• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.2
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• pp.93-98
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• 2015

This study focuses on simulation technology in the injection molding process for plastic optic lenses. The CAE program 3D TIMON was used to predict retardation, flow patterns and warpage deformation. The results were compared to the results of optic lenses as measured using the WPA-100 retardation measurement device with injection molding CAE for retardation predictions. According to the analysis and measured results, the distributions of retardation between the CAE results and the measurement results were similar. It was also confirmed that varying the injection speed had an effect on the injection pressure, warpage deformation and retardation distribution. As the injection speed increases, the injection pressure also increases and warpage deformation decreases. However, as the injection speed increases, the retardation distribution deteriorates.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.5
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• pp.499-506
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• 2007

The tiny camera module used in a modern cellular phone requires precise assembly processes. To meet the requirement of high resolution and functionality, the number of parts used in a camera module becomes larger and larger. As the market grows rapidly, an automatic camera phone assembly process is required. However, diverse production line and short life cycle make it difficult to build an affordable assembly line. To attack this problem, a flexible and expandable lens assembly system is proposed. To save the manufacturing line set-up time, modular concept is adopted. Also, each module is designed to have intelligence to simplify the set-up process. The assembly system is built up on the standard flat-form that includes a vibration free base, air and electric supplies, and electronic controllers, etc. Furthermore, the assembly cell has the capability of handling tiny, thin, or transparent parts which are very difficult to identify without machine vision.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1824-1827
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• 2003

The sheet metal shearing process is normally used in the precision elements such as semi-conductor components. In precision elements, burrs usually reduce the quality of machined parts and cause interference, jamming and misalignment during assembly procedures and because of their sharpness, they can be safety hazard to personnel. Furthermore, not only burrs are hard to predict and avoid, but also deburring, the process of removing burrs, is time-consuming and costly. In order to get the burr-free parts, therefore, we developed the precise burr measuring system using the laser. The laser burr measuring system consists of the laser probe, the photo detector, the achromatic doublet lens, and the rotary ＆ the X-Y table. In previous reports, we used simple vertical measuring method. But, as we used relatively bigger laser spot diameter and had the limited reflection angle, it was difficult to obtain the precise measuring results. So called, the spot size effect makes the profile of burr measured distorted and the burr height measured smaller. By introducing the novel laser measuring method which employing the achromatic lens system and the tilting mechanism, we could make the spot size smaller and get the appropriate beam direction angle. Through the experiments, the accuracy of the developed system is proved. The burr height measured during the punching process can be used for automatic deburring and in-situ aligning.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.275-281
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• 2010

This research's goal is to process directly aspherics with big sagment and thin center thickness. If we can process directly aspherics with big sagment and thin center thickness, we think it greatly helps to reduce the time of developing optical system. We made very thin glass using diamond grinding whetstone regarding the trace of tool and the detailed drawing of tool super precisive aspherics that has 0.46mm center thickness and over $30^{\circ}$ segment, $0.1{\mu}m$ machining accuracy, 15nm surface accuracy. We think this research's result will be effective to open new market because it is applied not only cell phone optical system but also CCTV robot optical system, internet phone optical system. Also we expect to enhance the super strong brittle precisive process's possibility with super precisive processing technique that achieves 0.46mm glass center thickness as first in the world.

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.381-385
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• 2012

In this paper, we present a novel integral imaging pickup method. We extract each pixel's actual depth data from a real object's surface using a depth camera, then generate elemental images based on the depth map. Since the proposed method generates elemental images without a lens array, it has simplified the pickup process and overcome some disadvantages caused by a conventional optical pickup process using a lens array. As a result, we can display a three-dimensional (3D) image in integral imaging. To show the usefulness of the proposed method, an experiment is presented. Though the pickup process has been simplified in the proposed method, the experimental results reveal that it can also display a full motion parallax image the same as the image reconstructed by the conventional method. In addition, if we improve calculation speed, it will be useful in a real-time integral imaging display system.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.70-71
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• 2004

Back light unit(BLU) using a microlens fabricated by the modified LIGA process for the liquid crystal display(LCD) is proposed, and some experimental results are presented. To realize the back light unit using microlens pattern, LIGA and reflow process are used.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.295-303
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• 2014

