• Publications of The Korean Astronomical Society
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• v.21 no.2
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• pp.43-49
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• 2006

The KASINICS (KASI Near Infrared Camera System) is a ground-based Near-Infrared (NIR) imaging instrument developed by the Korea Astronomy and Space Science Institute (KASI). In this paper, we report the test results of the KASINICS camera optics system which is comprised of a 1-1 Offner relay. We measure that the surface RMS fluctuations of the Offner mirrors are at the level of $10^{-1}-10^{-2}$ of the target wavelengths, showing that the mirrors are sufficiently smooth for NIR observations. The alignment of the Offner optics system has been checked too. Our ray-tracing simulations find that the image quality should not degrade more than the pixel size of the KASINICS ($40{\mu}m$), if a de-centering or a tilt of the Offner mirrors are within 5mm, or $2.5^{\circ}$. Our measurement shows that the de-centering or the tilt of the Offner mirrors are less than 1 mm or $0.5^{\circ}$, assuring that the KASINICS image quality are not affected by the alignment errors. We have also measured that the optics resolution is $20{\mu}m$ and it does not degrade more than 10% over the detector surface area of 14.3 mm ${/times}$ 14.3mm. Overall, we conclude that the KASINICS optics system satisfies the design requirements for NIR imaging observations.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.412-419
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• 2006

We design and fabricate an autostigmatic null lens system assembled in a fixed tube mount in order to evaluate the shape of an aluminum hyperbolic mirror with the diameter of 300 mm and the f-number of 1.98, which is fabricated by a high precision aspherical DTM (diamond turning machine). Also, we evaluate the degree of shape of the aspherical mirror by this autostigmatic null lens testing method. The autostigmatic null lens system assembling in a fixed tube mount has several advantages of light weight, good mechanical stability, etc. The permissible fabricating limits of null lenses and a mount are determined by considering various tolerances to assure the measurement reliability.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.262-268
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• 2008

A compact imaging spectrometer (COMIS) for use in the STSAT3 microsatellite is currently under development. It is scheduled to be launched into a low Sun-synchronous Earth orbit (${\sim}700km$) by the end of 2010. COMIS was inspired by the success of CHRIS, which is a small hyperspectral imager developed for the ESA microsatellite PROBA. COMIS is designed to achieve nearly equivalent imaging capabilities of CHRIS in a smaller (65 mm diameter and 4.3 kg mass) and mechanically superior (in terms of alignment and robustness) package. Its main operational goal will be the imaging of Earth's surface and atmosphere with ground sampling distances of ${\sim}30m$ at the $18{\sim}62$ spectral bands ($4.0{\sim}1.05{\mu}m$). This imaging will be used for environmental monitoring, such as the in-land water quality monitoring of Paldang Lake, which is located next to Seoul, South Korea. The optics of COMIS consists of two parts: imaging telescope and dispersing relay optics. The imaging telescope, which operates at an f-ratio of 4.6, forms an image (of Earth's surface or atmosphere) onto an intermediate image plane. The dispersion relay optics disperses the image and relay it onto a CCD plane. All COMIS lenses and mirrors are spherical and are made from used silica exclusively. In addition, the optics is designed such that the optical axis of the dispersed image is parallel to the optical axis of the telescope. Previous efforts focused on manufacturing ease, alignment, assembly, testing, and improved robustness in space environments.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.328-333
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• 2020

In this paper, we study the analysis method for the aspherical tolerance of a Korsch telescope using a Q polynomial. It is important to analyze the tolerances for evaluating quality in high-precision fabrication of aspherical reflectors for high-resolution satellites. Thus we express the aspheric surface in terms of a Q polynomial in which each coefficient term is composed independently, and analyze the tolerance of a Korsch telescope. We also analyze the tolerance using Zernike fringe sag, which expresses the shape error of an aspherical mirror. By comparing the two results, we confirm that the Q-polynomial method can be used to analyze an aspherical mirror.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.37-42
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• 2008

Purpose: The objective of the study: At present, the spectacles, with its use as a medical aids or a fashion trimming, are recognized as one of the living necessities which can't be separated from human body. One of the features of spectacles is that it must be worn on any part of human body. Such a feature has to be satisfied under the condition an user keeps feeling comfortable with the rim of spectacles worn. In order to ensure meeting this condition, a criterion has to be arranged for the design of the rim of spectacles. In order to manufacture a rim of spectacles which allows an user to secure a comfortable range of vision as well as enhancing the feeling when to be worn, a manufacturing standard has to be established based on optical science. No precise rim of spectacles could be made from the manufacturing method depending on the manufacturer's sensibility. When the rim of spectacles was manufactured according to the incorrect standards, it may cause an user such a fatal result as myopia, hyperopia or astigmatism. Methods: This study focuses on providing a detailed explanation about the design of rim, which is the most important element during designing a rim of spectacles, making use of the optical elements of spectacles, and helping the manufacturers and the people who work in the spectacles-related business understand and recognize what is correct and exact and then leading them to establish a standard in respect to the manufacture and selection of spectacles. Results, Conclusions: Considering the fact there happen many errors in relation with the names of rim stipulated in the provisions of International Standards Organization (ISO), due to wrong interpretation by some of the rim manufacturers, the right interpretation should be given about the bridge which is directly connected to rim, so that the rims of spectacles manufactured in Korea could keep a favorable position in competing with the foreign products of same kinds.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.1-7
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• 2010

