• 천문학회지
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• 제36권3호
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• pp.75-80
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• 2003

When a bright astronomical object (source) is gravitationally lensed by a foreground mass (lens), its image appears to be located at different positions. The lens equation describes the relations between the locations of the lens, source, and images. The lens equation used for the description of the lensing behavior caused by a lens system composed of multiple masses has a form with a linear combination of the individual single lens equations. In this paper, we examine the validity of the linear nature of the multi-lens equation based on the general relativistic point of view.

• 한국정밀공학회지
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• 제32권8호
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• pp.687-692
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• 2015

LAM (Laser-Assisted Machining) is an effective method for processing difficult-to-cut workpieces. The focal length of a LAM system is changed by the change of the workpiece shape during laser preheating; this problem is solved by changing the lens of the laser module. Linear- and rotary-type lens changers were developed to change the laser lens of a LAM system. The linear-type lens changer is operated by a motor with a ball-screw, and the rotary type is operated by a stepping motor. The natural frequency and structural stability of the laser lens changers were confirmed by using a finite element analysis; in addition, the functions of the lens changers were verified by measuring the iterative accuracy. The measured results show that the rotary-type lens changer is more accurate than the linear-type changer.

• 한국전기전자재료학회논문지
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• 제31권6호
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• pp.433-436
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• 2018

A total internal reflection (TIR) linear lens of size $190(W){\times}5(D){\times}2.1(H)mm^3$ has a directivity of $25^{\circ}$ and was made of a polydimethysiloxane (PDMS) silicone resin with a refractive index of 1.4 and a transmittance of 93% at 365 nm UV wavelength. A light source with a size of $190{\times}25.5mm^2$ was fabricated by installing a TIR linear lens on a chip on board (COB) type LED module mounted with a $1.1{\times}1.1mm^2$ size UV LED. The optical characteristics of the light source showed a maximum irradiation density of $3,840mW/cm^2$ at a working distance of 5 mm and a high uniformity of 91.6% over a $150{\times}25mm^2$ irradiation area. The thermal characteristics of the light source were measured at a supply current of 500 mA. The saturation temperature was reached after 30 min of operation, and measured to be $95^{\circ}C$.

• 한국전자파학회논문지
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• 제13권3호
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• pp.279-287
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• 2002

본 논문에서는 광대역에서 광각을 조양할 수 있는 대칭형 구조의 선형 우상배열 송신기용 초고주파 렌즈를 설계하였다. 선형 위상 배열 송신기의 정확한 빔 조향 특성을 얻기 위해 렌즈의 균일한 진폭 전달 특성을 얻는데 중점을 두었다. 빔 포트 8개, 배열 포트 8개로 구성된 초고주파렌즈의 입.출력 포트간 삽입손실의 편차는 $\pm$3.1㏈로써 6~18㎓ 대역에 대해 매우 균일한 특성을 얻었다. 8개로 선형 배열된 안테나를 이용해 방위각 $\pm$60$^{\circ}$의 조향 특성을 얻을 수 있음을 확인하였으며, 측정한 렌즈 특성과 다중빔 조향 패턴을 제시하였다.

• 전자공학회논문지B
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• 제29B권2호
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• pp.40-49
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• 1992

In this paper,a new approach-using the linear movement of the lens location in a camera and focal distance in each location for the measurement of the depth of the 3-D object from several 2-D images-is proposed. The sharply focused edges are extracted from the images obtained by moving the lens of the camera, that is, the distance between the lens and the image plane, in the range allowed by the camera lens system. Then the depthin formation of the edges are obtained by the lens location. In our method, the accurate and complicated control system of the camera and a special algorithm for tracing the accurate focus point are not necessary, and the method has some advantage that the depth of all objects in a scene are measured by only the linear movement of the lens location of the camera. The accuracy of the extracted depth information is approximately 5% of object distances between 1 and 2m. We can see the possibility of application of the method in the depth measurement of the 3-D objects.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.592-594
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• 2004

Camera calibration is an important problem to determine the relationship between 3D real world and 2D camera image. The existing calibration methods can be classified into linear and non-linear models. The linear methods are simple and robust against noise, but the accuracy expectation is generally poor. In comparison, if the non-linearity, which is due mainly to lens distortion, is corrected, the accuracy can be better. However, as the optical features of lens are diverse, no non-linear method can be always effective for diverse vision systems. In this paper, we propose a new approach to correct the calibration error of a linear method using GMDH algorithm. The proposed technique is simple in concept and showed improved accuracy in various cases.

• Journal of the Optical Society of Korea
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• 제18권4호
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• pp.345-349
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• 2014

A direct-lit color-matching liquid crystal display using a lenticular lens array with grouped lens elements that image linear RGB light sources on the RGB subpixels of a color filter to enhance transmittance is designed, simulated, and fabricated. The RGB LED linear light sources were fabricated using small RGB LEDs in a linear array arrangement, and the lenticular lens array consisted of eight units of the same structure with a gap of 2.19 mm. The optical transmittance of the liquid crystal panel was improved by as much as 240% due to the color matching.

• 한국광학회지
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• 제7권1호
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• pp.51-59
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• 1996

평면 광도파로 렌즈는 집적광학회로에 널리 사용된다. 본 논문에서는 새로운 형태의 평면 광도파로 렌즈를 제안하고 제작하여 기존의 볼록-평면렌즈와 그 특성을 비교하였다. 제안한 볼록-오목형 렌즈는 원형의 경계를 가지며 선형경계를 가지는 볼록-평면 렌즈에서 발생하는 구면 수차를 제거할 수 있다. Y-cut LiNbO$_{3}$ 기판 위에 Ti-내부확산 양자교환방식을 이용하여 제안한 볼록-오목 렌즈와 기존의 볼록-평면 렌즈에 비해 초점에서의 spot의 크기를 약 59% 정도 줄일 수 있었다.

• 한국정밀공학회지
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• 제31권12호
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• pp.1133-1139
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• 2014

This paper proposes a simple method to improve a sensitivity of a straightness measurement system for a linear stage, which is applied to a system based on a geometric optic method. An optical system for this method is composed of a corner-cube retro-reflector, a ball-lens and a twodimensional position sensitive detector (2D PSD). The effectiveness of the proposed method was examined theoretically, and verified experimentally using a prototype measurement system. The results show that the measuring sensitivity was dependent on the size of the ball-lens and the setup position of PSD from the ball-lens, and that the proposed method is efficient method to improve the measuring sensitivity.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.27-33
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• 2011

HCPV(High Concentrated PV) systems have well known for CPV market all over the world. Low concentration type silicon based modules have been introduced in the market. But low cost of standard flat silicon modules made them useless nowadays. High cost of compound semiconductor solar cell reduced cost effective cpv module production than that of recently silicon solar cell. In order to overcome increasing cost of CPV module, we study middle concentration type fresnel lens simulation using concentrated type silicon based solar cell. Linear type fresnel lens made production of CPV module without secondary optics such as light pipe or light tunnel. This type of fresnel lens design makes more cost effective solution for cpv niche market.