• Title/Summary/Keyword: 파면수차

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Two-axis latera I-shearing interferometer for performance test of lenses using a Dove prism (도브 프리즘을 이용한 렌즈 성능평가용 2축 층밀리기 간섭계)

  • 김승우;이혁교;김병창
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.384-387
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    • 1995
  • Two axes lateral-shearing interferometer(LSI) specially devised for production line inspection lenses is presented. The interferometer composed with four prisms and a dove prism can test the lens performance including asymmetric aspheric lens. The dove prism which rotates the input image with respect to optical axis makes it possible. The wavefront passing through the test lens is reconstsucted by the phase derivative obtained form the two axes LSI system. Zernike-polynomials fitting of this wavefront is presented for determinating quantitative aberration of aspherical lenses.

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

  • 이호철;김대식;이철우;김부태;양민양
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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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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Design of Optical Path for Small Form Factor Optical Disk Drive and Fabrication of Micro-Compensatory Lens (초소형 광 정보 저장 기기를 위한 광 경로 설계 및 마이크로 보정 렌즈 제작)

  • 김홍민;정경성;최우재;박노철;강신일;박영필
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.115-118
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    • 2002
  • The purpose of this paper is to design a pick-up for the small form factor optical disk drive and to fabricate a micro-compensatory lens for the pick-up using the micro-compression molding process. At design stage, the optical elements including the objective lens and the compensatory lens are miniaturized. The height of pick-up and free working distance are designed as 2mm and 0.2% respectively. To analyze the fabricated micro-compensatory lens, the system was analyzed using the surface profile of the fabricated micro-compensatory lens and CODE V which is commercial software. The RMS wave front aberration of the system using fabricated micro-compensatory lens is 0.01677λ which is lower than Marechal's criterion, 0.07λ.

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Wavefront Aberration Measurement with Shack-Hartmann Sensor and Point Source (Shack-Hartmann 파면분석기와 점광원을 이용한 광학부품의 수차 측정)

  • Lee, Jin-Seok;Kim, Hak-Young;Park, Yong-Pil;Park, No-Cheol;Hahn, Jae-Won
    • 정보저장시스템학회:학술대회논문집
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    • 2005.10a
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    • pp.160-161
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    • 2005
  • Using a Shack-Hartmann sensor, we construct an optical testing system measuring the wavefront error of small optical components. The systematic error of the sensor is compensated with a reference plane-wave system that produces almost perfect plane waves. Several types of lenses are tested using a point source that generates spherical waves emitted from a pinhole. The results of the optical testing obtained with the Shack- Hartman sensor are compared with those measured with Zygo interferometer.

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One dimensional inhomogeneous aperture modulation effects on the MTF of optical system II (일차원적 비균일 개구변조시 광학계의 최적상면 MTF에 미치는 영향)

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.9 no.5
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    • pp.277-281
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    • 1998
  • One dimensional inhomogeneous aperture modulation effects on the MTF of optical system was investigated. The lens under test was a doublet made in Korea. It has 10 mm effective diameter, 87.8 mm effective focal length. The ray-fans and spot diagrams were calculated and presented on the picture for on-axis and off-axis (field of view, $1^{\circ}$ and $2^{\circ}$). Aperture modulation was carried out by positioning a aperture modulator close contacter with the lens under test. We bought two modulators from Edmud Company in U.S.A. One was linear type and the other was stepped type. The MTFs were measured on the best of focus for each modulated aperture where the MTF has the highest value for 60 line/mm and were compared with one another. For on-axis, the MTFs of some modulated apertures had higher values than the MTF of unmodulated aperture in the high frequency region. In the case of off-axis, at the field of view $1^{\circ}$, the MTF values of some modulated aperture are improved prominently and some other one are disimproved. At the field of view $2^{\circ}$ most of the MTFs of modulated apertures had lower values than the MTF of unmodulated aperture except the MTFs of linear and inverse linear type aperture in the high frequency area. But the values of MTFs in high frequency region were too low for actual use.

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Catadioptric NA 0.6 Objective Design in 193 nm with 266 nm Autofocus (이중 파장 심자외선 카타디옵트릭 NA 0.6 대물렌즈 광학 설계)

  • Do Hee Kim;Seok Young Ju;Jun Ho Lee;Hagyong Kihm;Ho-Soon Yang
    • Korean Journal of Optics and Photonics
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    • v.34 no.2
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    • pp.53-60
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    • 2023
  • We designed a catadioptric objective lens with a 0.6 numerical aperture (NA) for semiconductor inspection at 193 nm. The objective lens meets major requirements such as a spatial resolution of 200 nm and a field of view (FOV) of 0.15 mm or more. We selected a wavelength of 266 nm for autofocus based on the availability of the light source. First, we built the objective lenses of three lens groups: a focusing lens group, a field-lens group, and an NA conversion group. In particular, the NA conversion group is a group of catadioptric lenses that convert the numerical aperture of the beam focused by the prior groups to the required value, i.e., 0.6. The last design comprises 11 optical elements with root-mean-squared (RMS) wavefront aberrations less than λ/80 over the entire field of view. We also achieved the athermalization of the objective lens with focus-shift alone satisfying the performance of RMS wavefront aberration below λ/30 at a temperature range of 20 ± 1.2 ℃.

