• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.278-279
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• 2009

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.1-9
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• 2001

This research chose the existing designed copier zoom lens system and analyzed to calculate the optical capacity. As this lens system was the zoom lens system of finite object point, differed form the general camera zoom lens of infinite object point, it got a limited movement range because it moved between the fixed object and the image. In the result of comparison the optical capacities between a symmetric form and a asymmetric form. We could find out the truth which a asymmetric form constituted comparative stable aberrations and existed a tracks of effort for aberration correction. Therefore, a symmetric form is allotted satisfactorily from improved aberrations by itself in the fixed focal lens system. However, it has a limit of improving for capacity when it is used a zoom lens system got a symmetric form.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.354-360
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• 2005

A high performance LWIR(long wavelength infra red) zoom thermal imaging sensor using $480{\times}6$ HgCdTe(MCT) linear detector has been developed by ADD Korea. The optical system consists of zoom telescope having large objective about 190 mm diameter and optically well corrected scanning system. The zoom ratio of the telescope is 3: 1 and its magnification change is performed by moving two lens groups. And also these moving groups are used for athermalization of the system. It is certain that the zoom sensor can be used in wide operating temperature range without any degradation of the system performance. Especially, the sensor image can be displayed with the HDTV(high definition television) format of which aspect ratio is 16:9. In case of HDTV format, the scanning system is able to display 620,000 pixels. This function can make wider horizontal field of view without any loss of performance than the normal TV format image. The MRTD(minimum resolvable temperature difference) of the LWIR thermal imaging sensor shows good results below 0.04 K at spatial frequency 2 cycles/mrad and 0.23 K at spatial frequency 8 cycles/mrad at the narrow field of view.

• Korean Journal of Optics and Photonics
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• v.19 no.5
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• pp.349-359
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• 2008

For an inner-focusing 3-groups zoom lens system, this study suggests a new initial design method which applies the process that changes thin lenses into thick ones effectively and quickly, using the hybrid lens system(thin lens+thick lens). In other words, the hybrid lens system is the semi-automatic design process that makes the thin lens of one group change into a thick one while the other groups are composed of thin lenses. Keeping the total power of the system fixed, the power of each group and the distance between principal planes can be fixed. Of course, the other groups composed of thin lenses could be changed into thick lenses sequentially by this process. This design conception results in the 1/4" 5 M inner-focusing 3-groups 2x zoom lens system satisfying the specifications and performances of zoom lens for phone cameras. Also aspherization on lens elements of glass and plastic material enhanced the resolution and reduced the lens size. As a result, we have an ultra-compact inner-focusing 3-groups 2x zoom lens system for a phone camera, with a slim size with TTL of 9.8 mm.

• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.1-7
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• 1995

A IR zoom telescope system was designed for thermal imagery. The magnification is 4-14 and the focal length of eye piece is 25 mm. First, the frame was built up with first order optics and started design with 3rd order optics. There after, we can get the final design by optimization technique through finite ray tracing. The optical system was optimized with ray aberration or angular aberration including higer orders. Finally, The performance of the optical system was accessed by calculating the diffraction MTF from the design data. data.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.28-29
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• 2003

각종 렌즈 및 카메라, 망원경, 현미경 등 다양한 광학계들이 설계 및 개발 되고 있는 시점에서 그 성능을 정확하게 평가하는 것이 매우 중요하다. 광학계의 성능 평가를 위해서는 크게 정성적인 방법과 정량적인 방법으로 나눌 수 있는데, 정성적인 방법에 의한 평가는 분해능 표판이나 주기적인 격자의 상을 스크린 등에 결상시킨 후 사람의 눈을 통해서 한계 분해능을 평가하는 방법이다. 정량적인 방법에 의한 평가는 OTF(Optical Transfer Function)를 측정하거나 설계 자료를 통해 계산해 내는 것이다. (중략)

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.613-622
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• 2003

The multi-configurative microscopic system for inspecting the wire-bonding of reed frame is designed. Rays refracted by objective lens group which is composed of common lens group of x2 and x6 are splitted by beam-splitter, and Rays through the central region and the boundary region of the object imaged at x2 and x6 through imaging lens groups, respectively. The depth of wire structure on the reed frame has about $\pm$3 mm, in order to observe by uniform magnification without the dependency on the variation of objective distance generated by the depth of wire structure on the reed frame, imaging lens groups should be moved on nonlinear locus like mechanically compensated zoom lenses. The nonlinear equations for zoom locus are derived by using the Gaussian bracket. Refraction powers and positions of each groups are numerically determined by solving the equations, and initial design data for each groups is obtained by using Seidel third order aberration theory. The optimization technique is finally utilized to obtain this microscopic system.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.18-19
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• 2004

• Korean Journal of Optics and Photonics
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• v.15 no.5
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• pp.423-428
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• 2004

The development of a compact and high performance MWIR thermal imaging sensor based on the SOFRADIR 320${\times}$240 element IRCCD detector is described. The sensor has 20 magnification zoom optics with the maximum 40$^{\circ}$${\times}$30$^{\circ}$ of super wide field of view and 7.6 cycles/mrad of resolving power with the operation of attached micro-scanning system. In order to correct nonuniformities of detector arrays, we have proposed a multi-point correction method using defocusing of the optics and we have acquired the highest quality images. The MRTD of our system shows good results below 0.05K at spatial frequency 1 cycles/mrad at narrow field of view. Experimental data and obtained performances are presented and discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.207-208
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• 2011