• Korean Journal of Optics and Photonics
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• v.19 no.2
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• pp.108-115
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• 2008

We designed optical systems for a mobile phone camera using a spherical SELFOC lens and an aspherical plastic lens. Since the radial index distribution gives an additional design parameter for optical design, an aspheric lens could be replaced by a spherical lens. The imaging performances of the design were compared with conventional 2P design composed of two aspherical plastic lenses. In the first stage of study, we designed 1GRIN 1P lenses by using commercially available SELFOC materials. But, the conventional 2P lenses had better performance than the 1GRIN 1P lenses. In the 1GRIN 1P designs, the performance depends on index variation of GRIN material, the larger variation gives the better performance. Hence, we tried to design by using fictitious GRIN materials which have large index variation. We found if the index variation could be increased to about 3 times that of currently available SELFOC materials, the 1GRIN 1P lens will have equivalent or better performance than the conventional 2P design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.132-136
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• 2002

Optical collimating lenses are play a role as maintenance parallel light and as a kind of optical collimating lens, there is Ball lenses, GRIN-rod lenses, spherical lenses and aspherical lenses etc. but recently GRIN lens has monopolized a market. The performance of optical collimator depended on the coupling efficiency. In this paper, we were compared and analyzed to be measured values of coupling efficiency with respect to optical working distance using GRIN rod lenses and spherical lenses. In the case of GRIN lenses with a beam size of 420 ${\mu}{\textrm}{m}$, the minimum coupling efficiency was obtained to a measured value of 0.15 ㏈ and in the case of spherical lenses was obtained to a measured value of 0.12 ㏈ on the same condition. In results, we found that a performance of spherical lenses be better as compared with a that of GRIN lens.

• Korean Journal of Optics and Photonics
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• v.20 no.6
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• pp.311-318
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• 2009

We present an attractive real time in-vivo endoscopic microscope with a resolution of submicron, in which two kinds of optical correcting plates are inserted to eliminate higher order spherical aberration and field curvature. And, since the conventional objective lens is replaced to GRIN lenses with diameter of 1 mm, the above endoscopic microscope can be effectively utilized to invade minimally for live animals.

• Korean Journal of Optics and Photonics
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• v.19 no.1
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• pp.31-35
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• 2008

A rod-type aspheric lens collimator for the optical telecommunication system which shows high coupling efficiency and experiences small coupling loss for misalignment errors is designed. The working distance, thickness, and diameter of the rod-type aspheric lens are determined to be close to those of the GRIN lens collimator in order to replace the GRIN lens with the rod-type aspheric lens. Since the coupling loss mainly originated from the spherical aberration of the lens, the spherical aberration in the rod-type aspheric lens is reduced drastically, and it turns out that the coupling efficiency of the rod-type aspheric lens collimator is higher than that of the available collimators, such as ball lens, GRIN lens, and C-type lens collimators.

• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.167-170
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• 2007

In this study, clinical data for emmetopia in young Koreans was taken in order to design the finite schematic eye, which had optical properties of real eyes including spherical aberration, astigmatism, field curvature and distortion. Furthermore, the crystalline lens with GRIN medium was optically analyzed, and the finite schematic eye with the GRIN crystalline lens was designed.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.61-64
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• 2011

Purpose: The purpose of this study was to design the finite model eye with GRIN lens similar to actual eye, which considered the effect of iris eccentricity on eyes. Methods: By using the finite model eye with Radial GRIN and Spherical GRIN, which were designed previously, the location of iris was eccentrically located by 0.5 mm in the direction of nose to show the same eye as actual one. For ray trace and design, Code V program of Optical Research Associates (ORA) was adopted. Results: Designed model eye was compared to actual eye depending on iris eccentricity and the model eye which showed reduced value was corrected according to actual eye to design the finite model eye. Conclusions: Ocular optical systems considered the point that iris was a rotational asymmetry and designed the finite model eye with GRIN lens, which was similar to actual eye, by considering the effect of iris eccentricity on eye.

• 연구논문집
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• s.32
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• pp.23-34
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• 2002

Up to now, collimators have teen generally produced by handwork and only a few companies have produced by semi-automatic system. Under this situation, automatic system for assembly of optical collimators has risen as a mast essential technique in the development of optical communication components. In this study, it was constructed to develop optical collimators with high functionality and we manufactured optical collimators with a GRIN rod lens and spherical lens using automatic system. Therefore, we worked a performance test through a comparison of collimators made by automatic system and handwork with angle augment, bean size. Also we selected a optimum assembly condition of GRIN rod lens and spherical lens. As a result, it brought a reduction of the tact time and an improvement of an efficiency and a productivity of optical collimators, therefore it was found that automatic system was indispensable for materialization of optical collimators with high functionality.

• Korean Journal of Optics and Photonics
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• v.28 no.2
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• pp.75-82
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• 2017

We present a new type of receiver-transmitter optical system that can be adapted to the sensor head of a displacement-measuring interferometer. The interferometer is utilized to control positioning error and repetition accuracy of a wafer, down to the order of 1 nm, in a semiconductor manufacturing process. Currently, according to the tendency of scale-up of wafers, an interferometer is demanded to measure a wider range of displacement. To solve this technical problem, we suggest a new type of receiver-transmitter optical system consisting of a GRIN lens-Collimating lens-Afocal lens system, compared to conventional receiver-transmitter using a single collimating lens. By adapting this new technological optical structure, we can improve coupling efficiency up to about 100 times that of a single conventional collimating lens.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.1
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• pp.49-54
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• 1997

We proved the feasibiltiy of a parallel optical interconnection technique using single GRIN (graded-index) rod lens as an intermediate coupling device, which increases the working distance and makes packaging easy. The proposed technique shows relatively less dependency on misalignments. In this paper, for convensience of experiments, we applied this method to 4-channel coupling between two fiber arrays, and compared it with butt-coupling and the method of using ball lens. The comparison shows the feasibility of adopting the proposed method to the parallel interconnection between a laser diode array and an optical fiber array.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.17-18
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• 2007