• Title/Summary/Keyword: Lens power

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Optical Evaluation of MR8 Material spectacle Lens with a New Method for the Analysis of Blue Light (새로운 청광 분석법을 적용한 MR8 안경재료의 광학적 시험 평가)

  • Kim, Ha-Rim;Jeong, Ju-Hyun
    • The Korean Journal of Vision Science
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    • v.20 no.4
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    • pp.413-420
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    • 2018
  • Purpose : We present a novel method for the analysis of blue light applied by the analysis method of David L. with optical experiment and blue light by measuring the transmittance by dividing it by the refractive power in the spectacle lens made by MR8. Methods : The lenses of -8.00D, -7.00D, -6.00D, -5.00D, -4.00D, -3.00D, and 0.00D manufactured by MR8 being sold in the market, were selected. The transmittance was measured at the intervals of 5 nm from 200 to 1000 nm with UV-VIS Spectrophotometers (SolidSpec 3700), and they were in range of the blue light (380 to 500 nm) analyzed by a David L.'s analysis method. Results : All of the MR8 lenses selected for this study almost completely blocked at the UV range. A lens of -8.00D was measured as the lowest transmittance of 59.56% in the blue light area and low values were measured at the blue areas 1 and 2 according to the analysis of David L.In the infrared ray area, the transmittance of all lenses gradually decreased. The average value of the luminous transmittance was 23.67% ~ 26.33% and then gradually decreased from -4.00D. Conclusion : Applying the analysis of David L., a minimum of 41.28% and a maximum of 46.60% were measured at the blue light 1 area and a minimum of 87.30% and a maximum of 97.55% were measured at the blue light 2 area. A minimum of 86.83% and a maximum of 96.55% were measured at the blue light 3 area, and the average was 94%. The luminous transmittance of the -3.00D lens was 26.33%, which was the highest, and that -8.00D was 23.67%, which was the lowest.

Temperature change in pulp chamber of teeth by $CO_2$ laser irradiation ($CO_2$ 레이저 광의 조사 조건에 따른 치아의 치수강내 온도변화)

  • 엄효순
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.45-48
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    • 1990
  • CO2 laser beam was focused by a ZnSe lens onto the center of the occlusal surface f extracted lower molars. K-type thermocouple was contacted with the pulp chamber and the changes of temperature in the during and after the laser irradiation were measured as function of the power of laser beam, the time of laser irradiation and thickness of the sample. An empirical formula for temperature effect was derived from the measured data.

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Study of Masking Effect of Soft Contact Lenses on Cornea after Refractive Surgery (각막굴절교정 수술 안에 대한 소프트콘택트렌즈 착용 시 Masking 효과)

  • Moon, Ye-Rim;Park, Hyung-Min;Chu, Byoung-Sun
    • Journal of Korean Ophthalmic Optics Society
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    • v.21 no.2
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    • pp.91-98
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    • 2016
  • Purpose: This study investigated the masking effect of the hydrogel lens and silicone hydrogel lens on the cornea with refractive surgery and without surgery. Methods: 24 university students (means age: $23.48{\pm}2.89years$) without refractive surgery (12, control group) and with refractive surgery (LASIK: 8, LASEK: 4, experimental group) participated in the study. Mean refractive errors of right eyes were -2.73 D for control group and -0.24 D for experimental group. The differences in the refractive power and corneal topography map between pre- and post-wearing the -3.00 D lenses were compared, and 2 kinds of hydrogel contact lenses (0.89 Mpa, 0.49 Mpa) and 2 kinds of silicone hydrogel lenses (1.5 Mpa, 0.8 Mpa) were used for -3.00 D lenses. NVision-K5001 (Shin nippon, Japan) was used to measure the refractive power and Keratograph 5M (Oculus, Germany) to measure the corneal topography map change. Results: Variations in the refractive power increased to the plus direction in the experimental group after wearing soft contact lenses. The corneal topography map showed significant changes on the both groups after wearing soft contact lenses (p<0.05). However there were no significant differences in the refractive power and corneal topography map variations by lens materials. Conclusions: Wearing soft contact lenses showed corneal topography map changes. Especially wearing soft contact lenses on the flat cornea after corneal refractive surgery showed greater corneal power changes. Therefore, it should pay attention to refractive change in case of prescribing soft contact lenses to patients with corneal refractive surgery.

DISCOVERY OF A STRONG LENSING GALAXY EMBEDDED IN A CLUSTER AT z = 1.62

  • WONG, KENNETH C.;TRAN, KIM-VY H.;SUYU, SHERRY H.;MOMCHEVA, IVELINA G.;BRAMMER, GABRIEL B.;BRODWIN, MARK;GONZALEZ, ANTHONY H.;HALKOLA, ALEKSI;KACPRZAK, GLENN G.;KOEKEMOER, ANTON M.;PAPOVICH, CASEY J.;RUDNICK, GREGORY H.
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.389-392
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    • 2015
  • We identify a strong lensing galaxy in the cluster IRC 0218 that is spectroscopically confirmed to be at z = 1.62, making it the highest-redshift strong lens galaxy known. The lens is one of the two brightest cluster galaxies and lenses a background source galaxy into an arc and a counterimage. With Hubble Space Telescope (HST) grism and Keck/LRIS spectroscopy, we measure the source redshift to be $z_S=2.26$. Using HST imaging, we model the lens mass distribution with an elliptical power-law profile and account for the effects of the cluster halo and nearby galaxies. The Einstein radius is $^{\theta}E=0.38^{+0.02{\prime}{\prime}}_{-0.01}$ ($3.2^{+0.2}_{-0.1}kpc$) and the total enclosed mass is $M_{tot}(<^{\theta}_E)=1.8^{+0.2}_{-0.1}{\times}10^{11}M_{\odot}$. We estimate that the cluster environment contributes ~ 10% of this total mass. Assuming a Chabrier IMF, the dark matter fraction within $^{\theta}E$ is $f^{Chab}_{DM}=0.3^{+0.1}_{-0.3}$, while a Salpeter IMF is marginally inconsistent with the enclosed mass ($f^{Salp}_{DM}=-0.3^{+0.2}_{-0.5}$).

