• 제목/요약/키워드: Numerical Aperture

검색결과 192건 처리시간 0.025초

Electromagnetic Penetration into an Annular Aperture in a Thick Conductor

  • Lee Haeng-Seon
    • Journal of electromagnetic engineering and science
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    • 제5권3호
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    • pp.146-151
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    • 2005
  • Electromagnetic penetration into an annular aperture in a thick conducting plane is investigated with the integral transform and eigen-function expansion method. The solution is analytic and is represented in rapidly-convergent series which is amenable to numerical analysis. Numerical computations shows that apertures with narrow annular gap have sharp transmit power peaks in frequency response.

입사광의 크기 조절을 통한 경사굴절률 플라스틱 광섬유의 수치구경 측정기법 (Measurement of Numerical Aperture of Graded-index Plastic Optical Fiber by Using a Variable Aperture)

  • 김대규;김보람;이병학;박승한
    • 한국광학회지
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    • 제22권1호
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    • pp.5-9
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    • 2011
  • 다중모드 경사굴절률 플라스틱 광섬유는 경사굴절률을 생성하기 위하여 첨가하는 미세입자, 불균일한 경사굴절률의 분포, 다른 모드 사이의 광학적인 간섭 등으로 인하여 스펙클 잡음이 크기 때문에, 광섬유 출력 단에서 방사되는 기하학적 광 세기 분포를 분석하여 측정하는 기존의 일반적인 수치구경 측정 방법으로는 수치구경 측정이 매우 어려운 문제점이 있다. 따라서 본 논문에서는 이와 같은 다중모드 경사굴절률 플라스틱 광섬유의 수치구경 측정을 위하여 입사 단에서 입사 광의 크기를 조절하여 수치구경을 구하는 새로운 방법을 제안하고, 이를 이용하여 플라스틱 광섬유의 수치구경을 측정하였다. 측정 결과, 기존의 방법으로 측정한 플라스틱 광섬유의 수치구경 값과 비교적 잘 일치함을 확인할 수 있었으며, 제안한 기법이 출력 단에서 방사되는 광세기 분포의 모호함을 배제할 수 있고 입력광의 입사 조건 및 광섬유 결합 효율을 최적화할 수 있는 장점이 있음을 알 수 있었다.

광 정보 저장 장치에서의 비구면 렌즈 가공 기술 (Aspherical Lens Manufacturing Technology in the Optical Storage Device)

  • 이호철;김대식;이철우;김부태;양민양
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.964-967
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    • 2001
  • Aspherical lens with the higher numerical aperture has been needed in the optical storage device to increase the recording density on the disk. However, high numerical aperture means the large slope angle at the clear aperture of the lens. Therefore, the measurement and manufacturing technique including the lens molding process for the slope angle should be developed. In this paper, the evaluation technique was described for the optical performance of the aspherical lens. Aspherical form error brings about the wavefront error and the side lobe of the beam intensity profile. A schematic diagram of the aspherical lens manufacturing was drawn to explain the aspherical form error compensation. Finally, form error of the aspherical lens was defined and plotted using the raw data of the Formtalysurf.

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A STUDY OF HYDRAULIC PROPERTIES IN A SINGLE FRACTURE WITH IN-PLANE HETEROGENEITY: AN EVALUATION USING OPTICAL MEASUREMENTS OF A TRANSPARENT REPLICA

  • Sawada, Atsushi;Sato, Hisashi
    • Nuclear Engineering and Technology
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    • 제42권1호
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    • pp.9-16
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    • 2010
  • Experimental examinations for evaluating fracutres were conducted by using transparent replicas of a single fracture in order to obtain the fracture data to contribute to the methodlogy on how to improve the definitaion of representative parameter values used for a parallel plate fracture model. Quantitative aperture distribution and quantitative tracer concentration data at each point in time were obtained by measuring the attenuation of transmitted light through the fracture in high spatial resolution. the representative aperture values evaluated from the multiple different measurement methods, such as arithmetic mean of aperture distribution measured by the optical method, transport aperture evaluated from the tracer test, and average aperture evaluated from the fracture void volume measurement converged to a unique value that indicates the accuracy of this experimental study. The aperture data was employed for verifying the numerical simulation under the assuption of Local Cubic Law and showed that the calculated flow rate through the fracture is 10%-100% larger than hydraulic test results. The quantitative tracer concentration data is also very valuable for validating existing numerical code for advection dispersion transport in-plane heterogeneous fractures.

블루레이 디스크 픽업용 초정밀 고개구율 플라스틱 대물렌즈 (Ultra-precision High Numerical Aperture Plastic Objective Lens for Blu-ray Disc Pick-up)

  • 김부태;현동훈;유경선
    • 한국생산제조학회지
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    • 제20권6호
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    • pp.811-816
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    • 2011
  • We develop a plastic object lens for blu-ray disc playing pick-up module as morethan 0.85 numerical aperture in this research. We design plastic object lens for blu-ray disc playing pick-up module's each factor's in balanced and made our designed lens by injection molding. Furthermore, by correction designing in mold-core, we optimization our lens efficiency as world grade; wave front aberration $0.028{\lambda}$. RMS, light axis differential 0.3967arcmin. We can manufacture localized blu-ray disc's pick-up lens's component and by this fact we obtain international competitiveness. The result of this research will be very helpful to develop a single objective lens for 3 different wavelength of laser diodes in playing and recording pick-up module.

