• Title/Summary/Keyword: NA(Numerical Aperture)

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Interference Fringe Signal Filtering Method for Performance Enhancing of White Light Interfrometry (가간섭 영역 외의 배경 잡음성 간섭무늬 신호 필터링을 통한 백색광 주사간섭계의 성능 향상)

  • Yim, Hae-Dong;Lee, Min-Woo;Lee, Seung-Gol;Park, Se-Geun;Lee, El-Hang;O, Beom-Hoan
    • Korean Journal of Optics and Photonics
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    • v.20 no.5
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    • pp.272-275
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    • 2009
  • In order to enhance the background noise filtering performance of the white light interferometry(WLI), we demonstrate the noise filtering performance of preprocessing of the measured fringe signals. The WLI was realized through a mirau interferometer which was equipped with a green LED. When measuring large-height and rough surface objects, the illumination optics are considered the numerical aperture(NA) and the depth of focus(DOF). In this case, the limited NA of the illumination optics has a considerable impact on the interference fringe. Therefore, we propose a preprocessing method that uses the intensity difference between the measured intensity and the moving average intensity. The performance is demonstrated by measuring an array of metal solder balls fabricated on printed circuit board(PCB). The proposed method reduces the noise pixels by 15 percent.

Performance Prediction for Plenoptic Microscopy Under Numerical Aperture Unmatching Conditions (수치 구경 불일치 플렌옵틱 현미경 성능 예측 방안 연구)

  • Ha Neul Yeon;Chan Lee;Seok Gi Han;Jun Ho Lee
    • Korean Journal of Optics and Photonics
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    • v.35 no.1
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    • pp.9-17
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    • 2024
  • A plenoptic optical system for microscopy comprises an objective lens, tube lens, microlens array (MLA), and an image sensor. Numerical aperture (NA) matching between the tube lens and MLA is used for optimal performance. This paper extends performance predictions from NA matching to unmatching cases and introduces a computational technique for plenoptic configurations using optical analysis software. Validation by fabricating and experimenting with two sample systems at 10× and 20× magnifications resulted in predicted spatial resolutions of 12.5 ㎛ and 6.2 ㎛ and depth of field (DOF) values of 530 ㎛ and 88 ㎛, respectively. The simulation showed resolutions of 11.5 ㎛ and 5.8 ㎛, with DOF values of 510 ㎛ and 70 ㎛, while experiments confirmed predictions with resolutions of 11.1 ㎛ and 5.8 ㎛ and DOF values of 470 ㎛ and 70 ㎛. Both formula-based prediction and simulations yielded similar results to experiments that were suitable for system design. However, regarding DOF values, simulations were closer to experimental values in accuracy, recommending reliance on simulation-based predictions before fabrication.

Design of Elliptic Solid Immersion Lens for Dual Layer Near Field Recording (미디어 내부 2층 근접장 광기록을 위한 타원형상 고체침지렌즈의 설계)

  • Kim, Wan-Chin;Choi, Hyun;Song, Tae-Sun;Park, No-Cheol;Park, Young-Pil
    • Transactions of the Society of Information Storage Systems
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    • v.2 no.4
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    • pp.219-223
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    • 2006
  • Near field recording(NFR) technology has been considered as a strong candidate to surpass the far-field diffraction limit imposed by the nature of light in present optical disk drives such as CD, DVD, and BD(Blu-ray Disk). In this paper, we suggest novel inside near-field dual layer recording concept using elliptic shape solid immersion lens(ESIL).

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The Simulation of Micro Optical Cross Connect Based On Ball Lens (구형렌즈를 사용한 초소형 광 스위치에서의 Simulation)

  • Lee, Doo-Won;Kim, Ho-Seong
    • Proceedings of the KIEE Conference
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    • 2000.11c
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    • pp.594-596
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    • 2000
  • The best simulation condition for the fiber collimator that uses ball lenses was investigated. This kind of fiber collimator can be used in a Micro-Optical-Cross-Connects(MOXC). MOXC is composed of collimating ball lenses, micro mirrors and single-mode fibers. In order to design a MOXC, it is very important to calculate beam path, beam radius, divergence angle that determines the insertion loss of the MOXC. Since the beam profile from the fiber facet is not exact Gaussian profile, it was found that the simulation condition in which beam waist exists on the fiber facet, ignoring Numerical Aperture(NA), gives best agreement with the experimental results. Beam radii were measured with conventional knife edge method.