Purpose: This study aims to observe bleaching resulted from multipurpose contact lens solutions used to manage lenses with the subjects of colored contact lenses being distributed in Korea. Methods: The lenses have been worn for six months, and their refraction is 0.00D. Three types of colored contact lenses of which margin has been colored with a different manufacturing method have been adopted (type 1: pigment application method, type 2: chemical bonding process, type 3: sandwich method), and multipurpose solutions used were two types containing different components. Each of the colored contact lenses was stored in the multipurpose solutions for 20 days and went through vortexing for 15 seconds per day. Their fluorescence absorbance, surface roughness, brightness index, and color coordinate index were measured before and after the vortexing to see the degree of bleaching. Results: In the two types of multipurpose solutions, every type of the color contact lenses showed no statistically significant difference in their fluorescence absorbance value before and after the vortexing. Regarding surface image, the front surface of the lenses was smooth in every type, and about the back surface, type 3 indicated less protrusion than type 1 and 2. About the difference of color on the lens surface before and after the vortexing, type 3 showed significantly less difference than type 1 and 2; however, all fell into the permissible error. Conclusions: About the bleaching of colored contact lenses resulted from multipurpose solutions for soft contact lenses, there was no difference observed in terms of fluorescence absorbance and color. According to the methods of manufacturing dyes, however, there was difference in the protrusion of the posterior surface image.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.27-36
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• 2019

The demand for a low dispersion lens with a small refractive index and a high refractive index is increasing, and accordingly, there is an increasing need for a releasable protective film with high heat resistance and abrasion resistance. On the other hand, the optical industry has not yet established a clear standard for the manufacturing process and quality standards for mold-releasing protective films used in aspheric glass lens molding. Optical lens manufacturers treat this technology as proprietary information. In this study, an experiment was conducted regarding the optimization of ion etching, magnetron, and arc current at each source and filter part, and bias voltage in FCVA (filtered cathode vacuum arc)-based Ta-C thin film coatings. This study found that compared to iridium-rhenium alloy thin film sputtering products, the coating conditions were improved by approximately 50%, 20%, and 40% in terms of thickness, hardness, and adhesive strength of the film, respectively. The thin-film coating process proposed in this study is expected to contribute significantly to the development and utilization of glass lenses, which will help enhance the minimum mechanical properties and quality of the mold-release thin film layer required for glass mold surface forming technology.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.139-144
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• 2007

Radiotherapy which is the most effective for orbit lymphoma has been used increasingly due to the increase of orbit or ocular adnexal tumor patients. Curative effects and convalescence have been being more satisfied thanks to remarkable development of cancer chemotherapy and medical treatments, but side effects such as cataract, dry eye and retinopathy still break out. Thus, in this study, a Lens Shielding Device (LSD hereafter) was designed to prevent occurring of cataract due to radiation therapy for orbit lymphoma and its efficacy through dosimetry were evaluated. And in this paper, its manufacturing process was also explained. LSD is composed of a cover body covering the lens and a side fixing part supporting the cover body. To measure radiation, the patient therapy conditions were simulated and the measurement of the radiation was conducted with Thermo Luminescence Detector (TLD) and Markus chamber. The average TLD value was 5.7% and the TLD value and Markus chamber value were acquired as 4.2% and 5.1% respectively at 6 mm depth where zero lens center was located. Only 1.5Gy ($300Gy{\times}\;5%$) or 5% of total 30Gy with 9 MeV electron beam is estimated to affect on patient's lens. That is smaller dose than the threshold value of cataract (2GY) or the value (5Gy) that was reported to cause cataract in clinical conditions. Thus, these findings suggest that LSD be very useful for prevention of cataract during radiotherapy for malignant lymphoma of orbit and ocular adnexa. Furthermore, it might be possible to reduce patient's discomfort caused by alien substances and to make it easier to fix the device with customized manufacturing manners.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.82-88
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• 2011

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. There are two types of concentration optics for solar energy conversion. One is to use mirrors, and the other is to use Fresnel lenses. The gains that can be achieved with a Fresnel lens or a parabolic mirror are compared. The result showed the gains are comparable and the two configurations were developed competitively. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. A convex linear Fresnel lens to improve the concentration ratio and the efficiency is devised and flat linear Fresnel lens in thermal energy collection is utilized. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. In the process, we compare the transmission efficiencies according to groove types. We performed rigorous ray tracing simulation of the flat Fresnel lenses. The computer aided simulation showed the 'grooves in case' has the better efficiency than that of 'grooves out case'. Based on the ray-trace results we designed and manufactured sample Fresnel lenses. The optical performance were measured and compared with ray-trace results. Finally, the optical efficiency was measured to be above 75%. All the design and manufacturing were performed based on that InGaP/InGaAs/Ge triple junction solar cell is used to convert the photon energy to electrical power. Field test will be made and analyzed in the near future.