• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.43-48
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• 2008

Purpose: This study is to evaluate reliability of geometrical optics properties of spectacle lenses by using ISO and the medical instrument standard of KFDA, which are being sold in Korea. Methods: We used samples of three hundred and ninety eight spectacle lenses of eight company in total. Refractive indices of each samples which were used in experiment were classified into three groups of medium index (1.55~1.56), high index (1.60~1.61) and extra high index (1.67). Results: Conformity of refractive power was 81.61% in total spectacle lenses. The results showed that thickness conformity 90%, appearance conformity 85.18%, size conformity 96.23% and optical center point conformity 99.50% in total. Conclusions: We found that they deviated from the permitting value in many spectacle lenses on refractive power. The results of errors on prism power, surface inspection and optical center point showed small values in total products. In experiment of lens size and thickness, the bulk of indication rates and conformities of samples deviated from the permitting errors.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.311-319
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• 2012

Purpose: One of the critical aspects on dispensing glasses is to match the center of pupils to the optical center of lenses as the mismatched glasses are able to induce uncomfortable effects called prism which has been known to induce phoria, a main cause for asthenopia in many cases. Therefore, we investigated the induced prism occurred by mismatching centers between the center of pupils and the optical center of lenses. Methods: In this study, total 103 subjects were examined whether the center of pupils and the optical center of lenses are matched in horizontal and vertical directions, and then, the data was categorized into 4 groups based on the structural components of glasses. Total amount of prism was compared to show the effect of the glasses frame on the prism induction, and the value of measured prism was compared with the German RAL-RG 915 regulations. Results: The results in respect to the horizontal component showed that the induced prism was not found in 10.7% of total subjects. 73.8% of total subjects were influenced by induced prism, the range of prism was in a tolerance level. However, the 15.5% of total subjects seemed to be influenced by prism which is out of the criterion of tolerance. In case of vertical component, 23.3% of total subjects showed no effects of prism while early adopting glasses, 54.4% of total subjects showed a little prism effect within the criterion of tolerance, and 22.3% of total subjects showed the prism effect out of the tolerance range. This data indicates that group A and B that are less likely adjustable by fitting induce more prism than group C and D in horizontal and vertical components. Conclusions: In higher refractive error condition, it was found that aligning the optical center of lenses with the center of pupils by pre-fitting of glasses frame minimized prism induction in horizontal and vertical components, which ameliorates ocular fatigue. Therefore, appropriate optometric dispensing through fitting by opticians and precise design about monocular PD and monocular Oh are necessary to improve visual perception.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1102-1105
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• 2003

The fiber drawing process induced defects in silica fiber have been investigated. This study has focused on the Oxygen Deficient Centers (ODCs) and E' centers induced by the fiberization process in low-OH silica fibers. To investigate those defects induced by the fiberization process, the optical absorption spectrum and Electron Spin Resonance (ESR) have both been employed. The concentration of Oxygen Deficient Centers (ODCs) and E' centers are increased by the fiber drawing process. The population of defects in the neck-down region has also been investigated. The most significant generation of defects during fiber drawing process has been shown to occur in this region of silica preform. The population of defects is higher on the edge region than in the center of neck-down region.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.13-18
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• 2000

In this paper, we use the C light which is a daylight and consider the incident beam having the Gaussian amplitude. We investigated the illuminance distributions and the variation in chromaticity of optical system having the truncated Gaussian amplitude on the focal plane and along the optical axis using the C light source. We also use the three sensitivity functions of human eye(CIE 1931) for wavelengths which are from 380nm to 780nm. When the truncation grade of incident beam having Gaussian amplitude decreases, the size of central spot on the focal plane and the depth of focus along the optical axis decrease, and the variation in chromaticity on the focal plane and along the axis increases rapidly. As the illuminance on the focal plane decreases the variation in chromaticity of optical system increases rapidly, and as the depth of focus increases the variation in chromaticity of optical system decreases.

• The Optical Journal
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• s.158
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• pp.58-60
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• 2015

드론이 인기다. 드론이 뜨고 있다. 드론은 왜 인기인가? 왜 드론이 인기인지를 인식해보아야 한다. 결론부터 이야기하면 드론이 인기인 이유는 드론이 MMM이기 때문이다. MMM은 필자가 2년 전 쯤에 만든 신조어로 Multipurpose Mobile Machine의 약자다. 다목적 이동 기계라는 말이다. 우리말로 줄이면 다이기(多移機)쯤 된다. 드론은 다목적 이동 기계, 즉 다이기이다. 인터넷이 군용으로 사용되다가 민간이 사용하게 된 것처럼 드론 역시 정찰, 감시, 폭격 등의 군사용으로 출발했지만, 민간이 사용하는 드론의 용도는 무척 다양하다. 사진 촬영, 영화 제작, 드라마 촬영, 음식 배달, 씨앗의 파종과 농약의 살포, 현장 탐사, 경계 근무 등 정말 다용도에 사용되고 있다. 중요한 것은 드론 각각이 다목적으로 사용될 수 있다는 것이다. 이는 드론이 단지 물리적 기계인 것이 아니라 스마트 기계로, 스마트폰과 같은 SW중심 기기와 드론에 내장된 OS와 SW에 의한 제어를 통해 비로소 실현된다. 즉, 드론은 MMM이기도 하지만, 정확히 SMM(Smart Mobile Machine)이기 때문에 그 잠재성이 인정받고 있는 것이다. 지금까지 스마트 폰, 스마트 워치, 스마트 TV 등은 모두 스마트 기기이기는 하지만 스마트 이동 기기는 아니다. 한편, 로봇 청소기 등 기존의 가정용 로봇이나 산업용 로봇은 대부분 단일목적 이동기기이거나 다목적 고정 기계이므로, 로봇이라 부르기가 민망한 기계들이었다. 필자는 드론이 이렇듯 새로운 스마트 기기 산업과 기존의 로봇 산업이 갈 길 또는 가고 있는 길을 보여주고 있다는 점에서 관심을 갖는다. 스마트 기기 산업의 관점에서는 이제 비로소 고정형(스마트TV), 부착형(스마트 워치), 휴대형(스마트 폰) 스마트 기기 산업에서 다목적 스마트 이동 기계라는 새로운 블루 오션 창출 산업이기에 의미가 있다.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.289-293
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• 2001

