• Title/Summary/Keyword: optical alignment

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Development of Automatic Alignment Height and Cross-section Inspection System for Fiber Bragg Grating Embedded Field Assembly Connector (FBG Embedded 현장 조립형 커넥터의 자동 정렬 및 단면 자동 검사 시스템 개발)

  • Lee, Jung-Ho;Park, Chan-Hee;Yoon, Jae-Soon;Lee, Hee-Kwan;Kim, Cheol-Sang;Kim, Jae-Won;Kim, Kyung;Kim, Jae-Jun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.1
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    • pp.94-101
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    • 2014
  • Recently, in order to reduce the time required to replace an optical jumper cord, many researchers are using a field-installable connector and applying the ferrule polishing method, ferrule mechanical contact method, or ferrule fusion contact method. However, the process of arranging the length of the optical fiber, i.e., inserting the optical fiber into the ferrule by hand and checking its cross section, takes 60% of the time required for the entire process, which increases the overall cost. Therefore, in order to make this task more cost-effective, we will develop an automated inspection system with automatic cross-sectional arrangement of a field-installable connector. This system will be able to decrease the failure rate from 10% to 2% compared with the conventional method when cutting the optical fiber inserted into the ferrule. It will also improve the productivity by decreasing the test time by 28% compared with the conventional method. Our studies showed that it was possible to reduce the production costs and improve the quality of a field-installable connector, and we expect it to dominate the market.

Development Plan for the GMT Fast-steering Secondary Mirror

  • Lee, Sugnho;Han, Jeong-Yeol;Park, Chan;Jeong, Ueejeong;Yoon, Yang-noh;Song, Je Heon;Moon, Bongkon;Park, Byeong-Gon;Cho, Myung K.;Dribusch, Christoph;Park, Won Hyun;Jun, Youra;Yang, Ho-Soon;Moon, Il-Kwon;Oh, Chang Jin;Kim, Ho-Sang;Lee, Kyoung-Don;Bernier, Robert;Gardner, Paul;Alongi, Chris;Rakich, Andrew;Dettmann, Lee;Rosenthal, Wylie
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.66.3-67
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    • 2016
  • The Giant Magellan Telescope (GMT) will feature two interchangeable Gregorian secondary mirrors, an adaptive secondary mirror (ASM) and a fast-steering secondary mirror (FSM). The FSM has an effective diameter of 3.2 m and built as seven 1.1 m diameter circular segments, which are conjugated 1:1 to the seven 8.4m segments of the primary. Each FSM segment contains a tip-tilt capability for fine co-alignment of the telescope subapertures and fast guiding to attenuate telescope wind shake and mount control jitter. This tip-tilt capability thus enhances performance of the telescope in the seeing limited observation mode. As the first stage of the FSM development, KASI conducted a Phase 0 study to develop a program plan detailing the design and manufacturing process for the seven FSM segments. The GMTO-KASI team matured this plan via an internal review in May 2016 and the revised plan was further assessed by an external review in June 2016. In this poster, we present the technical aspects of the FSM development plan.

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Focal Reducer for McDonald Otto Struve Telescope

  • Lim, Ju-Hee;Kim, Young-Ju;Park, Won-Kee;Kim, Jin-Young;Chang, Seung-Hyuk;Pak, Soo-Jong;Im, Myung-Shin
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.36.2-36.2
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    • 2010
  • The CQUEAN (Camera for QUasars in EArly uNiverse) is an optical CCD camera optimized for observation of high redshift objects. It is going to be attached to the cassegrain focus of 2.1m telescope at McDonald Observatory, USA. We are making a focal reducer for CQUEAN to secure a larger field of view. The focal reducer is composed of four spherical lens, and it reduces the focal length of telescope by one third. We designed the lens configuration, performed tolerance analysis, and estimated the optical performance with ZEMAX. The differences in optical performace with/without filters were also investigated. The result from ZEMAX shows that the system has ample margin of errors for median seeing of 1.2" at McDonald observatory. Even with aberration and alignment tolerance, the performance is better than the original requirement. The lenses are now being made, and the lens barrel and an adapter for assembly of the Andor CCD camera and the filter wheel is now under designing process. We expect that the manufacturing of the focal reducer system as well as its optical test will be finished by April 2010.