Purpose: To plan and improve consumers' satisfaction by analyzing consumers' purchasing behavior of spectacles. Also this will show the need of improvement in reliance of an optician. Methods: A total of 307 people (10 to 60 years) participated in individual questionnaires. Questionnaires comprised of general characteristic of surveyed people, purchasing spectacles behavior, satisfaction after purchasing spectacles, reliability of optician, and improvement points of optician. Results: Most important points in selecting the product were the design and the price of the spectacles. 142 people (46.3%) replied "average" and 140 people (45.6%) replied "satisfying" out of maximum point of satisfaction level which was 5 points. 72.3% of people have regularly visiting optical shop due to the high accessibility, after-sales care, and courteous optician. On the contrary, 27.7% replied "never visit same optician shop again" because of the low accessibility, minimal range of products, and high price. Data showed that people had high re liability about the opticians' knowledge of product, and their technique of eye refraction. Data revealed that people did not show high satisfaction about opticians' knowledge of ophthalmology, and price of products. Most important improvement points were accurate spectacle prescription by Opticians rating 42% of reply. Factors most considered during spectacle selection among the 10 to 20 age group were design by 34.8% and price by 10.1%. Among the 40 to 50 age group, most considered factors were design by 14% and spectacle frame material by 10.1%. Conclusions: Satisfaction rate of purchasing spectacles for the total participant group was 4.2 average grades. Reliability of opticians' eye refraction result and prescription was 50.5%. However consumers wanted to obtain more accurate eye refraction result and prescription with more comprehensive explanations. Also, consumers wanted opticians to be sensitive and have appreciative eye in select spectacles for customers, and to offer precise spectacle dispensing services and courteous after-sales care.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.371-380
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• 2004

The history of the glasses can say that we began with the development of the typography. Glasses were made for the first time from the skin which they tied. We came to make the rim as the horn tree afterwards or bone. And the snail glasses make the lens as the modification or glass and to put to connect the two to large snail was developed. The rim after he brought lots of style change. The development of the Bridge and eyewear form of the Temple of an entry today began to come out. The development of and various design and material. We reached practical style. development of design concentration new fashion trend lead can make it eyewear company and designer's. A rim of various style through historical development course because we have a present time's rim analysis. We try to try to investigate a method element of the glass design with a final cause form of the design in the viewpoint of the facility.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.113-121
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• 2002

Nowadays, developed camera, camcorder, CCTV and copier system accept a wide angle and a telephoto lens, and have an excellent capacity. Also, it is small as using aspheric surface. In this paper, after we evaluate and analyze two-group zoom lens system and three-group zoom lens system for camera, we refer to it, and design three-group zoom lens system for camera. Therefore, when we design a zoom lens system for camera, we use a symmetrical system. As using an aspheric surface, we can try to a miniaturization and an efficient improvement. We use optical valuable measure methods, a ray intercept plot, MTF and Seidel coefficient. So, we can confirm to have a similar level to compare with reference model.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.96-101
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• 2020

In this paper, we present the results of our research to perform 3D laser scanning functions by adding a focusing lens to a conventional 2D laser scanner. For the optical design, the ray-tracing technique was used along with a total of four lenses as the variable incident focusing lens, the collimating lens, and the F-Theta lens. As design variables, the curvature of the incident focusing lens (Lens #1) was assumed to be us, l mm and sumed mm, and the incident angles were set at 0cidenus, l. In addition, the distance between the focusing lens and the collimating lens was set to vary from 5 mm to 15 mm. When the incident focal length was varied from 5 mm to 15 mm, the exit focal length was calculated to vary from 67.5 mm to 56.8 mm for the lens with R = 100 mm and from 108.5 mm to 99.0 mm for the lens with R = 150 mm. When the incident angle was 0°, the focal aberration was only slightly observable at 10㎛ in both the x- and y-direction. At 7.5° was the focal aberration of approximately 20~50㎛ was measured at 20㎛. To investigate the chromatic aberration of the designed optical device, the distortion of the focus was observed when the 550 nm beam was simulated on lens designed for a 980 nm wavelength.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.491-497
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• 2016

This study aims to develop a vision inspection system for screw threads. To inspect external defects in screw threads, the vision inspection system was developed using front light illumination from which bright images can be obtained. The front light system, however, requires multiple side images for inspection of the entire thread surface, which can be performed by omnidirectional optics. In this study, an omnidirectional optical system was designed to obtain annular images of screw threads using an image sensor and two reflection mirrors; one large concave mirror and one small convex mirror. Optical simulations using backward and forward ray tracing were performed to determine the dimensional parameters of the proposed optical system, so that an annular image of the screw threads could be obtained with high quality and resolution. Microscale surface defects on the screw threads could be successfully detected using the developed annular inspection system.