• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.197-198
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• 2006

본 연구에서 개발하는 성형렌즈는 그림1과 같이 한쪽 면이 비구면인 평볼록 형상이다. Glass렌즈의 고온압축성형을 위해서는 초정밀 가공기술로 제작된 성형Mold가 필요하며, Mold재질에 따른 성형기술의 확립이 필수적이다. 또한, 성형Mold의 표면과 융착반응이 없는 Glass소재가 요구된다. 본 실험을 위한 성형Mold는 코발트(Co) 함량 0.5 %의 초경합금(WC; 일본, Everloy社, 002K)을 초정밀 연삭가공하여 제작하였다. Glass소재는 전이점(Transformation Point; Tg) $572\;^{\circ}C$,항복점(Yielding Point; At) $630\;^{\circ}C$의 열적 특성을 갖는 K-BK7(일본, Sumita社)을 사용하였으며, d선에서 굴절률 및 아베수는 각각 1.51633, 64.1이다. 비구면 Glass렌즈 성형은 GMP(Glass Molding Press; 일본, Sumitomo社, Nano Press-S)장비를 사용하여 성형온도 $625\;^{\circ}C$, 서냉온도 $550\;^{\circ}C$로 고정하고 성형압력를 200-800 N 범위에서 변화시켰다. 표 1에 성형변수로 사용한 서냉속도와 서냉전환온도 조건을 나타낸다. 표1과 같이 각 서냉조건별로5장의 렌즈를 성형 후 특성값이 평균치에 가까운 3장을 선별하여 그 특성을 비교하였다. 각 조건에 따른 성형렌즈의 형상정도(일본, Panasonic社, UA3P, 자유곡면형상측정기), 두께(일본, Mitutoyo社, MDC-25M, 마이크로메터), 굴절률(일본, Shimatus社, KPR-200, 정밀굴절률측정기) 및 MTF[해상도](독일, Trioptics社, Image Master HR, MTF-Field)를 측정하여 각각의 광학적 특성을 비교 평가하였다. 비구면 Glass렌즈 성형장비와 형상측정기를 그림 2, 3에 각각 나타낸다.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.203-212
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• 2017

A scientific model refers to a conceptual system that can describe, explain, and predict a particular physical phenomenon. The co-construction of the scientific model is attracting attention as a new teaching and learning strategy in the field of science education and various studies. The evaluation and modification of models compared with the predicted models of data from the real world is the core of modeling strategy. However, there were only a limited data provided by the teacher in many studies of modeling comparing the students' predictions of their own models. Most of the students were not given the opportunity to evaluate the suitability of the model with the data in the real world. The purpose of this study was to develop a scientific model co-construction program that can evaluate the model by directly comparing the predicted models with the observed data from the real world. Through a collaborative discussion between teachers and researchers for 6 months, a 5-session scientific model co-construction program on the subject 'image formation by convex lenses' for second grade middle school students was developed. Eighty (80) students in 3 classes and a science teacher with 20 years of service from general public co-educational middle school in Gyeonggi-do participated in this 2-week program. After the class, students were asked about the helpfulness and difficulty of the class, and whether they would like to recommend this class to a friend. After the class, 95.8% of the students constructed the scientific model more than the model using the construction rule. Students had difficulties to identify principles or understand their friends, but the result showed that they could understand through model evaluation experiment. 92.5% of the students said that they would be more than willing to recommend this program to their friends. It is expected that the developed program will be applied to the school and contribute to the improvement of students' modeling ability and co-construction ability.

• Journal of The Korean Association For Science Education
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• v.39 no.1
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• pp.73-88
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• 2019

The purpose of this study is to explore elementary teachers' difficulties on teaching science by analyzing questions that have been posted for a long time in an autonomous online teacher community named Indischool. For this purpose, 409 question postings(the 2007 and 2009 revised curriculum, third to sixth grade) were analyzed using the framework for analyzing questions about elementary teachers' science teaching(modified from Alake-Tuenter et al., 2013). The study revealed that there were more science-SMK questions than science-PCK questions, and most of the questions were 'about lenses' and 'in 2014 and 2015, when the curriculum was changing from the 2007 to the 2009 revised curriculum'. The long-standing difficulties in science-SMK were 'an application of facts and concepts in lenses' and 'an unexpected experimental error in electricity'. In particular, there are the principle of transparent cup-shaped objects acting as lenses, the process of image formation by convex lenses, experimental errors of 'compass movement due to current flow change' and experimental errors 'serial connection of bulbs'. The long-standing difficulties in science-PCK were 'understanding and response to context' and 'understanding and response to aims mentioned in standard document' and these are not related to physical units but to others. In particular, there are request class materials, activity ideas at the end of the semester and understanding the national curriculum guidelines. These teachers' difficulties should be reflected in the science teaching support system like a teacher's guide compilation, teacher's training curriculum development, etc.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.206-207
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• 2000

학생들은 수업 전에 어떠한 생각들을 가지고 있을까\ulcorner 과연 전통적인 수업방식은 학생들이 빛의 굴절에 관한 바른 개념을 형성하는데 도움이 되고 있는가\ulcorner 볼록 렌즈의 역할, 상의 개념, 스크린의 역할 등 기하광학의 기초개념에 대하여 정성적인 조사를 통하여 학부생의 수업전과 후의 개념유형 및 변화를 살펴보고 전통적 수업 방법에 대한 문제를 제기한다. (중략)

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.128.1-128.1
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• 2014