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A Reliable Low-Loss Field-Installable Optical Connector Design by Splicing Angle Adjustment (접속 각도 조정을 통한 신뢰성 있는 저 손실 현장조립 광커넥터 설계)

  • Park, Byung-Chul;Rim, Chong-Suck;Jung, Jun-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.48 no.9
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    • pp.6-12
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    • 2011
  • In this paper, we propose a design method for a reliable and improved field-installable optical connectors(FIOC) which are needed for long-distance and low loss FTTH configuration. To this end, we optimize the angle of splicing between the inner fiber and the field fiber of the FIOC, so that the low loss connection of optical fibers is possible without using any angle alignment tools as well as angled cleavers. More precisely, we set the cutting angle of the inner filber and the field fiber to be $2^{\circ}$ by using an angled cleaver and $0^{\circ}{\sim}1^{\circ}$ by using a general fiber cutter, respectively. Splicing these two optical fibers without any further adjustment, we can keep the insertion loss within 0.3dB and the reflection loss within -60dB.

Hybrid-integrated Tunable Laser Using Polymer-ring Resonator-based Add/Drop Filter Reflector and Reflective Semiconductor Optical Amplifier (폴리머 링 공진기 기반의 가감필터 반사기와 반사형 반도체 광 증폭기가 하이브리드 집적된 파장 가변 레이저)

  • Lee, Ho;Kim, Gun-Woo;Chung, Young-Chul;Kim, Su-Hyun
    • Korean Journal of Optics and Photonics
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    • v.20 no.4
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    • pp.217-222
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    • 2009
  • In this paper, a low-cost hybrid-integrated tunable laser is realized using a polymer-ring resonator-based add/drop filter reflector and a reflective semiconductor optical amplifier. The add/drop filter reflector, composed of a double-ring resonator with different radii, can have characteristics of selective wavelength reflection and wide wavelength tuning with an aid of vernier effect derived from the radii difference. By hybrid-integrating the reflective semiconductor optical amplifier with the add/drop filter reflector, a tunable laser can be realized through an active alignment method. The hybrid laser exhibited a single mode lasing with side mode suppression ratio of 26 dB and full width half maximum of 0.03 nm. In addition, applying a low current as small as 25 mA onto electrodes over add/drop filter reflector, a wavelength tuning range of 17 nm could be obtained.

Coma Aberration Correction of Optical System by using a Robot Arm Type Coordinated Measuring Machine (로봇팔 타입 삼차원좌표측정기를 이용한 광학계의 비축수차 보정)

  • Chun, Ho Bin;Kim, Goeun;Song, In-Woong;Kang, Hyug-Mo;Rhee, Hyug-Gyo;Ghim, Young-Sik;Yang, Ho-Soon;Kwon, Jong Hoon
    • Journal of the Semiconductor & Display Technology
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    • v.15 no.3
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    • pp.62-66
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    • 2016
  • Optical system needs to be aligned before its undergoing process, is usually shows coma aberrations, which occurred due to imperfection in the lens or other components results in off-axis point sources, appearing to have a tail like a comet. There are some methods to correct coma aberration. In this paper, to correct coma aberration in optical system, using a robot arm type coordinate measuring machine(CMM). CMMs are widely used to measure the form of accuracy of parts and positioning accuracy of systems. Among them, robot arm type CMM has more advantages than the others, such as its mobility and measuring range. However, robot arm type CMM has lower accuracy than cantilever type CMM. To prove robot arm type CMM's accuracy, several factors were suggested in this paper and the final measuring results were compared to a commercial cantilever type CMM. Based on this accuracy, a typical optical system was successfully aligned by using our robot arm type CMM.

