• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.339-340
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• 2006

Recently, many researches have been done to improve optical performance of LCD-BLU(Back Light Unit). One of the most important parts in LCD-BLU is LGP(Light Guiding Plate). Micro-patterned LGP is known to have different optical characteristics depending on their shape, pattern density and size, etc. In the present study, a micro-optical patterned LGP mold was fabricated using LiGA process. The difference in the optical characteristics between positive and negative patterned LGP's was investigated by fixing the density, location and size of each pattern. It was found that the negative patterned LGP showed better optical characteristics than positive one.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1470-1473
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• 2013

본 논문에서는 안드로이드 플랫폼에서 3D 타이포그래피를 쉽게 표현할 수 있도록 지원하는 라이브러리를 설계 구현하였다. 현재까지 모바일 플랫폼에서 3D 타이포그래피를 지원하기 위한 라이브러리는 iOS에서 사용가능한 FTGL ES만이 공개되었고 이를 직접 안드로이드 플랫폼에서 사용할 수 없으며 제공되는 3D 표현 기능 또한 제한적이었다. 본 연구에서는 iOS용 FTGL ES를 안드로이드 플랫폼에서 사용할 수 있도록 변환하고 OpenGL ES기능을 활용하여 다양한 3D 폰트 표현을 지원할 수 있는 3D 폰트 라이브러리를 개발하였다. Freetype 라이브러리를 통해 폰트의 Glyph 정보들을 얻고 이를 이용해 테두리, 양각, 음각 등 다양한 3D 문자 표현 기능을 구현하였고, 공간상에서 문자들의 배치를 수학적으로 모델링하여 다양한 3D 문자 배치 기능을 구현하였다. 개발된 3D 폰트 라이브러리를 이용하여 다양하게 문자들을 3D 공간에 표현할 수 있으면서, 기존 3D 타이포그래피 표현 방법들에 비해 더 쉽고 빠르게 3D 타이포그래피를 표현할 수 있도록 지원한다.

• Korean Journal of Optics and Photonics
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• v.32 no.1
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• pp.15-21
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• 2021

In this paper, an aircraft warning light's optical system was designed using an LED light-source module and a collimating Fresnel lens. As for the optical system, a collimator Fresnel lens was designed for each module to satisfy a vertical-elevation center luminous intensity of 20,000 cd and the divergence-angle luminous-intensity standard conditions of the Ministry of Land for Infrastructure and Transport for aircraft warning lights. In addition, the optical system was optimized by adjusting the position and tilt of the LED light-source module and Fresnel lens. By analyzing and comparing the light-distribution characteristics of the optical system, an aircraft-warning-light optical system with optimal performance was obtained.

• Journal of Korean Medical classics
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• v.18 no.4 s.31
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• pp.15-26
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• 2005

통과연구(通過硏究)${\ulcorner}$의학입문(醫學入門)${\lrcorner}$중대어삼음삼양각자이육기배속원리(中對於三陰三陽各自以六氣配屬原理), 육기납지(六氣納支), 절기방위(節氣方位), 표본음양속성(標本陰陽屬性), 경맥납지(經脈納支), 맥체(脈體), 치법(治法), 중기등진행분류급고찰(中氣等進行分類及考察), 득출결론여하(得出結論如下) : 1. 삼음삼양적속성여지지적배속불일치(三陰三陽的屬性與地支的配屬不一致). 태양화궐음수연이지지여진술화사해(太陽和厥陰雖然以地支與辰戌和巳亥), 인신상배속(寅申相配屬), 단시실제상표본적음양속성여납지적원리시부동적(但是實際上標本的陰陽屬性與納支的原理是不同的). 인차(因此), 재구별표본음양적특성상(在區別標本陰陽的特性上), 절기(節氣), 방위등불능성위일정기준(方位等不能成爲一定基準). 2. 삼음삼양본기적오행속성화경맥납지(三陰三陽本氣的五行屬性和經脈納支), 유가능불일치(有可能不一致). 양명조금지본(陽明操金之本), 불시수양명대장(不是手陽明大腸), 실제상족양명위재시본(實際上足陽明胃才是本), 소양상화지본(少陽相火之本), 역불시수소양삼초(亦不是手少陽三焦), 실제상족소양담재본(實際上足少陽膽才本). 3. 삼음삼양안조종화규율기치법각이(三陰三陽按照從化規律其治法各異). 제일(第一), 표여본적음양속성상반시용반치법(標與本的陰陽屬性相反時用反治法). 소음본열표한(少陰本熱標寒), 태양본한표열(太陽本寒標熱), 차한열부정(且寒熱不定), 고태양열인한용(故太陽熱因寒用), 이소음한인열용(而少陰寒因熱用). 제이(第二), 표여본적음양속성상동시용정치법(標與本的陰陽屬性相同時用正治法). 태음표본균한(太陰標本均寒), 소양표본균열(少陽標本均熱), 고태음한인한용(故太陰寒因寒用), 색인색용(塞因塞用), 이소양통인통용(而少陽通因通用). 제삼(第三), 표여본적음양속성상반(標與本的陰陽屬性相反), 차여중기적음양속성부동시(且與中氣的陰陽屬性不同時), 불능용정치혹반치법(不能用正治或反治法), 응구종어중진행치료(應驅從於中進行治療). 즉불능구니어궐음화양명적소정치법(卽不能拘泥於厥陰和陽明的所定治法), 응수기종중진행치료(應隨機從中進行治療). 4. ‘소음태양(少陰太陽) 종본종표(從本從標)’ 재응용어치료시(在應用於治療時), 가해석여하(可解釋如下): 제일(第一), 혹자종본(或者從本), 혹자종표(或者從標). 제이(第二), 혹자종본(或者從本), 혹자종표(或者從標), 단치료상유기선후지별(但治療上有其先後之別). 제삼(第三), 소음한인열용(少陰寒因熱用). 태양열인한용(太陽熱因寒用), 고동시구종어표본(故同時驅從於標本). 5. 재(在)‘양명궐음(陽明厥陰) 부종표본(不從標本) 종호중(從乎中)’적(的)‘종호중(從乎中)’, 가이해위재치법운용중가이(可理解爲在治法運用中可以)‘수기취중(隨機取中)’지의(之意).

• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.17-24
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• 2001

Two-dimensional binary-phase diffraction gratings which can be employed to fabricate two- and three-dimensional periodic structures are designed and analyzed using rigorous coupled-wave analysis. These gratings serve as phase-masks which generate several diffracted waves from a normally incident beam and thus can produce a periodic interference pattern in space via nearfield holography. The properties of the diffracted beams can be controlled by varying the polarization and wavelength of the incident beam, surface-profile, groove depth and duty cycle of the mask. For the two-dimensional structure, optimum results can be obtained when the diffraction efficiency of the zero-order beam is minimized while that of the first-order maximized. On the other hand, when the diffraction efficiency of the zero-order is appreciable or even greater than other orders, we can obtain a variety of three-dimensional interference patterns which may be used to fabricate photonic crystals of tetragonal-body-centered and hexagonal structures in a submicron scale. scale.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.265-272
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• 2003

This paper describes anodic bonding characteristics of MLCA (Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100%, input power $1\;W/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA and Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-0.08 %FS. Moreover, any damages or separation of MLCA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MLCA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.7-12
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• 2018

In today's rapidly growing contemporary society, there is a tendency for demand to automate production processes by utilizing the vision system. In general, image recognition is mainly concerned with embossed characters such as license plates, and research on recognition of intaglio characters is very limited. Especially, intaglio characters, which are marked on rubber related products such as tire surfaces, have difficulty in recognizing characters or numbers through image because the difference in brightness with surrounding is not so large. In this paper, we propose a system to improve the recognition rate of characters marked on intaglio rubber products such as tire surfaces. Also, it can be applied flexibly according to the lighting environment. Through the proposed system, production and inventory management and defect detection can be processed quickly by applying to the production process of tire and rubber products.

• Journal of Conservation Science
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• v.30 no.1
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• pp.81-93
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• 2014

As the Seated Iron Buddha Statues, Vairocana Buddha of Dopiansa Temple in Cheolwon, Nosana Buddha of Samhwasa Temple in Donghae and Sakyamuni of Mangisa Temple in Pyeongtaek were made during Unified Silla to Koryo Dynasty. These are damaged degradation which are crack, break-out, peel off and various pollutant. As a result of deterioration evaluation using radiography, crack, gap, break-out, pore space and restoration material are confirmed inside in the Buddha Statues. Based on iron strength, the Buddha Statues will be maintain current state as long as a high external impact is not applied. Also, iron core and nails used for fixing of internal and external framework were observed in the Buddha Statues. According to prominent line of surface, embossed inscription, hands cast separately and combined, the Buddha Statues were made by using division casting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.75-76
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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), LCP (Light Guide Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50{\sim}200{\mu}m$ in diameter on it by erosion method. But the surface of the erosion dots of LGP is very rough due to the characteristics of the erosion 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 dot patterned LGP, optical pattern design with $50{\mu}m$ micro-lens was applied in the present study. Especially, the negative and positive 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 pattern conditions to the brightness distribution of BLU with micro-lens patterned LGP. Finally, negative micro-lens patterned LGP showed superior results to the one made by positive in average luminance.

• Design & Manufacturing
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• v.2 no.2
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• pp.29-32
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• 2008

A back light unit (BLU) is a key module of a thin film transistor liquid crystal display (TFT-LCD), frequently utilized in various mobile displays. In this study, we experimentally characterize transcription and optical properties of concave and convex microlens arrays (MLAs) of light guide plate (LGP) fabricated by injection molding with polycarbonate as a LGP substrate material. Nickel mold inserts were manufactured by electroforming on the MLA which was fabricated by the thermal reflow of photoresist microstructures patterned by UV-photolithography. For the case of convex microlens, the height of replicated microlens was less than that of the mold insert while maintaining almost the same microlens diameter of the mold insert as the location of the microlens is far from the gate. In contrast, for the concave microlens, the diameter of replicated microlens was larger than that of mold insert, while showing almost the same microlens height as the mold insert. From the optical examination of replicated convex and concave MLAs, it was found that a higher luminance of the LGP was achieved by the concave MLAs compared to the convex MLAs (about 30% enhancement in this case)due to the utilization of a larger amount of light provided by the light sources.