• Journal of the Microelectronics and Packaging Society
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• v.19 no.2
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• pp.47-53
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• 2012

Recently, by the increasing of data transmission rates, PCB is required high-speed data transmission rates and thin packaging. So optical PCB which is the combination of electrical layer and optical layer can be one of the solution to overcome the limitations of conventional electrical PCB. The most important factor in the implementation of optical PCB is optical interconnection. So the research on high-efficiency and passive alignment has been active. In this paper, we suggest built-in lens pluggable waveguide and we simulate its coupling efficiency and structural stability. Optical simulation results show that the proposed structure has higher efficiency than no lens structure about 1.86 times in transmitter and about 1.42 times in receiver. In structure simulation, inner lens has no damage in desorption process. Therefore, we shown that the proposed structure has a high coupling efficiency and structural stability.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.125-131
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• 2015

Purpose: The effect of pigmentation in circle contact lens on lens wearers' tear film stability was investigated in this study. Methods: Non-invasive tear film break-up times of 54 normal eyes before and after lens wearing in twenties and the portion of first tear breakup were measured. The frontal and back surface roughness of circle contact lens was further observed with a scanning electron microscope. The clear lens which was made of hilafilcon B and circle contact lenses which were made of hilafilcon B, polymacon and copolymer of HEMA NVP were tested. Results: Non-invasive tear film breakup time was significantly reduced compared with it before lens wearing. In some case, statistically significant difference in tear film breakup time was also observed between circle contact lenses. The tear file break-up was usually early started in lower than upper portion, and in temporal than nasal portion although there was variation in the lens material. The tear film break-up of circle contact lenses made of hilafilcon B was more commonly observed in peripheral portion(pigmented area) compared with clear contact lens made of same material. Conclusions: The present study revealed that the stability of tear film was affected by wearing circle contact lens and the result seems to be used as the basis for the problem solving that can occur due to the pigmentation when wearing circle contact lens.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.47-53
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• 2010

Purpose: This study was performed to achieve an acceptable piggyback fit utilizing each subject's own GP lenses, in subjects with regular low myopic astigmatism. Methods: A randomized, prospective study of 15 subjects with the diagnosis of low myopic astigmatism was conducted. Nine subjects were female and 6 were male, and mean age was: 23.73${\pm}$1.68 years. Subjects were evaluated before participate on this study and then also evaluated with period of at two hours and two weeks after obtaining their lenses. All subjects were submitted to the following tests: measurement of comfort level by means of the analogical visual scale, best corrected visual acuity and over-refraction at distance. contrast sensitivity and stereo acuity. After evaluating the fit of plano soft lens, we applied each subject's own GP lens on top. Results: Vision, visual performance and satisfaction of piggyback contact lens system were stable, if not improved, for the 15 subjects when the data was compared to the patients' wear of rigid gas permeable contact lenses. Fit with a piggyback system had the same or improved comfort, visual acuity and contrast sensitivity compared to previous GP lens wear alone. The visual acuity, contrast sensitivity and stereo acuity did not show differences in relation to the studied lens type. Conclusions: These results suggest that it is possible to achieve a successful piggyback lens fitting utilizing a patient's own GP lens. The piggyback lens system satisfied the visual performance and visual requirements of this subject with GP lens alone for the correction of low myopic astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.555-560
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• 2013

Purpose: The aims of this study were to investigate the stereoacuity and subjective symptoms of aniseikonia with prescription of the size lens. Methods: Participants were myopic anisometropia patients with the binocular refraction difference between 1.75 D~3.50 D. Inclusion criteria of participants were no ocular pathology, no amblyopia, more than 1.0 of corrected visual acuity. With fully corrected spectacles and a correction with the size lens, Awaya aniseikonia test and Randot Stereo test were conducted respectively. In addition, subjective symptoms were also examined using questionnaire. Results: As the anisometropia increased, the aniseikonia increased. Under the anisometropia with same refractive correction was different for each individual. The prescription of size lens caused less aniseikonia than the general prescription of glasses. In addition, prescription of the size lens improved stereoacuity and relieved the symptoms of asthenopia. Conclusions: The prescription of size lens that can correct aniseikonia with prescription of glasses can improve stereoacuity and reduced asthenopia.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1493-1498
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• 2015

