• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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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.

• Current Optics and Photonics
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• 제2권6호
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• pp.612-622
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• 2018

In wave-front-sensor-less adaptive optics (WFS-less AO) systems, the Jacopo Antonello (JA) method belongs to the model-based class and requires few iterations to achieve acceptable distortion correction. However, this method needs a lot of measurements, especially when it deals with moderate or severe aberration, which is undesired in free-space optical communication (FSOC). On the contrary, the stochastic parallel gradient descent (SPGD) algorithm only requires three time measurements in each iteration, and is widely applied in WFS-less AO systems, even though plenty of iterations are necessary. For better and faster compensation, we propose a WFS-less hybrid approach, borrowing from the JA method to compensate for low-order wave front and from the SPGD algorithm to compensate for residual low-order wave front and high-order wave front. The correction results for this proposed method are provided by simulations to show its superior performance, through comparison of both the Strehl ratio and the convergence speed of the WFS-less hybrid approach to those of the JA method and SPGD algorithm.

• Current Optics and Photonics
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• 제3권1호
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• pp.72-77
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• 2019

This study was performed to analyze the optical aberrations of the cornea induced by myopic refractive surgery. Corneal total higher-order aberrations, spherical aberration and coma for 4-mm and 6-mm pupils were measured using a wave-front analyzer. The amount of aberrations of the oblate corneal optics by the achieved correction was found to be larger than for the prolate corneal shape with complete eye, in an emmetropia control group. The change in corneal shape acts as an optical factor that degrades the quality of the retinal image; it seems to be one of the important factors related to quality of vision.

• 한국광학회지
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• 제15권3호
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• pp.248-253
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• 2004

광섬유 탐침의 끝 단에서 반사하는 광을 이용하는 근접장 주사 광간섭계를 제안하고 제안한 근접장 주사 광간섭계를 이용하여 초점의 위치와 집광 초점면에서의 파면을 분석하였다. 파면의 분석은 광섬유 탐침의 끝 단에서 반사된 빛과 시료표면에서 반사된 빛을 간섭시키고, 탐침의 끝 단을 λ/4씩 위상천이 시키면서 4장의 간섭무늬를 얻은 후, 위상천이 알고리즘을 통하여 광학 수차를 구하는 방법을 이용하였다. 실험 결과 근접 주사시의 초점의 위치를 파장의 3분의 1 이하로 제어할 수 있음을 알 수 있었으며, 제안한 근접장 주사 광간섭계를 이용하여 구한 집광 초점면에서의 파면 수차 값이 트와이만-그린 간섭계를 이용하여 구한 파면 수차값과 잘 일치함을 확인할 수 있었다.

• 한국정밀공학회지
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• 제27권2호
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• pp.50-59
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• 2010

In this paper, two kind of free-form progressive addition lenses (PALs) were designed with Zernike polynomial surface and anatomically accurate finite presbyopic schematic eyes which have aspheric cornea, aspheric GRIN crystalline lens, aspheric retina, and Gaussian apodization factor. Geometrical and diffraction MTFs were used for the optimization process in sequence. 5th orders of Zernike polynomials were used for the evaluation of progression zones of the two examples. The target MTF was set as 0.22 at 100 lp/mm which satisfies the standard visual resolution. These examples were fabricated with a CNC diamond turning machine controlled by slow tool servo (STS). After polishing process, the wavefront aberrations were measured with a laser interferometer on the ten test points across the progression zones and then compared with three current commercially available PALs on the optical performance. Astigmatic aberrations of the examples are very lower than the three selected PALs and have more increased stabilized progressive intermediate zones and near zones. It is expected to give better clear and comfortable distance, intermediate and near visions than other conventional PALs and to improve the adaptability of presbyopic patients to PALs.

• 한국정밀공학회지
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• 제21권1호
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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.

• Journal of Astronomy and Space Sciences
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• 제15권2호
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• pp.359-371
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• 1998

본 연구에서는 원자외선 영역($900~1750AA$)에서 오로라, 주/DIRKS 대기 광 관측 및 천문학적 관측을 동시에 수행하기 위한 FUVS(Far Ultraviolet Spectrograph)를 설계하고, 그 성능을 평가하였다. FUVS의 설계는 에돌이발(grating)의 광학적 특성과 비구면 광학을 충분히 고려하여 이루어졌으며, 분해능 계산을 위해 ray-trace 방법과 파면수차 계산에 의한 방법을 사용하여 설계의 검증을 시도하였다. 두 가지 방법에 의한 결과가 오차범위 안에서 일치하여 분석 방법에 큰 문제점이 없다는 것을 간접적으로 확인할 수 있었고, 전 영역에 걸쳐 대략 $2~5AA$의 분해능을 얻었다. 또한, FUVS의 수행 임무 중 가장 검출이 힘들 것으로 생각되는 고온의 성간 플라즈마에서 방출되는 선 방출의 검출 가능성을 타진하기 위하여 FUVS의 최소 검출가능 플럭스(MDF)를 계산하였다. 이 계산을 위하여 지금까지 알려진 반사물질, MCP 등의 특성을 충분히 고려하였으며, 선의 세기에 따라 하루에서 일주일에 걸친 관측을 통해 고온의 성간 플라즈마에서 방출되는 선 방출을 검출할 수 있다는 결론을 얻었다.

• 한국광학회지
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• 제13권3호
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• pp.189-196
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• 2002

파장 50 $\AA$ 이하의 연엑스선 영역에서 사용될 평면결상형 연엑스선 분광기의 구성요소와 정렬조건을 결정하고 분광기의 분광학적 특성을 해석하였다. 평면결상형 연엑스선 분광기는 토로이드거울, 실틈, 비등간격 오목에돌이발, 연엑스선 검출기로 구성되어 있다. 토로이드거울과 홈간격이 2400 grooves/mm인 비등간격 오목에돌이발을 사용하여 공간분해된 빛띠가 단일 평면 위에 결상되도록 분광기를 구성하였다. 토로이드거울은 연엑스선 광선이 에돌이발에 비스듬하게 입사할 때 발생되는 비점 수차를 보상하기 위해 사용되었다. 파면수차 이론을 적용하여 분광기가 가지는 파장분해와 공간분해를 계산하고, 에돌이 현상에 대한 스칼라 이론을 적용하여 에돌이발의 에돌이효율을 계산하였다.