OPTICAL DESIGN OF THE FAR ULTRAVIOLET IMAGING SPECTROGRAPH (원자외선 영상/분광 측정기 광학설계)

  • ;;;Jerry Edelstein
    • Journal of Astronomy and Space Sciences
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    • v.15 no.2
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    • pp.359-371
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    • 1998
  • We present the design specifications and the performance estimation of the FUVS (Far Ultraviolet Spectrograph) proposed for the observations of aurora, day/night airglow and astronomical objects on small satelltes in the spectral range of $900~1750AA$. The design of FUVS is carried out with the full consideration of optical characteristics of the grating and the aspheric substrate. Two independent methods, ray-tracing and the wave front aberration theory, are employed to estimate the performance of the optical design and it is verified that both procedures yield the resolution of $2~5AA$ in the entire spectral range. MDF (Minimum Detectable Flux) is also estimated using the known characteristics of the reflecting material and MCP, to study the feasibility of detection for faint emission lines from the hot interstellar plasmas. The results give that the observations from 1 day to 1 week, depending on the line intensity, can detect such faint emission lines from diffuse interstellar plasmas.

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Development of diameter 450 mm Cassegrain tlne collimator (직경 450 mm Cassegrain 형태 시준장치의 제작)

  • 양호순;이재협;이윤우;이인원;김종운;김도형
    • Korean Journal of Optics and Photonics
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    • v.15 no.3
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    • pp.241-247
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    • 2004
  • The collimator is necessary for the assembly and evaluation of high resolution satellite telescope. Traditionally, the off-axis paraboloid has been used as a collimator. However, it has some disadvantages in that it can suffer from air turbulence when the focal length of a collimator is long, which may result in some error in the measurement. In contrast, since the Cassegrain type collimator folds the beam, it occupies smaller space compared to the off-axis paraboloid for the same focal length. This can reduce the air turbulence, which can improve the measurement accuracy. In this paper, we explain the process of design and manufacturing of a diameter 450 mm Cassegrain type collimator, to evaluate the diameter 300 mm satellite telescope. After assembly of primary and secondary mirrors, the final wavefront error of the collimator was 0.07λ(λ=633 nm), which is the diffraction limit.

Assembly of diameter 300 mm optical beam director (직경 300 mm 광집속장치의 광학정렬)

  • Yang, Ho-Soon;Lee, Yun-Woo;Kim, Jeong-Ju;Eum, Hae-Dong;Lee, Soo-Sang;Kim, Yeon-Soo;Kim, Hyun-Sook
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.521-526
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    • 2005
  • We assembled the optical beam director with diameter 300 mm. This consists of primary, secondary mirrors and 5 folding mirrors. Among them, the primary mirror is the most important component so that we measure any possible deformation on it at every step of assembly. Also, we developed the systematic alignment algorithm, which is essential because the number of mirrors is 7. The final wavefront error of the system is 1.9 wave rms (wave=633 nm) which is 7 times larger than we expected. The main source is the deformation of the 131ding mirrors. We expect that what we have learned from the assembly of this system would be helpful when we deal with a larger system in the future.

A Study on a Hartmann Test of Optical Mirror for On-Machine Measurement of Polishing machine (광학면 연마기의 OMM을 위한 Hartmann Test 방법 연구)

  • 김옥현;이응석;오창진;김용관
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.1
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    • pp.40-45
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    • 2004
  • Recently, aspheric optical lenses and mirrors, which are harder to manufacture and measure than the conventional spherical ones, are widely used, particularly in electronic fabrication process. Generally, interferometric optical method is used for the measurement of spherical optical surface. However, the interferometric method for aspheric surface measurement is difficult because it needs a precise null corrector and strict environmental conditions such as constant temperature, humidity and vibrations. We have been studied on the manufacturing of aspheric optics to improve the surface profile accuracy and productivity using a corrective polishing process. For the corrective polishing, a practical method of On-Machine Measurement (OMM) is required. For this purpose, an optical OMM system has been studied using the Shach-Hartmann test, which is very robust to the practical polishing environment. The wavefront has been reconstructed from the measured data using the primary aberration polynomial function by the least squares fitting. The measured result of the OMM system shows that the maximum deviation is less than 200 nm for the one of commercial Fizeau interferometer Wyko 6000.