The autofocus system is automatically to drive the focus. It is very important to computer vision system. In the case of a compact camera, the actuator technology is used for auto-focus in mass production. the position sensor is required, the circuit configuration and easy method is widely used in VCM, compared to the stability of the drive size and the noise is a big stepping motor type, size has a piezo system having a humidity problem and the small leaded vulnerability. In addition, there is a liquid lens system, the advantages of low power in a compact structure but also a structure with proven quality and reliability and features required pressure. In this paper, we implement two control systems that can control the actuator as a liquid range of VCM using a sharpness of the image acquired by the image sensor automatically initiates 5Mpixel class was the implementation verification of focusing.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.2
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• pp.36-36
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• 2001

간섭계를 이용하는 작업에서 가장 중요한 요구사항은 간섭 필드의 안정성을 높게 유지하는 것이며 이는 안정된 간섭패턴을 이용한 측정에 있어서 정밀성을 확보해 준다. 그러나 진동과 같은 위상잡음에 의해 안정성을 유지하기 힘들다. 본 논문에서는 BaTiO₃의 SPPCM 특성을 이용하여 마흐젠더 간섭계와 같은 전통적인 간섭계 측정시 발생 가능한 위상잡음의 영향을 줄여 안정된 간섭 패턴 확보 방법을 제안하였다. 또한 BaTiO₃로 빛을 입사시킬 때 구형렌즈를 기울여 입사빔을 원형이 아닌 타원형으로 입사시켜 원형 입사의 경우에 비해 SPPCM의 응답시간과 반사율을 개선하였다. 그리고 실험을 통해 결과를 확인하였다.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.121-127
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• 2001

While SVD and Gaussian elimination method were applied to the additive damped least squares(DLS), the convergence and the stability of the optimization process were examined in a triplet-type camera lens-system where the condition number is well conditioned. DLS with SVD method generated a suitable merit function but this merit function may be trapped in a local minimum by the nonlinearity of error function. Therefore, the least camera lens-system was further designed by the global optimization method is grid method, and this method is adopted to get merit function that convergent to global minimum without local minimum trapping.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.212-213
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• 2003

집적 광학(Integrated Optics) 소자에서 기존 광도파로와 광결정 도파로 간의 효율적 결합 및 접속의 안정성은 매우 중요한 과제이다. 기존의 단일모드 광도파로의 폭은 수 $mu extrm{m}$ 정도임에 비하여, 광 결정을 이용한 단일 결함 도파로인 경우 그 폭은 보통 1$\mu\textrm{m}$ 이하이다. 또한 광결정 도파로의 광 가둠 효과가 우수하여 기존 도파로와의 결합 사이에 모드 부정합 현상이 발생하며, 이것은 광결정 도파로의 광결합 효율은 낮게 하는 요인이 된다. (중략)

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.93-98
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• 2010

Recently, as digital photogrammetry bas been widely used in various fields including construction, it is also being applied to several industries. It is essential for interior orientation to determine accurate focal length of camera, lens distortion, location of principal point in order to apply high quality digital camera to digital photogrammetry. In this study we conducted interior orientation for zoom lens camera with regular time and zoom factors and analyzed change of radial distortion parameters and location of principal point to evaluate interior orientation stability. As a result, radial distortion parameters($k_1,k_2$) are converged into zero by increasing zoom factors. There are correlation between the change of location of point and zoom factors. The displacement of $x_p$, $y_p$ increase as zoom factors rise high.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.133-137
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• 2001

The method to make glass is tried first thing in domestic study for glasses lens. Tg of glass KzFSl was measured by DSC experiment and press method of glass of meniscus shape was studied for minimize the cost. Tg was increased $483^{\circ}C$ to $501^{\circ}C$ with increasing heating rate $2^{\circ}C/min$ to $20^{\circ}C/min$. It shows Arrhenius temperature dependence and the activation energy of Tg is ${\Delta}E$=409 kJ/mole(4.25eV) by using Ozawa method and Tg is near $480^{\circ}C$. The melt of KzFSl powder was poured to concave cast stainless and pressed convex cast stainless. The quenched glass was slow cooled with cooling rate $0.25^{\circ}C/min$ in temperature range $520{\sim}430^{\circ}C$. The glass was made without strain. It has meniscus shape and same size to commercial glasses lens.