PbO함유 다성분계 Glass Fiber의 제조 및 특성평가 (Fabrication and Properties of PbO Contained Multicomponent Glass Fiber)

  • 이회관;오영석;이용수;박만규;강원호
    • 한국산학기술학회논문지
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    • 제3권2호
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    • pp.89-93
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    • 2002
  • PbO 함유 다성분계유리 및 파이버를 제조하였으며, PbO함유 유리는 이중도가니법(double crucible methodo에 의한 높은 개구수를 갖는(high-numerical aperture : N.A.) 광파이버(optical fiber) 제조에 적합하였다. 본 실험에 있어서는 SiO₂, PbO를 주성분으로 하고 K₂O, Na₂O, B₂O₃, A1₂O₃등의 산화물을 적량 배합하였으며, 또한 double crucible method에 의해 제조된 파이버의 광학적, 기계적 및 구조적 특성을 관찰하였다.

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A NUMERICAL STUDY ON CHARACTERISTICS OF FLUID FLOW AND SOLUTE TRANSPORT IN A SELF-AFFINE VARIABLE-APERTURE FRACTURE UNDER NORMAL COMPLIANCE EFFECT

  • JEONG WOOCHANG;HWANG MANHA;KO ICKHWAN;SONG JAIWOO
    • Water Engineering Research
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    • 제6권2호
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    • pp.49-61
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    • 2005
  • This paper presents the numerical study to examine characteristics of fluid flow and solute transport in a rough fracture subject to effective normal stresses. The aperture distribution is generated by using the self-affine fractal model. In order to represent a nonlinear relationship between the supported normal stress and the fracture aperture, we combine a simple mechanical model with the local flow model. The solute transport is simulated using the random walk particle following algorithm. Results of numerical simulations show that the flow is significantly affected by the geometry of aperture distribution varying with the effective normal stress level while it is slightly affected by the fractal dimension that determines the degree of the fracture surface roughness. However, solute transport is influenced by the effective normal stress as well as the fracture surface roughness.

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3D Measurement of TSVs Using Low Numerical Aperture White-Light Scanning Interferometry

  • Jo, Taeyong;Kim, Seongryong;Pahk, Heuijae
    • Journal of the Optical Society of Korea
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    • 제17권4호
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    • pp.317-322
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    • 2013
  • We have proposed and demonstrated a low numerical aperture technique to measure the depth of through silicon vias (TSVs) using white-light scanning interferometry. The high aspect ratio hole like TSV's was considered to be impossible to measure using conventional optical methods due to low visibility at the bottom of the hole. We assumed that the limitation of the measurement was caused by reflection attenuation in TSVs. A novel interference theory which takes the structural reflection attenuation into consideration was proposed and simulated. As a result, we figured out that the low visibility in the interference signal was caused by the unbalanced light intensity between the object and the reference mirror. Unbalanced light can be balanced using an aperture at the illumination optics. As a result of simulation and experiment, we figured out that the interference signal can be enhanced using the proposed technique. With the proposed optics, the depth of TSVs having an aspect ratio of 11.2 was measured in 5 seconds. The proposed method is expected to be an alternative method for 3-D inspection of TSVs.

H-형태 소형 개구를 갖는 도파관 탐침의 등가회로 해석 (Equivalent Circuit Analysis of a Rectangular Waveguide Probe with H-type Small Aperture)

  • 고지환;조영기
    • 한국전자파학회논문지
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    • 제25권12호
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    • pp.1300-1305
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    • 2014
  • 근접장 마이크로파 현미경의 핵심 부품인 H-형태 소형 개구를 가진 도파관 탐침에 대해 등가회로를 표현하고 해석하였다. 파장에 비해 작은 사각형 또는 원형의 소형 개구는 유도성 성분인데, 여기에 리지 구조를 부착하는 것은 용량성 성분을 연결하여 이로 인해 투과 공진을 일으키는 것으로 볼 수 있다. 이러한 해석을 입증하기 위해 리지가 있는 소형 개구에서 용량 성분에 해당되는 리지 부분을 분리하여 대략 반파장 떨어진 지점에 세워 두고 구한 등가회로적 표현에 의한 계산 결과와 전자파 해석에 의한 계산 결과와 비교하여 거의 일치된 모습을 확인하였다. 또한, 도파관 탐침을 제작하여 반사손실을 측정하고, 계산 결과의 정확성을 확인하여 이론의 타당성을 검증하였다.

Polarizability for a Circular Aperture Near a Conducting Plane

  • Park, Yong-Bae;Kim, Il-Han;Eom, Hyo-Joon
    • Journal of electromagnetic engineering and science
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    • 제1권2호
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    • pp.173-175
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    • 2001
  • A polarizability fur a circular aperture near a conducting plane is derived. The Mantel-transform and mode-matching is used to obtain a simple series solution. The presented series solution is fast convergent so that it is very efficient fur numerical computations.

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