A metal capillary splice fiber-optic sensor was fabricated for use as an intensity-based macro-bending sensor. As the radius of curvature due to the macro-bending decreases, the angular misalignment of the fiber ends inside the metal capillary increases, i.e., the coupling efficiency of the fiber splice is reduced. Thus, macro-bending can be detected by the measurement of the reduction of transmitted power. The detectable range of macro-bending. was measured approximately from 20 mm to 85 mm. The center wavelengths of the fiber Bragg gratings are 1543.3 nm and 1549.5 nm, respectively. The maximum bending loss of this sensor was measured about -11.92 dB. Using this metal capillary spliced fiber sensor and fiber Bragg gratings, macro-bending detection has been demonstrated, and it is shown to have potential for multi-point macro-bending sensors. nsors.

• Journal of the Korean Vacuum Society
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• v.20 no.6
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• pp.442-448
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• 2011

Self-assembled InAs/InAlGaAs quantum dots (QDs) grown on an InP (001) substrate have been investigated by using photoluminescence (PL) and time-resolved PL measurements. The single layer (QD1) and seven stacks (QD2) of InAs/InAlGaAs QDs grown by the conventional S-K growth mode were used. The PL peak at 10 K was 1,320 nm for both QD1 and QD2. As the temperature increases from 10 to 300 K, the PL peaks for QD1 and QD2 were red-shifted in the amount of 178 and 264 nm, respectively. For QD1, the PL decay increased with increasing emission wavelength from 1,216 to 1,320 nm, reaching a maximum decay time of 1.49 ns at 1,320 nm, and then decreased as the emission wavelength was increased further. However, the PL decay time for QD2 decreased continuously from 1.83 to 1.22 ns as the emission wavelength was increased from 1,130 to 1,600 nm, respectively. These PL and TRPL results for QD2 can be explained by the large variation in the QD size with stacking number caused by the phase separation of InAlGaAs.

• Korean Journal of Optics and Photonics
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• v.30 no.4
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• pp.159-166
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• 2019

The trajectory of the transmission ellipsometric pseudoconstant ${\rho}=tan{\psi}_{\mu}e^{i{\Delta}_{\mu}}$ of a uniaxially anisotropic substrate like PET forms a circle in polar coordinates, as the phase-retardation angle is varied at a fixed azimuthal angle. The radius as well as the center's position of this circle are functions of the azimuthal angle only. This circle passes through the point (1,0), and the center of this circle is located on the real axis. These characteristics of the circle are examined analytically, and are utilized to derive simple expressions for the azimuthal angle and the phase-retardation angle of the uniaxially anisotropic substrate using the measured transmission ellipsometric constant. Finally, we confirm that the derived expressions are well applied to the analysis of the optical anisotropy of a PET film.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.413-428
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• 2013

Purpose: The purpose of this study was to evaluate students and optometrist opinion of the usefulness of different subjects of optometry curriculum.This date will then be used as base-line data during a process of curriculum development Methods: 292 of ophthalmic optic's students and 123 of optometrists were surveyed in the usefulness of curriculum (five-point scale) followed by statistical analysis of the results. Results: Optometrists gave a higher average score for curriculum usefulness (3.89) than the students (3.71). The subject which showed the highest usefulness for the student was optometry (4.55) but clinical practice was the highest for the optometrist (4.48). There was significant differences (p<.05) on optics, ophthalmology, basic science, optometrist related subject and foreign language but optometry and contact lenses showed high usefulness in common without significant difference. The usefulness of subject for the student showed significant difference according to gender, grade, age, and desired working place and has demonstrated significant difference depend on gender, age, scholarship, total working experience as an optometrist, workplace, and position for optometrists as well. Conclusions: It is necessary to continue research for the development of standard and bench-marked curriculum for ophthalmic optics and also the curriculum, which reflecting the usefulness and needs obtained from ophthalmic optics' students and optometrists need to be developed.

• Korean Journal of Optics and Photonics
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• v.21 no.1
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• pp.21-25
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• 2010

In this paper, in order to enhance the image reconstruction performance of white light scanning interferometry(WLI), we demonstrate the scattered point noise filtering performance of post-processing methods. Median filtering is similar to using an averaging filter. Because the median value is less sensitive than the mean to extreme values, the median filter can remove the scattered point noise from a height-map without significantly reducing the sharpness of the image. In several specific cases, however, the median filter can't remove the scattered point noise. Therefore, we propose a comparative mean filter that uses order-statistic filtering and the mean of the neighborhood pixels. The performance is demonstrated by measuring an array of metal solder balls fabricated on PCB. The proposed method reduced the noise pixels by 4.4 percent.