Development of Shape Determination Program for Suspension Bridge Using Digital Image Processing (디지털 화상처리기법을 이용한 현수교의 형상결정기법 개발)

  • Cheung, Jin-Hwan;Kang, Choong-Hyun;Kim, Nam-Shik;Park, Yong-Myoung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.1
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    • pp.117-126
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    • 2008
  • In this paper, it is presented a digital image processing method and the program (Visual C++) to determine the shape of the suspension bridge. To investigate the precision of this method, a suspension bridge is divided into 5, 13 and 19 images, respectively, by using the 6.3M pixels digital camera with 300mm zoom lens. Obtained results of the Kwang-Ahn Grand Bridge by using this method are fairly close to the real precision surveyed data. The accuracy is more improved by increasing the number of divided images of the structure. The total cost, man power and time of field survey by this method presented in this study could be much more reduced and the developed program could be applied with little modification for other structures like cable-stayed bridges, if lens compensation algorithms and program access capabilities are improved.

Control of Particle Contamination and Heat Build-Up for Noble Design of an Optical Disk Drive (광디스크 드라이브의 입자 오염 및 열축적 제어를 위한 설계 제안)

  • Oh, Seo-Young;Hwang, Jung-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.1
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    • pp.25-31
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    • 2003
  • Airborne contaminant particles are intruded into optical disk drives(ODD) due to the flow caused by disk rotation and can be adhered to lens or disk surfaces, which causes decrease of laser power and increase of read/write errors. Such a phenomenon can be more serious as the space between the disk and the lens is reduced fur high-density storage devices. The purpose of this paper is to understand design parameters to reduce the particle intrusion into an ODD. Suggestions are made to prevent the particle intrusion that can decrease the stability of an ODD and also prevent the potential heat build-up problem. The sealing effect of drive and the forced injection of clean air (using HEPA filter) into the drive minimizes intrusion of the outside air and dusts in an ODD remarkably. Moreover it is proved by experiments that the installation of a heatproof pad to isolate heat generation part (PCB) from information read/write sections and the forced injection of dust-free air reduce the gas temperature inside the drive as well as the amount of particles intruded.

Fabrication of Microstructure Array using the Projection Microstereolithography System (전사방식 마이크로광조형을 이용한 배열 형태 미세 구조물 가공)

  • Choi, Jae-Won;Ha, Young-Myoung;Lee, Seok-Hee
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.8 s.197
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    • pp.138-143
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    • 2007
  • Microstereolithography technology is similar to the conventional stereolithography process and enables to fabricate a complex 3D microstructure. This is divided into scanning and projection type according to aiming at precision and fabrication speed. The scanning MSL fabricates each layer using position control of laser spot on the resin surface, whereas the projection MSL fabricates one layer with one exposure using a mask. In the projection MSL, DMD used to generate dynamic pattern consists of $1024{\times}768$ micromirrors which have $13.68{\mu}m$ per side. The fabrication range and resolution are determined by the field of view of the DMD and the magnification of the projection lens. If using the projection lens with high power, very fine microstructures can be fabricated. In this paper, the projection MSL system adapted to a large surface for array-type fabrication is presented. This system covers the meso range, which is defined as the intermediate range between micro and macro, with a resolution of a few ${\mu}m$. The fabrication of array-type microstructures has been demonstrated to verify the performance of implemented system.

Simple Q-switched Waveguide $CO_2$ Laser Using Polygon Mirror (회전 다면셩을 이용한 도파관 $CO_2$ 레이저의 Q-스위칭)

  • 최종운;김용평;강응철;김재기
    • Korean Journal of Optics and Photonics
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    • v.6 no.1
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    • pp.21-25
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    • 1995
  • Q-switched Waveguide $CO_{2}$ laser using polygon mirror were constructed and their output characteristics were measured. Waveguide was made of the beryllium oxide tube of inner diameter of 2 mm, outer diameter of 20 mm, and length of 200 mm. A flat ZnSe output coupler of 80% reflectivity was placed on the 9 mm distance from the end of the waveguide. Convex lens was used to reduce the coupling loss between the polygon mirror and the waveguide. The polygon mirror was located behind of convex lens. With this condition, continuous output of the laser were measured as 1.2 W. In the Q-switched mode. pulse width 120 ns were measured with rotational speed 7,559 RPM. and peak power of up to 250 W. 250 W.

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Development Small Size RGB Sensor for Providing Long Detecting Range (원거리 검출범위를 제공하는 소형 RGB 센서 개발)

  • Seo, Jae Yong;Lee, Si Hyun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.12
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    • pp.174-182
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    • 2015
  • In this paper, we developed the small size RGB sensor that recognizes a long distance using a low-cost color sensor. Light receiving portion of the sensor was used as a camera lens for far distance recognition, and illuminating unit was increased the strength of the light by using a high-power white LED and a lens mounted on the reflector. RGB color recognition algorithm consists of the learning process and the realtime recognition process. We obtain a normalized RGB color reference data in the learning process using the specimens painted with target colors, and classifies the three colors using the Mahalanobis distance in recognition process. We apply the developed the RGB color recognition sensor to a prototype of the part classification system and evaluate the performance of its.