• 한국광학회지
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• 제19권1호
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• pp.31-35
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• 2008

결합효율이 높고 정렬오차 발생 시 결합효율의 저하가 작은 광통신용 비구면 렌즈 시준기를 설계하였다. 비구면 시준 렌즈는 GRIN 렌즈와 작동거리와 두께가 유사하고 외경이 동일한 원통형 막대 형태로 설계해 GRIN 렌즈를 대체할 수 있도록 하였다. 결합효율의 저하는 시준렌즈의 구면수차에 의해 주요하게 발생하므로, 비구면 렌즈 시준기가 볼 렌즈, GRIN 렌즈 및 C-렌즈 시준기보다 높은 결합효율을 가지도록 비구면 계수를 최적화 해 구면수차를 낮추었다. 설계한 비구면 렌즈 시준기의 결합효율은 기존 시준기들보다 높았으며 정렬오차에 따른 결합효율의 감소도 작았다.

• International Journal of Precision Engineering and Manufacturing
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• 제4권3호
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• pp.48-54
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• 2003

This paper deals with mirror grinding of a small-sized aspherical lens by a resin bonded diamond spherical wheel. Up to now, a spherical lens has been used for the lens of the optical communication optical part. However, recently, aspherical optical parts are mainly used in order to attempt the improvement in image quality and miniaturization of the optical device. It is possible to manufacture the aspherical lens which is presently being used in optical instrument through ultra-precision machining technology. Also, to realize compactness, efforts are being made to produce a micro aspherical lens, fur which the development of a high-precision, micro molding die is inevitable. Therefore, extensive research is being done on methods of producing a micro aspherical surface by high-precision grinding. In this paper, the spherical wheel was trued by cup-shaped truer and tool path was calculated by the radius of curvature of the wheel after truing and dressing. Then in the aspherical grinding experiment, WC material which is used as a melding die for the small-sized aspherical lens was ground. The results showed that a form accuracy of 0.1918 $\mu\textrm{m}$ P-V and a surface roughness of 0.064 $\mu\textrm{m}$ Rmax could be achieved.

• 제어로봇시스템학회논문지
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• 제14권6호
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• pp.558-563
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• 2008

Optical axis misalignment, which represents the position deviation of the objective lens from the optical axis, is an inevitable assembly error in an optical pick-up. Since the laser power intensity varies with respect to the distance from the optical axis, the misalignment leads to variation of the laser spot power intensity, which is one of the critical factors increasing data bit-error-rate in optical disc drives. In this paper, an auto-adjustment scheme for optical axis alignment is proposed to eliminate the undesirable variation of the laser spot power intensity in optical disc drives. An envelope of the data RF signal is extracted and utilized to detect the optical axis misalignment. Then an adjustment input is added to the driving input of the tracking actuator to shift the objective lens to the optical axis. Finally, the feasibility is verified by experiments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.289-289
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• 2009

Light emitting diode(LED) has many advantages including lower energy consumption and longer lifetime and eco-friendly in comparison with traditional light sources. Spheric plastic lens generally used in LED lighting occurs aberration and ghost image which give displeasure and deteriorate vision quality in human eyes. Using the optical program (LightTools$^{TM}$, CodeV$^{TM}$), we were confirm the aberration and ghost image in optical simulation and employed aspheric lens form in the lens design to improve these problems. From the comparison of the simulation results between the aspheric lens and the spheric lens, we were ascertain to be improved both aberration and Ghost image.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.197-202
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• 2005

An aspheric lens is one of a key point optical element in the optical industry. The feature of an aspheric lens is not to have the spherical aberration. An aspheric lens is also essential element for high-precision and light-weight in the optical machine. Generally it have been used in a tailor progression an aspheric lens modelling much. In this study we applied a lay back-tracer using a index of refraction to draw a creative aspheric lens. Also we developed the automatic design program for aspheric lens. We manufactured the aspheric lens and executed a comparison experiment for refraction situation of shape and straightness experiment to inspect the drawn aspheric lens in this study.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.79-82
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• 2005

Fresnel lens has number of applications in the optical systems because of its advantages. It is nearly flat lens that has small weight. It is conventionally used in lighthouse beacons, condensing unit of overhead projector and etc. Recently, demands of small size optical systems such as display units, information storage systems, optical detecting units had increased. Conventional manufacturing process of high quality Fresnel lens is direct machining. But it is not suitable for mass production because of high cost and long cycle time. Replication process is more suitable for mass production. But the Fresnel lens has number of sharp blade shape prism. In the replication process, this blade shape causes defects that can affect optical efficiency. In this study, replication process of blade shape pattern that has maximum height of $280{\mu}m$, aspect ratio 1.4 for Fresnel lens application.

• Journal of the Optical Society of Korea
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• 제19권5호
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• pp.531-536
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• 2015

This paper presents a new graphical method for selecting a pair of optical glass and housing materials to simultaneously achromatize and athermalize a multilens system composed of many elements. To take into account the lens spacing and housing, we quantify the lens power, chromatic power, and thermal power by weighting the ratio of the paraxial ray height at each lens to them. In addition, we introduce the equivalent single lens and the expanded athermal glass map including a housing material. Even though a lens system is composed of many elements, we can simply identify a pair of glass and housing materials that satisfies the athermal and achromatic conditions. Applying this method to design a black box camera lens equipped with a 1/4-inch image sensor having a pixel width of $2{\mu}m$, the chromatic and thermal defocusings are reduced to less than the depth of focus, over the specified ranges in temperature and frequency.

• 한국광학회:학술대회논문집
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• 한국광학회 1999년도 제16회 광학 및 양자전자 학술발표회Proceedings of 16th Optics and Quantum Electronics Conference, 1999
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• pp.128-129
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• 1999

Polygon Mirror Scanning(PMS) is composed of LED array, magnifying lens, polygon mirror and motor. It is important to correct the lens aberrations to gain the image we want to show. In this paper, we have simulated the lens aberration correction to reduce the spherical aberration . We have obtained a aspherical lens which is corrected the spherical aberration.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.123-126
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• 2005

Eye Glass Display (EGD) with microdisplay to realize the virtual display can make the large screen, so virtual image has been developed by using microdisplay panel. This paper shows study of low cost lens design and simulation for microdisplay system with 0.6"LCoS panel. Lens design optimized consider to spherical aberration, astigmatism, distortion, and chromatic aberration. Code V is used and it designed an aspheric lens about exit pupil 6mm, eye relief 20mm and 35 degree of field of view (FOV). With the application this aspheric lens to liquid crystal on silicon (LCOS) type's microdisplay, virtual image showed 50 inch at 2m. One side of the aspheric lens was constituted from diffractive optical element (DOE) for the improvement in a performance. It had less than 2.5% of distortion value and modulation transfer function in axial had 20% of resolution with 32 lp/mm spatial frequency. The optical system is suitable for display of 15.6 mm-diagonal with SVGA.

• 한국광학회지
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• 제3권4호
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• pp.217-221
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• 1992

광통신에 각종 modulator를 사용할 경우에 대비하여 plano-convex coupling 미세광학소자를 설계하였다. 광섬유에서 회절되는 광을 시준시켜 modulate할 수 있도록 하는 시준렌즈와 modulate된 광을 광섬유에 연결시키는 coupling렌즈를 설계하였다. 광원은 He-Ne 레이저 빔으로하고 렌즈의 초자는 BK-7 크라우ㅌ계 광학유리로 하였다. 곡률반경과, 거리 및 conic costant가 광학계의 광선수차에 미치는 영향을 조사하였다.