Influence of Electron Beam Irradiation on the Electrical and Optical Properties of InGaZnO Thin Film Transistor (InGaZnO 박막 트랜지스터의 전기 및 광학적 특성에 대한 전자빔 조사의 영향)

  • Cho, In-Hwan;Park, Hai-Woong;Kim, Chan-Joong;Jun, Byung-Hyuk
    • Korean Journal of Materials Research
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    • v.27 no.6
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    • pp.345-349
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    • 2017
  • The effects of electron beam(EB) irradiation on the electrical and optical properties of InGaZnO(IGZO) thin films fabricated using a sol-gel process were investigated. As the EB dose increased, the electrical characteristic of the IGZO TFTs changed from semiconductor to conductor, and the threshold voltage values shifted to the negative direction. X-ray photoelectron spectroscopy analysis of the O 1s core level showed that the relative area of oxygen vacancies increased from 14.68 to 19.08 % as the EB dose increased from 0 to $1.5{\times}10^{16}electrons/cm^2$. In addition, spectroscopic ellipsometer analysis showed that the optical band gap varied from 3.39 to 3.46 eV with increasing EB dose. From the result of band alignment, it was confirmed that the Fermi level($E_F$) of the sample irradiated with $1.5{\times}10^{16}electrons/cm^2$ was located at the closest position to the conduction band minimum(CBM) due to the increase of electron carrier concentration.

The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • v.17 no.12
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

Electro-optical characteristics of photo-aligned TN-LCD and LC alignment by using photo-depolymerization method (광분해법을 이용한 액정 배향 및 광배향 TN-LCD의 전기광학 특성)

  • 박태규;서대식
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.11a
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    • pp.343-346
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    • 1998
  • The generation of pretilt angle in nematic liquid crystal (NLC) and electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-LCD with oblique P-polarized ultraviolet (UV) light irradiation on the two kinds of the soluble polyimide (PI) surfaces containing trifluoromethyl moieties were investigated. The generated pretilt angle of NLC is about 2.5$^{\circ}$with P-polarized UV light irradiation of 20$^{\circ}$on PI-3 surface at 20 min.; However pretilt angle of about 0.5$^{\circ}$are observed on PI-1 and PI-2 surfaces. The generated pretilt angle of NLC on PI-3 surface may be attributed to the trifluoromethyl moieties attached to the lateral benzene rings. The voltage-transmittance and response time characteristics of photo-aligned TN-LCD with P-polarized UV light irradiation of 20$^{\circ}$on PI-1 surface at 20 min were almost same in comparison with the rubbing-aligned TN-LCD. However, the high threshold voltage and slow response are observed on PI-3 surface. Also, the decay time $\tau$$\sub$d/ of photo-aligned TN-LCD is attributed to the anchoring energy of NLC.

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Electro-optical Characteristics of VA mode LCOS depending on Cell Gap (VA Mode의 LCOS에서 Cell Gap의 변화에 따른 전기광학적 특성)

  • Kang, Jung-Won;Son, Hong-Bae
    • Journal of the Semiconductor & Display Technology
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    • v.7 no.3
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    • pp.41-43
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    • 2008
  • The electro-optical characteristics of the Liquid Crystal on Silicon (hereinafter "LCOS") micro-display on vertically alignment (VA) mode were studied depending on various cell gaps. 5 different cell gaps, such as $1.4{\mu}m,\;1.8{\mu}m,\;2.1{\mu}m,\;2.4{\mu}m$ and $2.8{\mu}m$, were selected. The reflectance-voltage (R-V) characteristics, distributions of reflected light and reflectance were calculated with 3-dimmensional LC code. At the center of cell, the smallest $1.4{\mu}m$ cell gap showed the lowest reflectance and the largest $2.8{\mu}m$ cell gap showed the highest reflectance due to the surface anchoring effect. In case of $2.1{\mu}m$ cell gap, the sum of reflectance overall cell was the highest value. Considering the reflectance and RV curve characteristic, the optimized cell gap was $2.1{\mu}m$.

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