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Design And Optimization Of Actuator For Micro Optical Disk Drive Using Response Surface Methodology (반응표면법을 이용한 초소형 광디스크 드라이브 구동기의 최적화 및 디자인)

  • 우기석;이동주;박노철;박영필
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.755-761
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    • 2003
  • Recently, the development of mobile devices demands information storage systems to use micro drive devices and cheap media. These should have several characteristics, for example, the subminiature of size, the robustness of shock, the minimum of cost and power consumption, and the removability of multiple applications. A conventional optical disk drive is more suitable for these specifications than the others. The optical storage system of the new generation to use a blue laser and a high numerical aperture (NA) is the perfect candidate for micro optical disk drives. In this paper, the micro actuator that can be applied to a micro optical disk drive is designed by response surface methodology to use a structural analysis and an electro-magnetic analysis. Based on above results, the coarse actuator and fine actuator are designed and improved from the point of view of the size and the power. Consequently, the designs of a micro actuator are proposed through these courses.

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Active Alignment and Performance Evaluation of Micro Hybrid Lens for Small Form Factor Optical Pickup (초소형 광 픽업용 하이브리드 렌즈의 능동 정렬 및 성능평가)

  • Kang Sung-Mook;Lee Jin-Eui;Cho Eun-Hyoung;Sohn Jin-Seung;Park No-Cheol;Park Young-Pil
    • 정보저장시스템학회:학술대회논문집
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    • 2005.10a
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    • pp.154-159
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    • 2005
  • The next generation of optical storage systems requires higher numerical aperture (NA) objective lenses and shorter wavelength laser in order to improve the unit areal density. A blu-ray technology satisfies a miniaturization and a high capacity which are the requirements of the portable device. In this paper, we analyze the optical performance of hybrid micro lens and do active alignment. The hybrid micro lens is manufactured by using a wafer based fabrication technology. Optical components of hybrid micro lens are evaluated. The measurement of the optical power, the spot size and the wavefront error awe performed to evaluate the hybrid micro lens with NA 0.85. Using the measured data, we estimate if the performance of hybrid micro lens corresponds to the designed performance. After the performance of hybrid micro lens is evaluated, the integrated optical pickup and the hybrid micro lens are assembled by active alignment using UV curing and the optical performance of SFFOP is satisfied with BD specifications.

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Active Alignment and Performance Evaluation of Micro Hybrid Lens for Small Form Factor Optical Pickup (초소형 광 픽업용 하이브리드 렌즈의 능동 정렬 및 성능평가)

  • Kang, Sung-Mook;Lee, Jin-Eui;Cho, Eun-Hyoung;Sohn, Jin-Seung;Park, No-Cheol;Park, Young-Pil
    • Transactions of the Society of Information Storage Systems
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    • v.2 no.1
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    • pp.79-84
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    • 2006
  • The next generation of optical storage systems requires higher numerical aperture(NA) objective lenses and shorter wavelength laser in order to improve the unit areal density. A blu-ray technology satisfies a miniaturization and a high capacity which are the requirements of the portable device. In this paper, we analyze the optical performance of hybrid micro lens and do active alignment. The hybrid micro lens is manufactured by using a wafer based fabrication technology. Optical components of hybrid micro lens are evaluated. The measurement of the optical power, the spot size and the wavefront error are performed to evaluate the hybrid micro lens with NA 0.85. Using the measured data, we estimate if the performance of hybrid micro lens corresponds to the designed performance. After the performance of hybrid micro lens is evaluated. the integrated optical pickup and the hybrid micro lens are assembled by active alignment using UV curing and the optical performance of SFFOP is satisfied with BD specifications.

