• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.10
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• pp.1077-1086
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• 2014

We propose a design method of a Rotman lens for curved array antenna applicable to conformal array. In this paper, design equations are derived to obtain an array curve, transmission line lengths of a Rotman lens in conjunction with a curved array antenna, and the phase error of a Rotman lens based on these design equations is minimized through the beam curve optimization procedure and the refocusing procedure. Rotman lenses designed by the proposed design equations and design procedures still maintain 3 focal points, can feed a convex or concave array antenna with circular curve, parabolic curve, V-shaped curve, etc as well as a straight line array antenna, and have minimal phase error.

• Korean Journal of Optics and Photonics
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• v.19 no.2
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• pp.87-94
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• 2008

We present a new design for an endoscope objective lens composed of a lexible fiber bundle with 30,000 core, and a gradient-index (GRIN) objective lens with an optical adaptor. The characteristic of this objective lens is to be minimally-invasive to be able to insert easily in the internal organs of live animals. The GRIN lens has a small diameter and a very simple construction, which is selected with the diameter of 1.0 mm and numerical aperture of 0.5 to achieve a minimally-invasive outer diameter and a high resolution. The resultant designed lens shows the performance as follows; a lateral resolution of 1.63 um and diameters of 100% encircled energy of $0.3\;{\mu}m$ and $0.83\;{\mu}m$ for the on-axis and the off-axis image point, respectively. Also, we can present a cheap solution with a lateral resolution of 1.74 um and diameters of 100% encircled energy of $1.10\;{\mu}m$ and $2.84\;{\mu}m$ for the on-axis and the off-axis image point, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.103-108
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• 2009

Purpose: The objective of this study is to compare and analyze the wearing status of refractive error correction devices of elders who reside in a city or in a small town district. Methods: Each of opticians from a small town or a city was selected for the study of wearing status of presbyopia correction device for each residential district in units of percentage. with the analysis of the age and gender distributions of the elders, numbers of elderly members, and the kinds of presbyopia correction. Results: The wearing rate of progressive lens was reduced in reverse proportion to the increase of the age for the people of presbyopia in a twon. Pepople in 60s living in a town perferred to wearing bifocal lens, but people of 50~60s preferred to single vision lenses. However, none of people living in a city who is diagnosed as presbyopia had refractive error correction device, and no one used bifical lenses. The progressive lens was mostly used in the people of 40~50s and using rate of those lenses reduced with the age; and single vision lens had the highest rate of in the 40~50s but no one wore it in the 70s. Conclusions: Among the refractive error correction devices, the progressive lens was most widely worn by presbyopia group who is living in a town or a city. In particular, the refractive error correction devices were most preferred in 40~50s of early presbyopia. The highest preference for the progressive lens in the people with the early presbyopia indicates that the wearing rate of the progressive will be increased in future. Therefore, the opportunity of systematic education on the progressive lens should be increased.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.232-238
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• 2000

The new collimation testing technique of a white light beam using vernier Moire fringes of two line or circular gratings with different pitches is presented. We can visually measure the defocusing ($\Deltaf$), the divergence angle ($\theta$), and the longitudinal chromatic aberration $(L_{ch})$ of a collimating lens by using the technique. For example, we obtained $\Deltaf$= 21.9 mm and $\theta=0.0038^{\circ}$ for a testing lens with the focallengthf = 120.0 mm and F-number of F/2.4. The longitudinal chromatic aberration $L_{ch}$ of another testing lens withf = 65.0 mm, F/1.6, and the Abbe number V = 64.1 for the incident wavelengths of $\lambda_1=480 nm and \lambda_2=640 nm$ is easily measured by same technique. It is found that the measured value $L_{ch}=1.59mm(\pm0.01mm)$ is well agreed with $L_{ch}=1.58mm(\pm0.01mm)$ obtained by the autofocus method.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.203-207
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• 2018

This paper deals with the design and development of a lens system capable of imaging an infrared image of $3{\sim}5{\mu}m$ wavelength bands with a focal length of 24mm and good atmospheric transmission characteristics. The design used CodeV, a commercial design program, and the optimization is carried out with weighting to eliminate chromatic aberration, spherical aberration and distortion. The designed lens system consists of two lenses consisting of Si and Ge. Each lens has an aspherical surface on one side. And this optical system has the resolution of the characteristics that the MTF value is 0.40 at the line width of 29lp/mm and the MTF value is 0.25 at the line width of 20lp/mm. This optical system is considered to have the capability to be applied to the thermal imaging camera for MWIR using the $206{\times}156$ array infrared detector of $25{\mu}m$ pixels and the $320{\times}240$ array infrared detector of $17{\mu}m$ pixels.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.2
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• pp.74-80
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• 2005

A new dimension measuring method for the measurement of diameter of an object has been developed using laser triangulation. The 3D data of an object was calculated from the 2 dimensional image information obtained by the laser stripe using the laser triangulation. The system that use existing theory can measure the diameter of hole not only in a normal plane but also ill an incline plane. However, in the existing theory, since the lens with fixed feral length was used, the area of measurement was fixed. The simplest way to solve this problem is to change distance between a CCD camera and object. Other way is to use a zoom lens having variable focal length. In this paper, the zoom lens with variable focal length was used. Therefore, we ran experiment with magnification that is optimized according to size of object using zoom lens with variable focal length.

• The Optical Journal
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• v.4 no.17 s.17
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• pp.42-44
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• 1992

• 대한치과교정학회:학술대회논문집
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• 2004.11a
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• pp.84.2-84.2
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• 2004

• The Optical Journal
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• s.121
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• pp.34-35
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.177-178
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• 2007