface finish. Although it needs further improvements it shows an application potential in rapid tooling of injection mold inserts as the investigation results show. To optimize the process for higher surface quality and accuracy effectively Taguchi method is applied to the experimental investigation. in this way relationships between process parameters and final product qualities such as tensile strength and surface hardness are found with minimal efforts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.632-636
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• 2005

Design process model represents how a design project proceeds. It encompasses the individual activities of design, their precedence relationships, and the relevant information related to each activity. In contrast to the conventional visual representation methods, ontology-based process model is machine-readable, and therefore it can be implemented in a software system without repeating the whole steps of coding, compiling and link. This paper proposes a framework for design process ontology that defines the relevant objects and attributes in the design process as well as the relationships between them. An example for injection mold design process is shown to explain the substance of the design process model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.777-780
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• 2005

The global consumption of aspheric surfaces will expand rapidly on the Electronics and Optical Components Information and Communications, Aerospace and Defense, and Medical optics markets etc. We must research on market, technology forecast and analysis of aspheric surfaces that is a principle step of ultra precision machine technology with a base one of optical elements. Especially, F-theta lens is one of the important parts in LSU(Laser scanning unit) because it affects on the optical performance of LSU dominantly. The core is most of important to produce plastic F-theta lens by plastic injection molding method, which is necessary to get the ultra-precision aspheric and non-axisymmetric machine processing technology.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.798-803
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• 2005

The increasing complexity of modem products requires the effective management of design knowledge, which partly resides in the product itself on the one hand. On the other hand, a lot of knowledge is gathered and/or generated during the design process, but disappears as the design project concludes. This paper describes a knowledge representation method to accommodate the implicit design knowledge. The method is based on the FBS(Function-Behavior-Structure) model and extends the object ontology with constraint entity. An example to represent the injection mold design knowledge is given to show its applicability.

• Design & Manufacturing
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• v.7 no.1
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• pp.55-59
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• 2013

A Light Emitting Diode(LED) is a semiconductor device which converts electricity into light. LEDs are widely used in a field of illumination, LCD(Liquid Crystal Display) backlight, mobile signals because they have several merits, such as low power consumption, long lifetime, high brightness, fast response, environment friendly. In general, LEDs production does die bonding and wire bonding on board, and do silicon and phosphor dispensing to protect LED chip and improve brightness. Then lens molding process is performed using mixed liquid silicon rubber(LSR) by resin and hardener. A mixture of resin and hardener affect the optical characteristics of the LED lens. In this paper, computational design of static mixer was performed for mixing of liquid silicon. To evaluate characteristic of mixing efficiency, finite element model of static mixer was generated, and fluidic analysis was performed according to length of mixing element. Finally, optimal condition of length of mixing element was applied to static mixer from result of fluidic analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.239-242
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• 2006

LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LGP (Light Guiding Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50{\sim}200$ um in diameter on it by etching process. But the surface of the etched dots of LGP is very rough due to the characteristics of the etching process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. In order to overcome the limit of current etched dot patterned LGP, optical pattern design with 50um micro-lens was applied in the present study. The micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP. The attention was paid to the effects of different aspect ratio (i.e. $0.2{\sim}0.5$) of optical pattern conditions to the brightness distribution of BLU with micro-lens patterned LGP. Finally, high aspect ratio micro-lens patterned LGP showed superior results to the one made by low aspect ratio in average luminance.