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Super Resolution Readout in Near Field Optical Data Storage System (근접장 광 기록 재생 시스템에서의 초해상 재생 현상 확인)

  • Lee, Jin-Kyung;Jeong, An-Sik;Shin, Jong-Hyun;Kim, Joo-Ho;Lee, Kyung-Geun;Kim, Joong-Gon;Park, No-Cheol;Park, Young-Pil
    • Transactions of the Society of Information Storage Systems
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    • v.4 no.1
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    • pp.1-5
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    • 2008
  • Super-resolution near-field structure (super-RENS) technology and solid immersion lens (SIL) based near-field (NF) technology have been expected as promising approaches to increase data capacity or areal density of optical disc. Super-RENS technology has been studied until now using mainly numerical aperture (NA) of 0.85 far-field optical system and possibility of tangential data density increment have been presented. NF technology has been studied with NA over 1 and presented demonstration of removable performance. To achieve much higher density, approach to increase NA of super-RENS by NF technology (Near-Field Super-Resolution, NFSR) can be a candidate and we think this technology would be advantageous compared to wavelength reduction or much higher NA increment of NF technology or much smaller effective optical spot size reduction of far-field super-resolution technology. In this paper we present readout result of ROM media having monotone pits using NF optical system with wavelength of 405nm and NA of 1.84 surface type SIL. GeSbTe material was used for super resolution active layer and pit length is 37.5nm which is shorter than resolution limit 55nm. We present the feasibility of NFSR technology by confirming the CNR threshold according to readout power (Pr) and CNR 33dB over threshold Pr.

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3D Shape Reconstruction using the Focus Estimator Value from Multi-Focus Cell Images (다초점 세포 영상으로부터 추정된 초점 값을 이용한 3차원 형태 복원)

  • Choi, Yea-Jun;Lee, Dong-Woo;Kim, Myoung-Hee;Choi, Soo-Mi
    • Journal of the Korea Computer Graphics Society
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    • v.23 no.4
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    • pp.31-40
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    • 2017
  • As 3D cell culture has recently become possible, it has been able to observe a 3D shape of cell and volume. Generally, 3D information of a cell should be observed with a special microscope such as a confocal microscope or an electron microscope. However, a confocal microscope is more expensive than a conventional microscope and takes longer time to capture images. Therefore, there is a need for a method that can reconstruct the 3D shape of cells using a common microscope. In this paper, we propose a method of reconstructing 3D cells using the focus estimator value from multi-focal fluorescence images of cells. Initially, 3D cultured cells are captured with an optical microscope by changing the focus. Then the approximate position of the cells is assigned as ROI (Region Of Interest) using the circular Hough transform in the images. The MSBF (Modified Sliding Band Filter) is applied to the obtained ROI to extract the outlines of the cell clusters, and the focus estimator values are computed based on the extracted outlines. Using the computed focus estimator values and the numerical aperture (NA) of the microscope, we extract the outline of the cell cluster considering the depth and reconstruct the cells into 3D based on the extracted outline. The reconstruction results are examined by comparing with the combined in-focus portions of the cell images.

Magneto-Optical Recording in Near-Field using Elliptic Solid Immersion Lens (타원형 고체잠입렌즈를 이용한 근접장 광자기 기록)

  • 박재혁;이문도;박노철;박영필
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.678-681
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    • 2003
  • In conventional optical data storage numerical aperture (NA) cannot be over 1 because of diffraction limit. To overcome this limitation. solid immersion lens(SIL) have produced a great interest in near-field optical data storage. In conventional optical recording method, the dual lens system using object lens and SIL had been studied generally. But the conventional SIL system has some critical problems that must be solved. The problems are heat, contamination. alignment of optical components and so on. To solve these problems. this work proposes enhanced SIL which has several advantages for mechanical and optical issues. This new SIL system named elliptic SIL(ESIL) can use evanescent energy in near-field more effectively. In addition. because of applying the inside recording unlike previous surface recording, ESIL can clear up the problems. The design and analysis of ESIL art executed by using CODE V. Also, in this paper we composed actual data recording system and achieved recording experiment by applying ESIL to magneto-optical recording. In conclusion. we analyze the improvement of aerial density and the reasonability of application to real data storage system.

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