잠자리, 벌 등 곤충과 새우, 가재 등 갑각류를 포함하는 절지동물류에서 발견되는 겹눈(compound eye)구조는 볼록한 형태이기 때문에 일반 단일렌즈(single lens)형 눈에 비해 매우 넓은 시야각을 가지며, 깊은 심도를 갖는 특징이 있다. 기존 카메라가 갖기 어려운 겹눈의 독특한 장점으로 인해, 곤충의 눈을 모방하는 연구는 많은 사람들의 주목을 받고 있다. 겹눈구조는 일반적으로 수백에서 수만개의 홑눈(ommatidium)이 모여 다발을 이루고 있으며, 각 홑눈은 겉에서부터 마이크로렌즈 형태의 각막, 수정추, 감간(rhabdom)형태로 이루어져 있다. 따라서 이러한 겹눈구조를 모방하기 위해서는 인공홑눈을 제작하고 이를 반구형으로 배열하는 것이 필수적이다. 그러나 실리콘 반도체를 기반으로 하는 이미지 센서는 딱딱하고 편평하여 굴곡진 형태로 배열이 어렵기 때문에 곤충눈을 모방한 형태의 구조물은 몇몇 연구그룹에서 개발된 사례가 있으나, 이미징이 가능한 곤충눈 시스템의 개발은 보고된 바가 없었다. 본 발표에서는 최근에 연구가 진행되고 있는 플렉서블 전자소자에 기반한 곤충눈을 모방한 이미징 시스템에 대해서 다루고자 한다.

• Korean Journal of Optics and Photonics
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• v.2 no.3
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• pp.121-126
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• 1991

The knife-edge scanning type OTF measuring equipment is improved to enhance the accuracy in off-axis OTF measurement and the accuracy of this equipment of evaluated by measuring the OTF of 50 mm plano-convex standard lens developed by SIRA group. Measured MTF values of the standard lens are in good agreement with SIRA results within $\pm$0.02 on axis and % $\pm$0.03 off-axis in 0-100 clmm frequency range except only a few spatial frequencies. Measured PTF values are good agreement with SIRA results within $\pm$$5^{\circ}$.

• Applied Microscopy
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• v.24 no.3
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• pp.1-9
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• 1994

Pardosa astrigera possessed eight eyes arranged in three rows on the frontal carapace. A pair of small anterior lateral eyes (ALE) flanked each side by an anterior median eyes (AME) lay along the anterior margin that was situated on the anterior row of clypeus. The anterior lateral eye was composed of cornea, vitreous body, and retina. Cornea was made up mainly of exocuticle lining the cuticle. Lens in anterior lateral eye was biconvex type which bulged into the cavity of the eyecup. Outer and inner central region of lens were approximately spherical with radius of curvature $5.6{\mu}m$ and $12.5{\mu}m$, respectly. Vitreous body formed a layer between the cuticular lens and retina. They formed biconcave shape. Retina of the anterior lateral eyes was composed of three types of cells: visual cells, glia cells, and pigment cells. The visual cells were unipolar neuron, as were the receptor of the posterior lateral eye. But cell body was unique to the anterior lateral eyes. They were giant cell, relatively a few in number, and under the layer of vitreous bodies. Each visual cell healed rhabdomeres for a short stretch beneath the cell body. Rhabdomes were irregulary pattern in retina and electron dense pigment granules scattered between the rhabdomes. Glia cell situated at the cell body of visual cell and glia cell process reached to rhabdomere portion. Below the rhabdome, tapetum were about $30{\mu}m$ distance from lens, which composed of 4-5 layers. It was about $25{\mu}m$ length that intermediate segment of distal portion of visual cell. Electron dense pigment granules between the intermediate segment were observed.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.260-265
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• 2003

A noncontact optical system that can measure displacement or vibration of an object is designed by employing the oblique ray method. By using a single convex lens which serves as both the input and output lenses, we made the optical system very compact and reliable. In addition, the bandwidth of the vibration measurement is more than 100 KHz by using the position-sensitive detector as the beam position sensor. The resolution and capture range of the system are $\pm$1 ${\mu}{\textrm}{m}$ and 1100 ${\mu}{\textrm}{m}$, respectively. As a sample test, the vibrations of a speaker and a rotating compact disc surface were measured.

• Journal of The Korean Association For Science Education
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• v.41 no.1
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• pp.11-18
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• 2021

The purpose of this study is to analyze the questions generated by elementary school pre-service teachers when reading the teacher's guide for the refraction of light, and to analyze the difficulties in understanding the concept and in making instructional plans. A total of 592 meaningful questions were generated by 283 elementary school pre-service teachers after reading the teacher's guide of 'light and lens' unit in the 6th grade of the 2015 revised curriculum. Of these, 306 questions are for understanding the concept of physics and 286 are pedagogical questions. As a result of the analysis, in terms of understanding the concept of physics, the elementary school pre-service teachers encounter difficulties in understanding the concept of the 'cause' of the phenomenon suggested in the textbook, such as the cause of refraction, the reason for scattering light, and the cause of the image change depending on the focal length of the convex lens. In terms of instructional planning, it was followed by questions about how to explain concepts, questions about not being able to explain concepts to elementary school students and having to teach only phenomena, specific explanation methods for specific concepts, and experimental methods. Although the teacher's guide contains various explanations and supplementary materials to help teachers understand the concept, it can be seen that there are many elementary pre-service teachers who cannot answer questions about some concepts even after reading the guide. For concepts with a high frequency of questions, it is necessary to prepare a tutorial that is more understandable. In the instructional plan, there were many questions about teaching methods and experimental methods, so it is necessary to provide more examples and specific experimental methods for explaining concepts in the teacher's guide.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.225-226
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• 2006