• Title/Summary/Keyword: Asymmetric Aspheric Lens

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Ultra Precision Machining of Injection Mold Core for Asymmetric Aspheric Lens using 6:4 Brass (비대칭비구면 렌즈 사출 코어용 6:4 황동 초정밀 형상 가공)

  • Lee, Dong-Kil;Gu, Hal-Bon;Kim, Jeong-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.427-427
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    • 2007
  • The global applications of aspherics surfaces will expand rapidly on the electronics, optical components, communications, aerospace, defense, and medical optics devices etc. Especially, Asymmetric aspheric prism lens is one of the important parts in HMD(Head Mounted Display) because it affects dominantly on the optical performance of HMD. The mold core is the most important device to produce the plastic lenses by injection molding method. In this study, the mold cores for asymmetric aspheric prism lens were processed using fly-cutting method which is kind of the ultra precision processing and form accuracy and surface roughness of the cores were measured.

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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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Simulation of the Through-Focus Modulation Transfer Functions According to the Change of Spherical Aberration in Pseudophakic Eyes

  • Kim, Jae-hyung;Kim, Myoung Joon;Yoon, Geunyoung;Kim, Jae Yong;Tchah, Hungwon
    • Journal of the Optical Society of Korea
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    • v.19 no.4
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    • pp.403-408
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    • 2015
  • To evaluate the effects of spherical aberration (SA) correction on optical quality in pseudophakic eyes, we simulated the optical quality of the human eye by computation of the modulation transfer function (MTF). We reviewed the medical records of patients who underwent cataract surgery in Asan Medical Center, retrospectively. A Zywave aberrometer was used to measure optical aberrations at 1-12 postoperative months in patients with AR40e intraocular lens implants. The MTF was calculated for a 5 mm pupil from measured wavefront aberrations. The area under the MTF curve (aMTF) was analyzed and the maximal aMTF was calculated while changing the SA ($-0.2{\sim}+0.2{\mu}m$) and the defocus (-2.0 ~ +2.0 D). Sixty-four eyes in 51 patients were examined. The maximal aMTF was $6.61{\pm}2.16$ at a defocus of $-0.25{\pm}0.66D$ with innate SA, and $7.64{\pm}2.63$ at a defocus of $0.08{\pm}0.53D$ when the SA was 0 (full correction of SA). With full SA correction, the aMTF increased in 47 eyes (73.4%; Group 1) and decreased in 17 eyes (26.6%; Group 2). There were statistically significant differences in Z(3, -1) (vertical coma; P = 0.01) and Z(4, 4) (tetrafoil; P = 0.04) between the groups. The maximal aMTF was obtained at an SA of $+0.01{\mu}m$ in Group 1 and an SA of $+0.13{\mu}m$ in Group 2. Optical quality can be improved by full correction of SA in most pseudophakic eyes. However, residual SA might provide benefits in eyes with significant radially asymmetric aberrations.