• Title/Summary/Keyword: 파면수차

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위상변조가 쌍안경 대물경 OTF에 미치는 영향

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.4 no.1
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    • pp.22-27
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    • 1993
  • We investigate the phase modulation effects on the OTFs of a binocular objective which is made in Korea.The OTFs are calculated from design data for FOV $0^{\circ}$ and $1.5^{\circ}$.The phase modulation is carried out by giving phase retardation $\pi$ on the aperture. The areas where the phases are retarded $\pi$ on the aperture are of an annular type. The OTFs of phase modulated aperture are also compared with that of unmodulated one. The OTFs of an aberration loaded system can be improved by proper phase modulation.

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A Study on Determination of Quantitative Aberration Using Lateral-Shearing Interferometer (층밀리기 간섭계에 의한 정량적 수차산출에 관한 연구)

  • 김승우;김병창;조우종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.459-463
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    • 1996
  • The lateral-shearing interferometer specially devised for production line inspection lenses is presented. The interferometer is composed with immersion oil and four prisms whose relative sliding motion provide lateral-shearing and phase-shifting. A special phase-measuring algorithm of a-bucket is adopted to compensate the phase-shifting error caused by the thickness reduction in the immersion oil Three different algorithm for determinating quantitative aberration of aspherical lenses are presented and compared with one another.

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Optical testing of a plastic lens depending on disc tilt (디스크 편향에 따른 플라스틱 렌즈의 광학적 평가)

  • 유장훈;이현호;박승한;박천호;김찬수
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.260-261
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    • 2003
  • 최근들어 플라스틱 렌즈는 여러 분야에 응용되고 있으며 광학적 시스템에도 널리 사용되고 있다. 광학적 플라스틱은 제작이 용이하고 크기에 제한을 받지 않아 그 수요가 크게 확대되고 있다. 그러나, 광학적인 시스템에 사용되기 위해서는 높은 순도가 요구되면서 또한 재질의 균일성이 확보되어야 하고 개구율이 점차 높아 가는 현실에서는 그 특성의 연구가 또한 중요하다. 본 연구에서는 간섭계를 구성하여 광학 디스크 경사에 따른 파면을 측정하고 광학수차 평가를 통하여 광학적인 시스템에 미치는 영향을 분석하였다. (중략)

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A Study for the Limitation of Measurement Accuracy and Reliability of Autostigmatic Null lens System by Adjustment and Fixing Process (조정방식과 경통고정방식에 대한 자동무수차점 널 렌즈 광학계의 측정 정밀도 한계 및 신뢰도)

  • Lee, Young-Hun;Rim, Cheon-Seog
    • Korean Journal of Optics and Photonics
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    • v.16 no.5
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    • pp.440-445
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    • 2005
  • The limitation of measurement accuracy and reliability of autostigmatic null lens system are studied for the cases of using inter-distance of null lenses as the adjustment factor of alignment and fixing the distance by mounting. If we investigate the first case, the wavefront aberration of null lens system is compensated by the adjustment process even though the shape of aspherical surface is not properly fabricated. As the result, it brings about the problem of measurement reliability. However, for the fixing process by mounting null lenses, it doesn't cause the reliability problem because the wavefront aberration of null lens system is not compensated. Further, the fixing process shows nearly same result in measurement accuracy to the adjustment process, that is, $0.0316{\lambda}$ vs. $0.0326{\lambda}$. So, we can conclude the setup for autostigmatic null lens system must be constituted by means of the fixing process. Meanwhile, we introduce and define the alignment aperture on aspheircal mirror, which can be approximated as spherical zone for alignment of null lens system, and besides, we calculate the required fabrication accuracy of the zone for the necessary measurement accuracy.

Effect of annular phase apodizer on the read-out signal in an optical disc system (환형 위상변조 Apodizer가 광학디스크 시스템의 재생신호에 미치는 영향)

  • jeong, Ho;Chung, Chang-Sub;Park, Seong-Jong
    • Korean Journal of Optics and Photonics
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    • v.12 no.4
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    • pp.270-275
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    • 2001
  • We have studied effects of annular phase apodizer and bump shapes on the read-out signal in an optical disc system, using scalar diffraction theory. In order to detennine the optimum parameters of annular phase apodizer which will minimize the influence of spherical aberration, we defined WR as the ratio between the maximum wavefront aberration and some absolute value of wavefront aberration at any position r in the pupil. A cylindric bump, a semi-conic bump and a conic bump were$.$ also considered as different types of bump shape. As the radius and shape of bump varies, the read-out signal from an optical disc system with an annular phase apodizer was similar to that from an optical disc system without apodizer. When spherical aberration increases, the maximum read-out signal of an optical disc system with an annular phase apodizer and minimum bump radii giving read-out signal higher than 0.6 rarely varied. Especially, the optimum parameters at $W_R$ = 0.4 , 0.6 gave the most compensated effect of a spherical aberration.ration.

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One dimensional inhomogeneous phase modulation effects on the MTF of an optical system (일차원적 비균일 위상변조가 광학계의 MTF에 미치는 영향)

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.10 no.1
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    • pp.10-14
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    • 1999
  • One dimensional inhomogeneous phase modulation effects on the MTF of optical system was investigated. The lens under test was a doublet made in Korea. It was 36 mm effective diameter, 128.04 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 $2^{\circ}$). Phase modulation was carried out by positioning a phase modulator close contacted with the lens under test. One was linear type that had linearly increasing phase retardation and the other was stepped type which had phase difference $\pi$ for each step. The MTFs were measured on the Gaussian image plane and were compared with one another. The MTFs of linear type phase modulated apertures had a little lower values than the MTF of unmodulated aperture for on-axis but most of all the MTFs of one dimensional phase modulated aperture are improved than the MTF of unmodulated aperture.

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Analysis of a flat-field soft x-ray spectrometer using a 2400-grooves/mm varied line-spacing concave grating (2400 grooves/mm 비등간격 오목에돌이발을 이용하는 평면결상형 연엑스선 분광기의 특성 해석)

  • 최일우;남창희
    • Korean Journal of Optics and Photonics
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    • v.13 no.3
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    • pp.189-196
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    • 2002
  • The components and alignment parameters of a flat-field soft x-ray spectrometer used in the wavelength range below 50 $\AA$ are determined, and the characteristics of the spectrometer are analyzed. It consists of a toroidal mirror, a slit, a varied line-spacing concave grating, and a soft x-ray detector. The space-resolved spectral image of a source is formed on a single plane using the tordidal mirror and the 2400-grooves/mm varied line-spacing concave grating. The former is used to compensate for the astigmatism caused by the grazing incidence of soft x-ray light on the concave grating. The spectral and spatial resolutions of the spectrometer are calculated by applying the wave front aberration theory, and the diffraction efficiency is calculated by applying the scalar diffraction theory.

Visual Performances of the Corrected Navarro Accommodation-Dependent Finite Model Eye (안구의 굴절능 조절을 고려한 수정된 Navarro 정밀모형안의 시성능 분석)

  • Choi, Ka-Ul;Song, Seok-Ho;Kim, Sang-Gee
    • Korean Journal of Optics and Photonics
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    • v.18 no.5
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    • pp.337-344
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    • 2007
  • In recent years, there has been rapid progress in different areas of vision science, such as refractive surgical procedures, contact lenses and spectacles, and near vision. This progress requires a highly accurate modeling of optical performance of the human eyes in different accommodation states. A new novel model-eye was designed using the Navarro accommodation-dependent finite model eye. For each of the vergence distances, ocular wavefront error, accommodative response, and visual acuity were calculated. Using the new model eye ocular wavefront error, accommodation dative response, and visual acuity are calculated for six vergence stimuli, -0.17D, 1D, 2D, 3D, 4D and -5D. Also, $3^{rd}\;and\;4^{th}$ order aberrations, modulation transfer function, and visual acuity of the accommodation-dependent model eye were analyzed. These results are well-matched to anatomical, biometric, and optical realities. Our corrected accommodation-dependent model-eye may provide a more accurate way to evaluate optical transfer functions and optical performances of the human eye.

One dimensional inhomogeneous aperture modulation effects on the MTF of optical system (일차원적 비균일 개구변조가 광학계 MTF에 미치는 영향)

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.9 no.2
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    • pp.59-62
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    • 1998
  • One dimensional inhomogeneous aperture modulation effects on the MTF of optical system was investigated. The lens undertest was a doublet made in Korea. It was 10 mm effective diameter, 87.8 mm effective focal length. The ray-fans and spot diagrams were caluculated 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 contacted with the lens undertest. 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 unmodulated apertue where the MTF has the largest value for 60 c/mm and were compared with one another. The MTFs of modulated apertures had a little lower values than the MTF of unmodulated aperture for on-axis but in the case off-axis, the values are highly improved as much as the wider field of view by modulating on the aperture.

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Wavefront Aberration Measurement of DVD pick-up lenses with a Shack-Hartmann Sensor and a Point Source (Shack-Hartmann 파면분석기와 점광원을 이용한 DVD 픽업 렌즈의 수차 측정)

  • Kang, Dong-Won;Lee, Jin-Seok;Hahn, Jae-Won
    • Transactions of the Society of Information Storage Systems
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    • v.3 no.3
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    • pp.135-138
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    • 2007
  • Using a Shack-Hartmann sensor and sub-wavelength sized pinhole point source, we develope an optical testing system that measures the wavefront error of high numerical aperture and small sized optical components. The subwavelength sized pinhole generates perfect spherical waves with large diffraction angle and this makes possible to test high numerical aperture optics. The Shack-Hartmann sensor reconstructs the wavefront and calculates the aberrations. We make a home-made reference plane wave source which generates nearly perfect plane waves and the calibration with this plane source gives the overall uncertainty of the optical testing system 0.010 $\lambda$ rms.

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